Re: [PATCH 6/6] dma-mapping: introduce DMA range map, supplanting dma_pfn_offset

Mathieu Poirier
2020-09-14T23:02:01Z

Hi Christoph,

On Mon, Sep 14, 2020 at 09:33:43AM +0200, Christoph Hellwig wrote:
> From: Jim Quinlan <james.quinlan@broadcom.com>
>
> The new field 'dma_range_map' in struct device is used to facilitate the
> use of single or multiple offsets between mapping regions of cpu addrs and
> dma addrs. It subsumes the role of "dev->dma_pfn_offset" which was only
> capable of holding a single uniform offset and had no region bounds
> checking.
>
> The function of_dma_get_range() has been modified so that it takes a single
> argument -- the device node -- and returns a map, NULL, or an error code.
> The map is an array that holds the information regarding the DMA regions.
> Each range entry contains the address offset, the cpu_start address, the
> dma_start address, and the size of the region.
>
> of_dma_configure() is the typical manner to set range offsets but there are
> a number of ad hoc assignments to "dev->dma_pfn_offset" in the kernel
> driver code. These cases now invoke the function
> dma_direct_set_offset(dev, cpu_addr, dma_addr, size).
>
> Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
> [hch: various interface cleanups]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> arch/arm/include/asm/dma-direct.h | 9 +--
> arch/arm/mach-keystone/keystone.c | 17 ++---
> arch/arm/mach-omap1/include/mach/memory.h | 4 +
> arch/sh/drivers/pci/pcie-sh7786.c | 9 ++-
> arch/x86/pci/sta2x11-fixup.c | 6 +-
> drivers/acpi/arm64/iort.c | 6 +-
> drivers/base/core.c | 2 +
> drivers/gpu/drm/sun4i/sun4i_backend.c | 8 +-
> drivers/iommu/io-pgtable-arm.c | 2 +-
> .../platform/sunxi/sun4i-csi/sun4i_csi.c | 9 ++-
> .../platform/sunxi/sun6i-csi/sun6i_csi.c | 11 ++-
> drivers/of/address.c | 73 ++++++++-----------
> drivers/of/device.c | 44 ++++++-----
> drivers/of/of_private.h | 11 +--
> drivers/of/unittest.c | 34 ++++++---
> drivers/remoteproc/remoteproc_core.c | 24 +++++-
> .../staging/media/sunxi/cedrus/cedrus_hw.c | 10 ++-
> include/linux/device.h | 4 +-
> include/linux/dma-direct.h | 52 +++++++++++--
> include/linux/dma-mapping.h | 9 ++-
> kernel/dma/coherent.c | 7 +-
> kernel/dma/direct.c | 51 ++++++++++++-
> 22 files changed, 284 insertions(+), 118 deletions(-)
>
> diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h
> index fbcf4367b5cb1a..436544aeb83405 100644
> --- a/arch/arm/include/asm/dma-direct.h
> +++ b/arch/arm/include/asm/dma-direct.h
> @@ -12,8 +12,8 @@
> #ifndef __arch_pfn_to_dma
> static inline dma_addr_t pfn_to_dma(struct device *dev, unsigned long pfn)
> {
> - if (dev)
> - pfn -= dev->dma_pfn_offset;
> + if (dev && dev->dma_range_map)
> + pfn = PFN_DOWN(translate_phys_to_dma(dev, PFN_PHYS(pfn)));
> return (dma_addr_t)__pfn_to_bus(pfn);
> }
>
> @@ -21,9 +21,8 @@ static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr)
> {
> unsigned long pfn = __bus_to_pfn(addr);
>
> - if (dev)
> - pfn += dev->dma_pfn_offset;
> -
> + if (dev && dev->dma_range_map)
> + pfn = PFN_DOWN(translate_dma_to_phys(dev, PFN_PHYS(pfn)));
> return pfn;
> }
>
> diff --git a/arch/arm/mach-keystone/keystone.c b/arch/arm/mach-keystone/keystone.c
> index dcd031ba84c2e0..09a65c2dfd7327 100644
> --- a/arch/arm/mach-keystone/keystone.c
