* [PATCH v5 7/9] driver core: Replace dev->dma_coherent with dev_dma_coherent()
From: Douglas Anderson @ 2026-04-06 23:23 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern
Cc: Alexey Kardashevskiy, Johan Hovold, Eric Dumazet, Leon Romanovsky,
Christoph Hellwig, Robin Murphy, maz, Alexander Lobakin,
Saravana Kannan, Douglas Anderson, Vinod Koul, Frank.Li, alex,
andre.przywara, andrew, aou, catalin.marinas, dmaengine,
driver-core, gregory.clement, iommu, jgg, kees, linux-arm-kernel,
linux-kernel, linux-mips, linux-riscv, linux-snps-arc, linux,
m.szyprowski, palmer, peter.ujfalusi, pjw, sebastian.hesselbarth,
tsbogend, vgupta, will, willy
In-Reply-To: <20260406232444.3117516-1-dianders@chromium.org>
In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_coherent" over to the "flags"
field so modifications are safe.
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).
NOTE: even though previously we only took up a bit if
CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE, CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU,
or CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL, in this change I reserve the
bit unconditionally. While we could get the "dynamic" behavior by
changing the flags definition to be an unnumbered "enum", Greg has
requested that the numbers be stable.
(no changes since v4)
Changes in v4:
- Use accessor functions for flags
Changes in v3:
- New
arch/arc/mm/dma.c | 4 ++--
arch/arm/mach-highbank/highbank.c | 2 +-
arch/arm/mach-mvebu/coherency.c | 2 +-
arch/arm/mm/dma-mapping-nommu.c | 4 ++--
arch/arm/mm/dma-mapping.c | 28 ++++++++++++++--------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/mips/mm/dma-noncoherent.c | 2 +-
arch/riscv/mm/dma-noncoherent.c | 2 +-
drivers/base/core.c | 2 +-
drivers/dma/ti/k3-udma-glue.c | 6 +++---
drivers/dma/ti/k3-udma.c | 6 +++---
include/linux/device.h | 11 ++++-------
include/linux/dma-map-ops.h | 2 +-
13 files changed, 35 insertions(+), 38 deletions(-)
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 6b85e94f3275..9b9adb02b4c5 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -98,8 +98,8 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
* DMA buffers.
*/
if (is_isa_arcv2() && ioc_enable && coherent)
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
dev_info(dev, "use %scoherent DMA ops\n",
- dev->dma_coherent ? "" : "non");
+ dev_dma_coherent(dev) ? "" : "non");
}
diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
index 47335c7dadf8..8b7d0929dac4 100644
--- a/arch/arm/mach-highbank/highbank.c
+++ b/arch/arm/mach-highbank/highbank.c
@@ -98,7 +98,7 @@ static int highbank_platform_notifier(struct notifier_block *nb,
if (of_property_read_bool(dev->of_node, "dma-coherent")) {
val = readl(sregs_base + reg);
writel(val | 0xff01, sregs_base + reg);
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
}
return NOTIFY_OK;
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index fa2c1e1aeb96..7234d487ff39 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -95,7 +95,7 @@ static int mvebu_hwcc_notifier(struct notifier_block *nb,
if (event != BUS_NOTIFY_ADD_DEVICE)
return NOTIFY_DONE;
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
return NOTIFY_OK;
}
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index fecac107fd0d..c6a70686507b 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -42,11 +42,11 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
* enough to check if MPU is in use or not since in absence of
* MPU system memory map is used.
*/
- dev->dma_coherent = cacheid ? coherent : true;
+ dev_assign_dma_coherent(dev, cacheid ? coherent : true);
} else {
/*
* Assume coherent DMA in case MMU/MPU has not been set up.
*/
- dev->dma_coherent = (get_cr() & CR_M) ? coherent : true;
+ dev_assign_dma_coherent(dev, (get_cr() & CR_M) ? coherent : true);
}
}
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f304037d1c34..f9bc53b60f99 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1076,7 +1076,7 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
struct page **pages;
void *addr = NULL;
- int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+ int coherent_flag = dev_dma_coherent(dev) ? COHERENT : NORMAL;
*handle = DMA_MAPPING_ERROR;
size = PAGE_ALIGN(size);
@@ -1124,7 +1124,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
if (vma->vm_pgoff >= nr_pages)
return -ENXIO;
- if (!dev->dma_coherent)
+ if (!dev_dma_coherent(dev))
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
err = vm_map_pages(vma, pages, nr_pages);
@@ -1141,7 +1141,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, unsigned long attrs)
{
- int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+ int coherent_flag = dev_dma_coherent(dev) ? COHERENT : NORMAL;
struct page **pages;
size = PAGE_ALIGN(size);
@@ -1202,7 +1202,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
phys_addr_t phys = page_to_phys(sg_page(s));
unsigned int len = PAGE_ALIGN(s->offset + s->length);
- if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ if (!dev_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_device(sg_phys(s), s->length, dir);
prot = __dma_info_to_prot(dir, attrs);
@@ -1304,7 +1304,7 @@ static void arm_iommu_unmap_sg(struct device *dev,
if (sg_dma_len(s))
__iommu_remove_mapping(dev, sg_dma_address(s),
sg_dma_len(s));
- if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ if (!dev_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_cpu(sg_phys(s), s->length, dir);
}
}
@@ -1323,7 +1323,7 @@ static void arm_iommu_sync_sg_for_cpu(struct device *dev,
struct scatterlist *s;
int i;
- if (dev->dma_coherent)
+ if (dev_dma_coherent(dev))
return;
for_each_sg(sg, s, nents, i)
@@ -1345,7 +1345,7 @@ static void arm_iommu_sync_sg_for_device(struct device *dev,
struct scatterlist *s;
int i;
- if (dev->dma_coherent)
+ if (dev_dma_coherent(dev))
return;
for_each_sg(sg, s, nents, i)
@@ -1371,7 +1371,7 @@ static dma_addr_t arm_iommu_map_phys(struct device *dev, phys_addr_t phys,
dma_addr_t dma_addr;
int ret, prot;
- if (!dev->dma_coherent &&
+ if (!dev_dma_coherent(dev) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO)))
arch_sync_dma_for_device(phys, size, dir);
@@ -1412,7 +1412,7 @@ static void arm_iommu_unmap_phys(struct device *dev, dma_addr_t handle,
if (!iova)
return;
- if (!dev->dma_coherent &&
+ if (!dev_dma_coherent(dev) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) {
phys_addr_t phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1431,7 +1431,7 @@ static void arm_iommu_sync_single_for_cpu(struct device *dev,
unsigned int offset = handle & ~PAGE_MASK;
phys_addr_t phys;
- if (dev->dma_coherent || !iova)
+ if (dev_dma_coherent(dev) || !iova)
return;
phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1446,7 +1446,7 @@ static void arm_iommu_sync_single_for_device(struct device *dev,
unsigned int offset = handle & ~PAGE_MASK;
phys_addr_t phys;
- if (dev->dma_coherent || !iova)
+ if (dev_dma_coherent(dev) || !iova)
return;
phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1701,13 +1701,13 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { }
void arch_setup_dma_ops(struct device *dev, bool coherent)
{
/*
- * Due to legacy code that sets the ->dma_coherent flag from a bus
- * notifier we can't just assign coherent to the ->dma_coherent flag
+ * Due to legacy code that sets the dma_coherent flag from a bus
+ * notifier we can't just assign coherent to the dma_coherent flag
* here, but instead have to make sure we only set but never clear it
* for now.
*/
if (coherent)
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
/*
* Don't override the dma_ops if they have already been set. Ideally
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..dc1fce939451 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -48,7 +48,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
dev_driver_string(dev), dev_name(dev),
ARCH_DMA_MINALIGN, cls);
- dev->dma_coherent = coherent;
+ dev_assign_dma_coherent(dev, coherent);
xen_setup_dma_ops(dev);
}
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index ab4f2a75a7d0..30ef3e247eb7 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -139,6 +139,6 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
#ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
void arch_setup_dma_ops(struct device *dev, bool coherent)
{
- dev->dma_coherent = coherent;
+ dev_assign_dma_coherent(dev, coherent);
}
#endif
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index cb89d7e0ba88..a1ec2d71d1c9 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -140,7 +140,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
"%s %s: device non-coherent but no non-coherent operations supported",
dev_driver_string(dev), dev_name(dev));
- dev->dma_coherent = coherent;
+ dev_assign_dma_coherent(dev, coherent);
}
void riscv_noncoherent_supported(void)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index e94749092345..8a83d7c93361 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3173,7 +3173,7 @@ void device_initialize(struct device *dev)
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
- dev->dma_coherent = dma_default_coherent;
+ dev_assign_dma_coherent(dev, dma_default_coherent);
#endif
swiotlb_dev_init(dev);
}
diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
index f87d244cc2d6..686dc140293e 100644
--- a/drivers/dma/ti/k3-udma-glue.c
+++ b/drivers/dma/ti/k3-udma-glue.c
@@ -312,7 +312,7 @@ k3_udma_glue_request_tx_chn_common(struct device *dev,
if (xudma_is_pktdma(tx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- tx_chn->common.chan_dev.dma_coherent = true;
+ dev_set_dma_coherent(&tx_chn->common.chan_dev);
dma_coerce_mask_and_coherent(&tx_chn->common.chan_dev,
DMA_BIT_MASK(48));
}
@@ -1003,7 +1003,7 @@ k3_udma_glue_request_rx_chn_priv(struct device *dev, const char *name,
if (xudma_is_pktdma(rx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- rx_chn->common.chan_dev.dma_coherent = true;
+ dev_set_dma_coherent(&rx_chn->common.chan_dev);
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
DMA_BIT_MASK(48));
}
@@ -1104,7 +1104,7 @@ k3_udma_glue_request_remote_rx_chn_common(struct k3_udma_glue_rx_channel *rx_chn
if (xudma_is_pktdma(rx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- rx_chn->common.chan_dev.dma_coherent = true;
+ dev_set_dma_coherent(&rx_chn->common.chan_dev);
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
DMA_BIT_MASK(48));
rx_chn->single_fdq = false;
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index c964ebfcf3b6..1cf158eb7bdb 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -428,18 +428,18 @@ static void k3_configure_chan_coherency(struct dma_chan *chan, u32 asel)
/* No special handling for the channel */
chan->dev->chan_dma_dev = false;
- chan_dev->dma_coherent = false;
+ dev_clear_dma_coherent(chan_dev);
chan_dev->dma_parms = NULL;
} else if (asel == 14 || asel == 15) {
chan->dev->chan_dma_dev = true;
- chan_dev->dma_coherent = true;
+ dev_set_dma_coherent(chan_dev);
dma_coerce_mask_and_coherent(chan_dev, DMA_BIT_MASK(48));
chan_dev->dma_parms = chan_dev->parent->dma_parms;
} else {
dev_warn(chan->device->dev, "Invalid ASEL value: %u\n", asel);
- chan_dev->dma_coherent = false;
+ dev_clear_dma_coherent(chan_dev);
chan_dev->dma_parms = NULL;
}
}
diff --git a/include/linux/device.h b/include/linux/device.h
index b7a8b902efb3..5b0fb6ad4c72 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -481,6 +481,8 @@ struct device_physical_location {
* @DEV_FLAG_STATE_SYNCED: The hardware state of this device has been synced to
* match the software state of this device by calling the
* driver/bus sync_state() callback.
+ * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
+ * architecture supports non-coherent devices.
*/
enum struct_device_flags {
DEV_FLAG_READY_TO_PROBE = 0,
@@ -489,6 +491,7 @@ enum struct_device_flags {
DEV_FLAG_DMA_SKIP_SYNC = 3,
DEV_FLAG_DMA_OPS_BYPASS = 4,
DEV_FLAG_STATE_SYNCED = 5,
+ DEV_FLAG_DMA_COHERENT = 6,
DEV_FLAG_COUNT
};
@@ -572,8 +575,6 @@ enum struct_device_flags {
* @offline: Set after successful invocation of bus type's .offline().
* @of_node_reused: Set if the device-tree node is shared with an ancestor
* device.
- * @dma_coherent: this particular device is dma coherent, even if the
- * architecture supports non-coherent devices.
* @flags: DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
*
* At the lowest level, every device in a Linux system is represented by an
@@ -681,11 +682,6 @@ struct device {
bool offline_disabled:1;
bool offline:1;
bool of_node_reused:1;
-#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
- defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
- defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
- bool dma_coherent:1;
-#endif
DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
};
@@ -718,6 +714,7 @@ __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
__create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
__create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
__create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
+__create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
#undef __create_dev_flag_accessors
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index edd7de60a957..44dd9035b4fe 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -230,7 +230,7 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
extern bool dma_default_coherent;
static inline bool dev_is_dma_coherent(struct device *dev)
{
- return dev->dma_coherent;
+ return dev_dma_coherent(dev);
}
#else
#define dma_default_coherent true
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply related
* [PATCH v5 0/9] driver core: Fix some race conditions
From: Douglas Anderson @ 2026-04-06 23:22 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern
Cc: Alexey Kardashevskiy, Johan Hovold, Eric Dumazet, Leon Romanovsky,
Christoph Hellwig, Robin Murphy, maz, Alexander Lobakin,
Saravana Kannan, Douglas Anderson, Andrew Morton, Frank.Li,
Jason Gunthorpe, alex, alexander.stein, andre.przywara, andrew,
andrew, andriy.shevchenko, aou, ardb, astewart, bhelgaas, brgl,
broonie, catalin.marinas, chleroy, davem, david, devicetree,
dmaengine, driver-core, gbatra, gregory.clement, hkallweit1,
iommu, jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb,
lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
m.szyprowski, maddy, mani, miko.lenczewski, mpe, netdev, npiggin,
osalvador, oupton, pabeni, palmer, peter.ujfalusi, peterz, pjw,
robh, sebastian.hesselbarth, tglx, tsbogend, vgupta, vkoul, will,
willy, yangyicong, yeoreum.yun
The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.
That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.
Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.
Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.
Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:
var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
echo $f
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
done
From v3 to v4, I transitioned to accessor functions with another ugly
sed script. I had git format the old patches, then transformed them
with:
for f in *.patch; do
echo $f
sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
done
...and then did a few manual touchups for spacing.
I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.
I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.
Changes in v5:
- ready_to_prove => ready_to_probe typo
- device_lock() while calling dev_set_ready_to_probe()
- Add comment before "can_match = true" from Danilo.
- undef __create_dev_flag_accessors
Changes in v4:
- Use accessor functions for flags
Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message
Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag
Douglas Anderson (9):
driver core: Don't let a device probe until it's ready
driver core: Replace dev->can_match with dev_can_match()
driver core: Replace dev->dma_iommu with dev_dma_iommu()
driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
driver core: Replace dev->state_synced with dev_state_synced()
driver core: Replace dev->dma_coherent with dev_dma_coherent()
driver core: Replace dev->of_node_reused with dev_of_node_reused()
driver core: Replace dev->offline + ->offline_disabled with accessors
arch/arc/mm/dma.c | 4 +-
arch/arm/mach-highbank/highbank.c | 2 +-
arch/arm/mach-mvebu/coherency.c | 2 +-
arch/arm/mm/dma-mapping-nommu.c | 4 +-
arch/arm/mm/dma-mapping.c | 28 ++--
arch/arm64/kernel/cpufeature.c | 2 +-
arch/arm64/mm/dma-mapping.c | 2 +-
arch/mips/mm/dma-noncoherent.c | 2 +-
arch/powerpc/kernel/dma-iommu.c | 8 +-
.../platforms/pseries/hotplug-memory.c | 4 +-
arch/riscv/mm/dma-noncoherent.c | 2 +-
drivers/acpi/scan.c | 2 +-
drivers/base/core.c | 55 +++++---
drivers/base/cpu.c | 4 +-
drivers/base/dd.c | 36 ++++--
drivers/base/memory.c | 2 +-
drivers/base/pinctrl.c | 2 +-
drivers/base/platform.c | 2 +-
drivers/dma/ti/k3-udma-glue.c | 6 +-
drivers/dma/ti/k3-udma.c | 6 +-
drivers/iommu/dma-iommu.c | 9 +-
drivers/iommu/iommu.c | 5 +-
drivers/net/pcs/pcs-xpcs-plat.c | 2 +-
drivers/of/device.c | 6 +-
drivers/pci/of.c | 2 +-
drivers/pci/pwrctrl/core.c | 2 +-
drivers/regulator/bq257xx-regulator.c | 2 +-
drivers/regulator/rk808-regulator.c | 2 +-
drivers/tty/serial/serial_base_bus.c | 2 +-
drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
include/linux/device.h | 122 ++++++++++++------
include/linux/dma-map-ops.h | 6 +-
include/linux/dma-mapping.h | 2 +-
include/linux/iommu-dma.h | 3 +-
kernel/cpu.c | 4 +-
kernel/dma/mapping.c | 12 +-
mm/hmm.c | 2 +-
37 files changed, 218 insertions(+), 142 deletions(-)
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply
* [PATCHv2] dmaengine: dw-axi-dmac: simplify allocation
From: Rosen Penev @ 2026-04-06 19:44 UTC (permalink / raw)
To: dmaengine
Cc: Eugeniy Paltsev, Vinod Koul, Frank Li, Kees Cook,
Gustavo A. R. Silva, open list,
open list:KERNEL HARDENING (not covered by other areas):Keyword:b__counted_by(_le|_be)?b
Use a flexible array member with kzalloc_flex() to combine allocations.
