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author | Catalin Marinas <catalin.marinas@arm.com> | 2009-07-24 11:35:02 (GMT) |
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committer | Catalin Marinas <catalin.marinas@arm.com> | 2009-07-24 11:35:02 (GMT) |
commit | ab6494f0c96f8953c7ad3e35301b2de2db3add57 (patch) | |
tree | 08ffb48cb7ce1ec66dc5deeddf7cf4b890882410 | |
parent | 2732f4b6f11689fa08e2db5689fc652d608936b5 (diff) | |
download | linux-ab6494f0c96f8953c7ad3e35301b2de2db3add57.tar.xz |
nommu: Add noMMU support to the DMA API
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r-- | arch/arm/mm/dma-mapping.c | 94 |
1 files changed, 72 insertions, 22 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 510c179..b30925f 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -36,7 +36,34 @@ #define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT) #define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT) +static u64 get_coherent_dma_mask(struct device *dev) +{ + u64 mask = ISA_DMA_THRESHOLD; + + if (dev) { + mask = dev->coherent_dma_mask; + + /* + * Sanity check the DMA mask - it must be non-zero, and + * must be able to be satisfied by a DMA allocation. + */ + if (mask == 0) { + dev_warn(dev, "coherent DMA mask is unset\n"); + return 0; + } + + if ((~mask) & ISA_DMA_THRESHOLD) { + dev_warn(dev, "coherent DMA mask %#llx is smaller " + "than system GFP_DMA mask %#llx\n", + mask, (unsigned long long)ISA_DMA_THRESHOLD); + return 0; + } + } + return mask; +} + +#ifdef CONFIG_MMU /* * These are the page tables (2MB each) covering uncached, DMA consistent allocations */ @@ -152,7 +179,8 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, struct page *page; struct arm_vm_region *c; unsigned long order; - u64 mask = ISA_DMA_THRESHOLD, limit; + u64 mask = get_coherent_dma_mask(dev); + u64 limit; if (!consistent_pte[0]) { printk(KERN_ERR "%s: not initialised\n", __func__); @@ -160,25 +188,8 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, return NULL; } - if (dev) { - mask = dev->coherent_dma_mask; - - /* - * Sanity check the DMA mask - it must be non-zero, and - * must be able to be satisfied by a DMA allocation. - */ - if (mask == 0) { - dev_warn(dev, "coherent DMA mask is unset\n"); - goto no_page; - } - - if ((~mask) & ISA_DMA_THRESHOLD) { - dev_warn(dev, "coherent DMA mask %#llx is smaller " - "than system GFP_DMA mask %#llx\n", - mask, (unsigned long long)ISA_DMA_THRESHOLD); - goto no_page; - } - } + if (!mask) + goto no_page; /* * Sanity check the allocation size. @@ -267,6 +278,31 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, *handle = ~0; return NULL; } +#else /* !CONFIG_MMU */ +static void * +__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, + pgprot_t prot) +{ + void *virt; + u64 mask = get_coherent_dma_mask(dev); + + if (!mask) + goto error; + + if (mask != 0xffffffff) + gfp |= GFP_DMA; + virt = kmalloc(size, gfp); + if (!virt) + goto error; + + *handle = virt_to_dma(dev, virt); + return virt; + +error: + *handle = ~0; + return NULL; +} +#endif /* CONFIG_MMU */ /* * Allocate DMA-coherent memory space and return both the kernel remapped @@ -311,9 +347,10 @@ EXPORT_SYMBOL(dma_alloc_writecombine); static int dma_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size) { + int ret = -ENXIO; +#ifdef CONFIG_MMU unsigned long flags, user_size, kern_size; struct arm_vm_region *c; - int ret = -ENXIO; user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; @@ -334,6 +371,7 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma, vma->vm_page_prot); } } +#endif /* CONFIG_MMU */ return ret; } @@ -358,6 +396,7 @@ EXPORT_SYMBOL(dma_mmap_writecombine); * free a page as defined by the above mapping. * Must not be called with IRQs disabled. */ +#ifdef CONFIG_MMU void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle) { struct arm_vm_region *c; @@ -444,6 +483,14 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr __func__, cpu_addr); dump_stack(); } +#else /* !CONFIG_MMU */ +void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle) +{ + if (dma_release_from_coherent(dev, get_order(size), cpu_addr)) + return; + kfree(cpu_addr); +} +#endif /* CONFIG_MMU */ EXPORT_SYMBOL(dma_free_coherent); /* @@ -451,10 +498,12 @@ EXPORT_SYMBOL(dma_free_coherent); */ static int __init consistent_init(void) { + int ret = 0; +#ifdef CONFIG_MMU pgd_t *pgd; pmd_t *pmd; pte_t *pte; - int ret = 0, i = 0; + int i = 0; u32 base = CONSISTENT_BASE; do { @@ -477,6 +526,7 @@ static int __init consistent_init(void) consistent_pte[i++] = pte; base += (1 << PGDIR_SHIFT); } while (base < CONSISTENT_END); +#endif /* !CONFIG_MMU */ return ret; } |