> +++ b/arch/arm/mach-keystone/keystone.c
> @@ -8,6 +8,7 @@
> */
> #include <linux/io.h>
> #include <linux/of.h>
> +#include <linux/dma-mapping.h>
> #include <linux/init.h>
> #include <linux/of_platform.h>
> #include <linux/of_address.h>
> @@ -25,8 +26,6 @@
> #include "keystone.h"
>
> #ifdef CONFIG_ARM_LPAE
> -static unsigned long keystone_dma_pfn_offset __read_mostly;
> -
> static int keystone_platform_notifier(struct notifier_block *nb,
> unsigned long event, void *data)
> {
> @@ -39,9 +38,12 @@ static int keystone_platform_notifier(struct notifier_block *nb,
> return NOTIFY_BAD;
>
> if (!dev->of_node) {
> - dev->dma_pfn_offset = keystone_dma_pfn_offset;
> - dev_err(dev, "set dma_pfn_offset%08lx\n",
> - dev->dma_pfn_offset);
> + int ret = dma_direct_set_offset(dev, KEYSTONE_HIGH_PHYS_START,
> + KEYSTONE_LOW_PHYS_START,
> + KEYSTONE_HIGH_PHYS_SIZE);
> + dev_err(dev, "set dma_offset%08llx%s\n",
> + KEYSTONE_HIGH_PHYS_START - KEYSTONE_LOW_PHYS_START,
> + ret ? " failed" : "");
> }
> return NOTIFY_OK;
> }
> @@ -54,11 +56,8 @@ static struct notifier_block platform_nb = {
> static void __init keystone_init(void)
> {
> #ifdef CONFIG_ARM_LPAE
> - if (PHYS_OFFSET >= KEYSTONE_HIGH_PHYS_START) {
> - keystone_dma_pfn_offset = PFN_DOWN(KEYSTONE_HIGH_PHYS_START -
> - KEYSTONE_LOW_PHYS_START);
> + if (PHYS_OFFSET >= KEYSTONE_HIGH_PHYS_START)
> bus_register_notifier(&platform_bus_type, &platform_nb);
> - }
> #endif
> keystone_pm_runtime_init();
> }
> diff --git a/arch/arm/mach-omap1/include/mach/memory.h b/arch/arm/mach-omap1/include/mach/memory.h
> index e43697c3297bf2..1142560e0078f5 100644
> --- a/arch/arm/mach-omap1/include/mach/memory.h
> +++ b/arch/arm/mach-omap1/include/mach/memory.h
> @@ -41,6 +41,10 @@
> __phys_to_pfn(__dma); \
> })
>
> +#define __arch_dma_to_virt(dev, addr) ({ (void *) (is_lbus_device(dev) ? \
> + lbus_to_virt(addr) : \
> + __phys_to_virt(addr)); })
> +
> #define __arch_virt_to_dma(dev, addr) ({ unsigned long __addr = (unsigned long)(addr); \
> (dma_addr_t) (is_lbus_device(dev) ? \
> virt_to_lbus(__addr) : \
> diff --git a/arch/sh/drivers/pci/pcie-sh7786.c b/arch/sh/drivers/pci/pcie-sh7786.c
> index e0b568aaa7014c..4468289ab2cac7 100644
> --- a/arch/sh/drivers/pci/pcie-sh7786.c
> +++ b/arch/sh/drivers/pci/pcie-sh7786.c
> @@ -12,6 +12,7 @@
> #include <linux/io.h>
> #include <linux/async.h>
> #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> #include <linux/slab.h>
> #include <linux/clk.h>
> #include <linux/sh_clk.h>
> @@ -31,6 +32,8 @@ struct sh7786_pcie_port {
> static struct sh7786_pcie_port *sh7786_pcie_ports;
> static unsigned int nr_ports;
> static unsigned long dma_pfn_offset;
> +size_t memsize;
> +u64 memstart;
>
> static struct sh7786_pcie_hwops {
> int (*core_init)(void);
> @@ -301,7 +304,6 @@ static int __init pcie_init(struct sh7786_pcie_port *port)
> struct pci_channel *chan = port->hose;
> unsigned int data;
> phys_addr_t memstart, memend;
> - size_t memsize;
> int ret, i, win;
>
> /* Begin initialization */
> @@ -368,8 +370,6 @@ static int __init pcie_init(struct sh7786_pcie_port *port)
> memstart = ALIGN_DOWN(memstart, memsize);
> memsize = roundup_pow_of_two(memend - memstart);
>
> - dma_pfn_offset = memstart >> PAGE_SHIFT;
> -
> /*
> * If there's more than 512MB of memory, we need to roll over to
> * LAR1/LAMR1.