Add __counted_by for extra runtime analysis.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
v2: use () for kzalloc_flex in description.
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 8 +-------
drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 4 ++--
2 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index 4d53f077e9d2..d3ca202dc478 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -294,15 +294,10 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
{
struct axi_dma_desc *desc;
- desc = kzalloc_obj(*desc, GFP_NOWAIT);
+ desc = kzalloc_flex(*desc, hw_desc, num, GFP_NOWAIT);
if (!desc)
return NULL;
- desc->hw_desc = kzalloc_objs(*desc->hw_desc, num, GFP_NOWAIT);
- if (!desc->hw_desc) {
- kfree(desc);
- return NULL;
- }
desc->nr_hw_descs = num;
return desc;
@@ -339,7 +334,6 @@ static void axi_desc_put(struct axi_dma_desc *desc)
dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
}
- kfree(desc->hw_desc);
kfree(desc);
atomic_sub(descs_put, &chan->descs_allocated);
dev_vdbg(chan2dev(chan), "%s: %d descs put, %d still allocated\n",
diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
index 67cc199e24d1..a04a4e03eb3d 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
@@ -98,14 +98,14 @@ struct axi_dma_hw_desc {
};
struct axi_dma_desc {
- struct axi_dma_hw_desc *hw_desc;
-
struct virt_dma_desc vd;
struct axi_dma_chan *chan;
u32 completed_blocks;
u32 length;
u32 period_len;
u32 nr_hw_descs;
+
+ struct axi_dma_hw_desc hw_desc[] __counted_by(nr_hw_descs);
};
struct axi_dma_chan_config {
--
2.53.0
^ permalink raw reply related
* Re: [PATCH v3] dmaengine: tegra210-adma: Add error logging on failure paths
From: Sheetal . @ 2026-04-06 11:07 UTC (permalink / raw)
To: Frank Li
Cc: Jon Hunter, Vinod Koul, Thierry Reding, Laxman Dewangan, Frank Li,
Mohan Kumar, dmaengine, linux-tegra, linux-kernel
In-Reply-To: <ac8uBTemDHCr4T6V@lizhi-Precision-Tower-5810>
On 03-04-2026 08:33, Frank Li wrote:
> External email: Use caution opening links or attachments
>
>
> On Mon, Mar 23, 2026 at 08:38:58AM +0000, Sheetal wrote:
>> Add dev_err/dev_err_probe logging across failure paths to improve
>> debuggability of DMA errors during runtime and probe.
>>
>> Signed-off-by: Sheetal <sheetal@nvidia.com>
>> ---
>> Changes in v3:
>> - Cast page_no to (unsigned long long) for %llu to fix -Wformat
>> warning on 32-bit builds where resource_size_t is unsigned int
>> - Remove redundant dev_err for devm_ioremap_resource failures since
>> the API already logs errors internally.
>>
>> Changes in v2:
>> - Fix format specifier for size_t: use %zu instead of %u for
>> desc->num_periods to resolve -Wformat warning with W=1
>>
>> drivers/dma/tegra210-adma.c | 37 +++++++++++++++++++++++++++-------
>> 1 file changed, 30 insertions(+), 7 deletions(-)
>>
> ...
>> @@ -1047,38 +1058,45 @@ static int tegra_adma_probe(struct platform_device *pdev)
>> res_page = platform_get_resource_byname(pdev, IORESOURCE_MEM, "page");
>> if (res_page) {
>> tdma->ch_base_addr = devm_ioremap_resource(&pdev->dev, res_page);
>> if (IS_ERR(tdma->ch_base_addr))
>> return PTR_ERR(tdma->ch_base_addr);
>>
>> res_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "global");
>> if (res_base) {
>> resource_size_t page_offset, page_no;
>> unsigned int ch_base_offset;
>>
>> - if (res_page->start < res_base->start)
>> + if (res_page->start < res_base->start) {
>> + dev_err(&pdev->dev, "invalid page/global resource order\n");
>> return -EINVAL;
>
> It is in probe function, return dev_err_probe(, -EINVAL, ...);
> check other place
ACK
>
>> + }
>> +
>> page_offset = res_page->start - res_base->start;
>> ch_base_offset = cdata->ch_base_offset;
>> if (!ch_base_offset)
>> return -EINVAL;
>>
>> page_no = div_u64(page_offset, ch_base_offset);
>> - if (!page_no || page_no > INT_MAX)
>> + if (!page_no || page_no > INT_MAX) {
>> + dev_err(&pdev->dev, "invalid page number %llu\n",
>> + (unsigned long long)page_no);
>> return -EINVAL;
>> + }
>>
>> tdma->ch_page_no = page_no - 1;
>> tdma->base_addr = devm_ioremap_resource(&pdev->dev, res_base);
>> if (IS_ERR(tdma->base_addr))
>> return PTR_ERR(tdma->base_addr);
>> }
>> } else {
>> /* If no 'page' property found, then reg DT binding would be legacy */
>> res_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> if (res_base) {
>> tdma->base_addr = devm_ioremap_resource(&pdev->dev, res_base);
>> if (IS_ERR(tdma->base_addr))
>> return PTR_ERR(tdma->base_addr);
>> } else {
>> + dev_err(&pdev->dev, "failed to get memory resource\n");
>> return -ENODEV;
>> }
>>
>> @@ -1130,6 +1147,7 @@ static int tegra_adma_probe(struct platform_device *pdev)
>> tdc->irq = of_irq_get(pdev->dev.of_node, i);
>> if (tdc->irq <= 0) {
>> ret = tdc->irq ?: -ENXIO;
>> + dev_err_probe(&pdev->dev, ret, "failed to get IRQ for channel %d\n", i);
>> goto irq_dispose;
>> }
>>
>> @@ -1141,12 +1159,16 @@ static int tegra_adma_probe(struct platform_device *pdev)
>> pm_runtime_enable(&pdev->dev);
>>
>> ret = pm_runtime_resume_and_get(&pdev->dev);
>> - if (ret < 0)
>> + if (ret < 0) {
>> + dev_err_probe(&pdev->dev, ret, "runtime PM resume failed\n");
>> goto rpm_disable;
>
> can you change to use devm_ firtly to elimiate goto first, then change to
> use
> return dev_err_probe() pattern
>
Thanks for the review, Frank.
For the devm_ conversion, it doesn't seem straightforward as the goto
cleanup paths handle multiple resources. I'd like to send that as a
separate follow-up patch.
>
> Frank
>
>> + }
>>
>> ret = tegra_adma_init(tdma);
>> - if (ret)
>> + if (ret) {
>> + dev_err(&pdev->dev, "failed to initialize ADMA: %d\n", ret);
>> goto rpm_put;
>> + }
>>
>> dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
>> dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
>> --
>> 2.17.1
>>
^ permalink raw reply
* Re: [PATCH] dmaengine: dw-axi-dmac: simplify allocation
From: Frank Li @ 2026-04-06 10:11 UTC (permalink / raw)
To: Rosen Penev
Cc: dmaengine, Eugeniy Paltsev, Vinod Koul, Frank Li, Kees Cook,
Gustavo A. R. Silva, open list,
open list:KERNEL HARDENING (not covered by other areas):Keyword:b__counted_by(_le|_be)?b
In-Reply-To: <20260330211128.12319-1-rosenp@gmail.com>
On Mon, Mar 30, 2026 at 02:11:28PM -0700, Rosen Penev wrote:
Subject should
"use kzalloc_flex() to simplify allocation"
> Use a flexible array member with kzalloc_flex to combine allocations.
function name need add (), kzalloc_flex()
Frank
>
> Add __counted_by for extra runtime analysis.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
> drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 8 +-------
> drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 4 ++--
> 2 files changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> index 4d53f077e9d2..d3ca202dc478 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -294,15 +294,10 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
> {
> struct axi_dma_desc *desc;
>
> - desc = kzalloc_obj(*desc, GFP_NOWAIT);
> + desc = kzalloc_flex(*desc, hw_desc, num, GFP_NOWAIT);
> if (!desc)
> return NULL;
>
> - desc->hw_desc = kzalloc_objs(*desc->hw_desc, num, GFP_NOWAIT);
> - if (!desc->hw_desc) {
> - kfree(desc);
> - return NULL;
> - }
> desc->nr_hw_descs = num;
>
> return desc;
> @@ -339,7 +334,6 @@ static void axi_desc_put(struct axi_dma_desc *desc)
> dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
> }
>
> - kfree(desc->hw_desc);
> kfree(desc);
> atomic_sub(descs_put, &chan->descs_allocated);
> dev_vdbg(chan2dev(chan), "%s: %d descs put, %d still allocated\n",
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> index 67cc199e24d1..a04a4e03eb3d 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> @@ -98,14 +98,14 @@ struct axi_dma_hw_desc {
> };
>
> struct axi_dma_desc {
> - struct axi_dma_hw_desc *hw_desc;
> -
> struct virt_dma_desc vd;
> struct axi_dma_chan *chan;
> u32 completed_blocks;
> u32 length;
> u32 period_len;
> u32 nr_hw_descs;
> +
> + struct axi_dma_hw_desc hw_desc[] __counted_by(nr_hw_descs);
> };
>
> struct axi_dma_chan_config {
> --
> 2.53.0
>
^ permalink raw reply
* Re: [PATCH] dmaengine: dw-axi-dmac: simplify allocation
From: Frank Li @ 2026-04-06 10:08 UTC (permalink / raw)
To: Rosen Penev
Cc: dmaengine, Eugeniy Paltsev, Vinod Koul, Frank Li, Kees Cook,
Gustavo A. R. Silva, open list,
open list:KERNEL HARDENING (not covered by other areas):Keyword:b__counted_by(_le|_be)?b
In-Reply-To: <20260330211128.12319-1-rosenp@gmail.com>
On Mon, Mar 30, 2026 at 02:11:28PM -0700, Rosen Penev wrote:
> Use a flexible array member with kzalloc_flex to combine allocations.
>
> Add __counted_by for extra runtime analysis.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
Reviewed-by: Frank Li <Frank.Li@nxp.com>
> drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 8 +-------
> drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 4 ++--
> 2 files changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> index 4d53f077e9d2..d3ca202dc478 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -294,15 +294,10 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
> {
> struct axi_dma_desc *desc;
>
> - desc = kzalloc_obj(*desc, GFP_NOWAIT);
> + desc = kzalloc_flex(*desc, hw_desc, num, GFP_NOWAIT);
> if (!desc)
> return NULL;
>
> - desc->hw_desc = kzalloc_objs(*desc->hw_desc, num, GFP_NOWAIT);
> - if (!desc->hw_desc) {
> - kfree(desc);
> - return NULL;
> - }
> desc->nr_hw_descs = num;
>
> return desc;
> @@ -339,7 +334,6 @@ static void axi_desc_put(struct axi_dma_desc *desc)
> dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
> }
>
> - kfree(desc->hw_desc);
> kfree(desc);
> atomic_sub(descs_put, &chan->descs_allocated);
> dev_vdbg(chan2dev(chan), "%s: %d descs put, %d still allocated\n",
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> index 67cc199e24d1..a04a4e03eb3d 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> @@ -98,14 +98,14 @@ struct axi_dma_hw_desc {
> };
>
> struct axi_dma_desc {
> - struct axi_dma_hw_desc *hw_desc;
> -
> struct virt_dma_desc vd;
> struct axi_dma_chan *chan;
> u32 completed_blocks;
> u32 length;
> u32 period_len;
> u32 nr_hw_descs;
> +
> + struct axi_dma_hw_desc hw_desc[] __counted_by(nr_hw_descs);
> };
>
> struct axi_dma_chan_config {
> --
> 2.53.0
>
^ permalink raw reply
* Re: [PATCH 1/3] dmaengine: dw-axi-dmac: fix Alignment should match open parenthesis
From: Vinod Koul @ 2026-04-06 5:56 UTC (permalink / raw)
To: Khairul Anuar Romli
Cc: Frank Li, Lars-Peter Clausen, Frank Li, dmaengine, linux-kernel,
Markus.Elfring
In-Reply-To: <46be45c0-ba15-47c4-b356-60a3d6491f6a@gmail.com>
On 04-04-26, 23:20, Khairul Anuar Romli wrote:
> On 30/3/2026 11:01 pm, Frank Li wrote:
> > On Sat, Mar 28, 2026 at 10:56:55AM +0800, Khairul Anuar Romli wrote:
> > > checkpatch.pl --strict reports a CHECK warning in dw-axi-dmac.c:
> > >
> > > CHECK: Alignment should match open parenthesis
> > >
> > > This warning occurs when multi-line function calls or expressions have
> > > continuation lines that don't properly align with the opening
> > > parenthesis position.
> > >
> > > Fixes all instances in dw-axi-dmac.c where continuation lines were
> > > indented with an inconsistent number of spaces/tabs that neither
> > > matched the parenthesis column nor followed a standard indent pattern.
> > > Proper alignment improves code readability and maintainability by
> > > making parameter lists visually consistent across the kernel codebase.
> > >
> > > Fixes: 0e3b67b348b8 ("dmaengine: Add support for the Analog Devices AXI-DMAC DMA controller")
> > > Fixes: e3923592f80b ("dmaengine: axi-dmac: populate residue info for completed xfers")
> > > Fixes: 3f8fd25936ee ("dmaengine: axi-dmac: Allocate hardware descriptors")
> > > Fixes: 921234e0c5d7 ("dmaengine: axi-dmac: Split too large segments")
> > > Fixes: a5b982af953b ("dmaengine: axi-dmac: add a check for devm_regmap_init_mmio")
> >
> > This is code cleanup and not user visiual problem. I think needn't add
> > fixes tags here.
> >
>
> I can remove the fixes tags in the next revision.
> Thanks for pointing this out.
