328 lines
8.6 KiB
C
328 lines
8.6 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/slab.h>
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#include <linux/kernel.h>
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#include <linux/module.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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dma_addr_t device_base;
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unsigned long pfn_base;
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int size;
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int flags;
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unsigned long *bitmap;
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spinlock_t spinlock;
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};
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static int dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_addr,
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size_t size, int flags,
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struct dma_coherent_mem **mem)
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{
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struct dma_coherent_mem *dma_mem = NULL;
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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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mem_base = ioremap(phys_addr, size);
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if (!mem_base)
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goto out;
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dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
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if (!dma_mem)
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goto out;
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dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
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if (!dma_mem->bitmap)
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goto out;
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dma_mem->virt_base = mem_base;
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dma_mem->device_base = device_addr;
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dma_mem->pfn_base = PFN_DOWN(phys_addr);
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dma_mem->size = pages;
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dma_mem->flags = flags;
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spin_lock_init(&dma_mem->spinlock);
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*mem = dma_mem;
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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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out:
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kfree(dma_mem);
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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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static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
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{
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if (!mem)
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return;
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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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static int dma_assign_coherent_memory(struct device *dev,
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struct dma_coherent_mem *mem)
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{
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if (dev->dma_mem)
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return -EBUSY;
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dev->dma_mem = mem;
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/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
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return 0;
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}
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int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
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dma_addr_t device_addr, size_t size, int flags)
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{
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struct dma_coherent_mem *mem;
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int ret;
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ret = dma_init_coherent_memory(phys_addr, device_addr, size, flags,
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&mem);
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if (ret == 0)
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return 0;
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if (dma_assign_coherent_memory(dev, mem) == 0)
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return ret;
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dma_release_coherent_memory(mem);
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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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dma_release_coherent_memory(mem);
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dev->dma_mem = NULL;
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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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unsigned long flags;
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int pos, err;
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size += device_addr & ~PAGE_MASK;
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if (!mem)
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return ERR_PTR(-EINVAL);
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spin_lock_irqsave(&mem->spinlock, flags);
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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(size));
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spin_unlock_irqrestore(&mem->spinlock, flags);
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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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* dma_alloc_from_coherent() - 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;
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int order = get_order(size);
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unsigned long flags;
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int pageno;
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if (!dev)
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return 0;
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mem = dev->dma_mem;
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if (!mem)
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return 0;
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*ret = NULL;
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spin_lock_irqsave(&mem->spinlock, flags);
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if (unlikely(size > (mem->size << PAGE_SHIFT)))
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goto err;
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pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
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if (unlikely(pageno < 0))
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goto err;
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/*
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* Memory was found in the per-device area.
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*/
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*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
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*ret = mem->virt_base + (pageno << PAGE_SHIFT);
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memset(*ret, 0, size);
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spin_unlock_irqrestore(&mem->spinlock, flags);
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return 1;
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err:
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spin_unlock_irqrestore(&mem->spinlock, flags);
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/*
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* In the case where the allocation can not be satisfied from the
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* per-device area, try to fall back to generic memory if the
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* constraints allow it.
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*/
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return mem->flags & DMA_MEMORY_EXCLUSIVE;
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}
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EXPORT_SYMBOL(dma_alloc_from_coherent);
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/**
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* dma_release_from_coherent() - 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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unsigned long flags;
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spin_lock_irqsave(&mem->spinlock, flags);
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bitmap_release_region(mem->bitmap, page, order);
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spin_unlock_irqrestore(&mem->spinlock, flags);
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return 1;
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}
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return 0;
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}
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EXPORT_SYMBOL(dma_release_from_coherent);
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/**
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* dma_mmap_from_coherent() - try to mmap the memory allocated from
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* per-device coherent memory pool to userspace
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* @dev: device from which the memory was allocated
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* @vma: vm_area for the userspace memory
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* @vaddr: cpu address returned by dma_alloc_from_coherent
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* @size: size of the memory buffer allocated by dma_alloc_from_coherent
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* @ret: result from remap_pfn_range()
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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, maps that memory to the provided vma.
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*
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* Returns 1 if we correctly mapped the memory, or 0 if the caller should
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* proceed with mapping memory from generic pools.
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*/
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int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
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void *vaddr, size_t size, int *ret)
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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 + size <=
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(mem->virt_base + (mem->size << PAGE_SHIFT))) {
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unsigned long off = vma->vm_pgoff;
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int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
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int user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
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int count = size >> PAGE_SHIFT;
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*ret = -ENXIO;
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if (off < count && user_count <= count - off) {
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unsigned long pfn = mem->pfn_base + start + off;
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*ret = remap_pfn_range(vma, vma->vm_start, pfn,
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user_count << PAGE_SHIFT,
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vma->vm_page_prot);
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}
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return 1;
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}
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return 0;
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}
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EXPORT_SYMBOL(dma_mmap_from_coherent);
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/*
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* Support for reserved memory regions defined in device tree
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*/
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#ifdef CONFIG_OF_RESERVED_MEM
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#include <linux/of.h>
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#include <linux/of_fdt.h>
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#include <linux/of_reserved_mem.h>
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static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
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{
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struct dma_coherent_mem *mem = rmem->priv;
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if (!mem &&
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dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
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DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
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&mem) != DMA_MEMORY_MAP) {
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pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
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&rmem->base, (unsigned long)rmem->size / SZ_1M);
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return -ENODEV;
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}
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rmem->priv = mem;
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dma_assign_coherent_memory(dev, mem);
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return 0;
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}
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static void rmem_dma_device_release(struct reserved_mem *rmem,
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struct device *dev)
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{
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dev->dma_mem = NULL;
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}
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static const struct reserved_mem_ops rmem_dma_ops = {
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.device_init = rmem_dma_device_init,
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.device_release = rmem_dma_device_release,
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};
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static int __init rmem_dma_setup(struct reserved_mem *rmem)
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{
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unsigned long node = rmem->fdt_node;
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if (of_get_flat_dt_prop(node, "reusable", NULL))
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return -EINVAL;
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#ifdef CONFIG_ARM
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if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
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pr_err("Reserved memory: regions without no-map are not yet supported\n");
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return -EINVAL;
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}
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#endif
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rmem->ops = &rmem_dma_ops;
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pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
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&rmem->base, (unsigned long)rmem->size / SZ_1M);
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return 0;
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}
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RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
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#endif
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