This patch changes dma-mapping subsystem to use generic vmalloc areas for all consistent dma allocations. This increases the total size limit of the consistent allocations and removes platform hacks and a lot of duplicated code.
Atomic allocations are served from special pool preallocated on boot, becasue vmalloc areas cannot be reliably created in atomic context.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com ---
Hello,
This is an updated version of the patch posted in the following thread: http://www.spinics.net/lists/kernel/msg1342885.html
This one has been rebased onto the ARM DMA-mapping redesign patches and includes a part for IOMMU-aware ARM DMA-mapping implementation. The ARM DMA-mapping redesign patches are available in the following thread: http://www.spinics.net/lists/arm-kernel/msg175729.html
Best regards Marek Szyprowski Samsung Poland R&D Center
--- Documentation/kernel-parameters.txt | 4 + arch/arm/include/asm/dma-mapping.h | 2 +- arch/arm/mm/dma-mapping.c | 497 ++++++++++++++++------------------- 3 files changed, 228 insertions(+), 275 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index c1601e5..ba58f50 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -515,6 +515,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. a hypervisor. Default: yes
+ coherent_pool=nn[KMG] [ARM,KNL] + Sets the size of memory pool for coherent, atomic dma + allocations. + code_bytes [X86] How many bytes of object code to print in an oops report. Range: 0 - 8192 diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index bbef15d..80777d87 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -226,7 +226,7 @@ static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struc * DMA region above it's default value of 2MB. It must be called before the * memory allocator is initialised, i.e. before any core_initcall. */ -extern void __init init_consistent_dma_size(unsigned long size); +static inline void init_consistent_dma_size(unsigned long size) { }
/* * For SA-1111, IXP425, and ADI systems the dma-mapping functions are "magic" diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 3ac4760..2e98403 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -20,6 +20,7 @@ #include <linux/highmem.h> #include <linux/slab.h> #include <linux/iommu.h> +#include <linux/io.h> #include <linux/vmalloc.h>
#include <asm/memory.h> @@ -228,204 +229,170 @@ static void __dma_free_buffer(struct page *page, size_t size) }
#ifdef CONFIG_MMU - -#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - consistent_base) >> PAGE_SHIFT) -#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - consistent_base) >> PMD_SHIFT) - -/* - * These are the page tables (2MB each) covering uncached, DMA consistent allocations - */ -static pte_t **consistent_pte; - -#define DEFAULT_CONSISTENT_DMA_SIZE SZ_2M - -unsigned long consistent_base = CONSISTENT_END - DEFAULT_CONSISTENT_DMA_SIZE; - -void __init init_consistent_dma_size(unsigned long size) -{ - unsigned long base = CONSISTENT_END - ALIGN(size, SZ_2M); - - BUG_ON(consistent_pte); /* Check we're called before DMA region init */ - BUG_ON(base < VMALLOC_END); - - /* Grow region to accommodate specified size */ - if (base < consistent_base) - consistent_base = base; -} - -#include "vmregion.h" - -static struct arm_vmregion_head consistent_head = { - .vm_lock = __SPIN_LOCK_UNLOCKED(&consistent_head.vm_lock), - .vm_list = LIST_HEAD_INIT(consistent_head.vm_list), - .vm_end = CONSISTENT_END, -}; - #ifdef CONFIG_HUGETLB_PAGE #error ARM Coherent DMA allocator does not (yet) support huge TLB #endif
-/* - * Initialise the consistent memory allocation. - */ -static int __init consistent_init(void) -{ - int ret = 0; - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - int i = 0; - unsigned long base = consistent_base; - unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT; - - consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL); - if (!consistent_pte) { - pr_err("%s: no memory\n", __func__); - return -ENOMEM; - } - - pr_debug("DMA memory: 0x%08lx - 0x%08lx:\n", base, CONSISTENT_END); - consistent_head.vm_start = base; - - do { - pgd = pgd_offset(&init_mm, base); - - pud = pud_alloc(&init_mm, pgd, base); - if (!pud) { - pr_err("%s: no pud tables\n", __func__); - ret = -ENOMEM; - break; - } - - pmd = pmd_alloc(&init_mm, pud, base); - if (!pmd) { - pr_err("%s: no pmd tables\n", __func__); - ret = -ENOMEM; - break; - } - WARN_ON(!pmd_none(*pmd)); - - pte = pte_alloc_kernel(pmd, base); - if (!pte) { - pr_err("%s: no pte tables\n", __func__); - ret = -ENOMEM; - break; - } - - consistent_pte[i++] = pte; - base += PMD_SIZE; - } while (base < CONSISTENT_END); - - return ret; -} - -core_initcall(consistent_init); - static void * __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot, const void *caller) { - struct arm_vmregion *c; - size_t align; - int bit; + struct vm_struct *area; + unsigned long addr;