These kind of code formatting dont help much. These cause problems
porting fixes to stable. So I am not very inclined to take these
>
> Best Regards,
> Khairul
>
> > Frank
> >
> > > Signed-off-by: Khairul Anuar Romli <karom.9560@gmail.com>
> > > ---
> > > drivers/dma/dma-axi-dmac.c | 28 +++++++++++++++-------------
> > > 1 file changed, 15 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
> > > index 45c2c8e4bc45..0017f4dc6dcc 100644
> > > --- a/drivers/dma/dma-axi-dmac.c
> > > +++ b/drivers/dma/dma-axi-dmac.c
> > > @@ -193,7 +193,7 @@ static struct axi_dmac_desc *to_axi_dmac_desc(struct virt_dma_desc *vdesc)
> > > }
> > >
> > > static void axi_dmac_write(struct axi_dmac *axi_dmac, unsigned int reg,
> > > - unsigned int val)
> > > + unsigned int val)
> > > {
> > > writel(val, axi_dmac->base + reg);
> > > }
> > > @@ -382,7 +382,7 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
> > > }
> > >
> > > static inline unsigned int axi_dmac_total_sg_bytes(struct axi_dmac_chan *chan,
> > > - struct axi_dmac_sg *sg)
> > > + struct axi_dmac_sg *sg)
> > > {
> > > if (chan->hw_2d)
> > > return (sg->hw->x_len + 1) * (sg->hw->y_len + 1);
> > > @@ -437,7 +437,7 @@ static void axi_dmac_dequeue_partial_xfers(struct axi_dmac_chan *chan)
> > > }
> > >
> > > static void axi_dmac_compute_residue(struct axi_dmac_chan *chan,
> > > - struct axi_dmac_desc *active)
> > > + struct axi_dmac_desc *active)
> > > {
> > > struct dmaengine_result *rslt = &active->vdesc.tx_result;
> > > unsigned int start = active->num_completed - 1;
> > > @@ -517,7 +517,7 @@ static bool axi_dmac_handle_cyclic_eot(struct axi_dmac_chan *chan,
> > > }
> > >
> > > static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
> > > - unsigned int completed_transfers)
> > > + unsigned int completed_transfers)
> > > {
> > > struct axi_dmac_desc *active;
> > > struct axi_dmac_sg *sg;
> > > @@ -667,7 +667,7 @@ axi_dmac_alloc_desc(struct axi_dmac_chan *chan, unsigned int num_sgs)
> > > desc->chan = chan;
> > >
> > > hws = dma_alloc_coherent(dev, PAGE_ALIGN(num_sgs * sizeof(*hws)),
> > > - &hw_phys, GFP_ATOMIC);
> > > + &hw_phys, GFP_ATOMIC);
> > > if (!hws) {
> > > kfree(desc);
> > > return NULL;
> > > @@ -703,9 +703,11 @@ static void axi_dmac_free_desc(struct axi_dmac_desc *desc)
> > > }
> > >
> > > static struct axi_dmac_sg *axi_dmac_fill_linear_sg(struct axi_dmac_chan *chan,
> > > - enum dma_transfer_direction direction, dma_addr_t addr,
> > > - unsigned int num_periods, unsigned int period_len,
> > > - struct axi_dmac_sg *sg)
> > > + enum dma_transfer_direction direction,
> > > + dma_addr_t addr,
> > > + unsigned int num_periods,
> > > + unsigned int period_len,
> > > + struct axi_dmac_sg *sg)
> > > {
> > > unsigned int num_segments, i;
> > > unsigned int segment_size;
> > > @@ -817,7 +819,7 @@ static struct dma_async_tx_descriptor *axi_dmac_prep_slave_sg(
> > > }
> > >
> > > dsg = axi_dmac_fill_linear_sg(chan, direction, sg_dma_address(sg), 1,
> > > - sg_dma_len(sg), dsg);
> > > + sg_dma_len(sg), dsg);
> > > }
> > >
> > > desc->cyclic = false;
> > > @@ -857,7 +859,7 @@ static struct dma_async_tx_descriptor *axi_dmac_prep_dma_cyclic(
> > > desc->sg[num_sgs - 1].hw->flags &= ~AXI_DMAC_HW_FLAG_LAST;
> > >
> > > axi_dmac_fill_linear_sg(chan, direction, buf_addr, num_periods,
> > > - period_len, desc->sg);
> > > + period_len, desc->sg);
> > >
> > > desc->cyclic = true;
> > >
> > > @@ -1006,7 +1008,7 @@ static void axi_dmac_adjust_chan_params(struct axi_dmac_chan *chan)
> > > * features are implemented and how it should behave.
> > > */
> > > static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
> > > - struct axi_dmac_chan *chan)
> > > + struct axi_dmac_chan *chan)
> > > {
> > > u32 val;
> > > int ret;
> > > @@ -1295,7 +1297,7 @@ static int axi_dmac_probe(struct platform_device *pdev)
> > > return ret;
> > >
> > > ret = of_dma_controller_register(pdev->dev.of_node,
> > > - of_dma_xlate_by_chan_id, dma_dev);
> > > + of_dma_xlate_by_chan_id, dma_dev);
> > > if (ret)
> > > return ret;
> > >
> > > @@ -1310,7 +1312,7 @@ static int axi_dmac_probe(struct platform_device *pdev)
> > > return ret;
> > >
> > > regmap = devm_regmap_init_mmio(&pdev->dev, dmac->base,
> > > - &axi_dmac_regmap_config);
> > > + &axi_dmac_regmap_config);
> > >
> > > return PTR_ERR_OR_ZERO(regmap);
> > > }
> > > --
> > > 2.43.0
> > >
--
~Vinod
^ permalink raw reply
* Re: [PATCH v4 7/9] driver core: Replace dev->dma_coherent with dev_dma_coherent()
From: Vinod Koul @ 2026-04-06 5:49 UTC (permalink / raw)
To: Douglas Anderson
Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern, Saravana Kannan, Christoph Hellwig, Eric Dumazet,
Johan Hovold, Leon Romanovsky, Alexander Lobakin,
Alexey Kardashevskiy, Robin Murphy, Frank.Li, alex,
andre.przywara, andrew, aou, catalin.marinas, dmaengine,
driver-core, gregory.clement, iommu, jgg, kees, linux-arm-kernel,
linux-kernel, linux-mips, linux-riscv, linux-snps-arc, linux,
m.szyprowski, palmer, peter.ujfalusi, pjw, sebastian.hesselbarth,
tsbogend, vgupta, will, willy
In-Reply-To: <20260403170432.v4.7.If839f6dde98979fce177f70c6c74689a1904ee76@changeid>
On 03-04-26, 17:05, Douglas Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "dma_coherent" over to the "flags"
> field so modifications are safe.
Acked-by: Vinod Koul <vkoul@kernel.org>
--
~Vinod
^ permalink raw reply
* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Doug Anderson @ 2026-04-05 22:43 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Rafael J . Wysocki, Danilo Krummrich, Alan Stern, Saravana Kannan,
Christoph Hellwig, Eric Dumazet, Johan Hovold, Leon Romanovsky,
Alexander Lobakin, Alexey Kardashevskiy, Robin Murphy,
Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
bhelgaas, brgl, broonie, catalin.marinas, chleroy, davem, david,
devicetree, dmaengine, driver-core, gbatra, gregory.clement,
hkallweit1, iommu, jirislaby, joel, joro, kees, kevin.brodsky,
kuba, lenb, lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed,
linux-cxl, linux-kernel, linux-mips, linux-mm, linux-pci,
linux-riscv, linux-serial, linux-snps-arc, linux-usb, linux,
linuxppc-dev, m.szyprowski, maddy, mani, maz, miko.lenczewski,
mpe, netdev, npiggin, osalvador, oupton, pabeni, palmer,
peter.ujfalusi, peterz, pjw, robh, sebastian.hesselbarth, tglx,
tsbogend, vgupta, vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <2026040539-sponge-publisher-2b42@gregkh>
Hi,
On Sat, Apr 4, 2026 at 10:28 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Fri, Apr 03, 2026 at 05:04:54PM -0700, Douglas Anderson wrote:
> > NOTE: one potentially "controversial" choice I made in some patches
> > was to always reserve a flag ID even if a flag is only used under
> > certain CONFIG_ settings. This is a change from how things were
> > before. Keeping the numbering consistent and allowing easy
> > compile-testing of both CONFIG settings seemed worth it, especially
> > since it won't take up any extra space until we've added a lot more
> > flags.
>
> Nah, this is fine, I don't see any problems with this as the original
> code kind of was doing the same thing with the "hole" in the structure
> if those options were not enabled.
>
> > I only marked the first patch as a "Fix" since it is the only one
> > fixing observed problems. Other patches could be considered fixes too
> > if folks want.
> >
> > I tested the first patch in the series backported to kernel 6.6 on the
> > Pixel phone that was experiencing the race. I added extra printouts to
> > make sure that the problem was hitting / addressed. The rest of the
> > patches are tested with allmodconfig with arm32, arm64, ppc, and
> > x86. I boot tested on an arm64 Chromebook running mainline.
>
> I'm guessing your tests passed? :)
Yup, all the tests that I've run have passed. I also threw in an
"allnoconfig" compile test just for good measure.
> Anyway, this looks great, unless there are any objections, other than
> the "needs to be undefined", which a follow-on patch can handle, I'll
> queue them up next week for 7.1-rc1.
Thanks. As per the other thread, I'm happy if you or Danilo want to
apply it, and I'm happy if you want to make minor fixups when
applying.
When I see the patches applied, I'll send a followup patch to address
the "needs to be undefined" comment, unless Danilo makes that change
himself when applying.
-Doug
^ permalink raw reply
* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Danilo Krummrich @ 2026-04-05 12:02 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Douglas Anderson, Rafael J . Wysocki, Alan Stern, Saravana Kannan,
Christoph Hellwig, Eric Dumazet, Johan Hovold, Leon Romanovsky,
Alexander Lobakin, Alexey Kardashevskiy, Robin Murphy,
Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
bhelgaas, brgl, broonie, catalin.marinas, chleroy, davem, david,
devicetree, dmaengine, driver-core, gbatra, gregory.clement,
hkallweit1, iommu, jirislaby, joel, joro, kees, kevin.brodsky,
kuba, lenb, lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed,
linux-cxl, linux-kernel, linux-mips, linux-mm, linux-pci,
linux-riscv, linux-serial, linux-snps-arc, linux-usb, linux,
linuxppc-dev, m.szyprowski, maddy, mani, maz, miko.lenczewski,
mpe, netdev, npiggin, osalvador, oupton, pabeni, palmer,
peter.ujfalusi, peterz, pjw, robh, sebastian.hesselbarth, tglx,
tsbogend, vgupta, vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <2026040539-sponge-publisher-2b42@gregkh>
On Sun Apr 5, 2026 at 7:27 AM CEST, Greg Kroah-Hartman wrote:
> Anyway, this looks great, unless there are any objections, other than
> the "needs to be undefined", which a follow-on patch can handle, I'll
> queue them up next week for 7.1-rc1.
Sounds good, for the series:
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
^ permalink raw reply
* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Greg Kroah-Hartman @ 2026-04-05 5:27 UTC (permalink / raw)
To: Douglas Anderson
Cc: Rafael J . Wysocki, Danilo Krummrich, Alan Stern, Saravana Kannan,
Christoph Hellwig, Eric Dumazet, Johan Hovold, Leon Romanovsky,
Alexander Lobakin, Alexey Kardashevskiy, Robin Murphy,
Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
bhelgaas, brgl, broonie, catalin.marinas, chleroy, davem, david,
devicetree, dmaengine, driver-core, gbatra, gregory.clement,
hkallweit1, iommu, jirislaby, joel, joro, kees, kevin.brodsky,
kuba, lenb, lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed,
linux-cxl, linux-kernel, linux-mips, linux-mm, linux-pci,
linux-riscv, linux-serial, linux-snps-arc, linux-usb, linux,
linuxppc-dev, m.szyprowski, maddy, mani, maz, miko.lenczewski,
mpe, netdev, npiggin, osalvador, oupton, pabeni, palmer,
peter.ujfalusi, peterz, pjw, robh, sebastian.hesselbarth, tglx,
tsbogend, vgupta, vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <20260404000644.522677-1-dianders@chromium.org>
On Fri, Apr 03, 2026 at 05:04:54PM -0700, Douglas Anderson wrote:
> NOTE: one potentially "controversial" choice I made in some patches
> was to always reserve a flag ID even if a flag is only used under
> certain CONFIG_ settings. This is a change from how things were
> before. Keeping the numbering consistent and allowing easy
> compile-testing of both CONFIG settings seemed worth it, especially
> since it won't take up any extra space until we've added a lot more
> flags.
Nah, this is fine, I don't see any problems with this as the original
code kind of was doing the same thing with the "hole" in the structure
if those options were not enabled.
> I only marked the first patch as a "Fix" since it is the only one
> fixing observed problems. Other patches could be considered fixes too
> if folks want.
>
> I tested the first patch in the series backported to kernel 6.6 on the
> Pixel phone that was experiencing the race. I added extra printouts to
> make sure that the problem was hitting / addressed. The rest of the
> patches are tested with allmodconfig with arm32, arm64, ppc, and
> x86. I boot tested on an arm64 Chromebook running mainline.
I'm guessing your tests passed? :)
Anyway, this looks great, unless there are any objections, other than
the "needs to be undefined", which a follow-on patch can handle, I'll
queue them up next week for 7.1-rc1.
thanks,
greg k-h
^ permalink raw reply
* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Rafael J. Wysocki @ 2026-04-04 17:11 UTC (permalink / raw)
To: Douglas Anderson
Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern, Saravana Kannan, Christoph Hellwig, Eric Dumazet,
Johan Hovold, Leon Romanovsky, Alexander Lobakin,
Alexey Kardashevskiy, Robin Murphy, Andrew Morton, Frank.Li,
Jason Gunthorpe, alex, alexander.stein, andre.przywara, andrew,
andrew, andriy.shevchenko, aou, ardb, bhelgaas, brgl, broonie,
catalin.marinas, chleroy, davem, david, devicetree, dmaengine,
driver-core, gbatra, gregory.clement, hkallweit1, iommu,
jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb, lgirdwood,
linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
m.szyprowski, maddy, mani, maz, miko.lenczewski, mpe, netdev,
npiggin, osalvador, oupton, pabeni, palmer, peter.ujfalusi,
peterz, pjw, robh, sebastian.hesselbarth, tglx, tsbogend, vgupta,
vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <20260404000644.522677-1-dianders@chromium.org>
On Sat, Apr 4, 2026 at 2:07 AM Douglas Anderson <dianders@chromium.org> wrote:
>
> The main goal of this series is to fix the observed bug talked about
> in the first patch ("driver core: Don't let a device probe until it's
> ready"). That patch fixes a problem that has been observed in the real
> world and could land even if the rest of the patches are found
> unacceptable or need to be spun.
>
> That said, during patch review Danilo correctly pointed out that many
> of the bitfield accesses in "struct device" are unsafe. I added a
> bunch of patches in the series to address each one.
>
> Danilo said he's most worried about "can_match", so I put that one
> first. After that, I tried to transition bitfields to flags in reverse
> order to when the bitfield was added.
>
> Even if transitioning from bitfields to flags isn't truly needed for
> correctness, it seems silly (and wasteful of space in struct device)
> to have some in bitfields and some as flags. Thus I didn't spend time
> for each bitfield showing that it's truly needed for correctness.
>
> Transition was done semi manually. Presumably someone skilled at
> coccinelle could do a better job, but I just used sed in a heavy-
> handed manner and then reviewed/fixed the results, undoing anything my
> script got wrong. My terrible/ugly script was:
>
> var=can_match
> caps="${var^^}"
> for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
> echo $f
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
> sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
> done
>
> From v3 to v4, I transitioned to accessor functions with another ugly
> sed script. I had git format the old patches, then transformed them
> with:
>
> for f in *.patch; do
> echo $f
> sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
> sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
> sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
> done
>
> ...and then did a few manual touchups for spacing.
>
> NOTE: one potentially "controversial" choice I made in some patches
> was to always reserve a flag ID even if a flag is only used under
> certain CONFIG_ settings. This is a change from how things were
> before. Keeping the numbering consistent and allowing easy
> compile-testing of both CONFIG settings seemed worth it, especially
> since it won't take up any extra space until we've added a lot more
> flags.
>
> I only marked the first patch as a "Fix" since it is the only one
> fixing observed problems. Other patches could be considered fixes too
> if folks want.
>
> I tested the first patch in the series backported to kernel 6.6 on the
> Pixel phone that was experiencing the race. I added extra printouts to
> make sure that the problem was hitting / addressed. The rest of the
> patches are tested with allmodconfig with arm32, arm64, ppc, and
> x86. I boot tested on an arm64 Chromebook running mainline.
