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author | Ming Lei <tom.leiming@gmail.com> | 2009-07-12 21:44:55 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-09-15 09:50:47 -0700 |
commit | a56af87648054089d89874b52e3fc23ed4f274ad (patch) | |
tree | 81714be5cc39f830b4acf55ec782b46f36e67ebe /drivers/base | |
parent | 162dd4212409fd2d36ff22547ea821bf3e86bcc9 (diff) | |
download | linux-stable-a56af87648054089d89874b52e3fc23ed4f274ad.tar.gz linux-stable-a56af87648054089d89874b52e3fc23ed4f274ad.tar.bz2 linux-stable-a56af87648054089d89874b52e3fc23ed4f274ad.zip |
driver-core: move dma-coherent.c from kernel to driver/base
Placing dma-coherent.c in driver/base is better than in kernel,
since it contains code to do per-device coherent dma memory
handling.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/Makefile | 1 | ||||
-rw-r--r-- | drivers/base/dma-coherent.c | 176 |
2 files changed, 177 insertions, 0 deletions
diff --git a/drivers/base/Makefile b/drivers/base/Makefile index b5b8ba512b28..1b2640ce74f0 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -6,6 +6,7 @@ obj-y := core.o sys.o bus.o dd.o \ attribute_container.o transport_class.o obj-y += power/ obj-$(CONFIG_HAS_DMA) += dma-mapping.o +obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o obj-$(CONFIG_ISA) += isa.o obj-$(CONFIG_FW_LOADER) += firmware_class.o obj-$(CONFIG_NUMA) += node.o diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c new file mode 100644 index 000000000000..962a3b574f21 --- /dev/null +++ b/drivers/base/dma-coherent.c @@ -0,0 +1,176 @@ +/* + * Coherent per-device memory handling. + * Borrowed from i386 + */ +#include <linux/kernel.h> +#include <linux/dma-mapping.h> + +struct dma_coherent_mem { + void *virt_base; + u32 device_base; + int size; + int flags; + unsigned long *bitmap; +}; + +int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr, + dma_addr_t device_addr, size_t size, int flags) +{ + void __iomem *mem_base = NULL; + int pages = size >> PAGE_SHIFT; + int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long); + + if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0) + goto out; + if (!size) + goto out; + if (dev->dma_mem) + goto out; + + /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */ + + mem_base = ioremap(bus_addr, size); + if (!mem_base) + goto out; + + dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL); + if (!dev->dma_mem) + goto out; + dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL); + if (!dev->dma_mem->bitmap) + goto free1_out; + + dev->dma_mem->virt_base = mem_base; + dev->dma_mem->device_base = device_addr; + dev->dma_mem->size = pages; + dev->dma_mem->flags = flags; + + if (flags & DMA_MEMORY_MAP) + return DMA_MEMORY_MAP; + + return DMA_MEMORY_IO; + + free1_out: + kfree(dev->dma_mem); + out: + if (mem_base) + iounmap(mem_base); + return 0; +} +EXPORT_SYMBOL(dma_declare_coherent_memory); + +void dma_release_declared_memory(struct device *dev) +{ + struct dma_coherent_mem *mem = dev->dma_mem; + + if (!mem) + return; + dev->dma_mem = NULL; + iounmap(mem->virt_base); + kfree(mem->bitmap); + kfree(mem); +} +EXPORT_SYMBOL(dma_release_declared_memory); + +void *dma_mark_declared_memory_occupied(struct device *dev, + dma_addr_t device_addr, size_t size) +{ + struct dma_coherent_mem *mem = dev->dma_mem; + int pos, err; + + size += device_addr & ~PAGE_MASK; + + if (!mem) + return ERR_PTR(-EINVAL); + + pos = (device_addr - mem->device_base) >> PAGE_SHIFT; + err = bitmap_allocate_region(mem->bitmap, pos, get_order(size)); + if (err != 0) + return ERR_PTR(err); + return mem->virt_base + (pos << PAGE_SHIFT); +} +EXPORT_SYMBOL(dma_mark_declared_memory_occupied); + +/** + * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area + * + * @dev: device from which we allocate memory + * @size: size of requested memory area + * @dma_handle: This will be filled with the correct dma handle + * @ret: This pointer will be filled with the virtual address + * to allocated area. + * + * This function should be only called from per-arch dma_alloc_coherent() + * to support allocation from per-device coherent memory pools. + * + * Returns 0 if dma_alloc_coherent should continue with allocating from + * generic memory areas, or !0 if dma_alloc_coherent should return @ret. + */ +int dma_alloc_from_coherent(struct device *dev, ssize_t size, + dma_addr_t *dma_handle, void **ret) +{ + struct dma_coherent_mem *mem; + int order = get_order(size); + int pageno; + + if (!dev) + return 0; + mem = dev->dma_mem; + if (!mem) + return 0; + + *ret = NULL; + + if (unlikely(size > (mem->size << PAGE_SHIFT))) + goto err; + + pageno = bitmap_find_free_region(mem->bitmap, mem->size, order); + if (unlikely(pageno < 0)) + goto err; + + /* + * Memory was found in the per-device area. + */ + *dma_handle = mem->device_base + (pageno << PAGE_SHIFT); + *ret = mem->virt_base + (pageno << PAGE_SHIFT); + memset(*ret, 0, size); + + return 1; + +err: + /* + * In the case where the allocation can not be satisfied from the + * per-device area, try to fall back to generic memory if the + * constraints allow it. + */ + return mem->flags & DMA_MEMORY_EXCLUSIVE; +} +EXPORT_SYMBOL(dma_alloc_from_coherent); + +/** + * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool + * @dev: device from which the memory was allocated + * @order: the order of pages allocated + * @vaddr: virtual address of allocated pages + * + * This checks whether the memory was allocated from the per-device + * coherent memory pool and if so, releases that memory. + * + * Returns 1 if we correctly released the memory, or 0 if + * dma_release_coherent() should proceed with releasing memory from + * generic pools. + */ +int dma_release_from_coherent(struct device *dev, int order, void *vaddr) +{ + struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; + + if (mem && vaddr >= mem->virt_base && vaddr < + (mem->virt_base + (mem->size << PAGE_SHIFT))) { + int page = (vaddr - mem->virt_base) >> PAGE_SHIFT; + + bitmap_release_region(mem->bitmap, page, order); + return 1; + } + return 0; +} +EXPORT_SYMBOL(dma_release_from_coherent); |