> @@ -487,7 +487,8 @@ int pcibios_map_platform_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
>
> void pcibios_bus_add_device(struct pci_dev *pdev)
> {
> - pdev->dev.dma_pfn_offset = dma_pfn_offset;
> + dma_direct_set_offset(&pdev->dev, __pa(memory_start),
> + __pa(memory_start) - memstart, memsize);
> }
>
> static int __init sh7786_pcie_core_init(void)
> diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
> index c313d784efabb9..324a207f99956b 100644
> --- a/arch/x86/pci/sta2x11-fixup.c
> +++ b/arch/x86/pci/sta2x11-fixup.c
> @@ -133,7 +133,7 @@ static void sta2x11_map_ep(struct pci_dev *pdev)
> struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
> struct device *dev = &pdev->dev;
> u32 amba_base, max_amba_addr;
> - int i;
> + int i, ret;
>
> if (!instance)
> return;
> @@ -141,7 +141,9 @@ static void sta2x11_map_ep(struct pci_dev *pdev)
> pci_read_config_dword(pdev, AHB_BASE(0), &amba_base);
> max_amba_addr = amba_base + STA2X11_AMBA_SIZE - 1;
>
> - dev->dma_pfn_offset = PFN_DOWN(-amba_base);
> + ret = dma_direct_set_offset(dev, 0, amba_base, STA2X11_AMBA_SIZE);
> + if (ret)
> + dev_err(dev, "sta2x11: could not set DMA offset\n");
>
> dev->bus_dma_limit = max_amba_addr;
> pci_set_consistent_dma_mask(pdev, max_amba_addr);
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index ec782e4a0fe419..de18c07ca02cc4 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -18,6 +18,7 @@
> #include <linux/pci.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> +#include <linux/dma-mapping.h>
>
> #define IORT_TYPE_MASK(type) (1 << (type))
> #define IORT_MSI_TYPE (1 << ACPI_IORT_NODE_ITS_GROUP)
> @@ -1184,8 +1185,9 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
> *dma_addr = dmaaddr;
> *dma_size = size;
>
> - dev->dma_pfn_offset = PFN_DOWN(offset);
> - dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);
> + ret = dma_direct_set_offset(dev, dmaaddr + offset, dmaaddr, size);
> +
> + dev_dbg(dev, "dma_offset(%#08llx)%s\n", offset, ret ? " failed!" : "");
> }
>
> static void __init acpi_iort_register_irq(int hwirq, const char *name,
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index f6f620aa94086d..b893056e39459c 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1792,6 +1792,8 @@ static void device_release(struct kobject *kobj)
> */
> devres_release_all(dev);
>
> + kfree(dev->dma_range_map);
> +
> if (dev->release)
> dev->release(dev);
> else if (dev->type && dev->type->release)
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index 072ea113e6be55..05e9f0d28196d9 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -11,6 +11,7 @@
> #include <linux/module.h>
> #include <linux/of_device.h>
> #include <linux/of_graph.h>
> +#include <linux/dma-mapping.h>
> #include <linux/platform_device.h>
> #include <linux/reset.h>
>
> @@ -811,8 +812,13 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
> * because of an old DT, we need to set the DMA offset by hand
> * on our device since the RAM mapping is at 0 for the DMA bus,
> * unlike the CPU.
> + *
> + * XXX(hch): this has no business in a driver and needs to move
> + * to the device tree.
> */
> - drm->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
> + ret = dma_direct_set_offset(drm->dev, PHYS_OFFSET, 0, SZ_4G);
> + if (ret)
> + return ret;
> }
>
> backend->engine.node = dev->of_node;
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index dc7bcf858b6d2d..d77e881516a4ab 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -751,7 +751,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
> if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
> return NULL;
>
> - if (!selftest_running && cfg->iommu_dev->dma_pfn_offset) {
> + if (!selftest_running && cfg->iommu_dev->dma_range_map) {
> dev_err(cfg->iommu_dev, "Cannot accommodate DMA offset for IOMMU page tables\n");
> return NULL;
> }
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> index 5319eb1ab30927..307997ee7f96a2 100644
> --- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> @@ -7,6 +7,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> #include <linux/interrupt.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> @@ -182,8 +183,14 @@ static int sun4i_csi_probe(struct platform_device *pdev)
> if (ret)
> return ret;
> } else {
> + /*
> + * XXX(hch): this has no business in a driver and needs to move
> + * to the device tree.
> + */
> #ifdef PHYS_PFN_OFFSET
> - csi->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
> + ret = dma_direct_set_offset(csi->dev, PHYS_OFFSET, 0, SZ_4G);
> + if (ret)
> + return ret;
> #endif
> }
>
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> index 28e89340fed981..e69e14379fc6e4 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> @@ -899,8 +899,15 @@ static int sun6i_csi_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> sdev->dev = &pdev->dev;
> - /* The DMA bus has the memory mapped at 0 */
> - sdev->dev->dma_pfn_offset = PHYS_OFFSET >> PAGE_SHIFT;
> + /*
> + * The DMA bus has the memory mapped at 0.
> + *
> + * XXX(hch): this has no business in a driver and needs to move
> + * to the device tree.