>
> Changes in v4:
> - Use accessor functions for flags
>
> Changes in v3:
> - Use a new "flags" bitfield
> - Add missing \n in probe error message
>
> Changes in v2:
> - Instead of adjusting the ordering, use "ready_to_probe" flag
>
> Douglas Anderson (9):
> driver core: Don't let a device probe until it's ready
> driver core: Replace dev->can_match with dev_can_match()
> driver core: Replace dev->dma_iommu with dev_dma_iommu()
> driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
> driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
> driver core: Replace dev->state_synced with dev_state_synced()
> driver core: Replace dev->dma_coherent with dev_dma_coherent()
> driver core: Replace dev->of_node_reused with dev_of_node_reused()
> driver core: Replace dev->offline + ->offline_disabled with accessors
>
> arch/arc/mm/dma.c | 4 +-
> arch/arm/mach-highbank/highbank.c | 2 +-
> arch/arm/mach-mvebu/coherency.c | 2 +-
> arch/arm/mm/dma-mapping-nommu.c | 4 +-
> arch/arm/mm/dma-mapping.c | 28 ++--
> arch/arm64/kernel/cpufeature.c | 2 +-
> arch/arm64/mm/dma-mapping.c | 2 +-
> arch/mips/mm/dma-noncoherent.c | 2 +-
> arch/powerpc/kernel/dma-iommu.c | 8 +-
> .../platforms/pseries/hotplug-memory.c | 4 +-
> arch/riscv/mm/dma-noncoherent.c | 2 +-
> drivers/acpi/scan.c | 2 +-
> drivers/base/core.c | 53 +++++---
> drivers/base/cpu.c | 4 +-
> drivers/base/dd.c | 28 ++--
> drivers/base/memory.c | 2 +-
> drivers/base/pinctrl.c | 2 +-
> drivers/base/platform.c | 2 +-
> drivers/dma/ti/k3-udma-glue.c | 6 +-
> drivers/dma/ti/k3-udma.c | 6 +-
> drivers/iommu/dma-iommu.c | 9 +-
> drivers/iommu/iommu.c | 5 +-
> drivers/net/pcs/pcs-xpcs-plat.c | 2 +-
> drivers/of/device.c | 6 +-
> drivers/pci/of.c | 2 +-
> drivers/pci/pwrctrl/core.c | 2 +-
> drivers/regulator/bq257xx-regulator.c | 2 +-
> drivers/regulator/rk808-regulator.c | 2 +-
> drivers/tty/serial/serial_base_bus.c | 2 +-
> drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
> include/linux/device.h | 120 ++++++++++++------
> include/linux/dma-map-ops.h | 6 +-
> include/linux/dma-mapping.h | 2 +-
> include/linux/iommu-dma.h | 3 +-
> kernel/cpu.c | 4 +-
> kernel/dma/mapping.c | 12 +-
> mm/hmm.c | 2 +-
> 37 files changed, 206 insertions(+), 142 deletions(-)
>
> --
For the whole set
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
^ permalink raw reply
* Re: [PATCH 1/3] dmaengine: dw-axi-dmac: fix Alignment should match open parenthesis
From: Khairul Anuar Romli @ 2026-04-04 15:20 UTC (permalink / raw)
To: Frank Li
Cc: Lars-Peter Clausen, Vinod Koul, Frank Li, dmaengine, linux-kernel,
Markus.Elfring
In-Reply-To: <acqQTmr5ti8RWfnV@lizhi-Precision-Tower-5810>
On 30/3/2026 11:01 pm, Frank Li wrote:
> On Sat, Mar 28, 2026 at 10:56:55AM +0800, Khairul Anuar Romli wrote:
>> checkpatch.pl --strict reports a CHECK warning in dw-axi-dmac.c:
>>
>> CHECK: Alignment should match open parenthesis
>>
>> This warning occurs when multi-line function calls or expressions have
>> continuation lines that don't properly align with the opening
>> parenthesis position.
>>
>> Fixes all instances in dw-axi-dmac.c where continuation lines were
>> indented with an inconsistent number of spaces/tabs that neither
>> matched the parenthesis column nor followed a standard indent pattern.
>> Proper alignment improves code readability and maintainability by
>> making parameter lists visually consistent across the kernel codebase.
>>
>> Fixes: 0e3b67b348b8 ("dmaengine: Add support for the Analog Devices AXI-DMAC DMA controller")
>> Fixes: e3923592f80b ("dmaengine: axi-dmac: populate residue info for completed xfers")
>> Fixes: 3f8fd25936ee ("dmaengine: axi-dmac: Allocate hardware descriptors")
>> Fixes: 921234e0c5d7 ("dmaengine: axi-dmac: Split too large segments")
>> Fixes: a5b982af953b ("dmaengine: axi-dmac: add a check for devm_regmap_init_mmio")
>
> This is code cleanup and not user visiual problem. I think needn't add
> fixes tags here.
>
I can remove the fixes tags in the next revision.
Thanks for pointing this out.
Best Regards,
Khairul
> Frank
>
>> Signed-off-by: Khairul Anuar Romli <karom.9560@gmail.com>
>> ---
>> drivers/dma/dma-axi-dmac.c | 28 +++++++++++++++-------------
>> 1 file changed, 15 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
>> index 45c2c8e4bc45..0017f4dc6dcc 100644
>> --- a/drivers/dma/dma-axi-dmac.c
>> +++ b/drivers/dma/dma-axi-dmac.c
>> @@ -193,7 +193,7 @@ static struct axi_dmac_desc *to_axi_dmac_desc(struct virt_dma_desc *vdesc)
>> }
>>
>> static void axi_dmac_write(struct axi_dmac *axi_dmac, unsigned int reg,
>> - unsigned int val)
>> + unsigned int val)
>> {
>> writel(val, axi_dmac->base + reg);
>> }
>> @@ -382,7 +382,7 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
>> }
>>
>> static inline unsigned int axi_dmac_total_sg_bytes(struct axi_dmac_chan *chan,
>> - struct axi_dmac_sg *sg)
>> + struct axi_dmac_sg *sg)
>> {
>> if (chan->hw_2d)
>> return (sg->hw->x_len + 1) * (sg->hw->y_len + 1);
>> @@ -437,7 +437,7 @@ static void axi_dmac_dequeue_partial_xfers(struct axi_dmac_chan *chan)
>> }
>>
>> static void axi_dmac_compute_residue(struct axi_dmac_chan *chan,
>> - struct axi_dmac_desc *active)
>> + struct axi_dmac_desc *active)
>> {
>> struct dmaengine_result *rslt = &active->vdesc.tx_result;
>> unsigned int start = active->num_completed - 1;
>> @@ -517,7 +517,7 @@ static bool axi_dmac_handle_cyclic_eot(struct axi_dmac_chan *chan,
>> }
>>
>> static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
>> - unsigned int completed_transfers)
>> + unsigned int completed_transfers)
>> {
>> struct axi_dmac_desc *active;
>> struct axi_dmac_sg *sg;
>> @@ -667,7 +667,7 @@ axi_dmac_alloc_desc(struct axi_dmac_chan *chan, unsigned int num_sgs)
>> desc->chan = chan;
>>
>> hws = dma_alloc_coherent(dev, PAGE_ALIGN(num_sgs * sizeof(*hws)),
>> - &hw_phys, GFP_ATOMIC);
>> + &hw_phys, GFP_ATOMIC);
>> if (!hws) {
>> kfree(desc);
>> return NULL;
>> @@ -703,9 +703,11 @@ static void axi_dmac_free_desc(struct axi_dmac_desc *desc)
>> }
>>
>> static struct axi_dmac_sg *axi_dmac_fill_linear_sg(struct axi_dmac_chan *chan,
>> - enum dma_transfer_direction direction, dma_addr_t addr,
>> - unsigned int num_periods, unsigned int period_len,
>> - struct axi_dmac_sg *sg)
>> + enum dma_transfer_direction direction,
>> + dma_addr_t addr,
>> + unsigned int num_periods,
>> + unsigned int period_len,
>> + struct axi_dmac_sg *sg)
>> {
>> unsigned int num_segments, i;
>> unsigned int segment_size;
>> @@ -817,7 +819,7 @@ static struct dma_async_tx_descriptor *axi_dmac_prep_slave_sg(
>> }
>>
>> dsg = axi_dmac_fill_linear_sg(chan, direction, sg_dma_address(sg), 1,
>> - sg_dma_len(sg), dsg);
>> + sg_dma_len(sg), dsg);
>> }
>>
>> desc->cyclic = false;
>> @@ -857,7 +859,7 @@ static struct dma_async_tx_descriptor *axi_dmac_prep_dma_cyclic(
>> desc->sg[num_sgs - 1].hw->flags &= ~AXI_DMAC_HW_FLAG_LAST;
>>
>> axi_dmac_fill_linear_sg(chan, direction, buf_addr, num_periods,
>> - period_len, desc->sg);
>> + period_len, desc->sg);
>>
>> desc->cyclic = true;
>>
>> @@ -1006,7 +1008,7 @@ static void axi_dmac_adjust_chan_params(struct axi_dmac_chan *chan)
>> * features are implemented and how it should behave.
>> */
>> static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
>> - struct axi_dmac_chan *chan)
>> + struct axi_dmac_chan *chan)
>> {
>> u32 val;
>> int ret;
>> @@ -1295,7 +1297,7 @@ static int axi_dmac_probe(struct platform_device *pdev)
>> return ret;
>>
>> ret = of_dma_controller_register(pdev->dev.of_node,
>> - of_dma_xlate_by_chan_id, dma_dev);
>> + of_dma_xlate_by_chan_id, dma_dev);
>> if (ret)
>> return ret;
>>
>> @@ -1310,7 +1312,7 @@ static int axi_dmac_probe(struct platform_device *pdev)
>> return ret;
>>
>> regmap = devm_regmap_init_mmio(&pdev->dev, dmac->base,
>> - &axi_dmac_regmap_config);
>> + &axi_dmac_regmap_config);
>>
>> return PTR_ERR_OR_ZERO(regmap);
>> }
>> --
>> 2.43.0
>>
^ permalink raw reply
* Re: [PATCH] dmaengine: imx-sdma: Refine spba bus searching in probe
From: Frank Li @ 2026-04-04 1:48 UTC (permalink / raw)
To: Shengjiu Wang
Cc: vkoul, Frank.Li, s.hauer, kernel, festevam, dmaengine, imx,
linux-arm-kernel, linux-kernel
In-Reply-To: <20260403083313.1172292-1-shengjiu.wang@nxp.com>
On Fri, Apr 03, 2026 at 04:33:13PM +0800, Shengjiu Wang wrote:
> There are multi spba-busses for i.MX8M* platforms, if only search for
> the first spba-bus in DT, the found spba-bus may not the real bus of
> audio devices, which cause issue for sdma p2p case, as the sdma p2p
> script presently does not deal with the transactions involving two devices
> connected to the AIPS bus.
It is bug fixes. add fixes tags.
>
> Search the SDMA parent node first, which should be the AIPS bus, then
> search the child node whose compatible string is spba-bus under that AIPS
> bus for the above multi spba-busses case.
>
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> ---
> drivers/dma/imx-sdma.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index 3d527883776b..be2fb87b7a89 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -2364,13 +2364,16 @@ static int sdma_probe(struct platform_device *pdev)
> return dev_err_probe(&pdev->dev, ret,
> "failed to register controller\n");
>
> - spba_bus = of_find_compatible_node(NULL, NULL, "fsl,spba-bus");
> + struct device_node *sdma_parent_np = of_get_parent(np);
use cleanup struct device_node *__free(device_node) * ...
You can change spba_bus in another patch also.
Frank
> +
> + spba_bus = of_get_compatible_child(sdma_parent_np, "fsl,spba-bus");
> ret = of_address_to_resource(spba_bus, 0, &spba_res);
> if (!ret) {
> sdma->spba_start_addr = spba_res.start;
> sdma->spba_end_addr = spba_res.end;
> }
> of_node_put(spba_bus);
> + of_node_put(sdma_parent_np);
> }
>
> /*
> --
> 2.34.1
>
^ permalink raw reply
* [PATCH v4 7/9] driver core: Replace dev->dma_coherent with dev_dma_coherent()
From: Douglas Anderson @ 2026-04-04 0:05 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern
Cc: Saravana Kannan, Christoph Hellwig, Eric Dumazet, Johan Hovold,
Leon Romanovsky, Alexander Lobakin, Alexey Kardashevskiy,
Robin Murphy, Douglas Anderson, Frank.Li, alex, andre.przywara,
andrew, aou, catalin.marinas, dmaengine, driver-core,
gregory.clement, iommu, jgg, kees, linux-arm-kernel, linux-kernel,
linux-mips, linux-riscv, linux-snps-arc, linux, m.szyprowski,
palmer, peter.ujfalusi, pjw, sebastian.hesselbarth, tsbogend,
vgupta, vkoul, will, willy
In-Reply-To: <20260404000644.522677-1-dianders@chromium.org>
In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_coherent" over to the "flags"
field so modifications are safe.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).
NOTE: even though previously we only took up a bit if
CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE, CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU,
or CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL, in this change I reserve the
bit unconditionally. While we could get the "dynamic" behavior by
changing the flags definition to be an "enum", it doesn't seem worth
it at this point.
Changes in v4:
- Use accessor functions for flags
Changes in v3:
- New
arch/arc/mm/dma.c | 4 ++--
arch/arm/mach-highbank/highbank.c | 2 +-
arch/arm/mach-mvebu/coherency.c | 2 +-
arch/arm/mm/dma-mapping-nommu.c | 4 ++--
arch/arm/mm/dma-mapping.c | 28 ++++++++++++++--------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/mips/mm/dma-noncoherent.c | 2 +-
arch/riscv/mm/dma-noncoherent.c | 2 +-
drivers/base/core.c | 2 +-
drivers/dma/ti/k3-udma-glue.c | 6 +++---
drivers/dma/ti/k3-udma.c | 6 +++---
include/linux/device.h | 11 ++++-------
include/linux/dma-map-ops.h | 2 +-
13 files changed, 35 insertions(+), 38 deletions(-)
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 6b85e94f3275..9b9adb02b4c5 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -98,8 +98,8 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
* DMA buffers.
*/
if (is_isa_arcv2() && ioc_enable && coherent)
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
dev_info(dev, "use %scoherent DMA ops\n",
- dev->dma_coherent ? "" : "non");
+ dev_dma_coherent(dev) ? "" : "non");
}
diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
index 47335c7dadf8..8b7d0929dac4 100644
--- a/arch/arm/mach-highbank/highbank.c
+++ b/arch/arm/mach-highbank/highbank.c
@@ -98,7 +98,7 @@ static int highbank_platform_notifier(struct notifier_block *nb,
if (of_property_read_bool(dev->of_node, "dma-coherent")) {
val = readl(sregs_base + reg);
writel(val | 0xff01, sregs_base + reg);
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
}
return NOTIFY_OK;
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index fa2c1e1aeb96..7234d487ff39 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -95,7 +95,7 @@ static int mvebu_hwcc_notifier(struct notifier_block *nb,
if (event != BUS_NOTIFY_ADD_DEVICE)
return NOTIFY_DONE;
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
return NOTIFY_OK;
}
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index fecac107fd0d..c6a70686507b 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -42,11 +42,11 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
* enough to check if MPU is in use or not since in absence of
* MPU system memory map is used.
*/
- dev->dma_coherent = cacheid ? coherent : true;
+ dev_assign_dma_coherent(dev, cacheid ? coherent : true);
} else {
/*
* Assume coherent DMA in case MMU/MPU has not been set up.
