summaryrefslogtreecommitdiffstats
path: root/kernel/dma
diff options
context:
space:
mode:
authorJim Quinlan <james.quinlan@broadcom.com>2020-09-17 18:43:40 +0200
committerChristoph Hellwig <hch@lst.de>2020-09-17 18:43:56 +0200
commite0d072782c734d27f5af062c62266f2598f68542 (patch)
treef259e9eaab55ae8ffedaea07a19e8f147dcceb9a /kernel/dma
parent6eb0233ec2d0df288fe8515d5b0b2b15562e05bb (diff)
downloadlinux-e0d072782c734d27f5af062c62266f2598f68542.tar.bz2
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 'kernel/dma')
-rw-r--r--kernel/dma/coherent.c7
-rw-r--r--kernel/dma/direct.c51
2 files changed, 52 insertions, 6 deletions
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index f85d14bbfcbe..c0685196fb6d 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 54db9cfdaecc..750659f7447c 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);