--- /dev/null
+/*
+ * Coherent per-device memory handling.
+ * Borrowed from i386
+ */
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+
+struct dma_coherent_mem {
+ void *virt_base;
+ dma_addr_t device_base;
+ unsigned long pfn_base;
+ int size;
+ int flags;
+ unsigned long *bitmap;
+ spinlock_t spinlock;
+};
+
+static int dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_addr,
+ size_t size, int flags,
+ struct dma_coherent_mem **mem)
+{
+ struct dma_coherent_mem *dma_mem = NULL;
+ 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;
+
+ mem_base = ioremap(phys_addr, size);
+ if (!mem_base)
+ goto out;
+
+ dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
+ if (!dma_mem)
+ goto out;
+ dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+ if (!dma_mem->bitmap)
+ goto out;
+
+ dma_mem->virt_base = mem_base;
+ dma_mem->device_base = device_addr;
+ dma_mem->pfn_base = PFN_DOWN(phys_addr);
+ dma_mem->size = pages;
+ dma_mem->flags = flags;
+ spin_lock_init(&dma_mem->spinlock);
+
+ *mem = dma_mem;
+
+ if (flags & DMA_MEMORY_MAP)
+ return DMA_MEMORY_MAP;
+
+ return DMA_MEMORY_IO;
+
+out:
+ kfree(dma_mem);
+ if (mem_base)
+ iounmap(mem_base);
+ return 0;
+}
+
+static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
+{
+ if (!mem)
+ return;
+ iounmap(mem->virt_base);
+ kfree(mem->bitmap);
+ kfree(mem);
+}
+
+static int dma_assign_coherent_memory(struct device *dev,
+ struct dma_coherent_mem *mem)
+{
+ if (dev->dma_mem)
+ return -EBUSY;
+
+ dev->dma_mem = mem;
+ /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
+
+ return 0;
+}
+
+int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
+ dma_addr_t device_addr, size_t size, int flags)
+{
+ struct dma_coherent_mem *mem;
+ int ret;
+
+ ret = dma_init_coherent_memory(phys_addr, device_addr, size, flags,
+ &mem);
+ if (ret == 0)
+ return 0;
+
+ if (dma_assign_coherent_memory(dev, mem) == 0)
+ return ret;
+
+ dma_release_coherent_memory(mem);
+ 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;
+ dma_release_coherent_memory(mem);
+ dev->dma_mem = NULL;
+}
+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;
+ unsigned long flags;
+ int pos, err;
+
+ size += device_addr & ~PAGE_MASK;
+
+ if (!mem)
+ return ERR_PTR(-EINVAL);
+
+ spin_lock_irqsave(&mem->spinlock, flags);
+ pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
+ err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
+ spin_unlock_irqrestore(&mem->spinlock, flags);
+
+ 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);
+ unsigned long flags;
+ int pageno;
+
+ if (!dev)
+ return 0;
+ mem = dev->dma_mem;
+ if (!mem)
+ return 0;
+
+ *ret = NULL;
+ spin_lock_irqsave(&mem->spinlock, flags);
+
+ 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);
+ spin_unlock_irqrestore(&mem->spinlock, flags);
+
+ return 1;
+
+err:
+ spin_unlock_irqrestore(&mem->spinlock, flags);
+ /*
+ * 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;
+ unsigned long flags;
+
+ spin_lock_irqsave(&mem->spinlock, flags);
+ bitmap_release_region(mem->bitmap, page, order);
+ spin_unlock_irqrestore(&mem->spinlock, flags);
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(dma_release_from_coherent);
+
+/**
+ * dma_mmap_from_coherent() - try to mmap the memory allocated from
+ * per-device coherent memory pool to userspace
+ * @dev: device from which the memory was allocated
+ * @vma: vm_area for the userspace memory
+ * @vaddr: cpu address returned by dma_alloc_from_coherent
+ * @size: size of the memory buffer allocated by dma_alloc_from_coherent
+ * @ret: result from remap_pfn_range()
+ *
+ * This checks whether the memory was allocated from the per-device
+ * coherent memory pool and if so, maps that memory to the provided vma.
+ *
+ * Returns 1 if we correctly mapped the memory, or 0 if the caller should
+ * proceed with mapping memory from generic pools.
+ */
+int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
+ void *vaddr, size_t size, int *ret)
+{
+ struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+
+ if (mem && vaddr >= mem->virt_base && vaddr + size <=
+ (mem->virt_base + (mem->size << PAGE_SHIFT))) {
+ unsigned long off = vma->vm_pgoff;
+ int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+ int user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ int count = size >> PAGE_SHIFT;
+
+ *ret = -ENXIO;
+ if (off < count && user_count <= count - off) {
+ unsigned long pfn = mem->pfn_base + start + off;
+ *ret = remap_pfn_range(vma, vma->vm_start, pfn,
+ user_count << PAGE_SHIFT,
+ vma->vm_page_prot);
+ }
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(dma_mmap_from_coherent);
+
+/*
+ * Support for reserved memory regions defined in device tree
+ */
+#ifdef CONFIG_OF_RESERVED_MEM
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+
+static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
+{
+ struct dma_coherent_mem *mem = rmem->priv;
+
+ if (!mem &&
+ dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
+ DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
+ &mem) != DMA_MEMORY_MAP) {
+ pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
+ &rmem->base, (unsigned long)rmem->size / SZ_1M);
+ return -ENODEV;
+ }
+ rmem->priv = mem;
+ dma_assign_coherent_memory(dev, mem);
+ return 0;
+}
+
+static void rmem_dma_device_release(struct reserved_mem *rmem,
+ struct device *dev)
+{
+ dev->dma_mem = NULL;
+}
+
+static const struct reserved_mem_ops rmem_dma_ops = {
+ .device_init = rmem_dma_device_init,
+ .device_release = rmem_dma_device_release,
+};
+
+static int __init rmem_dma_setup(struct reserved_mem *rmem)
+{
+ unsigned long node = rmem->fdt_node;
+
+ if (of_get_flat_dt_prop(node, "reusable", NULL))
+ return -EINVAL;
+
+#ifdef CONFIG_ARM
+ if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
+ pr_err("Reserved memory: regions without no-map are not yet supported\n");
+ return -EINVAL;
+ }
+#endif
+
+ rmem->ops = &rmem_dma_ops;
+ pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
+ &rmem->base, (unsigned long)rmem->size / SZ_1M);
+ return 0;
+}
+RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
+#endif
Code Review / kvmfornfv.git / blobdiff