*/
- dev->dma_coherent = (get_cr() & CR_M) ? coherent : true;
+ dev_assign_dma_coherent(dev, (get_cr() & CR_M) ? coherent : true);
}
}
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f304037d1c34..f9bc53b60f99 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1076,7 +1076,7 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
struct page **pages;
void *addr = NULL;
- int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+ int coherent_flag = dev_dma_coherent(dev) ? COHERENT : NORMAL;
*handle = DMA_MAPPING_ERROR;
size = PAGE_ALIGN(size);
@@ -1124,7 +1124,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
if (vma->vm_pgoff >= nr_pages)
return -ENXIO;
- if (!dev->dma_coherent)
+ if (!dev_dma_coherent(dev))
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
err = vm_map_pages(vma, pages, nr_pages);
@@ -1141,7 +1141,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, unsigned long attrs)
{
- int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+ int coherent_flag = dev_dma_coherent(dev) ? COHERENT : NORMAL;
struct page **pages;
size = PAGE_ALIGN(size);
@@ -1202,7 +1202,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
phys_addr_t phys = page_to_phys(sg_page(s));
unsigned int len = PAGE_ALIGN(s->offset + s->length);
- if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ if (!dev_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_device(sg_phys(s), s->length, dir);
prot = __dma_info_to_prot(dir, attrs);
@@ -1304,7 +1304,7 @@ static void arm_iommu_unmap_sg(struct device *dev,
if (sg_dma_len(s))
__iommu_remove_mapping(dev, sg_dma_address(s),
sg_dma_len(s));
- if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ if (!dev_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_cpu(sg_phys(s), s->length, dir);
}
}
@@ -1323,7 +1323,7 @@ static void arm_iommu_sync_sg_for_cpu(struct device *dev,
struct scatterlist *s;
int i;
- if (dev->dma_coherent)
+ if (dev_dma_coherent(dev))
return;
for_each_sg(sg, s, nents, i)
@@ -1345,7 +1345,7 @@ static void arm_iommu_sync_sg_for_device(struct device *dev,
struct scatterlist *s;
int i;
- if (dev->dma_coherent)
+ if (dev_dma_coherent(dev))
return;
for_each_sg(sg, s, nents, i)
@@ -1371,7 +1371,7 @@ static dma_addr_t arm_iommu_map_phys(struct device *dev, phys_addr_t phys,
dma_addr_t dma_addr;
int ret, prot;
- if (!dev->dma_coherent &&
+ if (!dev_dma_coherent(dev) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO)))
arch_sync_dma_for_device(phys, size, dir);
@@ -1412,7 +1412,7 @@ static void arm_iommu_unmap_phys(struct device *dev, dma_addr_t handle,
if (!iova)
return;
- if (!dev->dma_coherent &&
+ if (!dev_dma_coherent(dev) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) {
phys_addr_t phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1431,7 +1431,7 @@ static void arm_iommu_sync_single_for_cpu(struct device *dev,
unsigned int offset = handle & ~PAGE_MASK;
phys_addr_t phys;
- if (dev->dma_coherent || !iova)
+ if (dev_dma_coherent(dev) || !iova)
return;
phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1446,7 +1446,7 @@ static void arm_iommu_sync_single_for_device(struct device *dev,
unsigned int offset = handle & ~PAGE_MASK;
phys_addr_t phys;
- if (dev->dma_coherent || !iova)
+ if (dev_dma_coherent(dev) || !iova)
return;
phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1701,13 +1701,13 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { }
void arch_setup_dma_ops(struct device *dev, bool coherent)
{
/*
- * Due to legacy code that sets the ->dma_coherent flag from a bus
- * notifier we can't just assign coherent to the ->dma_coherent flag
+ * Due to legacy code that sets the dma_coherent flag from a bus
+ * notifier we can't just assign coherent to the dma_coherent flag
* here, but instead have to make sure we only set but never clear it
* for now.
*/
if (coherent)
- dev->dma_coherent = true;
+ dev_set_dma_coherent(dev);
/*
* Don't override the dma_ops if they have already been set. Ideally
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..dc1fce939451 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -48,7 +48,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
dev_driver_string(dev), dev_name(dev),
ARCH_DMA_MINALIGN, cls);
- dev->dma_coherent = coherent;
+ dev_assign_dma_coherent(dev, coherent);
xen_setup_dma_ops(dev);
}
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index ab4f2a75a7d0..30ef3e247eb7 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -139,6 +139,6 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
#ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
void arch_setup_dma_ops(struct device *dev, bool coherent)
{
- dev->dma_coherent = coherent;
+ dev_assign_dma_coherent(dev, coherent);
}
#endif
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index cb89d7e0ba88..a1ec2d71d1c9 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -140,7 +140,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
"%s %s: device non-coherent but no non-coherent operations supported",
dev_driver_string(dev), dev_name(dev));
- dev->dma_coherent = coherent;
+ dev_assign_dma_coherent(dev, coherent);
}
void riscv_noncoherent_supported(void)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 0986051a6f14..531f02a5469a 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3173,7 +3173,7 @@ void device_initialize(struct device *dev)
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
- dev->dma_coherent = dma_default_coherent;
+ dev_assign_dma_coherent(dev, dma_default_coherent);
#endif
swiotlb_dev_init(dev);
}
diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
index f87d244cc2d6..686dc140293e 100644
--- a/drivers/dma/ti/k3-udma-glue.c
+++ b/drivers/dma/ti/k3-udma-glue.c
@@ -312,7 +312,7 @@ k3_udma_glue_request_tx_chn_common(struct device *dev,
if (xudma_is_pktdma(tx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- tx_chn->common.chan_dev.dma_coherent = true;
+ dev_set_dma_coherent(&tx_chn->common.chan_dev);
dma_coerce_mask_and_coherent(&tx_chn->common.chan_dev,
DMA_BIT_MASK(48));
}
@@ -1003,7 +1003,7 @@ k3_udma_glue_request_rx_chn_priv(struct device *dev, const char *name,
if (xudma_is_pktdma(rx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- rx_chn->common.chan_dev.dma_coherent = true;
+ dev_set_dma_coherent(&rx_chn->common.chan_dev);
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
DMA_BIT_MASK(48));
}
@@ -1104,7 +1104,7 @@ k3_udma_glue_request_remote_rx_chn_common(struct k3_udma_glue_rx_channel *rx_chn
if (xudma_is_pktdma(rx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- rx_chn->common.chan_dev.dma_coherent = true;
+ dev_set_dma_coherent(&rx_chn->common.chan_dev);
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
DMA_BIT_MASK(48));
rx_chn->single_fdq = false;
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index c964ebfcf3b6..1cf158eb7bdb 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -428,18 +428,18 @@ static void k3_configure_chan_coherency(struct dma_chan *chan, u32 asel)
/* No special handling for the channel */
chan->dev->chan_dma_dev = false;
- chan_dev->dma_coherent = false;
+ dev_clear_dma_coherent(chan_dev);
chan_dev->dma_parms = NULL;
} else if (asel == 14 || asel == 15) {
chan->dev->chan_dma_dev = true;
- chan_dev->dma_coherent = true;
+ dev_set_dma_coherent(chan_dev);
dma_coerce_mask_and_coherent(chan_dev, DMA_BIT_MASK(48));
chan_dev->dma_parms = chan_dev->parent->dma_parms;
} else {
dev_warn(chan->device->dev, "Invalid ASEL value: %u\n", asel);
- chan_dev->dma_coherent = false;
+ dev_clear_dma_coherent(chan_dev);
chan_dev->dma_parms = NULL;
}
}
diff --git a/include/linux/device.h b/include/linux/device.h
index a1d59ff9702c..fca986cef2ed 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -481,6 +481,8 @@ struct device_physical_location {
* @DEV_FLAG_STATE_SYNCED: The hardware state of this device has been synced to
* match the software state of this device by calling the
* driver/bus sync_state() callback.
+ * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
+ * architecture supports non-coherent devices.
*/
enum struct_device_flags {
DEV_FLAG_READY_TO_PROBE = 0,
@@ -489,6 +491,7 @@ enum struct_device_flags {
DEV_FLAG_DMA_SKIP_SYNC = 3,
DEV_FLAG_DMA_OPS_BYPASS = 4,
DEV_FLAG_STATE_SYNCED = 5,
+ DEV_FLAG_DMA_COHERENT = 6,
DEV_FLAG_COUNT
};
@@ -572,8 +575,6 @@ enum struct_device_flags {
* @offline: Set after successful invocation of bus type's .offline().
* @of_node_reused: Set if the device-tree node is shared with an ancestor
* device.
- * @dma_coherent: this particular device is dma coherent, even if the
- * architecture supports non-coherent devices.
* @flags: DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
*
* At the lowest level, every device in a Linux system is represented by an
@@ -681,11 +682,6 @@ struct device {
bool offline_disabled:1;
bool offline:1;
bool of_node_reused:1;
-#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
- defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
- defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
- bool dma_coherent:1;
-#endif
DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
};
@@ -718,6 +714,7 @@ __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU);
__create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
__create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
__create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
+__create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
/**
* struct device_link - Device link representation.
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index edd7de60a957..44dd9035b4fe 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -230,7 +230,7 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
extern bool dma_default_coherent;
static inline bool dev_is_dma_coherent(struct device *dev)
{
- return dev->dma_coherent;
+ return dev_dma_coherent(dev);
}
#else
#define dma_default_coherent true
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply related
* [PATCH v4 0/9] driver core: Fix some race conditions
From: Douglas Anderson @ 2026-04-04 0:04 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern
Cc: Saravana Kannan, Christoph Hellwig, Eric Dumazet, Johan Hovold,
Leon Romanovsky, Alexander Lobakin, Alexey Kardashevskiy,
Robin Murphy, Douglas Anderson, Andrew Morton, Frank.Li,
Jason Gunthorpe, alex, alexander.stein, andre.przywara, andrew,
andrew, andriy.shevchenko, aou, ardb, bhelgaas, brgl, broonie,
catalin.marinas, chleroy, davem, david, devicetree, dmaengine,
driver-core, gbatra, gregory.clement, hkallweit1, iommu,
jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb, lgirdwood,
linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
m.szyprowski, maddy, mani, maz, miko.lenczewski, mpe, netdev,
npiggin, osalvador, oupton, pabeni, palmer, peter.ujfalusi,
peterz, pjw, robh, sebastian.hesselbarth, tglx, tsbogend, vgupta,
vkoul, will, willy, yangyicong, yeoreum.yun
The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.
That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.
Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.
Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.
Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:
var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
echo $f
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
done
From v3 to v4, I transitioned to accessor functions with another ugly
sed script. I had git format the old patches, then transformed them
with:
for f in *.patch; do
echo $f
sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
done
...and then did a few manual touchups for spacing.
NOTE: one potentially "controversial" choice I made in some patches
was to always reserve a flag ID even if a flag is only used under
certain CONFIG_ settings. This is a change from how things were
before. Keeping the numbering consistent and allowing easy
compile-testing of both CONFIG settings seemed worth it, especially
since it won't take up any extra space until we've added a lot more
flags.
I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.
I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.
Changes in v4:
- Use accessor functions for flags
Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message
Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag
Douglas Anderson (9):
driver core: Don't let a device probe until it's ready
driver core: Replace dev->can_match with dev_can_match()
driver core: Replace dev->dma_iommu with dev_dma_iommu()
driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
driver core: Replace dev->state_synced with dev_state_synced()
driver core: Replace dev->dma_coherent with dev_dma_coherent()
driver core: Replace dev->of_node_reused with dev_of_node_reused()
driver core: Replace dev->offline + ->offline_disabled with accessors
arch/arc/mm/dma.c | 4 +-
arch/arm/mach-highbank/highbank.c | 2 +-
arch/arm/mach-mvebu/coherency.c | 2 +-
arch/arm/mm/dma-mapping-nommu.c | 4 +-
arch/arm/mm/dma-mapping.c | 28 ++--
arch/arm64/kernel/cpufeature.c | 2 +-
arch/arm64/mm/dma-mapping.c | 2 +-
arch/mips/mm/dma-noncoherent.c | 2 +-
arch/powerpc/kernel/dma-iommu.c | 8 +-
.../platforms/pseries/hotplug-memory.c | 4 +-
arch/riscv/mm/dma-noncoherent.c | 2 +-
drivers/acpi/scan.c | 2 +-
drivers/base/core.c | 53 +++++---
drivers/base/cpu.c | 4 +-
drivers/base/dd.c | 28 ++--
drivers/base/memory.c | 2 +-
drivers/base/pinctrl.c | 2 +-
drivers/base/platform.c | 2 +-
drivers/dma/ti/k3-udma-glue.c | 6 +-
drivers/dma/ti/k3-udma.c | 6 +-
drivers/iommu/dma-iommu.c | 9 +-
drivers/iommu/iommu.c | 5 +-
drivers/net/pcs/pcs-xpcs-plat.c | 2 +-
drivers/of/device.c | 6 +-
drivers/pci/of.c | 2 +-
drivers/pci/pwrctrl/core.c | 2 +-
drivers/regulator/bq257xx-regulator.c | 2 +-
drivers/regulator/rk808-regulator.c | 2 +-
drivers/tty/serial/serial_base_bus.c | 2 +-
drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
include/linux/device.h | 120 ++++++++++++------
include/linux/dma-map-ops.h | 6 +-
include/linux/dma-mapping.h | 2 +-
include/linux/iommu-dma.h | 3 +-
kernel/cpu.c | 4 +-
kernel/dma/mapping.c | 12 +-
mm/hmm.c | 2 +-
37 files changed, 206 insertions(+), 142 deletions(-)
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply
* [PATCH] dmaengine: imx-sdma: Refine spba bus searching in probe
From: Shengjiu Wang @ 2026-04-03 8:33 UTC (permalink / raw)
To: vkoul, Frank.Li, s.hauer, kernel, festevam, dmaengine, imx,
linux-arm-kernel, linux-kernel
There are multi spba-busses for i.MX8M* platforms, if only search for
the first spba-bus in DT, the found spba-bus may not the real bus of
audio devices, which cause issue for sdma p2p case, as the sdma p2p
script presently does not deal with the transactions involving two devices
connected to the AIPS bus.
Search the SDMA parent node first, which should be the AIPS bus, then
search the child node whose compatible string is spba-bus under that AIPS
bus for the above multi spba-busses case.
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
drivers/dma/imx-sdma.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 3d527883776b..be2fb87b7a89 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -2364,13 +2364,16 @@ static int sdma_probe(struct platform_device *pdev)
return dev_err_probe(&pdev->dev, ret,
"failed to register controller\n");
- spba_bus = of_find_compatible_node(NULL, NULL, "fsl,spba-bus");
+ struct device_node *sdma_parent_np = of_get_parent(np);
+
+ spba_bus = of_get_compatible_child(sdma_parent_np, "fsl,spba-bus");
ret = of_address_to_resource(spba_bus, 0, &spba_res);
if (!ret) {
sdma->spba_start_addr = spba_res.start;
sdma->spba_end_addr = spba_res.end;
}
of_node_put(spba_bus);
+ of_node_put(sdma_parent_np);
}
/*
--
2.34.1
^ permalink raw reply related
* Re: [PATCH v3] dmaengine: tegra210-adma: Add error logging on failure paths
From: Frank Li @ 2026-04-03 3:03 UTC (permalink / raw)
To: Sheetal
Cc: Jon Hunter, Vinod Koul, Thierry Reding, Laxman Dewangan, Frank Li,
Mohan Kumar, dmaengine, linux-tegra, linux-kernel
In-Reply-To: <20260323083858.2777285-1-sheetal@nvidia.com>
On Mon, Mar 23, 2026 at 08:38:58AM +0000, Sheetal wrote:
> Add dev_err/dev_err_probe logging across failure paths to improve
> debuggability of DMA errors during runtime and probe.
>
> Signed-off-by: Sheetal <sheetal@nvidia.com>
> ---
> Changes in v3:
> - Cast page_no to (unsigned long long) for %llu to fix -Wformat
> warning on 32-bit builds where resource_size_t is unsigned int
> - Remove redundant dev_err for devm_ioremap_resource failures since
> the API already logs errors internally.
>
> Changes in v2:
> - Fix format specifier for size_t: use %zu instead of %u for
> desc->num_periods to resolve -Wformat warning with W=1
>
> drivers/dma/tegra210-adma.c | 37 +++++++++++++++++++++++++++-------
> 1 file changed, 30 insertions(+), 7 deletions(-)
>
...
