/*
   * drivers/base/dma-mapping.c - arch-independent dma-mapping routines
   *
   * Copyright (c) 2006  SUSE Linux Products GmbH
   * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
   *
   * This file is released under the GPLv2.
   */
  
  #include <linux/dma-mapping.h>
  #include <linux/export.h>
  #include <linux/gfp.h>
  #include <asm-generic/dma-coherent.h>
  
  /*
   * Managed DMA API
   */
  struct dma_devres {
  	size_t		size;
  	void		*vaddr;
  	dma_addr_t	dma_handle;
  };
  
  static void dmam_coherent_release(struct device *dev, void *res)
  {
  	struct dma_devres *this = res;
  
  	dma_free_coherent(dev, this->size, this->vaddr, this->dma_handle);
  }
  
  static void dmam_noncoherent_release(struct device *dev, void *res)
  {
  	struct dma_devres *this = res;
  
  	dma_free_noncoherent(dev, this->size, this->vaddr, this->dma_handle);
  }
  
  static int dmam_match(struct device *dev, void *res, void *match_data)
  {
  	struct dma_devres *this = res, *match = match_data;
  
  	if (this->vaddr == match->vaddr) {
  		WARN_ON(this->size != match->size ||
  			this->dma_handle != match->dma_handle);
  		return 1;
  	}
  	return 0;
  }
  
  /**
   * dmam_alloc_coherent - Managed dma_alloc_coherent()
   * @dev: Device to allocate coherent memory for
   * @size: Size of allocation
   * @dma_handle: Out argument for allocated DMA handle
   * @gfp: Allocation flags
   *
   * Managed dma_alloc_coherent().  Memory allocated using this function
   * will be automatically released on driver detach.
   *
   * RETURNS:
   * Pointer to allocated memory on success, NULL on failure.
   */
  void * dmam_alloc_coherent(struct device *dev, size_t size,
  			   dma_addr_t *dma_handle, gfp_t gfp)
  {
  	struct dma_devres *dr;
  	void *vaddr;
  
  	dr = devres_alloc(dmam_coherent_release, sizeof(*dr), gfp);
  	if (!dr)
  		return NULL;
  
  	vaddr = dma_alloc_coherent(dev, size, dma_handle, gfp);
  	if (!vaddr) {
  		devres_free(dr);
  		return NULL;
  	}
  
  	dr->vaddr = vaddr;
  	dr->dma_handle = *dma_handle;
  	dr->size = size;
  
  	devres_add(dev, dr);
  
  	return vaddr;
  }
  EXPORT_SYMBOL(dmam_alloc_coherent);
  
  /**
   * dmam_free_coherent - Managed dma_free_coherent()
   * @dev: Device to free coherent memory for
   * @size: Size of allocation
   * @vaddr: Virtual address of the memory to free
   * @dma_handle: DMA handle of the memory to free
   *
   * Managed dma_free_coherent().
   */
  void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
  			dma_addr_t dma_handle)
  {
  	struct dma_devres match_data = { size, vaddr, dma_handle };
  
  	dma_free_coherent(dev, size, vaddr, dma_handle);
  	WARN_ON(devres_destroy(dev, dmam_coherent_release, dmam_match,
  			       &match_data));
  }
  EXPORT_SYMBOL(dmam_free_coherent);
  
  /**
   * dmam_alloc_non_coherent - Managed dma_alloc_non_coherent()
   * @dev: Device to allocate non_coherent memory for
   * @size: Size of allocation
   * @dma_handle: Out argument for allocated DMA handle
   * @gfp: Allocation flags
   *
   * Managed dma_alloc_non_coherent().  Memory allocated using this
   * function will be automatically released on driver detach.
   *
   * RETURNS:
   * Pointer to allocated memory on success, NULL on failure.
   */
  void *dmam_alloc_noncoherent(struct device *dev, size_t size,
  			     dma_addr_t *dma_handle, gfp_t gfp)
  {
  	struct dma_devres *dr;
  	void *vaddr;
  
  	dr = devres_alloc(dmam_noncoherent_release, sizeof(*dr), gfp);
  	if (!dr)
  		return NULL;
  
  	vaddr = dma_alloc_noncoherent(dev, size, dma_handle, gfp);
  	if (!vaddr) {
  		devres_free(dr);
  		return NULL;
  	}
  
  	dr->vaddr = vaddr;
  	dr->dma_handle = *dma_handle;
  	dr->size = size;
  
  	devres_add(dev, dr);
  
  	return vaddr;
  }
  EXPORT_SYMBOL(dmam_alloc_noncoherent);
  
