arm64: add atomic pool for non-coherent and CMA allocations

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>

1 files changed, 145 insertions, 19 deletions

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 2c71077cacfd..d92094203913 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -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