arm64: add atomic pool for non-coherent and CMA allocations
authorLaura Abbott <lauraa@codeaurora.org>
Thu, 9 Oct 2014 22:26:44 +0000 (15:26 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 10 Oct 2014 02:25:52 +0000 (22:25 -0400)
Neither CMA nor noncoherent allocations support atomic allocations.
Add a dedicated atomic pool to support this.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Riley <davidriley@chromium.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Ritesh Harjain <ritesh.harjani@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/arm64/Kconfig
arch/arm64/mm/dma-mapping.c

index 9746dc2..e96cbe8 100644 (file)
@@ -18,6 +18,7 @@ config ARM64
        select COMMON_CLK
        select CPU_PM if (SUSPEND || CPU_IDLE)
        select DCACHE_WORD_ACCESS
+       select GENERIC_ALLOCATOR
        select GENERIC_CLOCKEVENTS
        select GENERIC_CLOCKEVENTS_BROADCAST if SMP
        select GENERIC_CPU_AUTOPROBE
index 2c71077..d920942 100644 (file)
@@ -20,6 +20,7 @@
 #include <linux/gfp.h>
 #include <linux/export.h>
 #include <linux/slab.h>
+#include <linux/genalloc.h>
 #include <linux/dma-mapping.h>
 #include <linux/dma-contiguous.h>
 #include <linux/vmalloc.h>
@@ -38,6 +39,54 @@ static pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot,
        return prot;
 }
 
+static struct gen_pool *atomic_pool;
+
+#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
+static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE;
+
+static int __init early_coherent_pool(char *p)
+{
+       atomic_pool_size = memparse(p, &p);
+       return 0;
+}
+early_param("coherent_pool", early_coherent_pool);
+
+static void *__alloc_from_pool(size_t size, struct page **ret_page)
+{
+       unsigned long val;
+       void *ptr = NULL;
+
+       if (!atomic_pool) {
+               WARN(1, "coherent pool not initialised!\n");
+               return NULL;
+       }
+
+       val = gen_pool_alloc(atomic_pool, size);
+       if (val) {
+               phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
+
+               *ret_page = phys_to_page(phys);
+               ptr = (void *)val;
+       }
+
+       return ptr;
+}
+
+static bool __in_atomic_pool(void *start, size_t size)
+{
+       return addr_in_gen_pool(atomic_pool, (unsigned long)start, size);
+}
+
+static int __free_from_pool(void *start, size_t size)
+{
+       if (!__in_atomic_pool(start, size))
+               return 0;
+
+       gen_pool_free(atomic_pool, (unsigned long)start, size);
+
+       return 1;
+}
+
 static void *__dma_alloc_coherent(struct device *dev, size_t size,
                                  dma_addr_t *dma_handle, gfp_t flags,
                                  struct dma_attrs *attrs)
@@ -50,7 +99,7 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
        if (IS_ENABLED(CONFIG_ZONE_DMA) &&
            dev->coherent_dma_mask <= DMA_BIT_MASK(32))
                flags |= GFP_DMA;
-       if (IS_ENABLED(CONFIG_DMA_CMA)) {
+       if (IS_ENABLED(CONFIG_DMA_CMA) && (flags & __GFP_WAIT)) {
                struct page *page;
 
                size = PAGE_ALIGN(size);
@@ -70,50 +119,54 @@ static void __dma_free_coherent(struct device *dev, size_t size,
                                void *vaddr, dma_addr_t dma_handle,
                                struct dma_attrs *attrs)
 {
+       bool freed;
+       phys_addr_t paddr = dma_to_phys(dev, dma_handle);
+
        if (dev == NULL) {
                WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
                return;
        }
 
-       if (IS_ENABLED(CONFIG_DMA_CMA)) {
-               phys_addr_t paddr = dma_to_phys(dev, dma_handle);
-
-               dma_release_from_contiguous(dev,
+       freed = dma_release_from_contiguous(dev,
                                        phys_to_page(paddr),
                                        size >> PAGE_SHIFT);
-       } else {
+       if (!freed)
                swiotlb_free_coherent(dev, size, vaddr, dma_handle);
-       }
 }
 
 static void *__dma_alloc_noncoherent(struct device *dev, size_t size,
                                     dma_addr_t *dma_handle, gfp_t flags,
                                     struct dma_attrs *attrs)
 {
-       struct page *page, **map;
+       struct page *page;
        void *ptr, *coherent_ptr;
-       int order, i;
 
