From mboxrd@z Thu Jan 1 00:00:00 1970 From: vladimir.murzin@arm.com (Vladimir Murzin) Date: Tue, 10 Jan 2017 14:18:42 +0000 Subject: [RFC PATCH v4 2/5] drivers: dma-coherent: Introduce default DMA pool In-Reply-To: <1484057925-23586-1-git-send-email-vladimir.murzin@arm.com> References: <1484057925-23586-1-git-send-email-vladimir.murzin@arm.com> Message-ID: <1484057925-23586-3-git-send-email-vladimir.murzin@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This patch introduces default coherent DMA pool similar to default CMA area concept. To keep other users safe code kept under CONFIG_ARM. Cc: Marek Szyprowski Suggested-by: Robin Murphy Signed-off-by: Vladimir Murzin --- .../bindings/reserved-memory/reserved-memory.txt | 3 ++ drivers/base/dma-coherent.c | 59 +++++++++++++++++++--- 2 files changed, 55 insertions(+), 7 deletions(-) diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index 3da0ebd..16291f2 100644 --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt @@ -68,6 +68,9 @@ Linux implementation note: - If a "linux,cma-default" property is present, then Linux will use the region for the default pool of the contiguous memory allocator. +- If a "linux,dma-default" property is present, then Linux will use the + region for the default pool of the consistent DMA allocator. + Device node references to reserved memory ----------------------------------------- Regions in the /reserved-memory node may be referenced by other device diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c index 640a7e6..b52ba27 100644 --- a/drivers/base/dma-coherent.c +++ b/drivers/base/dma-coherent.c @@ -18,6 +18,15 @@ struct dma_coherent_mem { spinlock_t spinlock; }; +static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init; + +static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev) +{ + if (dev && dev->dma_mem) + return dev->dma_mem; + return dma_coherent_default_memory; +} + static bool dma_init_coherent_memory( phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags, struct dma_coherent_mem **mem) @@ -83,6 +92,9 @@ static void dma_release_coherent_memory(struct dma_coherent_mem *mem) static int dma_assign_coherent_memory(struct device *dev, struct dma_coherent_mem *mem) { + if (!dev) + return -ENODEV; + if (dev->dma_mem) return -EBUSY; @@ -161,15 +173,12 @@ EXPORT_SYMBOL(dma_mark_declared_memory_occupied); int dma_alloc_from_coherent(struct device *dev, ssize_t size, dma_addr_t *dma_handle, void **ret) { - struct dma_coherent_mem *mem; + struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); int order = get_order(size); unsigned long flags; int pageno; int dma_memory_map; - if (!dev) - return 0; - mem = dev->dma_mem; if (!mem) return 0; @@ -223,7 +232,7 @@ EXPORT_SYMBOL(dma_alloc_from_coherent); */ int dma_release_from_coherent(struct device *dev, int order, void *vaddr) { - struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; + struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) { @@ -257,7 +266,7 @@ EXPORT_SYMBOL(dma_release_from_coherent); int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma, void *vaddr, size_t size, int *ret) { - struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; + struct dma_coherent_mem *mem = dev_get_coherent_memory(dev); if (mem && vaddr >= mem->virt_base && vaddr + size <= (mem->virt_base + (mem->size << PAGE_SHIFT))) { @@ -287,6 +296,8 @@ EXPORT_SYMBOL(dma_mmap_from_coherent); #include #include +static struct reserved_mem *dma_reserved_default_memory __initdata; + static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev) { struct dma_coherent_mem *mem = rmem->priv; @@ -307,7 +318,8 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev) static void rmem_dma_device_release(struct reserved_mem *rmem, struct device *dev) { - dev->dma_mem = NULL; + if (dev) + dev->dma_mem = NULL; } static const struct reserved_mem_ops rmem_dma_ops = { @@ -327,6 +339,12 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem) pr_err("Reserved memory: regions without no-map are not yet supported\n"); return -EINVAL; } + + if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) { + WARN(dma_reserved_default_memory, + "Reserved memory: region for default DMA coherent area is redefined\n"); + dma_reserved_default_memory = rmem; + } #endif rmem->ops = &rmem_dma_ops; @@ -334,5 +352,32 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem) &rmem->base, (unsigned long)rmem->size / SZ_1M); return 0; } + +static int __init dma_init_reserved_memory(void) +{ + const struct reserved_mem_ops *ops; + int ret; + + if (!dma_reserved_default_memory) + return -ENOMEM; + + ops = dma_reserved_default_memory->ops; + + /* + * We rely on rmem_dma_device_init() does not propagate error of + * dma_assign_coherent_memory() for "NULL" device. + */ + ret = ops->device_init(dma_reserved_default_memory, NULL); + + if (!ret) { + dma_coherent_default_memory = dma_reserved_default_memory->priv; + pr_info("DMA: default coherent area is set\n"); + } + + return ret; +} + +core_initcall(dma_init_reserved_memory); + RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup); #endif -- 2.0.0