> @@ -1047,38 +1058,45 @@ static int tegra_adma_probe(struct platform_device *pdev)
> res_page = platform_get_resource_byname(pdev, IORESOURCE_MEM, "page");
> if (res_page) {
> tdma->ch_base_addr = devm_ioremap_resource(&pdev->dev, res_page);
> if (IS_ERR(tdma->ch_base_addr))
> return PTR_ERR(tdma->ch_base_addr);
>
> res_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "global");
> if (res_base) {
> resource_size_t page_offset, page_no;
> unsigned int ch_base_offset;
>
> - if (res_page->start < res_base->start)
> + if (res_page->start < res_base->start) {
> + dev_err(&pdev->dev, "invalid page/global resource order\n");
> return -EINVAL;
It is in probe function, return dev_err_probe(, -EINVAL, ...);
check other place
> + }
> +
> page_offset = res_page->start - res_base->start;
> ch_base_offset = cdata->ch_base_offset;
> if (!ch_base_offset)
> return -EINVAL;
>
> page_no = div_u64(page_offset, ch_base_offset);
> - if (!page_no || page_no > INT_MAX)
> + if (!page_no || page_no > INT_MAX) {
> + dev_err(&pdev->dev, "invalid page number %llu\n",
> + (unsigned long long)page_no);
> return -EINVAL;
> + }
>
> tdma->ch_page_no = page_no - 1;
> tdma->base_addr = devm_ioremap_resource(&pdev->dev, res_base);
> if (IS_ERR(tdma->base_addr))
> return PTR_ERR(tdma->base_addr);
> }
> } else {
> /* If no 'page' property found, then reg DT binding would be legacy */
> res_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> if (res_base) {
> tdma->base_addr = devm_ioremap_resource(&pdev->dev, res_base);
> if (IS_ERR(tdma->base_addr))
> return PTR_ERR(tdma->base_addr);
> } else {
> + dev_err(&pdev->dev, "failed to get memory resource\n");
> return -ENODEV;
> }
>
> @@ -1130,6 +1147,7 @@ static int tegra_adma_probe(struct platform_device *pdev)
> tdc->irq = of_irq_get(pdev->dev.of_node, i);
> if (tdc->irq <= 0) {
> ret = tdc->irq ?: -ENXIO;
> + dev_err_probe(&pdev->dev, ret, "failed to get IRQ for channel %d\n", i);
> goto irq_dispose;
> }
>
> @@ -1141,12 +1159,16 @@ static int tegra_adma_probe(struct platform_device *pdev)
> pm_runtime_enable(&pdev->dev);
>
> ret = pm_runtime_resume_and_get(&pdev->dev);
> - if (ret < 0)
> + if (ret < 0) {
> + dev_err_probe(&pdev->dev, ret, "runtime PM resume failed\n");
> goto rpm_disable;
can you change to use devm_ firtly to elimiate goto first, then change to
use
return dev_err_probe() pattern
Frank
> + }
>
> ret = tegra_adma_init(tdma);
> - if (ret)
> + if (ret) {
> + dev_err(&pdev->dev, "failed to initialize ADMA: %d\n", ret);
> goto rpm_put;
> + }
>
> dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
> dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
> --
> 2.17.1
>
^ permalink raw reply
* [PATCH v3 7/9] driver core: Replace dev->dma_coherent with DEV_FLAG_DMA_COHERENT
From: Douglas Anderson @ 2026-04-03 0:49 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern
Cc: Robin Murphy, Leon Romanovsky, Paul Burton, Saravana Kannan,
Alexander Lobakin, Eric Dumazet, Toshi Kani, Christoph Hellwig,
Alexey Kardashevskiy, Johan Hovold, Douglas Anderson, Frank.Li,
alex, andre.przywara, andrew, aou, catalin.marinas, dmaengine,
driver-core, gregory.clement, iommu, jgg, kees, linux-arm-kernel,
linux-kernel, linux-mips, linux-riscv, linux-snps-arc, linux,
m.szyprowski, palmer, peter.ujfalusi, pjw, sebastian.hesselbarth,
tsbogend, vgupta, vkoul, will, willy
In-Reply-To: <20260403005005.30424-1-dianders@chromium.org>
In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "dma_coherent" over to the "flags"
field so modifications are safe.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).
NOTE: even though previously we only took up a bit if
CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE, CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU,
or CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL, in this change I reserve the
bit unconditionally. While we could get the "dynamic" behavior by
changing the flags definition to be an "enum", it doesn't seem worth
it at this point.
Changes in v3:
- New
arch/arc/mm/dma.c | 4 ++--
arch/arm/mach-highbank/highbank.c | 2 +-
arch/arm/mach-mvebu/coherency.c | 2 +-
arch/arm/mm/dma-mapping-nommu.c | 4 ++--
arch/arm/mm/dma-mapping.c | 30 ++++++++++++++++--------------
arch/arm64/mm/dma-mapping.c | 2 +-
arch/mips/mm/dma-noncoherent.c | 2 +-
arch/riscv/mm/dma-noncoherent.c | 2 +-
drivers/base/core.c | 2 +-
drivers/dma/ti/k3-udma-glue.c | 6 +++---
drivers/dma/ti/k3-udma.c | 6 +++---
include/linux/device.h | 10 +++-------
include/linux/dma-map-ops.h | 2 +-
13 files changed, 36 insertions(+), 38 deletions(-)
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 6b85e94f3275..3d56878cb6a2 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -98,8 +98,8 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
* DMA buffers.
*/
if (is_isa_arcv2() && ioc_enable && coherent)
- dev->dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &dev->flags);
dev_info(dev, "use %scoherent DMA ops\n",
- dev->dma_coherent ? "" : "non");
+ test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) ? "" : "non");
}
diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
index 47335c7dadf8..ffa3f591f57a 100644
--- a/arch/arm/mach-highbank/highbank.c
+++ b/arch/arm/mach-highbank/highbank.c
@@ -98,7 +98,7 @@ static int highbank_platform_notifier(struct notifier_block *nb,
if (of_property_read_bool(dev->of_node, "dma-coherent")) {
val = readl(sregs_base + reg);
writel(val | 0xff01, sregs_base + reg);
- dev->dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &dev->flags);
}
return NOTIFY_OK;
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index fa2c1e1aeb96..8391303a6a17 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -95,7 +95,7 @@ static int mvebu_hwcc_notifier(struct notifier_block *nb,
if (event != BUS_NOTIFY_ADD_DEVICE)
return NOTIFY_DONE;
- dev->dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &dev->flags);
return NOTIFY_OK;
}
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index fecac107fd0d..ac0a976e30a0 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -42,11 +42,11 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
* enough to check if MPU is in use or not since in absence of
* MPU system memory map is used.
*/
- dev->dma_coherent = cacheid ? coherent : true;
+ assign_bit(DEV_FLAG_DMA_COHERENT, &dev->flags, cacheid ? coherent : true);
} else {
/*
* Assume coherent DMA in case MMU/MPU has not been set up.
*/
- dev->dma_coherent = (get_cr() & CR_M) ? coherent : true;
+ assign_bit(DEV_FLAG_DMA_COHERENT, &dev->flags, (get_cr() & CR_M) ? coherent : true);
}
}
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f304037d1c34..9c2c635d7ac0 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1076,7 +1076,7 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
struct page **pages;
void *addr = NULL;
- int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+ int coherent_flag = test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) ? COHERENT : NORMAL;
*handle = DMA_MAPPING_ERROR;
size = PAGE_ALIGN(size);
@@ -1124,7 +1124,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
if (vma->vm_pgoff >= nr_pages)
return -ENXIO;
- if (!dev->dma_coherent)
+ if (!test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags))
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
err = vm_map_pages(vma, pages, nr_pages);
@@ -1141,7 +1141,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, unsigned long attrs)
{
- int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+ int coherent_flag = test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) ? COHERENT : NORMAL;
struct page **pages;
size = PAGE_ALIGN(size);
@@ -1202,7 +1202,8 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
phys_addr_t phys = page_to_phys(sg_page(s));
unsigned int len = PAGE_ALIGN(s->offset + s->length);
- if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ if (!test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_device(sg_phys(s), s->length, dir);
prot = __dma_info_to_prot(dir, attrs);
@@ -1304,7 +1305,8 @@ static void arm_iommu_unmap_sg(struct device *dev,
if (sg_dma_len(s))
__iommu_remove_mapping(dev, sg_dma_address(s),
sg_dma_len(s));
- if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ if (!test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_cpu(sg_phys(s), s->length, dir);
}
}
@@ -1323,7 +1325,7 @@ static void arm_iommu_sync_sg_for_cpu(struct device *dev,
struct scatterlist *s;
int i;
- if (dev->dma_coherent)
+ if (test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags))
return;
for_each_sg(sg, s, nents, i)
@@ -1345,7 +1347,7 @@ static void arm_iommu_sync_sg_for_device(struct device *dev,
struct scatterlist *s;
int i;
- if (dev->dma_coherent)
+ if (test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags))
return;
for_each_sg(sg, s, nents, i)
@@ -1371,7 +1373,7 @@ static dma_addr_t arm_iommu_map_phys(struct device *dev, phys_addr_t phys,
dma_addr_t dma_addr;
int ret, prot;
- if (!dev->dma_coherent &&
+ if (!test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO)))
arch_sync_dma_for_device(phys, size, dir);
@@ -1412,7 +1414,7 @@ static void arm_iommu_unmap_phys(struct device *dev, dma_addr_t handle,
if (!iova)
return;
- if (!dev->dma_coherent &&
+ if (!test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) &&
!(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) {
phys_addr_t phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1431,7 +1433,7 @@ static void arm_iommu_sync_single_for_cpu(struct device *dev,
unsigned int offset = handle & ~PAGE_MASK;
phys_addr_t phys;
- if (dev->dma_coherent || !iova)
+ if (test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) || !iova)
return;
phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1446,7 +1448,7 @@ static void arm_iommu_sync_single_for_device(struct device *dev,
unsigned int offset = handle & ~PAGE_MASK;
phys_addr_t phys;
- if (dev->dma_coherent || !iova)
+ if (test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags) || !iova)
return;
phys = iommu_iova_to_phys(mapping->domain, iova);
@@ -1701,13 +1703,13 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { }
void arch_setup_dma_ops(struct device *dev, bool coherent)
{
/*
- * Due to legacy code that sets the ->dma_coherent flag from a bus
- * notifier we can't just assign coherent to the ->dma_coherent flag
+ * Due to legacy code that sets DEV_FLAG_DMA_COHERENT from a bus
+ * notifier we can't just assign coherent to DEV_FLAG_DMA_COHERENT
* here, but instead have to make sure we only set but never clear it
* for now.
*/
if (coherent)
- dev->dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &dev->flags);
/*
* Don't override the dma_ops if they have already been set. Ideally
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..256c7631aff5 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -48,7 +48,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
dev_driver_string(dev), dev_name(dev),
ARCH_DMA_MINALIGN, cls);
- dev->dma_coherent = coherent;
+ assign_bit(DEV_FLAG_DMA_COHERENT, &dev->flags, coherent);
xen_setup_dma_ops(dev);
}
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index ab4f2a75a7d0..496bf5f4999c 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -139,6 +139,6 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
#ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
void arch_setup_dma_ops(struct device *dev, bool coherent)
{
- dev->dma_coherent = coherent;
+ assign_bit(DEV_FLAG_DMA_COHERENT, &dev->flags, coherent);
}
#endif
diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index cb89d7e0ba88..3b793a1cc607 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -140,7 +140,7 @@ void arch_setup_dma_ops(struct device *dev, bool coherent)
"%s %s: device non-coherent but no non-coherent operations supported",
dev_driver_string(dev), dev_name(dev));
- dev->dma_coherent = coherent;
+ assign_bit(DEV_FLAG_DMA_COHERENT, &dev->flags, coherent);
}
void riscv_noncoherent_supported(void)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8dbb7a9c7aab..00005777c21f 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3174,7 +3174,7 @@ void device_initialize(struct device *dev)
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
- dev->dma_coherent = dma_default_coherent;
+ assign_bit(DEV_FLAG_DMA_COHERENT, &dev->flags, dma_default_coherent);
#endif
swiotlb_dev_init(dev);
}
diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
index f87d244cc2d6..cda8f4a8f440 100644
--- a/drivers/dma/ti/k3-udma-glue.c
+++ b/drivers/dma/ti/k3-udma-glue.c
@@ -312,7 +312,7 @@ k3_udma_glue_request_tx_chn_common(struct device *dev,
if (xudma_is_pktdma(tx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- tx_chn->common.chan_dev.dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &tx_chn->common.chan_dev.flags);
dma_coerce_mask_and_coherent(&tx_chn->common.chan_dev,
DMA_BIT_MASK(48));
}
@@ -1003,7 +1003,7 @@ k3_udma_glue_request_rx_chn_priv(struct device *dev, const char *name,
if (xudma_is_pktdma(rx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- rx_chn->common.chan_dev.dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &rx_chn->common.chan_dev.flags);
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
DMA_BIT_MASK(48));
}
@@ -1104,7 +1104,7 @@ k3_udma_glue_request_remote_rx_chn_common(struct k3_udma_glue_rx_channel *rx_chn
if (xudma_is_pktdma(rx_chn->common.udmax)) {
/* prepare the channel device as coherent */
- rx_chn->common.chan_dev.dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &rx_chn->common.chan_dev.flags);
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
DMA_BIT_MASK(48));
rx_chn->single_fdq = false;
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index c964ebfcf3b6..770aae467fc5 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -428,18 +428,18 @@ static void k3_configure_chan_coherency(struct dma_chan *chan, u32 asel)
/* No special handling for the channel */
chan->dev->chan_dma_dev = false;
- chan_dev->dma_coherent = false;
+ clear_bit(DEV_FLAG_DMA_COHERENT, &chan_dev->flags);
chan_dev->dma_parms = NULL;
} else if (asel == 14 || asel == 15) {
chan->dev->chan_dma_dev = true;
- chan_dev->dma_coherent = true;
+ set_bit(DEV_FLAG_DMA_COHERENT, &chan_dev->flags);
dma_coerce_mask_and_coherent(chan_dev, DMA_BIT_MASK(48));
chan_dev->dma_parms = chan_dev->parent->dma_parms;
} else {
dev_warn(chan->device->dev, "Invalid ASEL value: %u\n", asel);
- chan_dev->dma_coherent = false;
+ clear_bit(DEV_FLAG_DMA_COHERENT, &chan_dev->flags);
chan_dev->dma_parms = NULL;
}
}
diff --git a/include/linux/device.h b/include/linux/device.h
index 6c961dac9fdb..c2a6dba7a036 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -480,6 +480,8 @@ struct device_physical_location {
* @DEV_FLAG_STATE_SYNCED: The hardware state of this device has been synced to
* match the software state of this device by calling the
* driver/bus sync_state() callback.
+ * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
+ * architecture supports non-coherent devices.
*/
enum struct_device_flags {
DEV_FLAG_READY_TO_PROBE,
@@ -488,6 +490,7 @@ enum struct_device_flags {
DEV_FLAG_DMA_SKIP_SYNC,
DEV_FLAG_DMA_OPS_BYPASS,
DEV_FLAG_STATE_SYNCED,
+ DEV_FLAG_DMA_COHERENT,
};
/**
@@ -569,8 +572,6 @@ enum struct_device_flags {
* @offline: Set after successful invocation of bus type's .offline().
* @of_node_reused: Set if the device-tree node is shared with an ancestor
* device.
- * @dma_coherent: this particular device is dma coherent, even if the
- * architecture supports non-coherent devices.
* @flags: DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
*
* At the lowest level, every device in a Linux system is represented by an
@@ -678,11 +679,6 @@ struct device {
bool offline_disabled:1;
bool offline:1;
bool of_node_reused:1;
-#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
- defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
- defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
- bool dma_coherent:1;
-#endif
unsigned long flags;
};
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 4d9d1fe3277c..91d34678657c 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -230,7 +230,7 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
extern bool dma_default_coherent;
static inline bool dev_is_dma_coherent(struct device *dev)
{
- return dev->dma_coherent;
+ return test_bit(DEV_FLAG_DMA_COHERENT, &dev->flags);
}
#else
#define dma_default_coherent true
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply related
* [PATCH v3 0/9] driver core: Fix some race conditions
From: Douglas Anderson @ 2026-04-03 0:49 UTC (permalink / raw)
To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
Alan Stern
Cc: Robin Murphy, Leon Romanovsky, Paul Burton, Saravana Kannan,
Alexander Lobakin, Eric Dumazet, Toshi Kani, Christoph Hellwig,
Alexey Kardashevskiy, Johan Hovold, Douglas Anderson,
Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
astewart, bhelgaas, brgl, broonie, catalin.marinas, chleroy,
davem, david, devicetree, dmaengine, driver-core, gbatra,
gregory.clement, hkallweit1, iommu, jirislaby, joel, joro, kees,
kevin.brodsky, kuba, lenb, lgirdwood, linux-acpi,
linux-arm-kernel, linux-aspeed, linux-cxl, linux-kernel,
linux-mips, linux-mm, linux-pci, linux-riscv, linux-serial,
linux-snps-arc, linux-usb, linux, linuxppc-dev, m.szyprowski,
maddy, mani, maz, miko.lenczewski, mpe, netdev, npiggin,
osalvador, oupton, pabeni, palmer, peter.ujfalusi, peterz, pjw,
robh, sebastian.hesselbarth, tglx, tsbogend, vgupta, vkoul, will,
willy, yangyicong, yeoreum.yun
The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.
That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.
Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.
Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.
Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:
var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
echo $f
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1.flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1.flags)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1.flags, \\2)/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1.flags)\\2/" "$f"
done
NOTE: one potentially "controversial" choice I made in some patches
was to always reserve a flag ID even if a flag is only used under
certain CONFIG_ settings. This is a change from how things were
before. Keeping the numbering consistent and allowing easy
compile-testing of both CONFIG settings seemed worth it, especially
since it won't take up any extra space until we've added a lot more
flags.
I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.
I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.
Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message
Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag
Douglas Anderson (9):
driver core: Don't let a device probe until it's ready
driver core: Replace dev->can_match with DEV_FLAG_CAN_MATCH
driver core: Replace dev->dma_iommu with DEV_FLAG_DMA_IOMMU
driver core: Replace dev->dma_skip_sync with DEV_FLAG_DMA_SKIP_SYNC
driver core: Replace dev->dma_ops_bypass with DEV_FLAG_DMA_OPS_BYPASS
driver core: Replace dev->state_synced with DEV_FLAG_STATE_SYNCED
driver core: Replace dev->dma_coherent with DEV_FLAG_DMA_COHERENT
driver core: Replace dev->of_node_reused with DEV_FLAG_OF_NODE_REUSED
driver core: Replace dev->offline + ->offline_disabled with DEV_FLAGs
arch/arc/mm/dma.c | 4 +-
arch/arm/mach-highbank/highbank.c | 2 +-
arch/arm/mach-mvebu/coherency.c | 2 +-
arch/arm/mm/dma-mapping-nommu.c | 4 +-
arch/arm/mm/dma-mapping.c | 30 +++----
arch/arm64/kernel/cpufeature.c | 2 +-
arch/arm64/mm/dma-mapping.c | 2 +-
arch/mips/mm/dma-noncoherent.c | 2 +-
arch/powerpc/kernel/dma-iommu.c | 8 +-
.../platforms/pseries/hotplug-memory.c | 4 +-
arch/riscv/mm/dma-noncoherent.c | 2 +-
drivers/acpi/scan.c | 3 +-
drivers/base/core.c | 55 +++++++-----
drivers/base/cpu.c | 4 +-
drivers/base/dd.c | 28 +++++--
drivers/base/memory.c | 2 +-
drivers/base/pinctrl.c | 2 +-
drivers/base/platform.c | 2 +-
drivers/dma/ti/k3-udma-glue.c | 6 +-
drivers/dma/ti/k3-udma.c | 6 +-
drivers/iommu/dma-iommu.c | 9 +-
drivers/iommu/iommu.c | 5 +-
drivers/net/pcs/pcs-xpcs-plat.c | 2 +-
drivers/of/device.c | 6 +-
drivers/pci/of.c | 2 +-
drivers/pci/pwrctrl/core.c | 2 +-
drivers/regulator/bq257xx-regulator.c | 2 +-
drivers/regulator/rk808-regulator.c | 2 +-
drivers/tty/serial/serial_base_bus.c | 2 +-
drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
include/linux/device.h | 83 ++++++++++---------
include/linux/dma-map-ops.h | 6 +-
include/linux/dma-mapping.h | 2 +-
include/linux/iommu-dma.h | 4 +-
kernel/cpu.c | 4 +-
kernel/dma/mapping.c | 16 ++--
mm/hmm.c | 2 +-
37 files changed, 178 insertions(+), 143 deletions(-)
--
2.53.0.1213.gd9a14994de-goog
^ permalink raw reply
* Re: [PATCH] dmaengine: idxd: fix double free in idxd_alloc() error path
From: Vinicius Costa Gomes @ 2026-04-02 17:36 UTC (permalink / raw)
To: Guangshuo Li
Cc: Dave Jiang, Vinod Koul, Shuai Xue, Fenghua Yu, dmaengine,
linux-kernel, stable
In-Reply-To: <CANUHTR94+ZEO6d3+Pm1cdHw3firrAaVqxO90XwfHGrAkx37wsg@mail.gmail.com>
Guangshuo Li <lgs201920130244@gmail.com> writes:
> Hi Vinicius,
>
> Thanks for reviewing — the feedback is helpful.
>
> I'm working on top of v6.19-rc8-214-ge7aa57247700.
>
> Regarding the concern about put_device(conf_dev) triggering
> idxd_conf_device_release() and hitting a NULL idxd->wq in
> destroy_workqueue():
>
> idxd_conf_device_release() does not call destroy_workqueue(). That
> call lives in idxd_cleanup_internals(), which is a separate code path.
> The actual release callback is:
>
Current master includes that code:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/dma/idxd/sysfs.c#n1839
That modification was part of fix series that I proposed and was applied
on time for v7.0. It seems that I didn't do a good enough job of going
through the error paths.
Cheers,
--
Vinicius
^ permalink raw reply
* Re: [PATCH v2 4/4] dmaengine: dma-axi-dmac: Defer freeing DMA descriptors
From: Nuno Sá @ 2026-04-02 17:06 UTC (permalink / raw)
To: Frank Li
Cc: Nuno Sá, dmaengine, linux-kernel, Lars-Peter Clausen,
Vinod Koul, Frank Li, Eliza Balas
In-Reply-To: <ac2bzkImYBdujGPS@lizhi-Precision-Tower-5810>
On Wed, Apr 01, 2026 at 06:27:26PM -0400, Frank Li wrote:
> On Wed, Apr 01, 2026 at 05:14:16PM +0100, Nuno Sá wrote:
> > On Tue, Mar 31, 2026 at 04:21:06PM +0100, Nuno Sá wrote:
> > > On Tue, Mar 31, 2026 at 10:16:09AM -0400, Frank Li wrote:
> > > > On Tue, Mar 31, 2026 at 09:53:45AM +0100, Nuno Sá wrote:
> > > > > On Mon, Mar 30, 2026 at 11:24:34AM -0400, Frank Li wrote:
> > > > > > On Fri, Mar 27, 2026 at 04:58:41PM +0000, Nuno Sá wrote:
> > > > > > > From: Eliza Balas <eliza.balas@analog.com>
> > > > > > >
> > > > > > > This IP core can be used in architectures (like Microblaze) where DMA
> > > > > > > descriptors are allocated with vmalloc().
> > > > > >
> > > > > > strage, why use vmalloc()?
> > > > >
> > > > > It's just one of the paths in dma_alloc_coherent(). It should be
> > > > > architecture dependant.
> > > >
> > > > Which architectures, this may common problem, dma_alloc/free_coherent() is
> > > > quite common at other dma-engine driver.
> > >
> > > I'll double check this but I believe this was triggered on microblaze
> > > where we also use this IP. Will come back with confirmation!
> > >
> >
> > Hi Frank,
> >
> > I now went to the bottom of the issue! The problem is that for archs
> > like microblaze and arm64 we have DMA_DIRECT_REMAP which means that when
> > calling dma_alloc_coherent() in [1] we will get into the code path in
> > [2]. Now I did some research and we might have other solution for this
> > that does not involve this refcount craziness plus async work. But I
> > need to test it. FYI, what I have in mind is similar to the what
> > loongson2-apb-dma.c does. This means, using the dma pool API. IIUC, with
> > the pool we only actually free the memory (dma_free_coherent()) in the
> > .terminate_all() callback (when destroying the pool) which should not
> > happen in interrupt context right?
>
> I think so. If your dma engineer descriptor is link-list, suggest use dma
> pool. If it is cicylic buffer, suggest pre-alloc enough descriptors when
> apply channel.
Yeah, I ran some tests and dma pool seems to work just fine. I'll still
ask a colleague to test my patch in the platform that triggered the
BUG().
- Nuno Sá
>
> Frank
> >
> > [1]: https://elixir.bootlin.com/linux/v7.0-rc6/source/drivers/dma/dma-axi-dmac.c#L549
> > [2]: https://elixir.bootlin.com/linux/v7.0-rc6/source/kernel/dma/direct.c#L278
> >
> > - Nuno Sá
> >
> > > - Nuno Sá
> > > >
> > > > Frank
> > > >
> > > > >
> > > > > - Nuno Sá
> > > > >
> > > > > >
> > > > > > Frank
> > > > > >
> > > > > > > Hence, given that freeing the
> > > > > > > descriptors happen in softirq context, vunmpap() will BUG().
> > > > > > >
> > > > > > > To solve the above, we setup a work item during allocation of the
> > > > > > > descriptors and schedule in softirq context. Hence, the actual freeing
> > > > > > > happens in threaded context.
> > > > > > >
> > > > > > > Also note that to account for the possible race where the struct axi_dmac
> > > > > > > object is gone between scheduling the work and actually running it, we
> > > > > > > now save and get a reference of struct device when allocating the
> > > > > > > descriptor (given that's all we need in axi_dmac_free_desc()) and
> > > > > > > release it in axi_dmac_free_desc().
> > > > > > >
> > > > > > > Signed-off-by: Eliza Balas <eliza.balas@analog.com>
> > > > > > > Co-developed-by: Nuno Sá <nuno.sa@analog.com>
> > > > > > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > > > > > > ---
> > > > > > > drivers/dma/dma-axi-dmac.c | 50 ++++++++++++++++++++++++++++++++++------------
> > > > > > > 1 file changed, 37 insertions(+), 13 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
> > > > > > > index 70d3ad7e7d37..46f1ead0c7d7 100644
> > > > > > > --- a/drivers/dma/dma-axi-dmac.c
> > > > > > > +++ b/drivers/dma/dma-axi-dmac.c
> > > > > > > @@ -25,6 +25,7 @@
> > > > > > > #include <linux/regmap.h>
> > > > > > > #include <linux/slab.h>
> > > > > > > #include <linux/spinlock.h>
> > > > > > > +#include <linux/workqueue.h>
> > > > > > >
> > > > > > > #include <dt-bindings/dma/axi-dmac.h>
> > > > > > >
> > > > > > > @@ -133,6 +134,9 @@ struct axi_dmac_sg {
> > > > > > > struct axi_dmac_desc {
> > > > > > > struct virt_dma_desc vdesc;
> > > > > > > struct axi_dmac_chan *chan;
> > > > > > > + struct device *dev;
> > > > > > > +
> > > > > > > + struct work_struct sched_work;
> > > > > > >
> > > > > > > bool cyclic;
> > > > > > > bool cyclic_eot;
> > > > > > > @@ -666,6 +670,25 @@ static void axi_dmac_issue_pending(struct dma_chan *c)
> > > > > > > spin_unlock_irqrestore(&chan->vchan.lock, flags);
> > > > > > > }
> > > > > > >
> > > > > > > +static void axi_dmac_free_desc(struct axi_dmac_desc *desc)
> > > > > > > +{
> > > > > > > + struct axi_dmac_hw_desc *hw = desc->sg[0].hw;
> > > > > > > + dma_addr_t hw_phys = desc->sg[0].hw_phys;
> > > > > > > +
> > > > > > > + dma_free_coherent(desc->dev, PAGE_ALIGN(desc->num_sgs * sizeof(*hw)),
> > > > > > > + hw, hw_phys);
> > > > > > > + put_device(desc->dev);
> > > > > > > + kfree(desc);
> > > > > > > +}
> > > > > > > +
> > > > > > > +static void axi_dmac_free_desc_schedule_work(struct work_struct *work)
> > > > > > > +{
> > > > > > > + struct axi_dmac_desc *desc = container_of(work, struct axi_dmac_desc,
> > > > > > > + sched_work);
> > > > > > > +
> > > > > > > + axi_dmac_free_desc(desc);
> > > > > > > +}
> > > > > > > +
> > > > > > > static struct axi_dmac_desc *
> > > > > > > axi_dmac_alloc_desc(struct axi_dmac_chan *chan, unsigned int num_sgs)
> > > > > > > {
> > > > > > > @@ -681,6 +704,7 @@ axi_dmac_alloc_desc(struct axi_dmac_chan *chan, unsigned int num_sgs)
> > > > > > > return NULL;
> > > > > > > desc->num_sgs = num_sgs;
> > > > > > > desc->chan = chan;
> > > > > > > + desc->dev = get_device(dmac->dma_dev.dev);
> > > > > > >
> > > > > > > hws = dma_alloc_coherent(dev, PAGE_ALIGN(num_sgs * sizeof(*hws)),
> > > > > > > &hw_phys, GFP_ATOMIC);
> > > > > > > @@ -703,21 +727,18 @@ axi_dmac_alloc_desc(struct axi_dmac_chan *chan, unsigned int num_sgs)
> > > > > > > /* The last hardware descriptor will trigger an interrupt */
> > > > > > > desc->sg[num_sgs - 1].hw->flags = AXI_DMAC_HW_FLAG_LAST | AXI_DMAC_HW_FLAG_IRQ;
> > > > > > >
> > > > > > > + /*
> > > > > > > + * We need to setup a work item because this IP can be used on archs
> > > > > > > + * that rely on vmalloced memory for descriptors. And given that freeing
> > > > > > > + * the descriptors happens in softirq context, vunmpap() will BUG().
> > > > > > > + * Hence, setup the worker so that we can queue it and free the
> > > > > > > + * descriptor in threaded context.
> > > > > > > + */
> > > > > > > + INIT_WORK(&desc->sched_work, axi_dmac_free_desc_schedule_work);
> > > > > > > +
> > > > > > > return desc;
> > > > > > > }
> > > > > > >
> > > > > > > -static void axi_dmac_free_desc(struct axi_dmac_desc *desc)
> > > > > > > -{
> > > > > > > - struct axi_dmac *dmac = chan_to_axi_dmac(desc->chan);
> > > > > > > - struct device *dev = dmac->dma_dev.dev;
> > > > > > > - struct axi_dmac_hw_desc *hw = desc->sg[0].hw;
> > > > > > > - dma_addr_t hw_phys = desc->sg[0].hw_phys;
> > > > > > > -
> > > > > > > - dma_free_coherent(dev, PAGE_ALIGN(desc->num_sgs * sizeof(*hw)),
> > > > > > > - hw, hw_phys);
> > > > > > > - kfree(desc);
> > > > > > > -}
> > > > > > > -
> > > > > > > static struct axi_dmac_sg *axi_dmac_fill_linear_sg(struct axi_dmac_chan *chan,
> > > > > > > enum dma_transfer_direction direction, dma_addr_t addr,
> > > > > > > unsigned int num_periods, unsigned int period_len,
> > > > > > > @@ -958,7 +979,10 @@ static void axi_dmac_free_chan_resources(struct dma_chan *c)
> > > > > > >
> > > > > > > static void axi_dmac_desc_free(struct virt_dma_desc *vdesc)
> > > > > > > {
> > > > > > > - axi_dmac_free_desc(to_axi_dmac_desc(vdesc));
> > > > > > > + struct axi_dmac_desc *desc = to_axi_dmac_desc(vdesc);
> > > > > > > +
> > > > > > > + /* See the comment in axi_dmac_alloc_desc() for the why! */
> > > > > > > + schedule_work(&desc->sched_work);
> > > > > > > }
> > > > > > >
> > > > > > > static bool axi_dmac_regmap_rdwr(struct device *dev, unsigned int reg)
> > > > > > >
> > > > > > > --
> > > > > > > 2.53.0
> > > > > > >
^ permalink raw reply
* [PATCh v3 2/2] dma: sh: rz-dmac: Add DMA ACK signal routing support
From: John Madieu @ 2026-04-02 16:22 UTC (permalink / raw)
To: Vinod Koul, Frank Li, Thomas Gleixner, Geert Uytterhoeven,
Fabrizio Castro
Cc: Claudiu Beznea, Biju Das, Lad Prabhakar, Cosmin Tanislav,
john.madieu, linux-renesas-soc, dmaengine, linux-kernel,
John Madieu
In-Reply-To: <20260402162212.12016-1-john.madieu.xa@bp.renesas.com>
Some peripherals on RZ/G3E SoCs (SSIU, SPDIF, SCU/SRC, DVC, PFC)
require explicit ACK signal routing through the ICU for level-based DMA
handshaking.
Rather than extending the DT binding with an optional second #dma-cells
(which would require all DMA consumers to supply two cells even when ACK
routing is not needed), derive the ACK signal number directly from the
MID/RID request number using the linear mapping defined in RZ/G3E hardware
manual Table 4.6-28:
PFC external DMA pins (DREQ0..DREQ4):
req_no 0x000-0x004 -> ACK No. 84-88
SSIU BUSIFs (ssip00..ssip93):
req_no 0x161-0x198 -> ACK No. 28-83
SPDIF (CH0..CH2) + SCU SRC (sr0..sr9) + DVC (cmd0..cmd1):
req_no 0x199-0x1b4 -> ACK No. 0-27
ACK routing is programmed when a channel is prepared for transfer and
cleared when the channel is released or the transfer times out, following
the same pattern as MID/RID request routing.
Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
---
Changes:
v3: No changes
v2:
- Drop DMA ACK second cell from DT specifier
- Derive ACK signal number in-driver from MID/RID using arithmetic formulas
per ICU Table 4.6-28 (3 linear peripheral groups)
drivers/dma/sh/rz-dmac.c | 72 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 95a89c9d2925..bde3da96b37e 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -97,6 +97,7 @@ struct rz_dmac_chan {
u32 chcfg;
u32 chctrl;
int mid_rid;
+ int dmac_ack;
struct {
u32 nxla;
@@ -124,6 +125,9 @@ struct rz_dmac_icu {
struct rz_dmac_info {
void (*icu_register_dma_req)(struct platform_device *icu_dev,
u8 dmac_index, u8 dmac_channel, u16 req_no);
+ void (*icu_register_dma_ack)(struct platform_device *icu_dev,
+ u8 dmac_index, u8 dmac_channel, u16 ack_no);
+ u16 default_dma_ack_no;
u16 default_dma_req_no;
};
@@ -362,6 +366,60 @@ static void rz_dmac_set_dma_req_no(struct rz_dmac *dmac, unsigned int index,
rz_dmac_set_dmars_register(dmac, index, req_no);
}
+/*
+ * Map MID/RID request number (bits[0:9] of DMA specifier) to the ICU
+ * DMA ACK signal number, per RZ/G3E hardware manual Table 4.6-28.
+ *
+ * Three peripheral groups cover all ACK-capable peripherals:
+ *
+ * PFC external DMA pins (DREQ0..DREQ4):
+ * req_no 0x000-0x004 -> ACK No. 84-88 (ack = req_no + 84)
+ *
+ * SSIU BUSIFs (ssip00..ssip93):
+ * req_no 0x161-0x198 -> ACK No. 28-83 (ack = req_no - 0x145)
+ *
+ * SPDIF (CH0..CH2) + SCU SRC (sr0..sr9) + DVC (cmd0..cmd1):
+ * req_no 0x199-0x1b4 -> ACK No. 0-27 (ack = req_no - 0x199)
+ */
+static int rz_dmac_get_ack_no(const struct rz_dmac_info *info, u16 req_no)
+{
+ if (!info->icu_register_dma_ack)
+ return -EINVAL;
+
+ switch (req_no) {
+ case 0x000 ... 0x004:
+ /* PFC external DMA pins: ACK No. 84-88 */
+ return req_no + 84;
+ case 0x161 ... 0x198:
+ /* SSIU BUSIFs: ACK No. 28-83 */
+ return req_no - 0x145;
+ case 0x199 ... 0x1b4:
+ /* SPDIF + SCU SRC + DVC: ACK No. 0-27 */
+ return req_no - 0x199;
+ default:
+ return -EINVAL;
+ }
+}
+
+static void rz_dmac_set_dma_ack_no(struct rz_dmac *dmac, unsigned int index,
+ int ack_no)
+{
+ if (ack_no < 0 || !dmac->info->icu_register_dma_ack)
+ return;
+
+ dmac->info->icu_register_dma_ack(dmac->icu.pdev, dmac->icu.dmac_index,
+ index, ack_no);
+}
+
+static void rz_dmac_reset_dma_ack_no(struct rz_dmac *dmac, int ack_no)
+{
+ if (ack_no < 0 || !dmac->info->icu_register_dma_ack)
+ return;
+
+ dmac->info->icu_register_dma_ack(dmac->icu.pdev, dmac->icu.dmac_index,
+ dmac->info->default_dma_ack_no, ack_no);
+}
+
static void rz_dmac_prepare_desc_for_memcpy(struct rz_dmac_chan *channel)
{
struct dma_chan *chan = &channel->vc.chan;
@@ -431,6 +489,7 @@ static void rz_dmac_prepare_descs_for_slave_sg(struct rz_dmac_chan *channel)
channel->lmdesc.tail = lmdesc;
rz_dmac_set_dma_req_no(dmac, channel->index, channel->mid_rid);
+ rz_dmac_set_dma_ack_no(dmac, channel->index, channel->dmac_ack);
}
static void rz_dmac_prepare_descs_for_cyclic(struct rz_dmac_chan *channel)
@@ -485,6 +544,7 @@ static void rz_dmac_prepare_descs_for_cyclic(struct rz_dmac_chan *channel)
channel->lmdesc.tail = lmdesc;
rz_dmac_set_dma_req_no(dmac, channel->index, channel->mid_rid);
+ rz_dmac_set_dma_ack_no(dmac, channel->index, channel->dmac_ack);
}
static int rz_dmac_xfer_desc(struct rz_dmac_chan *chan)
@@ -567,6 +627,9 @@ static void rz_dmac_free_chan_resources(struct dma_chan *chan)
channel->mid_rid = -EINVAL;
}
+ rz_dmac_reset_dma_ack_no(dmac, channel->dmac_ack);
+ channel->dmac_ack = -EINVAL;
+
spin_unlock_irqrestore(&channel->vc.lock, flags);
list_for_each_entry_safe(desc, _desc, &channel->ld_free, node) {
@@ -814,6 +877,7 @@ static void rz_dmac_device_synchronize(struct dma_chan *chan)
dev_warn(dmac->dev, "DMA Timeout");
rz_dmac_set_dma_req_no(dmac, channel->index, dmac->info->default_dma_req_no);
+ rz_dmac_reset_dma_ack_no(dmac, channel->dmac_ack);
}
static struct rz_lmdesc *
@@ -1164,6 +1228,8 @@ static bool rz_dmac_chan_filter(struct dma_chan *chan, void *arg)
channel->chcfg = CHCFG_FILL_TM(ch_cfg) | CHCFG_FILL_AM(ch_cfg) |
CHCFG_FILL_LVL(ch_cfg) | CHCFG_FILL_HIEN(ch_cfg);
+ channel->dmac_ack = rz_dmac_get_ack_no(dmac->info, channel->mid_rid);
+
return !test_and_set_bit(channel->mid_rid, dmac->modules);
}
@@ -1200,6 +1266,7 @@ static int rz_dmac_chan_probe(struct rz_dmac *dmac,
channel->index = index;
channel->mid_rid = -EINVAL;
+ channel->dmac_ack = -EINVAL;
/* Request the channel interrupt. */
scnprintf(pdev_irqname, sizeof(pdev_irqname), "ch%u", index);
@@ -1569,6 +1636,9 @@ static int rz_dmac_resume(struct device *dev)
guard(spinlock_irqsave)(&channel->vc.lock);
+ rz_dmac_set_dma_req_no(dmac, channel->index, channel->mid_rid);
+ rz_dmac_set_dma_ack_no(dmac, channel->index, channel->dmac_ack);
+
if (!(channel->status & BIT(RZ_DMAC_CHAN_STATUS_CYCLIC))) {
rz_dmac_ch_writel(&dmac->channels[i], CHCTRL_DEFAULT, CHCTRL, 1);
continue;
@@ -1601,6 +1671,8 @@ static const struct dev_pm_ops rz_dmac_pm_ops = {
static const struct rz_dmac_info rz_dmac_v2h_info = {
.icu_register_dma_req = rzv2h_icu_register_dma_req,
+ .icu_register_dma_ack = rzv2h_icu_register_dma_ack,
+ .default_dma_ack_no = RZV2H_ICU_DMAC_ACK_NO_DEFAULT,
.default_dma_req_no = RZV2H_ICU_DMAC_REQ_NO_DEFAULT,
};
--
2.25.1
^ permalink raw reply related
* [PATCh v3 1/2] irqchip/renesas-rzv2h: Add DMA ACK signal routing support
From: John Madieu @ 2026-04-02 16:22 UTC (permalink / raw)
To: Vinod Koul, Frank Li, Thomas Gleixner, Geert Uytterhoeven,
Fabrizio Castro
Cc: Claudiu Beznea, Biju Das, Lad Prabhakar, Cosmin Tanislav,
john.madieu, linux-renesas-soc, dmaengine, linux-kernel,
John Madieu
In-Reply-To: <20260402162212.12016-1-john.madieu.xa@bp.renesas.com>
Some peripherals on RZ/G3E SoCs (SSIU, SPDIF, SCU/SRC, DVC) require
explicit ACK signal routing through the ICU via the ICU_DMACKSELk
registers for level-based DMA handshaking.
Add rzv2h_icu_register_dma_ack() to configure ICU_DMACKSELk, routing
a DMAC channel's ACK signal to the specified peripheral.
Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
---
Changes:
v3: No changes
v2: No changes
drivers/irqchip/irq-renesas-rzv2h.c | 40 +++++++++++++++++++++++
include/linux/irqchip/irq-renesas-rzv2h.h | 5 +++
2 files changed, 45 insertions(+)
diff --git a/drivers/irqchip/irq-renesas-rzv2h.c b/drivers/irqchip/irq-renesas-rzv2h.c
index 31f191641ff8..4ebcb91c0b6c 100644
--- a/drivers/irqchip/irq-renesas-rzv2h.c
+++ b/drivers/irqchip/irq-renesas-rzv2h.c
@@ -151,6 +151,12 @@ struct rzv2h_hw_info {
#define ICU_DMAC_PREP_DMAREQ(sel, up) (FIELD_PREP(ICU_DMAC_DkRQ_SEL_MASK, (sel)) \
<< ICU_DMAC_DMAREQ_SHIFT(up))
+/* DMAC ACK routing - 4 x 7-bit fields per 32-bit register, 8-bit spacing */
+#define ICU_DMAC_DACK_SEL_MASK GENMASK(6, 0)
+#define ICU_DMAC_DACK_SHIFT(n) ((n) * 8)
+#define ICU_DMAC_DACK_FIELD_MASK(n) (ICU_DMAC_DACK_SEL_MASK << ICU_DMAC_DACK_SHIFT(n))
+#define ICU_DMAC_PREP_DACK(val, n) (((val) & ICU_DMAC_DACK_SEL_MASK) << ICU_DMAC_DACK_SHIFT(n))
+
/**
* struct rzv2h_icu_priv - Interrupt Control Unit controller private data structure.
* @base: Controller's base address
@@ -188,6 +194,40 @@ void rzv2h_icu_register_dma_req(struct platform_device *icu_dev, u8 dmac_index,
}
EXPORT_SYMBOL_GPL(rzv2h_icu_register_dma_req);
+/**
+ * rzv2h_icu_register_dma_ack - Configure DMA ACK signal routing
+ * @icu_dev: ICU platform device
+ * @dmac_index: DMAC instance index (0-4)
+ * @dmac_channel: DMAC channel number (0-15), or RZV2H_ICU_DMAC_ACK_NO_DEFAULT
+ * to disconnect routing for a given ack_no
+ * @ack_no: Peripheral ACK number (0-88) per RZ/G3E manual Table 4.6-28,
+ * used as index into ICU_DMACKSELk
+ *
+ * Routes the ACK signal of the peripheral identified by @ack_no to DMAC
+ * channel @dmac_channel of instance @dmac_index. When @dmac_channel is
+ * RZV2H_ICU_DMAC_ACK_NO_DEFAULT the field is reset, disconnecting any
+ * previously configured routing for that peripheral.
+ */
+void rzv2h_icu_register_dma_ack(struct platform_device *icu_dev, u8 dmac_index,
+ u8 dmac_channel, u16 ack_no)
+{
+ struct rzv2h_icu_priv *priv = platform_get_drvdata(icu_dev);
+ u8 reg_idx = ack_no / 4;
+ u8 field_idx = ack_no & 0x3;
+ u8 dmac_ack_src = (dmac_channel == RZV2H_ICU_DMAC_ACK_NO_DEFAULT) ?
+ RZV2H_ICU_DMAC_ACK_NO_DEFAULT :
+ (dmac_index * 16 + dmac_channel);
+ u32 val;
+
+ guard(raw_spinlock_irqsave)(&priv->lock);
+
+ val = readl(priv->base + ICU_DMACKSELk(reg_idx));
+ val &= ~ICU_DMAC_DACK_FIELD_MASK(field_idx);
+ val |= ICU_DMAC_PREP_DACK(dmac_ack_src, field_idx);
+ writel(val, priv->base + ICU_DMACKSELk(reg_idx));
+}
+EXPORT_SYMBOL_GPL(rzv2h_icu_register_dma_ack);
+
static inline struct rzv2h_icu_priv *irq_data_to_priv(struct irq_data *data)
{
return data->domain->host_data;
diff --git a/include/linux/irqchip/irq-renesas-rzv2h.h b/include/linux/irqchip/irq-renesas-rzv2h.h
index 618a60d2eac0..4ffa898eaaf2 100644
--- a/include/linux/irqchip/irq-renesas-rzv2h.h
+++ b/include/linux/irqchip/irq-renesas-rzv2h.h
@@ -11,13 +11,18 @@
#include <linux/platform_device.h>
#define RZV2H_ICU_DMAC_REQ_NO_DEFAULT 0x3ff
+#define RZV2H_ICU_DMAC_ACK_NO_DEFAULT 0x7f
#ifdef CONFIG_RENESAS_RZV2H_ICU
void rzv2h_icu_register_dma_req(struct platform_device *icu_dev, u8 dmac_index, u8 dmac_channel,
u16 req_no);
+void rzv2h_icu_register_dma_ack(struct platform_device *icu_dev, u8 dmac_index,
+ u8 dmac_channel, u16 ack_no);
#else
static inline void rzv2h_icu_register_dma_req(struct platform_device *icu_dev, u8 dmac_index,
u8 dmac_channel, u16 req_no) { }
+static inline void rzv2h_icu_register_dma_ack(struct platform_device *icu_dev, u8 dmac_index,
+ u8 dmac_channel, u16 ack_no) { }
#endif
#endif /* __LINUX_IRQ_RENESAS_RZV2H */
--
2.25.1
^ permalink raw reply related
* [PATCh v3 0/2] Add DMA ACK signal routing for RZ/V2H family
From: John Madieu @ 2026-04-02 16:22 UTC (permalink / raw)
To: Vinod Koul, Frank Li, Thomas Gleixner, Geert Uytterhoeven,
Fabrizio Castro
Cc: Claudiu Beznea, Biju Das, Lad Prabhakar, Cosmin Tanislav,
john.madieu, linux-renesas-soc, dmaengine, linux-kernel,
John Madieu
Some peripherals on RZ/V2H, RZ/V2N, and RZ/G3E SoCs require explicit
DMA ACK signal routing through the ICU for level-based DMA handshaking.
Rather than encoding the ACK signal number as a second DMA specifier
cell, derive it in-driver from the MID/RID request number using
arithmetic formulas based on ICU Table 4.6-28 (3 linear peripheral
groups). It must also be noted that DMA ack register is located in
the ICU block
This series adds:
- ICU driver extension to register/deregister DMA ACK signals
(DMA ACK register is located in the ICU block)
- rz-dmac driver support for ACK signal routing via MID/RID lookup,
including restore on system resume
Note: patch 2/2 depends upon [1], the Cyclic DMA series from Claudiu.
Changes:
v3:
- Splitout from v2 [2] into DMA-specific series
- No code change
v2:
- Drop DMA ACK second cell from DT specifier
- Derive ACK signal number in-driver from MID/RID using arithmetic
formulas per ICU Table 4.6-28 (3 linear peripheral groups)
[1] https://lore.kernel.org/all/20260320112838.2200198-1-claudiu.beznea.uj@bp.renesas.com/
[2] https://lore.kernel.org/all/20260402090524.9137-1-john.madieu.xa@bp.renesas.com/
John Madieu (2):
irqchip/renesas-rzv2h: Add DMA ACK signal routing support
dma: sh: rz-dmac: Add DMA ACK signal routing support
drivers/dma/sh/rz-dmac.c | 72 +++++++++++++++++++++++
drivers/irqchip/irq-renesas-rzv2h.c | 40 +++++++++++++
include/linux/irqchip/irq-renesas-rzv2h.h | 5 ++
3 files changed, 117 insertions(+)
--
2.25.1
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