- if (!consistent_pte) { - pr_err("%s: not initialised\n", __func__); + area = get_vm_area_caller(size, VM_DMA | VM_USERMAP, caller); + if (!area) + return NULL; + addr = (unsigned long)area->addr; + area->phys_addr = __pfn_to_phys(page_to_pfn(page)); + + if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) { + vunmap((void *)addr); + return NULL; + } + return (void *)addr; +} + +static void __dma_free_remap(void *cpu_addr, size_t size) +{ + struct vm_struct *area; + + read_lock(&vmlist_lock); + area = find_vm_area(cpu_addr); + if (!area) { + pr_err("%s: trying to free invalid coherent area: %p\n", + __func__, cpu_addr); + dump_stack(); + read_unlock(&vmlist_lock); + return; + } + unmap_kernel_range((unsigned long)cpu_addr, size); + read_unlock(&vmlist_lock); + vunmap(cpu_addr); +} + +struct dma_pool { + size_t size; + spinlock_t lock; + unsigned long *bitmap; + unsigned long count; + void *vaddr; + struct page *page; +}; + +static struct dma_pool atomic_pool = { + .size = SZ_256K, +}; + +static int __init early_coherent_pool(char *p) +{ + atomic_pool.size = memparse(p, &p); + return 0; +} +early_param("coherent_pool", early_coherent_pool); + +/* + * Initialise the coherent pool for atomic allocations. + */ +static int __init atomic_pool_init(void) +{ + struct dma_pool *pool = &atomic_pool; + pgprot_t prot = pgprot_dmacoherent(pgprot_kernel); + unsigned long count = pool->size >> PAGE_SHIFT; + gfp_t gfp = GFP_KERNEL | GFP_DMA; + unsigned long *bitmap; + struct page *page; + void *ptr; + int bitmap_size = BITS_TO_LONGS(count) * sizeof(long); + + bitmap = kzalloc(bitmap_size, GFP_KERNEL); + if (!bitmap) + goto no_bitmap; + + page = __dma_alloc_buffer(NULL, pool->size, gfp); + if (!page) + goto no_page; + + ptr = __dma_alloc_remap(page, pool->size, gfp, prot, NULL); + if (ptr) { + spin_lock_init(&pool->lock); + pool->vaddr = ptr; + pool->page = page; + pool->bitmap = bitmap; + pool->count = count; + pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n", + (unsigned)pool->size / 1024); + return 0; + } + + __dma_free_buffer(page, pool->size); +no_page: + kfree(bitmap); +no_bitmap: + pr_err("DMA: failed to allocate %u KiB pool for atomic coherent allocation\n", + (unsigned)pool->size / 1024); + return -ENOMEM; +} +core_initcall(atomic_pool_init); + +static void *__alloc_from_pool(size_t size, struct page **ret_page) +{ + struct dma_pool *pool = &atomic_pool; + unsigned int count = size >> PAGE_SHIFT; + unsigned int pageno; + unsigned long flags; + void *ptr = NULL; + size_t align; + + if (!pool->vaddr) { + pr_err("%s: coherent pool not initialised!\n", __func__); dump_stack(); return NULL; }
/* - * Align the virtual region allocation - maximum alignment is - * a section size, minimum is a page size. This helps reduce - * fragmentation of the DMA space, and also prevents allocations - * smaller than a section from crossing a section boundary. + * Align the region allocation - allocations from pool are rather + * small, so align them to their order in pages, minimum is a page + * size. This helps reduce fragmentation of the DMA space. */ - bit = fls(size - 1); - if (bit > SECTION_SHIFT) - bit = SECTION_SHIFT; - align = 1 << bit; + align = PAGE_SIZE << get_order(size);
- /* - * Allocate a virtual address in the consistent mapping region. - */ - c = arm_vmregion_alloc(&consistent_head, align, size, - gfp & ~(__GFP_DMA | __GFP_HIGHMEM), caller); - if (c) { - pte_t *pte; - int idx = CONSISTENT_PTE_INDEX(c->vm_start); - u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1); - - pte = consistent_pte[idx] + off; - c->priv = page; - - do { - BUG_ON(!pte_none(*pte)); - - set_pte_ext(pte, mk_pte(page, prot), 0); - page++; - pte++; - off++; - if (off >= PTRS_PER_PTE) { - off = 0; - pte = consistent_pte[++idx]; - } - } while (size -= PAGE_SIZE); - - dsb(); - - return (void *)c->vm_start; + spin_lock_irqsave(&pool->lock, flags); + pageno = bitmap_find_next_zero_area(pool->bitmap, pool->count, + 0, count, (1 << align) - 1); + if (pageno < pool->count) { + bitmap_set(pool->bitmap, pageno, count); + ptr = pool->vaddr + PAGE_SIZE * pageno; + *ret_page = pool->page + pageno; } - return NULL; + spin_unlock_irqrestore(&pool->lock, flags); + + return ptr; }
