151 lines
3.6 KiB
C
151 lines
3.6 KiB
C
/*
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* Dynamic DMA mapping support.
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*
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* On i386 there is no hardware dynamic DMA address translation,
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* so consistent alloc/free are merely page allocation/freeing.
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* The rest of the dynamic DMA mapping interface is implemented
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* in asm/pci.h.
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*/
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/pci.h>
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#include <linux/module.h>
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#include <asm/io.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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void *dma_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp)
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{
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void *ret;
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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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/* ignore region specifiers */
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gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
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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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return ret;
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}
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if (mem->flags & DMA_MEMORY_EXCLUSIVE)
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return NULL;
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}
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if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
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gfp |= GFP_DMA;
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ret = (void *)__get_free_pages(gfp, order);
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if (ret != NULL) {
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memset(ret, 0, size);
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*dma_handle = virt_to_phys(ret);
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}
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return ret;
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}
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EXPORT_SYMBOL(dma_alloc_coherent);
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void dma_free_coherent(struct device *dev, size_t size,
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void *vaddr, dma_addr_t dma_handle)
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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 && vaddr >= mem->virt_base && vaddr < (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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} else
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free_pages((unsigned long)vaddr, order);
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}
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EXPORT_SYMBOL(dma_free_coherent);
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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 = (pages + 31)/32;
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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->bitmap);
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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 pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
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int pos, err;
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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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