        size = PAGE_ALIGN(size);
-       order = get_order(size);
+
+       if (!(flags & __GFP_WAIT)) {
+               struct page *page = NULL;
+               void *addr = __alloc_from_pool(size, &page);
+
+               if (addr)
+                       *dma_handle = phys_to_dma(dev, page_to_phys(page));
+
+               return addr;
+
+       }
 
        ptr = __dma_alloc_coherent(dev, size, dma_handle, flags, attrs);
        if (!ptr)
                goto no_mem;
-       map = kmalloc(sizeof(struct page *) << order, flags & ~GFP_DMA);
-       if (!map)
-               goto no_map;
 
        /* remove any dirty cache lines on the kernel alias */
        __dma_flush_range(ptr, ptr + size);
 
        /* create a coherent mapping */
        page = virt_to_page(ptr);
-       for (i = 0; i < (size >> PAGE_SHIFT); i++)
-               map[i] = page + i;
-       coherent_ptr = vmap(map, size >> PAGE_SHIFT, VM_MAP,
-                           __get_dma_pgprot(attrs, __pgprot(PROT_NORMAL_NC), false));
-       kfree(map);
+       coherent_ptr = dma_common_contiguous_remap(page, size, VM_USERMAP,
+                               __get_dma_pgprot(attrs,
+                                       __pgprot(PROT_NORMAL_NC), false),
+                                       NULL);
        if (!coherent_ptr)
                goto no_map;
 
@@ -132,6 +185,8 @@ static void __dma_free_noncoherent(struct device *dev, size_t size,
 {
        void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
 
+       if (__free_from_pool(vaddr, size))
+               return;
        vunmap(vaddr);
        __dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
 }
@@ -307,6 +362,67 @@ EXPORT_SYMBOL(coherent_swiotlb_dma_ops);
 
 extern int swiotlb_late_init_with_default_size(size_t default_size);
 
+static int __init atomic_pool_init(void)
+{
+       pgprot_t prot = __pgprot(PROT_NORMAL_NC);
+       unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
+       struct page *page;
+       void *addr;
+       unsigned int pool_size_order = get_order(atomic_pool_size);
+
+       if (dev_get_cma_area(NULL))
+               page = dma_alloc_from_contiguous(NULL, nr_pages,
+                                                       pool_size_order);
+       else
+               page = alloc_pages(GFP_DMA, pool_size_order);
+
+       if (page) {
+               int ret;
+               void *page_addr = page_address(page);
+
+               memset(page_addr, 0, atomic_pool_size);
+               __dma_flush_range(page_addr, page_addr + atomic_pool_size);
+
+               atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
+               if (!atomic_pool)
+                       goto free_page;
+
+               addr = dma_common_contiguous_remap(page, atomic_pool_size,
+                                       VM_USERMAP, prot, atomic_pool_init);
+
+               if (!addr)
+                       goto destroy_genpool;
+
+               ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
+                                       page_to_phys(page),
+                                       atomic_pool_size, -1);
+               if (ret)
+                       goto remove_mapping;
+
+               gen_pool_set_algo(atomic_pool,
+                                 gen_pool_first_fit_order_align,
+                                 (void *)PAGE_SHIFT);
+
+               pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
+                       atomic_pool_size / 1024);
+               return 0;
+       }
+       goto out;
+
+remove_mapping:
+       dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP);
+destroy_genpool:
+       gen_pool_destroy(atomic_pool);
+       atomic_pool = NULL;
+free_page:
+       if (!dma_release_from_contiguous(NULL, page, nr_pages))
+               __free_pages(page, pool_size_order);
+out:
+       pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
+               atomic_pool_size / 1024);
+       return -ENOMEM;
+}
+
 static int __init swiotlb_late_init(void)
 {
        size_t swiotlb_size = min(SZ_64M, MAX_ORDER_NR_PAGES << PAGE_SHIFT);
@@ -315,7 +431,17 @@ static int __init swiotlb_late_init(void)
 
        return swiotlb_late_init_with_default_size(swiotlb_size);
 }
-arch_initcall(swiotlb_late_init);
+
+static int __init arm64_dma_init(void)
+{
+       int ret = 0;
+
+       ret |= swiotlb_late_init();
+       ret |= atomic_pool_init();
+
+       return ret;
+}
+arch_initcall(arm64_dma_init);
 
 #define PREALLOC_DMA_DEBUG_ENTRIES     4096