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authorJim Quinlan <james.quinlan@broadcom.com>2020-09-17 19:43:40 +0300
committerChristoph Hellwig <hch@lst.de>2020-09-17 19:43:56 +0300
commite0d072782c734d27f5af062c62266f2598f68542 (patch)
treef259e9eaab55ae8ffedaea07a19e8f147dcceb9a /include/linux/dma-direct.h
parent6eb0233ec2d0df288fe8515d5b0b2b15562e05bb (diff)
downloadlinux-e0d072782c734d27f5af062c62266f2598f68542.tar.xz
dma-mapping: introduce DMA range map, supplanting dma_pfn_offset
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> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Diffstat (limited to 'include/linux/dma-direct.h')
-rw-r--r--include/linux/dma-direct.h53
1 files changed, 47 insertions, 6 deletions
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 2929685e88aa..83f797e0cb78 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 (phys_addr_t)-1;
+}
+
#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;
}
/*
@@ -39,10 +74,14 @@ static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
return __sme_set(phys_to_dma_unencrypted(dev, paddr));
}
-static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
+static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_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);
}
@@ -62,6 +101,8 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
{
dma_addr_t end = addr + size - 1;
+ 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;