> + */
> + ret = dma_direct_set_offset(sdev->dev, PHYS_OFFSET, 0, SZ_4G);
> + if (ret)
> + return ret;
>
> ret = sun6i_csi_resource_request(sdev, pdev);
> if (ret)
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index da4f7341323f22..a49ef87aaaf21c 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -13,6 +13,7 @@
> #include <linux/sizes.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> +#include <linux/dma-direct.h> /* for bus_dma_region */
>
> #include "of_private.h"
>
> @@ -937,33 +938,33 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,
> }
> EXPORT_SYMBOL(of_io_request_and_map);
>
> +#ifdef CONFIG_HAS_DMA
> /**
> - * of_dma_get_range - Get DMA range info
> + * of_dma_get_range - Get DMA range info and put it into a map array
> * @np: device node to get DMA range info
> - * @dma_addr: pointer to store initial DMA address of DMA range
> - * @paddr: pointer to store initial CPU address of DMA range
> - * @size: pointer to store size of DMA range
> + * @map: dma range structure to return
> *
> * Look in bottom up direction for the first "dma-ranges" property
> - * and parse it.
> - * dma-ranges format:
> + * and parse it. Put the information into a DMA offset map array.
> + *
> + * dma-ranges format:
> * DMA addr (dma_addr) : naddr cells
> * CPU addr (phys_addr_t) : pna cells
> * size : nsize cells
> *
> - * It returns -ENODEV if "dma-ranges" property was not found
> - * for this device in DT.
> + * It returns -ENODEV if "dma-ranges" property was not found for this
> + * device in the DT.
> */
> -int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *size)
> +int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
> {
> struct device_node *node = of_node_get(np);
> const __be32 *ranges = NULL;
> - int len;
> - int ret = 0;
> bool found_dma_ranges = false;
> struct of_range_parser parser;
> struct of_range range;
> - u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
> + struct bus_dma_region *r;
> + int len, num_ranges = 0;
> + int ret = 0;
>
> while (node) {
> ranges = of_get_property(node, "dma-ranges", &len);
> @@ -989,49 +990,39 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz
> }
>
> of_dma_range_parser_init(&parser, node);
> + for_each_of_range(&parser, &range)
> + num_ranges++;
> +
> + r = kcalloc(num_ranges + 1, sizeof(*r), GFP_KERNEL);
> + if (!r) {
> + ret = -ENOMEM;
> + goto out;
> + }
>
> + /*
> + * Record all info in the generic DMA ranges array for struct device.
> + */
> + *map = r;
> + of_dma_range_parser_init(&parser, node);
> for_each_of_range(&parser, &range) {
> pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
> range.bus_addr, range.cpu_addr, range.size);
> -
> - if (dma_offset && range.cpu_addr - range.bus_addr != dma_offset) {
> - pr_warn("Can't handle multiple dma-ranges with different offsets on node(%pOF)\n", node);
> - /* Don't error out as we'd break some existing DTs */
> - continue;
> - }
> if (range.cpu_addr == OF_BAD_ADDR) {
> pr_err("translation of DMA address(%llx) to CPU address failed node(%pOF)\n",
> range.bus_addr, node);
> continue;
> }
> - dma_offset = range.cpu_addr - range.bus_addr;
> -
> - /* Take lower and upper limits */
> - if (range.bus_addr < dma_start)
> - dma_start = range.bus_addr;
> - if (range.bus_addr + range.size > dma_end)
> - dma_end = range.bus_addr + range.size;
> - }
> -
> - if (dma_start >= dma_end) {
> - ret = -EINVAL;
> - pr_debug("Invalid DMA ranges configuration on node(%pOF)\n",
> - node);
> - goto out;
> + r->cpu_start = range.cpu_addr;
> + r->dma_start = range.bus_addr;
> + r->size = range.size;
> + r->offset = range.cpu_addr - range.bus_addr;
> + r++;
> }
> -
> - *dma_addr = dma_start;
> - *size = dma_end - dma_start;
> - *paddr = dma_start + dma_offset;
> -
> - pr_debug("final: dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
> - *dma_addr, *paddr, *size);
> -
> out:
> of_node_put(node);
> -
> return ret;
> }
> +#endif /* CONFIG_HAS_DMA */
>
> /**
> * of_dma_is_coherent - Check if device is coherent