-static void __dma_free_remap(void *cpu_addr, size_t size) +static int __free_from_pool(void *start, size_t size) { - struct arm_vmregion *c; - unsigned long addr; - pte_t *ptep; - int idx; - u32 off; + struct dma_pool *pool = &atomic_pool; + unsigned long pageno, count; + unsigned long flags;
- c = arm_vmregion_find_remove(&consistent_head, (unsigned long)cpu_addr); - if (!c) { - pr_err("%s: trying to free invalid coherent area: %p\n", - __func__, cpu_addr); + if (start < pool->vaddr || start > pool->vaddr + pool->size) + return 0; + + if (start + size > pool->vaddr + pool->size) { + pr_err("%s: freeing wrong coherent size from pool\n", __func__); dump_stack(); - return; + return 0; }
- if ((c->vm_end - c->vm_start) != size) { - pr_err("%s: freeing wrong coherent size (%ld != %d)\n", - __func__, c->vm_end - c->vm_start, size); - dump_stack(); - size = c->vm_end - c->vm_start; - } + pageno = (start - pool->vaddr) >> PAGE_SHIFT; + count = size >> PAGE_SHIFT;
- idx = CONSISTENT_PTE_INDEX(c->vm_start); - off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1); - ptep = consistent_pte[idx] + off; - addr = c->vm_start; - do { - pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep); + spin_lock_irqsave(&pool->lock, flags); + bitmap_clear(pool->bitmap, pageno, count); + spin_unlock_irqrestore(&pool->lock, flags);
- ptep++; - addr += PAGE_SIZE; - off++; - if (off >= PTRS_PER_PTE) { - off = 0; - ptep = consistent_pte[++idx]; - } - - if (pte_none(pte) || !pte_present(pte)) - pr_crit("%s: bad page in kernel page table\n", - __func__); - } while (size -= PAGE_SIZE); - - flush_tlb_kernel_range(c->vm_start, c->vm_end); - - arm_vmregion_free(&consistent_head, c); + return 1; }
static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot) @@ -441,6 +408,8 @@ static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot) #define __dma_alloc_remap(page, size, gfp, prot, c) page_address(page) #define __dma_free_remap(addr, size) do { } while (0) #define __get_dma_pgprot(attrs, prot) __pgprot(0) +#define __alloc_from_pool(size, ret_page) NULL +#define __free_from_pool(addr, size) 0
#endif /* CONFIG_MMU */
@@ -463,6 +432,16 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, *handle = DMA_ERROR_CODE; size = PAGE_ALIGN(size);
+ /* + * Atomic allocations need special handling + */ + if (gfp & GFP_ATOMIC && !arch_is_coherent()) { + addr = __alloc_from_pool(size, &page); + if (addr) + *handle = pfn_to_dma(dev, page_to_pfn(page)); + return addr; + } + page = __dma_alloc_buffer(dev, size, gfp); if (!page) return NULL; @@ -506,30 +485,21 @@ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma, { int ret = -ENXIO; #ifdef CONFIG_MMU - unsigned long user_size, kern_size; - struct arm_vmregion *c; + unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; + unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; + unsigned long pfn = dma_to_pfn(dev, dma_addr); + unsigned long off = vma->vm_pgoff;
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) return ret;
- user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; - - c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr); - if (c) { - unsigned long off = vma->vm_pgoff; - struct page *pages = c->priv; - - kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT; - - if (off < kern_size && - user_size <= (kern_size - off)) { - ret = remap_pfn_range(vma, vma->vm_start, - page_to_pfn(pages) + off, - user_size << PAGE_SHIFT, - vma->vm_page_prot); - } + if (off < count && user_count <= (count - off)) { + ret = remap_pfn_range(vma, vma->vm_start, + pfn + off, + user_count << PAGE_SHIFT, + vma->vm_page_prot); } #endif /* CONFIG_MMU */
@@ -543,13 +513,16 @@ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma, void arm_dma_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle, struct dma_attrs *attrs) { - WARN_ON(irqs_disabled()); - if (dma_release_from_coherent(dev, get_order(size), cpu_addr)) return;
size = PAGE_ALIGN(size);
+ if (__free_from_pool(cpu_addr, size)) + return; + + WARN_ON(irqs_disabled()); + if (!arch_is_coherent()) __dma_free_remap(cpu_addr, size);
@@ -769,9 +742,6 @@ static int arm_dma_set_mask(struct device *dev, u64 dma_mask)
