diff options
| -rw-r--r-- | Documentation/DMA-attributes.txt | 9 | ||||
| -rw-r--r-- | arch/powerpc/platforms/cell/iommu.c | 113 | ||||
| -rw-r--r-- | include/linux/dma-attrs.h | 1 |
3 files changed, 118 insertions, 5 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index 6d772f84b47..b768cc0e402 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -22,3 +22,12 @@ ready and available in memory. The DMA of the "completion indication" could race with data DMA. Mapping the memory used for completion indications with DMA_ATTR_WRITE_BARRIER would prevent the race. +DMA_ATTR_WEAK_ORDERING +---------------------- + +DMA_ATTR_WEAK_ORDERING specifies that reads and writes to the mapping +may be weakly ordered, that is that reads and writes may pass each other. + +Since it is optional for platforms to implement DMA_ATTR_WEAK_ORDERING, +those that do not will simply ignore the attribute and exhibit default +behavior. diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c index 3b7078453e7..208005ca262 100644 --- a/arch/powerpc/platforms/cell/iommu.c +++ b/arch/powerpc/platforms/cell/iommu.c @@ -199,6 +199,8 @@ static void tce_build_cell(struct iommu_table *tbl, long index, long npages, base_pte = IOPTE_PP_W | IOPTE_PP_R | IOPTE_M | IOPTE_SO_RW | (window->ioid & IOPTE_IOID_Mask); #endif + if (unlikely(dma_get_attr(DMA_ATTR_WEAK_ORDERING, attrs))) + base_pte &= ~IOPTE_SO_RW; io_pte = (unsigned long *)tbl->it_base + (index - tbl->it_offset); @@ -539,7 +541,9 @@ static struct cbe_iommu *cell_iommu_for_node(int nid) static unsigned long cell_dma_direct_offset; static unsigned long dma_iommu_fixed_base; -struct dma_mapping_ops dma_iommu_fixed_ops; + +/* iommu_fixed_is_weak is set if booted with iommu_fixed=weak */ +static int iommu_fixed_is_weak; static struct iommu_table *cell_get_iommu_table(struct device *dev) { @@ -563,6 +567,98 @@ static struct iommu_table *cell_get_iommu_table(struct device *dev) return &window->table; } +/* A coherent allocation implies strong ordering */ + +static void *dma_fixed_alloc_coherent(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t flag) +{ + if (iommu_fixed_is_weak) + return iommu_alloc_coherent(dev, cell_get_iommu_table(dev), + size, dma_handle, + device_to_mask(dev), flag, + dev->archdata.numa_node); + else + return dma_direct_ops.alloc_coherent(dev, size, dma_handle, + flag); +} + +static void dma_fixed_free_coherent(struct device *dev, size_t size, + void *vaddr, dma_addr_t dma_handle) +{ + if (iommu_fixed_is_weak) + iommu_free_coherent(cell_get_iommu_table(dev), size, vaddr, + dma_handle); + else + dma_direct_ops.free_coherent(dev, size, vaddr, dma_handle); +} + +static dma_addr_t dma_fixed_map_single(struct device *dev, void *ptr, + size_t size, + enum dma_data_direction direction, + struct dma_attrs *attrs) +{ + if (iommu_fixed_is_weak == dma_get_attr(DMA_ATTR_WEAK_ORDERING, attrs)) + return dma_direct_ops.map_single(dev, ptr, size, direction, + attrs); + else + return iommu_map_single(dev, cell_get_iommu_table(dev), ptr, + size, device_to_mask(dev), direction, + attrs); +} + +static void dma_fixed_unmap_single(struct device *dev, dma_addr_t dma_addr, + size_t