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index b439c1e054349b..6e3ae7ebc33eeb 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -5,7 +5,7 @@
> #include <linux/of_device.h>
> #include <linux/of_address.h>
> #include <linux/of_iommu.h>
> -#include <linux/dma-mapping.h>
> +#include <linux/dma-direct.h> /* for bus_dma_region */
> #include <linux/init.h>
> #include <linux/module.h>
> #include <linux/mod_devicetable.h>
> @@ -90,14 +90,14 @@ int of_device_add(struct platform_device *ofdev)
> int of_dma_configure_id(struct device *dev, struct device_node *np,
> bool force_dma, const u32 *id)
> {
> - u64 dma_addr, paddr, size = 0;
> - int ret;
> - bool coherent;
> - unsigned long offset;
> const struct iommu_ops *iommu;
> - u64 mask, end;
> + const struct bus_dma_region *map = NULL;
> + dma_addr_t dma_start = 0;
> + u64 mask, end, size = 0;
> + bool coherent;
> + int ret;
>
> - ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
> + ret = of_dma_get_range(np, &map);
> if (ret < 0) {
> /*
> * For legacy reasons, we have to assume some devices need
> @@ -106,26 +106,35 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
> */
> if (!force_dma)
> return ret == -ENODEV ? 0 : ret;
> -
> - dma_addr = offset = 0;
> } else {
> - offset = PFN_DOWN(paddr - dma_addr);
> + const struct bus_dma_region *r = map;
> + dma_addr_t dma_end = 0;
> +
> + /* Determine the overall bounds of all DMA regions */
> + for (dma_start = ~(dma_addr_t)0; r->size; r++) {
> + /* Take lower and upper limits */
> + if (r->dma_start < dma_start)
> + dma_start = r->dma_start;
> + if (r->dma_start + r->size > dma_end)
> + dma_end = r->dma_start + r->size;
> + }
> + size = dma_end - dma_start;
>
> /*
> * Add a work around to treat the size as mask + 1 in case
> * it is defined in DT as a mask.
> */
> if (size & 1) {
> - dev_warn(dev, "Invalid size 0x%llx for dma-range\n",
> + dev_warn(dev, "Invalid size 0x%llx for dma-range(s)\n",
> size);
> size = size + 1;
> }
>
> if (!size) {
> dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
> + kfree(map);
> return -EINVAL;
> }
> - dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
> }
>
> /*
> @@ -144,13 +153,11 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
> else if (!size)
> size = 1ULL << 32;
>
> - dev->dma_pfn_offset = offset;
> -
> /*
> * Limit coherent and dma mask based on size and default mask
> * set by the driver.
> */
> - end = dma_addr + size - 1;
> + end = dma_start + size - 1;
> mask = DMA_BIT_MASK(ilog2(end) + 1);
> dev->coherent_dma_mask &= mask;
> *dev->dma_mask &= mask;
> @@ -163,14 +170,17 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
> coherent ? " " : " not ");
>
> iommu = of_iommu_configure(dev, np, id);
> - if (PTR_ERR(iommu) == -EPROBE_DEFER)
> + if (PTR_ERR(iommu) == -EPROBE_DEFER) {
> + kfree(map);
> return -EPROBE_DEFER;
> + }
>
> dev_dbg(dev, "device is%sbehind an iommu\n",
> iommu ? " " : " not ");
>
> - arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
> + arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
>
> + dev->dma_range_map = map;
> return 0;
> }
> EXPORT_SYMBOL_GPL(of_dma_configure_id);
> diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
> index edc682249c0015..d9e6a324de0a77 100644
> --- a/drivers/of/of_private.h
> +++ b/drivers/of/of_private.h
> @@ -157,12 +157,13 @@ extern void __of_sysfs_remove_bin_file(struct device_node *np,
> extern int of_bus_n_addr_cells(struct device_node *np);
> extern int of_bus_n_size_cells(struct device_node *np);
>
> -#ifdef CONFIG_OF_ADDRESS
> -extern int of_dma_get_range(struct device_node *np, u64 *dma_addr,
> - u64 *paddr, u64 *size);
> +struct bus_dma_region;
> +#if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
> +int of_dma_get_range(struct device_node *np,
> + const struct bus_dma_region **map);
> #else
> -static inline int of_dma_get_range(struct device_node *np, u64 *dma_addr,
> - u64 *paddr, u64 *size)
> +static inline int of_dma_get_range(struct device_node *np,
> + const struct bus_dma_region **map)
> {
> return -ENODEV;
> }
> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