static int __init dma_debug_do_init(void) { -#ifdef CONFIG_MMU - arm_vmregion_create_proc("dma-mappings", &consistent_head); -#endif dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); return 0; } @@ -888,61 +858,30 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t s * Create a CPU mapping for a specified pages */ static void * -__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot) +__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot, + const void *caller) { - struct arm_vmregion *c; - size_t align; - size_t count = size >> PAGE_SHIFT; - int bit; + unsigned int i, count = size >> PAGE_SHIFT; + struct vm_struct *area; + unsigned long p;
- if (!consistent_pte[0]) { - pr_err("%s: not initialised\n", __func__); - dump_stack(); + area = get_vm_area_caller(size, VM_DMA | VM_USERMAP, caller); + if (!area) return NULL; + + area->pages = pages; + p = (unsigned long)area->addr; + + for (i = 0; i < count; i++) { + phys_addr_t phys = __pfn_to_phys(page_to_pfn(pages[i])); + if (ioremap_page_range(p, p + PAGE_SIZE, phys, prot)) + goto err; + p += PAGE_SIZE; } - - /* - * Align the virtual region allocation - maximum alignment is - * a section size, minimum is a page size. This helps reduce - * fragmentation of the DMA space, and also prevents allocations - * smaller than a section from crossing a section boundary. - */ - bit = fls(size - 1); - if (bit > SECTION_SHIFT) - bit = SECTION_SHIFT; - align = 1 << bit; - - /* - * Allocate a virtual address in the consistent mapping region. - */ - c = arm_vmregion_alloc(&consistent_head, align, size, - gfp & ~(__GFP_DMA | __GFP_HIGHMEM), NULL); - if (c) { - pte_t *pte; - int idx = CONSISTENT_PTE_INDEX(c->vm_start); - int i = 0; - u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1); - - pte = consistent_pte[idx] + off; - c->priv = pages; - - do { - BUG_ON(!pte_none(*pte)); - - set_pte_ext(pte, mk_pte(pages[i], prot), 0); - pte++; - off++; - i++; - if (off >= PTRS_PER_PTE) { - off = 0; - pte = consistent_pte[++idx]; - } - } while (i < count); - - dsb(); - - return (void *)c->vm_start; - } + return area->addr; +err: + unmap_kernel_range((unsigned long)area->addr, size); + vunmap(area->addr); return NULL; }
@@ -1001,6 +940,17 @@ static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t si return 0; }
+static struct page **__iommu_get_pages(void *cpu_addr) +{ + struct vm_struct *area; + read_lock(&vmlist_lock); + area = find_vm_area(cpu_addr); + read_unlock(&vmlist_lock); + if (area) + return area->pages; + return NULL; +} + static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs) { @@ -1019,7 +969,8 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, if (*handle == DMA_ERROR_CODE) goto err_buffer;
- addr = __iommu_alloc_remap(pages, size, gfp, prot); + addr = __iommu_alloc_remap(pages, size, gfp, prot, + __builtin_return_address(0)); if (!addr) goto err_mapping;
@@ -1036,31 +987,25 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs) { - struct arm_vmregion *c; + unsigned long uaddr = vma->vm_start; + unsigned long usize = vma->vm_end - vma->vm_start; + struct page **pages = __iommu_get_pages(cpu_addr);
vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot); - c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
- if (c) { - struct page **pages = c->priv; + if (!pages) + return -ENXIO;
- unsigned long uaddr = vma->vm_start; - unsigned long usize = vma->vm_end - vma->vm_start; - int i = 0; + do { + int ret = vm_insert_page(vma, uaddr, *pages++); + if (ret) { + pr_err("Remapping memory failed: %d\n", ret); + return ret; + } + uaddr += PAGE_SIZE; + usize -= PAGE_SIZE; + } while (usize > 0);
- do { - int ret; - - ret = vm_insert_page(vma, uaddr, pages[i++]); - if (ret) { - pr_err("Remapping memory, error: %d\n", ret); - return ret; - } - - uaddr += PAGE_SIZE; - usize -= PAGE_SIZE; - } while (usize > 0); - } return 0; }
@@ -1071,16 +1016,20 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle, struct dma_attrs *attrs) { - struct arm_vmregion *c; + struct page **pages = __iommu_get_pages(cpu_addr); size = PAGE_ALIGN(size);
- c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr); - if (c) { - struct page **pages = c->priv; - __dma_free_remap(cpu_addr, size); - __iommu_remove_mapping(dev, handle, size); - __iommu_free_buffer(dev, pages, size); + if (!pages) { + pr_err("%s: trying to free invalid coherent area: %p\n", + __func__, cpu_addr); + dump_stack(); + return; } + + unmap_kernel_range((unsigned long)cpu_addr, size); + vunmap(cpu_addr); + __iommu_remove_mapping(dev, handle, size); + __iommu_free_buffer(dev, pages, size); }
/*