389 lines
9.9 KiB
C
389 lines
9.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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/io.h>
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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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unsigned long *bitmap;
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spinlock_t spinlock;
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bool use_dev_dma_pfn_offset;
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};
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static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
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static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
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{
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if (dev && dev->dma_mem)
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return dev->dma_mem;
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return NULL;
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}
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static inline dma_addr_t dma_get_device_base(struct device *dev,
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struct dma_coherent_mem * mem)
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{
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if (mem->use_dev_dma_pfn_offset)
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return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
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else
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return mem->device_base;
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}
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static int dma_init_coherent_memory(phys_addr_t phys_addr,
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dma_addr_t device_addr, size_t size,
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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 *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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int ret;
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if (!size) {
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ret = -EINVAL;
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goto out;
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}
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mem_base = memremap(phys_addr, size, MEMREMAP_WC);
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if (!mem_base) {
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ret = -EINVAL;
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goto out;
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}
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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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ret = -ENOMEM;
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goto out;
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}
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dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
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if (!dma_mem->bitmap) {
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ret = -ENOMEM;
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goto out;
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}
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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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spin_lock_init(&dma_mem->spinlock);
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*mem = dma_mem;
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return 0;
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out:
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kfree(dma_mem);
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if (mem_base)
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memunmap(mem_base);
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return ret;
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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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memunmap(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)
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return -ENODEV;
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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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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)
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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, &mem);
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if (ret)
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return ret;
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ret = dma_assign_coherent_memory(dev, mem);
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if (ret)
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dma_release_coherent_memory(mem);
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return ret;
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}
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static void *__dma_alloc_from_coherent(struct device *dev,
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struct dma_coherent_mem *mem,
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ssize_t size, dma_addr_t *dma_handle)
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{
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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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void *ret;
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spin_lock_irqsave(&mem->spinlock, flags);
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if (unlikely(size > ((dma_addr_t)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 coherent area.
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*/
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*dma_handle = dma_get_device_base(dev, mem) +
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((dma_addr_t)pageno << PAGE_SHIFT);
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ret = mem->virt_base + ((dma_addr_t)pageno << PAGE_SHIFT);
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spin_unlock_irqrestore(&mem->spinlock, flags);
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memset(ret, 0, size);
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return ret;
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err:
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spin_unlock_irqrestore(&mem->spinlock, flags);
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return NULL;
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}
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/**
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* dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
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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_dev_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_get_coherent_memory(dev);
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if (!mem)
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return 0;
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*ret = __dma_alloc_from_coherent(dev, mem, size, dma_handle);
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return 1;
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}
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void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
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dma_addr_t *dma_handle)
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{
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if (!dma_coherent_default_memory)
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return NULL;
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return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
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dma_handle);
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}
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static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
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int order, void *vaddr)
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{
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if (mem && vaddr >= mem->virt_base && vaddr <
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(mem->virt_base + ((dma_addr_t)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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/**
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* dma_release_from_dev_coherent() - free memory to 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 the caller should
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* proceed with releasing memory from generic pools.
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*/
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int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
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{
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struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
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return __dma_release_from_coherent(mem, order, vaddr);
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}
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int dma_release_from_global_coherent(int order, void *vaddr)
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{
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if (!dma_coherent_default_memory)
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return 0;
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return __dma_release_from_coherent(dma_coherent_default_memory, order,
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vaddr);
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}
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static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
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struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
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{
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if (mem && vaddr >= mem->virt_base && vaddr + size <=
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(mem->virt_base + ((dma_addr_t)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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unsigned long user_count = vma_pages(vma);
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int count = PAGE_ALIGN(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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/**
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* dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
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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_dev_coherent
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* @size: size of the memory buffer allocated
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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 @vaddr belongs to the device coherent pool and the caller
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* should return @ret, or 0 if they should proceed with mapping memory from
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* generic areas.
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*/
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int dma_mmap_from_dev_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_get_coherent_memory(dev);
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return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
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}
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int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
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size_t size, int *ret)
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{
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if (!dma_coherent_default_memory)
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return 0;
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return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
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vaddr, size, ret);
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}
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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 struct reserved_mem *dma_reserved_default_memory __initdata;
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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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int ret;
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if (!mem) {
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ret = dma_init_coherent_memory(rmem->base, rmem->base,
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rmem->size, &mem);
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if (ret) {
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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 ret;
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}
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}
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mem->use_dev_dma_pfn_offset = true;
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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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if (dev)
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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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if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
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WARN(dma_reserved_default_memory,
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"Reserved memory: region for default DMA coherent area is redefined\n");
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dma_reserved_default_memory = rmem;
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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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static int __init dma_init_reserved_memory(void)
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{
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const struct reserved_mem_ops *ops;
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int ret;
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if (!dma_reserved_default_memory)
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return -ENOMEM;
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ops = dma_reserved_default_memory->ops;
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/*
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* We rely on rmem_dma_device_init() does not propagate error of
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* dma_assign_coherent_memory() for "NULL" device.
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*/
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ret = ops->device_init(dma_reserved_default_memory, NULL);
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if (!ret) {
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dma_coherent_default_memory = dma_reserved_default_memory->priv;
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pr_info("DMA: default coherent area is set\n");
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}
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return ret;
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}
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core_initcall(dma_init_reserved_memory);
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RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
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#endif
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