  /**
   * dmam_free_coherent - Managed dma_free_noncoherent()
   * @dev: Device to free noncoherent memory for
   * @size: Size of allocation
   * @vaddr: Virtual address of the memory to free
   * @dma_handle: DMA handle of the memory to free
   *
   * Managed dma_free_noncoherent().
   */
  void dmam_free_noncoherent(struct device *dev, size_t size, void *vaddr,
  			   dma_addr_t dma_handle)
  {
  	struct dma_devres match_data = { size, vaddr, dma_handle };
  
  	dma_free_noncoherent(dev, size, vaddr, dma_handle);
  	WARN_ON(!devres_destroy(dev, dmam_noncoherent_release, dmam_match,
  				&match_data));
  }
  EXPORT_SYMBOL(dmam_free_noncoherent);
  
  #ifdef ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY
  
  static void dmam_coherent_decl_release(struct device *dev, void *res)
  {
  	dma_release_declared_memory(dev);
  }
  
  /**
   * dmam_declare_coherent_memory - Managed dma_declare_coherent_memory()
   * @dev: Device to declare coherent memory for
   * @bus_addr: Bus address of coherent memory to be declared
   * @device_addr: Device address of coherent memory to be declared
   * @size: Size of coherent memory to be declared
   * @flags: Flags
   *
   * Managed dma_declare_coherent_memory().
   *
   * RETURNS:
   * 0 on success, -errno on failure.
   */
  int dmam_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
  				 dma_addr_t device_addr, size_t size, int flags)
  {
  	void *res;
  	int rc;
  
  	res = devres_alloc(dmam_coherent_decl_release, 0, GFP_KERNEL);
  	if (!res)
  		return -ENOMEM;
  
  	rc = dma_declare_coherent_memory(dev, bus_addr, device_addr, size,
  					 flags);
  	if (rc == 0)
  		devres_add(dev, res);
  	else
  		devres_free(res);
  
  	return rc;
  }
  EXPORT_SYMBOL(dmam_declare_coherent_memory);
  
  /**
   * dmam_release_declared_memory - Managed dma_release_declared_memory().
   * @dev: Device to release declared coherent memory for
   *
   * Managed dmam_release_declared_memory().
   */
  void dmam_release_declared_memory(struct device *dev)
  {
  	WARN_ON(devres_destroy(dev, dmam_coherent_decl_release, NULL, NULL));
  }
  EXPORT_SYMBOL(dmam_release_declared_memory);
  
  #endif
  
  /*
   * Create scatter-list for the already allocated DMA buffer.
   */
  int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
  		 void *cpu_addr, dma_addr_t handle, size_t size)
  {
  	struct page *page = virt_to_page(cpu_addr);
  	int ret;
  
  	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
  	if (unlikely(ret))
  		return ret;
  
  	sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
  	return 0;
  }
  EXPORT_SYMBOL(dma_common_get_sgtable);
  
  /*
   * Create userspace mapping for the DMA-coherent memory.
   */
  int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
  		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
  {
  	int ret = -ENXIO;
  #ifdef CONFIG_MMU
  	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
  	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
  	unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
  	unsigned long off = vma->vm_pgoff;
  
  	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  
  	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
  		return ret;
  
  	if (off < count && user_count <= (count - off)) {
  		ret = remap_pfn_range(vma, vma->vm_start,
  				      pfn + off,
  				      user_count << PAGE_SHIFT,
  				      vma->vm_page_prot);
  	}
  #endif	/* CONFIG_MMU */
  
  	return ret;
  }
  EXPORT_SYMBOL(dma_common_mmap);