size, + enum dma_data_direction direction, + struct dma_attrs *attrs) +{ + if (iommu_fixed_is_weak == dma_get_attr(DMA_ATTR_WEAK_ORDERING, attrs)) + dma_direct_ops.unmap_single(dev, dma_addr, size, direction, + attrs); + else + iommu_unmap_single(cell_get_iommu_table(dev), dma_addr, size, + direction, attrs); +} + +static int dma_fixed_map_sg(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction direction, + struct dma_attrs *attrs) +{ + if (iommu_fixed_is_weak == dma_get_attr(DMA_ATTR_WEAK_ORDERING, attrs)) + return dma_direct_ops.map_sg(dev, sg, nents, direction, attrs); + else + return iommu_map_sg(dev, cell_get_iommu_table(dev), sg, nents, + device_to_mask(dev), direction, attrs); +} + +static void dma_fixed_unmap_sg(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction direction, + struct dma_attrs *attrs) +{ + if (iommu_fixed_is_weak == dma_get_attr(DMA_ATTR_WEAK_ORDERING, attrs)) + dma_direct_ops.unmap_sg(dev, sg, nents, direction, attrs); + else + iommu_unmap_sg(cell_get_iommu_table(dev), sg, nents, direction, + attrs); +} + +static int dma_fixed_dma_supported(struct device *dev, u64 mask) +{ + return mask == DMA_64BIT_MASK; +} + +static int dma_set_mask_and_switch(struct device *dev, u64 dma_mask); + +struct dma_mapping_ops dma_iommu_fixed_ops = { + .alloc_coherent = dma_fixed_alloc_coherent, + .free_coherent = dma_fixed_free_coherent, + .map_single = dma_fixed_map_single, + .unmap_single = dma_fixed_unmap_single, + .map_sg = dma_fixed_map_sg, + .unmap_sg = dma_fixed_unmap_sg, + .dma_supported = dma_fixed_dma_supported, + .set_dma_mask = dma_set_mask_and_switch, +}; + static void cell_dma_dev_setup_fixed(struct device *dev); static void cell_dma_dev_setup(struct device *dev) @@ -919,9 +1015,16 @@ static void cell_iommu_setup_fixed_ptab(struct cbe_iommu *iommu, pr_debug("iommu: mapping 0x%lx pages from 0x%lx\n", fsize, fbase); - base_pte = IOPTE_PP_W | IOPTE_PP_R | IOPTE_M | IOPTE_SO_RW + base_pte = IOPTE_PP_W | IOPTE_PP_R | IOPTE_M | (cell_iommu_get_ioid(np) & IOPTE_IOID_Mask); + if (iommu_fixed_is_weak) + pr_info("IOMMU: Using weak ordering for fixed mapping\n"); + else { + pr_info("IOMMU: Using strong ordering for fixed mapping\n"); + base_pte |= IOPTE_SO_RW; + } + for (uaddr = 0; uaddr < fsize; uaddr += (1 << 24)) { /* Don't touch the dynamic region */ ioaddr = uaddr + fbase; @@ -1037,9 +1140,6 @@ static int __init cell_iommu_fixed_mapping_init(void) cell_iommu_setup_window(iommu, np, dbase, dsize, 0); } - dma_iommu_fixed_ops = dma_direct_ops; - dma_iommu_fixed_ops.set_dma_mask = dma_set_mask_and_switch; - dma_iommu_ops.set_dma_mask = dma_set_mask_and_switch; set_pci_dma_ops(&dma_iommu_ops); @@ -1053,6 +1153,9 @@ static int __init setup_iommu_fixed(char *str) if (strcmp(str, "off") == 0) iommu_fixed_disabled = 1; + else if (strcmp(str, "weak") == 0) + iommu_fixed_is_weak = 1; + return 1; } __setup("iommu_fixed=", setup_iommu_fixed); diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index 1677e2bfa00..71ad34eca6e 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -12,6 +12,7 @@ */ enum dma_attr { DMA_ATTR_WRITE_BARRIER, + DMA_ATTR_WEAK_ORDERING, DMA_ATTR_MAX, }; |