> index 9b7e84bdc7d446..06cc988faf78b3 100644
> --- a/drivers/of/unittest.c
> +++ b/drivers/of/unittest.c
> @@ -7,6 +7,7 @@
>
> #include <linux/memblock.h>
> #include <linux/clk.h>
> +#include <linux/dma-direct.h> /* to test phys_to_dma/dma_to_phys */
> #include <linux/err.h>
> #include <linux/errno.h>
> #include <linux/hashtable.h>
> @@ -869,10 +870,11 @@ static void __init of_unittest_changeset(void)
> }
>
> static void __init of_unittest_dma_ranges_one(const char *path,
> - u64 expect_dma_addr, u64 expect_paddr, u64 expect_size)
> + u64 expect_dma_addr, u64 expect_paddr)
> {
> +#ifdef CONFIG_HAS_DMA
> struct device_node *np;
> - u64 dma_addr, paddr, size;
> + const struct bus_dma_region *map = NULL;
> int rc;
>
> np = of_find_node_by_path(path);
> @@ -881,28 +883,40 @@ static void __init of_unittest_dma_ranges_one(const char *path,
> return;
> }
>
> - rc = of_dma_get_range(np, &dma_addr, &paddr, &size);
> + rc = of_dma_get_range(np, &map);
>
> unittest(!rc, "of_dma_get_range failed on node %pOF rc=%i\n", np, rc);
> +
> if (!rc) {
> - unittest(size == expect_size,
> - "of_dma_get_range wrong size on node %pOF size=%llx\n", np, size);
> + phys_addr_t paddr;
> + dma_addr_t dma_addr;
> + struct device dev_bogus;
> +
> + dev_bogus.dma_range_map = map;
> + paddr = dma_to_phys(&dev_bogus, expect_dma_addr);
> + dma_addr = phys_to_dma(&dev_bogus, expect_paddr);
> +
> unittest(paddr == expect_paddr,
> - "of_dma_get_range wrong phys addr (%llx) on node %pOF", paddr, np);
> + "of_dma_get_range: wrong phys addr %pap (expecting %llx) on node %pOF\n",
> + &paddr, expect_paddr, np);
> unittest(dma_addr == expect_dma_addr,
> - "of_dma_get_range wrong DMA addr (%llx) on node %pOF", dma_addr, np);
> + "of_dma_get_range: wrong DMA addr %pad (expecting %llx) on node %pOF\n",
> + &dma_addr, expect_dma_addr, np);
> +
> + kfree(map);
> }
> of_node_put(np);
> +#endif
> }
>
> static void __init of_unittest_parse_dma_ranges(void)
> {
> of_unittest_dma_ranges_one("/testcase-data/address-tests/device@70000000",
> - 0x0, 0x20000000, 0x40000000);
> + 0x0, 0x20000000);
> of_unittest_dma_ranges_one("/testcase-data/address-tests/bus@80000000/device@1000",
> - 0x100000000, 0x20000000, 0x2000000000);
> + 0x100000000, 0x20000000);
> of_unittest_dma_ranges_one("/testcase-data/address-tests/pci@90000000",
> - 0x80000000, 0x20000000, 0x10000000);
> + 0x80000000, 0x20000000);
> }
>
> static void __init of_unittest_pci_dma_ranges(void)
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 7f90eeea67e279..8157dd491d2819 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -23,6 +23,7 @@
> #include <linux/slab.h>
> #include <linux/mutex.h>
> #include <linux/dma-mapping.h>
> +#include <linux/dma-direct.h> /* XXX: pokes into bus_dma_range */
> #include <linux/firmware.h>
> #include <linux/string.h>
> #include <linux/debugfs.h>
> @@ -458,6 +459,25 @@ static void rproc_rvdev_release(struct device *dev)
> kfree(rvdev);
> }
>
> +static int copy_dma_range_map(struct device *to, struct device *from)
> +{
> + const struct bus_dma_region *map = from->dma_range_map, *new_map, *r;
> + int num_ranges = 0;
> +
> + if (!map)
> + return 0;
> +
> + for (r = map; r->size; r++)
> + num_ranges++;
> +
> + new_map = kmemdup(map, array_size(num_ranges + 1, sizeof(*map)),
> + GFP_KERNEL);
> + if (!new_map)
> + return -ENOMEM;
> + to->dma_range_map = new_map;
> + return 0;
> +}
> +

This patch seemed Ok to me but it broke the stm32 remoteproc implementation. When
I tested things out function dma_coerce_mask_and_cohenrent() returns -5 and the
rest of the initialisation fails. I isolated things to function dma_to_pfn()
[2]. In the original implementation __bus_to_pfn() returns 0xfffff and
dev->dma_pfn_offset is equal to 0x38000. As such the function returns 0x137fff
and dma_supported() a non-zero value[3].

With this set function dma_to_pfn() received a face lift. Function
__bus_to_pfn() still returns 0xfffff but translate_dma_to_phys() returns 0,
which forces dma_supported() to also return 0 and that is where the -5 (-EIO)
comes from.

