[PATCH v3 3/7] ACPI/IORT: Handle memory address size limits as limits

Robin Murphy
2024-02-09T16:50:35Z

Return the Root Complex/Named Component memory address size limit as an
inclusive limit value, rather than an exclusive size. This saves having
to fudge an off-by-one for the 64-bit case, and simplifies our caller.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
v2: Avoid undefined shifts (grr...)
---
drivers/acpi/arm64/dma.c | 9 +++------
drivers/acpi/arm64/iort.c | 20 ++++++++++----------
include/linux/acpi_iort.h | 4 ++--
3 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/acpi/arm64/dma.c b/drivers/acpi/arm64/dma.c
index 93d796531af3..b98a149f8d50 100644
--- a/drivers/acpi/arm64/dma.c
+++ b/drivers/acpi/arm64/dma.c
@@ -8,7 +8,6 @@ void acpi_arch_dma_setup(struct device *dev)
{
int ret;
u64 end, mask;
- u64 size = 0;
const struct bus_dma_region *map = NULL;

/*
@@ -23,9 +22,9 @@ void acpi_arch_dma_setup(struct device *dev)
}

if (dev->coherent_dma_mask)
- size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
+ end = dev->coherent_dma_mask;
else
- size = 1ULL << 32;
+ end = (1ULL << 32) - 1;

ret = acpi_dma_get_range(dev, &map);
if (!ret && map) {
@@ -36,18 +35,16 @@ void acpi_arch_dma_setup(struct device *dev)
end = r->dma_start + r->size - 1;
}

- size = end + 1;
dev->dma_range_map = map;
}

if (ret == -ENODEV)
- ret = iort_dma_get_ranges(dev, &size);
+ ret = iort_dma_get_ranges(dev, &end);
if (!ret) {
/*
* Limit coherent and dma mask based on size retrieved from
* firmware.
*/
- end = size - 1;
mask = DMA_BIT_MASK(ilog2(end) + 1);
dev->bus_dma_limit = end;
dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 6496ff5a6ba2..c0b1c2c19444 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1367,7 +1367,7 @@ int iort_iommu_configure_id(struct device *dev, const u32 *input_id)
{ return -ENODEV; }
#endif

-static int nc_dma_get_range(struct device *dev, u64 *size)
+static int nc_dma_get_range(struct device *dev, u64 *limit)
{
struct acpi_iort_node *node;
struct acpi_iort_named_component *ncomp;
@@ -1384,13 +1384,13 @@ static int nc_dma_get_range(struct device *dev, u64 *size)
return -EINVAL;
}

- *size = ncomp->memory_address_limit >= 64 ? U64_MAX :
- 1ULL<<ncomp->memory_address_limit;
+ *limit = ncomp->memory_address_limit >= 64 ? U64_MAX :
+ (1ULL << ncomp->memory_address_limit) - 1;

return 0;
}

-static int rc_dma_get_range(struct device *dev, u64 *size)
+static int rc_dma_get_range(struct device *dev, u64 *limit)
{
struct acpi_iort_node *node;
struct acpi_iort_root_complex *rc;
@@ -1408,8 +1408,8 @@ static int rc_dma_get_range(struct device *dev, u64 *size)
return -EINVAL;
}

- *size = rc->memory_address_limit >= 64 ? U64_MAX :
- 1ULL<<rc->memory_address_limit;
+ *limit = rc->memory_address_limit >= 64 ? U64_MAX :
+ (1ULL << rc->memory_address_limit) - 1;

return 0;
}
@@ -1417,16 +1417,16 @@ static int rc_dma_get_range(struct device *dev, u64 *size)
/**
* iort_dma_get_ranges() - Look up DMA addressing limit for the device
* @dev: device to lookup
- * @size: DMA range size result pointer
+ * @limit: DMA limit result pointer
*
* Return: 0 on success, an error otherwise.
*/
-int iort_dma_get_ranges(struct device *dev, u64 *size)
+int iort_dma_get_ranges(struct device *dev, u64 *limit)
{
if (dev_is_pci(dev))
- return rc_dma_get_range(dev, size);
+ return rc_dma_get_range(dev, limit);
else
- return nc_dma_get_range(dev, size);
+ return nc_dma_get_range(dev, limit);
}

static void __init acpi_iort_register_irq(int hwirq, const char *name,
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 1cb65592c95d..d4ed5622cf2b 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -39,7 +39,7 @@ void iort_get_rmr_sids(struct fwnode_handle *iommu_fwnode,
void iort_put_rmr_sids(struct fwnode_handle *iommu_fwnode,
struct list_head *head);
/* IOMMU interface */
-int iort_dma_get_ranges(struct device *dev, u64 *size);
+int iort_dma_get_ranges(struct device *dev, u64 *limit);
int iort_iommu_configure_id(struct device *dev, const u32 *id_in);
void iort_iommu_get_resv_regions(struct device *dev, struct list_head *head);
phys_addr_t acpi_iort_dma_get_max_cpu_address(void);
@@ -55,7 +55,7 @@ void iort_get_rmr_sids(struct fwnode_handle *iommu_fwnode, struct list_head *hea
static inline
void iort_put_rmr_sids(struct fwnode_handle *iommu_fwnode, struct list_head *head) { }
/* IOMMU interface */
-static inline int iort_dma_get_ranges(struct device *dev, u64 *size)
+static inline int iort_dma_get_ranges(struct device *dev, u64 *limit)
{ return -ENODEV; }
static inline int iort_iommu_configure_id(struct device *dev, const u32 *id_in)
{ return -ENODEV; }
--
2.39.2.101.g768bb238c484.dirty