155 lines
4.0 KiB
C
155 lines
4.0 KiB
C
/*
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* Coherent per-device memory handling.
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* Borrowed from i386
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*/
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#include <linux/kernel.h>
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#include <linux/dma-mapping.h>
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struct dma_coherent_mem {
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void *virt_base;
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u32 device_base;
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int size;
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int flags;
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unsigned long *bitmap;
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};
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int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
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dma_addr_t device_addr, size_t size, int flags)
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{
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void __iomem *mem_base = NULL;
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int pages = size >> PAGE_SHIFT;
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int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
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if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
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goto out;
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if (!size)
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goto out;
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if (dev->dma_mem)
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goto out;
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/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
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mem_base = ioremap(bus_addr, size);
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if (!mem_base)
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goto out;
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dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
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if (!dev->dma_mem)
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goto out;
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dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
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if (!dev->dma_mem->bitmap)
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goto free1_out;
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dev->dma_mem->virt_base = mem_base;
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dev->dma_mem->device_base = device_addr;
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dev->dma_mem->size = pages;
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dev->dma_mem->flags = flags;
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if (flags & DMA_MEMORY_MAP)
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return DMA_MEMORY_MAP;
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return DMA_MEMORY_IO;
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free1_out:
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kfree(dev->dma_mem);
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out:
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if (mem_base)
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iounmap(mem_base);
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return 0;
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}
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EXPORT_SYMBOL(dma_declare_coherent_memory);
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void dma_release_declared_memory(struct device *dev)
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{
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struct dma_coherent_mem *mem = dev->dma_mem;
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if (!mem)
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return;
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dev->dma_mem = NULL;
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iounmap(mem->virt_base);
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kfree(mem->bitmap);
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kfree(mem);
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}
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EXPORT_SYMBOL(dma_release_declared_memory);
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void *dma_mark_declared_memory_occupied(struct device *dev,
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dma_addr_t device_addr, size_t size)
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{
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struct dma_coherent_mem *mem = dev->dma_mem;
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int pos, err;
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int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1);
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pages >>= PAGE_SHIFT;
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if (!mem)
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return ERR_PTR(-EINVAL);
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pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
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err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
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if (err != 0)
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return ERR_PTR(err);
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return mem->virt_base + (pos << PAGE_SHIFT);
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}
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EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
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/**
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* Try to allocate memory from the per-device coherent area.
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*
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* @dev: device from which we allocate memory
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* @size: size of requested memory area
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* @dma_handle: This will be filled with the correct dma handle
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* @ret: This pointer will be filled with the virtual address
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* to allocated area.
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*
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* This function should be only called from per-arch %dma_alloc_coherent()
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* to support allocation from per-device coherent memory pools.
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*
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* Returns 0 if dma_alloc_coherent should continue with allocating from
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* generic memory areas, or !0 if dma_alloc_coherent should return %ret.
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*/
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int dma_alloc_from_coherent(struct device *dev, ssize_t size,
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dma_addr_t *dma_handle, void **ret)
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{
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struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
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int order = get_order(size);
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if (mem) {
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int page = bitmap_find_free_region(mem->bitmap, mem->size,
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order);
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if (page >= 0) {
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*dma_handle = mem->device_base + (page << PAGE_SHIFT);
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*ret = mem->virt_base + (page << PAGE_SHIFT);
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memset(*ret, 0, size);
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} else if (mem->flags & DMA_MEMORY_EXCLUSIVE)
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*ret = NULL;
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}
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return (mem != NULL);
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}
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/**
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* Try to free the memory allocated from per-device coherent memory pool.
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* @dev: device from which the memory was allocated
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* @order: the order of pages allocated
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* @vaddr: virtual address of allocated pages
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*
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* This checks whether the memory was allocated from the per-device
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* coherent memory pool and if so, releases that memory.
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*
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* Returns 1 if we correctly released the memory, or 0 if
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* %dma_release_coherent() should proceed with releasing memory from
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* generic pools.
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*/
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int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
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{
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struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
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if (mem && vaddr >= mem->virt_base && vaddr <
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(mem->virt_base + (mem->size << PAGE_SHIFT))) {
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int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
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bitmap_release_region(mem->bitmap, page, order);
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return 1;
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}
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return 0;
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}
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