Taking a futher look at translate_dma_to_phy(), @dma_addr never falls within the
bus_dma_region ranges and returns 0.

I'm suspecting an initialisation problem and if it occurred here, it will
likely show up elsewhere.

Thanks,
Mathieu

[1]. https://elixir.bootlin.com/linux/v5.9-rc4/source/drivers/remoteproc/stm32_rproc.c#L773
[2]. https://elixir.bootlin.com/linux/v5.9-rc4/source/arch/arm/include/asm/dma-mapping.h#L43
[3]. https://elixir.bootlin.com/linux/v5.9-rc4/source/kernel/dma/mapping.c#L539

> /**
> * rproc_handle_vdev() - handle a vdev fw resource
> * @rproc: the remote processor
> @@ -529,7 +549,9 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
> /* Initialise vdev subdevice */
> snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
> rvdev->dev.parent = &rproc->dev;
> - rvdev->dev.dma_pfn_offset = rproc->dev.parent->dma_pfn_offset;
> + ret = copy_dma_range_map(&rvdev->dev, rproc->dev.parent);
> + if (ret)
> + return ret;
> rvdev->dev.release = rproc_rvdev_release;
> dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
> dev_set_drvdata(&rvdev->dev, rvdev);
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> index 1744e6fcc99980..bcf050a04ffc45 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> @@ -227,11 +227,17 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
> * the RAM offset to the physcal addresses.
> *
> * This information will eventually be obtained from device-tree.
> + *
> + * XXX(hch): this has no business in a driver and needs to move
> + * to the device tree.
> */
>
> #ifdef PHYS_PFN_OFFSET
> - if (!(variant->quirks & CEDRUS_QUIRK_NO_DMA_OFFSET))
> - dev->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
> + if (!(variant->quirks & CEDRUS_QUIRK_NO_DMA_OFFSET)) {
> + ret = dma_direct_set_offset(dev->dev, PHYS_OFFSET, 0, SZ_4G);
> + if (ret)
> + return ret;
> + }
> #endif
>
> ret = of_reserved_mem_device_init(dev->dev);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index ca18da4768e3e8..1c78621fc3c01f 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -466,7 +466,7 @@ struct dev_links_info {
> * such descriptors.
> * @bus_dma_limit: Limit of an upstream bridge or bus which imposes a smaller
> * DMA limit than the device itself supports.
> - * @dma_pfn_offset: offset of DMA memory range relatively of RAM
> + * @dma_range_map: map for DMA memory ranges relative to that of RAM
> * @dma_parms: A low level driver may set these to teach IOMMU code about
> * segment limitations.
> * @dma_pools: Dma pools (if dma'ble device).
> @@ -561,7 +561,7 @@ struct device {
> 64 bit addresses for consistent
> allocations such descriptors. */
> u64 bus_dma_limit; /* upstream dma constraint */
> - unsigned long dma_pfn_offset;
> + const struct bus_dma_region *dma_range_map;
>
> struct device_dma_parameters *dma_parms;
>
> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
> index 805010ea5346f9..bd619579505687 100644
> --- a/include/linux/dma-direct.h
> +++ b/include/linux/dma-direct.h
> @@ -14,6 +14,41 @@
>
> extern unsigned int zone_dma_bits;
>
> +/*
> + * Record the mapping of CPU physical to DMA addresses for a given region.
> + */
> +struct bus_dma_region {
> + phys_addr_t cpu_start;
> + dma_addr_t dma_start;
> + u64 size;
> + u64 offset;
> +};
> +
> +static inline dma_addr_t translate_phys_to_dma(struct device *dev,
> + phys_addr_t paddr)
> +{
> + const struct bus_dma_region *m;
> +
> + for (m = dev->dma_range_map; m->size; m++)
> + if (paddr >= m->cpu_start && paddr - m->cpu_start < m->size)
> + return (dma_addr_t)paddr - m->offset;
> +
> + /* make sure dma_capable fails when no translation is available */
> + return DMA_MAPPING_ERROR;
> +}
> +
> +static inline phys_addr_t translate_dma_to_phys(struct device *dev,
> + dma_addr_t dma_addr)
> +{
> + const struct bus_dma_region *m;
> +
> + for (m = dev->dma_range_map; m->size; m++)
> + if (dma_addr >= m->dma_start && dma_addr - m->dma_start < m->size)
> + return (phys_addr_t)dma_addr + m->offset;
> +
> + return 0;
> +}
> +
> #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
> #include <asm/dma-direct.h>
> #ifndef phys_to_dma_unencrypted
> @@ -23,9 +58,9 @@ extern unsigned int zone_dma_bits;
> static inline dma_addr_t phys_to_dma_unencrypted(struct device *dev,
> phys_addr_t paddr)
> {
> - dma_addr_t dev_addr = (dma_addr_t)paddr;
> -
> - return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
> + if (dev->dma_range_map)
> + return translate_phys_to_dma(dev, paddr);
> + return paddr;
> }
>
> /*
> @@ -41,8 +76,12 @@ static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
>
> static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> {
> - phys_addr_t paddr = (phys_addr_t)dev_addr +
> - ((phys_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
> + phys_addr_t paddr;
> +
> + if (dev->dma_range_map)
> + paddr = translate_dma_to_phys(dev, dma_addr);
> + else
> + paddr = dma_addr;
>
> return __sme_clr(paddr);
> }
> @@ -64,7 +103,8 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
>
> if (!dev->dma_mask)
> return false;
> -
> + if (addr == DMA_MAPPING_ERROR)
> + return false;
> if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
> min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
> return false;
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index df0bff2ea750e0..bb138ac6f5e63e 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -730,4 +730,11 @@ static inline int dma_mmap_wc(struct device *dev,
> #define dma_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
> #endif
>
> -#endif
> +/*
> + * Legacy interface to set up the dma offset map. Drivers really should not
> + * actually use it, but we have a few legacy cases left.
