diff options
Diffstat (limited to 'kernel/dma/direct.c')
| -rw-r--r-- | kernel/dma/direct.c | 51 |
1 files changed, 49 insertions, 2 deletions
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); |