1 files changed, 104 insertions, 10 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4e7d1182e8a3..051204fc4617 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -267,17 +267,19 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
         vunmap(cpu_addr);
 }
 
+#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
+
 struct dma_pool {
         size_t size;
         spinlock_t lock;
         unsigned long *bitmap;
         unsigned long nr_pages;
         void *vaddr;
-        struct page *page;
+        struct page **pages;
 };
 
 static struct dma_pool atomic_pool = {
-        .size = SZ_256K,
+        .size = DEFAULT_DMA_COHERENT_POOL_SIZE,
 };
 
 static int __init early_coherent_pool(char *p)
@@ -287,6 +289,21 @@ static int __init early_coherent_pool(char *p)
 }
 early_param("coherent_pool", early_coherent_pool);
 
+void __init init_dma_coherent_pool_size(unsigned long size)
+{
+        /*
+         * Catch any attempt to set the pool size too late.
+         */
+        BUG_ON(atomic_pool.vaddr);
+
+        /*
+         * Set architecture specific coherent pool size only if
+         * it has not been changed by kernel command line parameter.
+         */
+        if (atomic_pool.size == DEFAULT_DMA_COHERENT_POOL_SIZE)
+                atomic_pool.size = size;
+}
+
 /*
  * Initialise the coherent pool for atomic allocations.
  */
@@ -297,6 +314,7 @@ static int __init atomic_pool_init(void)
         unsigned long nr_pages = pool->size >> PAGE_SHIFT;
         unsigned long *bitmap;
         struct page *page;
+        struct page **pages;
         void *ptr;
         int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long);
 
@@ -304,21 +322,31 @@ static int __init atomic_pool_init(void)
         if (!bitmap)
                 goto no_bitmap;
 
+        pages = kzalloc(nr_pages * sizeof(struct page *), GFP_KERNEL);
+        if (!pages)
+                goto no_pages;
+
         if (IS_ENABLED(CONFIG_CMA))
                 ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page);
         else
                 ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot,
                                            &page, NULL);
         if (ptr) {
+                int i;
+
+                for (i = 0; i < nr_pages; i++)
+                        pages[i] = page + i;
+
                 spin_lock_init(&pool->lock);
                 pool->vaddr = ptr;
-                pool->page = page;
+                pool->pages = pages;
                 pool->bitmap = bitmap;
                 pool->nr_pages = nr_pages;
                 pr_info("DMA: preallocated %u KiB pool for atomic coherent allocations\n",
                        (unsigned)pool->size / 1024);
                 return 0;
         }
+no_pages:
         kfree(bitmap);
 no_bitmap:
         pr_err("DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
@@ -443,27 +471,45 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page)
         if (pageno < pool->nr_pages) {
                 bitmap_set(pool->bitmap, pageno, count);
                 ptr = pool->vaddr + PAGE_SIZE * pageno;
-                *ret_page = pool->page + pageno;
+                *ret_page = pool->pages[pageno];
+        } else {
+                pr_err_once("ERROR: %u KiB atomic DMA coherent pool is too small!\n"
+                            "Please increase it with coherent_pool= kernel parameter!\n",
+                            (unsigned)pool->size / 1024);
         }
         spin_unlock_irqrestore(&pool->lock, flags);
 
         return ptr;
 }
 
+static bool __in_atomic_pool(void *start, size_t size)
+{
+        struct dma_pool *pool = &atomic_pool;
+        void *end = start + size;
+        void *pool_start = pool->vaddr;
+        void *pool_end = pool->vaddr + pool->size;
+
+        if (start < pool_start || start > pool_end)
+                return false;
+
+        if (end <= pool_end)
+                return true;
+
+        WARN(1, "Wrong coherent size(%p-%p) from atomic pool(%p-%p)\n",
+             start, end - 1, pool_start, pool_end - 1);
+
+        return false;
+}
+
 static int __free_from_pool(void *start, size_t size)
 {
         struct dma_pool *pool = &atomic_pool;
         unsigned long pageno, count;
         unsigned long flags;
 
-        if (start < pool->vaddr || start > pool->vaddr + pool->size)
+        if (!__in_atomic_pool(start, size))
                 return 0;
 
-        if (start + size > pool->vaddr + pool->size) {
-                WARN(1, "freeing wrong coherent size from pool\n");
-                return 0;
-        }
-
         pageno = (start - pool->vaddr) >> PAGE_SHIFT;
         count = size >> PAGE_SHIFT;
 
@@ -1090,10 +1136,22 @@ static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t si
         return 0;
 }
 
+static struct page **__atomic_get_pages(void *addr)
+{
+        struct dma_pool *pool = &atomic_pool;
+        struct page **pages = pool->pages;
+        int offs = (addr - pool->vaddr) >> PAGE_SHIFT;
+
+        return pages + offs;
+}
+
 static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs *attrs)
 {
         struct vm_struct *area;
 
+        if (__in_atomic_pool(cpu_addr, PAGE_SIZE))
+                return __atomic_get_pages(cpu_addr);
+
         if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs))
                 return cpu_addr;
 
@@ -1103,6 +1161,34 @@ static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs *attrs)
         return NULL;
 }
 
+static void *__iommu_alloc_atomic(struct device *dev, size_t size,
+                                  dma_addr_t *handle)
+{
+        struct page *page;
+        void *addr;
+
+        addr = __alloc_from_pool(size, &page);
+        if (!addr)
+                return NULL;
+
+        *handle = __iommu_create_mapping(dev, &page, size);
+        if (*handle == DMA_ERROR_CODE)
+                goto err_mapping;
+
+        return addr;
+
+err_mapping:
+        __free_from_pool(addr, size);
+        return NULL;
+}
+
+static void __iommu_free_atomic(struct device *dev, struct page **pages,
+                                dma_addr_t handle, size_t size)
+{
+        __iommu_remove_mapping(dev, handle, size);
+        __free_from_pool(page_address(pages[0]), size);
+}
+
 static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
             dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
 {
@@ -1113,6 +1199,9 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
         *handle = DMA_ERROR_CODE;
         size = PAGE_ALIGN(size);
 
+        if (gfp & GFP_ATOMIC)
+                return __iommu_alloc_atomic(dev, size, handle);
+
         pages = __iommu_alloc_buffer(dev, size, gfp);
         if (!pages)
                 return NULL;
@@ -1179,6 +1268,11 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
                 return;
         }
 
+        if (__in_atomic_pool(cpu_addr, size)) {
+                __iommu_free_atomic(dev, pages, handle, size);
+                return;
+        }
+
         if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) {
                 unmap_kernel_range((unsigned long)cpu_addr, size);
                 vunmap(cpu_addr);