> + */
> +int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
> + dma_addr_t dma_start, u64 size);
> +
> +#endif /* _LINUX_DMA_MAPPING_H */
> diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
> index f85d14bbfcbe03..c0685196fb6d42 100644
> --- a/kernel/dma/coherent.c
> +++ b/kernel/dma/coherent.c
> @@ -7,7 +7,7 @@
> #include <linux/slab.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> -#include <linux/dma-mapping.h>
> +#include <linux/dma-direct.h>
>
> struct dma_coherent_mem {
> void *virt_base;
> @@ -32,9 +32,8 @@ static inline dma_addr_t dma_get_device_base(struct device *dev,
> struct dma_coherent_mem * mem)
> {
> if (mem->use_dev_dma_pfn_offset)
> - return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
> - else
> - return mem->device_base;
> + return phys_to_dma(dev, PFN_PHYS(mem->pfn_base));
> + return mem->device_base;
> }
>
> static int dma_init_coherent_memory(phys_addr_t phys_addr,
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 54db9cfdaecc6d..750659f7447c4b 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -13,6 +13,7 @@
> #include <linux/pfn.h>
> #include <linux/vmalloc.h>
> #include <linux/set_memory.h>
> +#include <linux/slab.h>
>
> /*
> * Most architectures use ZONE_DMA for the first 16 Megabytes, but some use it
> @@ -66,8 +67,12 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
>
> static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
> {
> - return phys_to_dma_direct(dev, phys) + size - 1 <=
> - min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
> + dma_addr_t dma_addr = phys_to_dma_direct(dev, phys);
> +
> + if (dma_addr == DMA_MAPPING_ERROR)
> + return false;
> + return dma_addr + size - 1 <=
> + min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
> }
>
> /*
> @@ -461,3 +466,45 @@ bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr)
> return !dev_is_dma_coherent(dev) ||
> is_swiotlb_buffer(dma_to_phys(dev, dma_addr));
> }
> +
> +/**
> + * dma_direct_set_offset - Assign scalar offset for a single DMA range.
> + * @dev: device pointer; needed to "own" the alloced memory.
> + * @cpu_start: beginning of memory region covered by this offset.
> + * @dma_start: beginning of DMA/PCI region covered by this offset.
> + * @size: size of the region.
> + *
> + * This is for the simple case of a uniform offset which cannot
> + * be discovered by "dma-ranges".
> + *
> + * It returns -ENOMEM if out of memory, -EINVAL if a map
> + * already exists, 0 otherwise.
> + *
> + * Note: any call to this from a driver is a bug. The mapping needs
> + * to be described by the device tree or other firmware interfaces.
> + */
> +int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
> + dma_addr_t dma_start, u64 size)
> +{
> + struct bus_dma_region *map;
> + u64 offset = (u64)cpu_start - (u64)dma_start;
> +
> + if (dev->dma_range_map) {
> + dev_err(dev, "attempt to add DMA range to existing map\n");
> + return -EINVAL;
> + }
> +
> + if (!offset)
> + return 0;
> +
> + map = kcalloc(2, sizeof(*map), GFP_KERNEL);
> + if (!map)
> + return -ENOMEM;
> + map[0].cpu_start = cpu_start;
> + map[0].dma_start = dma_start;
> + map[0].offset = offset;
> + map[0].size = size;
> + dev->dma_range_map = map;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(dma_direct_set_offset);
> --
> 2.28.0
>