diff options
author | Jim Quinlan <james.quinlan@broadcom.com> | 2020-09-17 18:43:40 +0200 |
---|---|---|
committer | Christoph Hellwig <hch@lst.de> | 2020-09-17 18:43:56 +0200 |
commit | e0d072782c734d27f5af062c62266f2598f68542 (patch) | |
tree | f259e9eaab55ae8ffedaea07a19e8f147dcceb9a /kernel/dma | |
parent | 6eb0233ec2d0df288fe8515d5b0b2b15562e05bb (diff) | |
download | linux-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.c | 7 | ||||
-rw-r--r-- | kernel/dma/direct.c | 51 |
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); |