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kernel/linux-imx6_3.14.28/arch/frv/mb93090-mb00/pci-dma-nommu.c 3.43 KB
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  /* pci-dma-nommu.c: Dynamic DMA mapping support for the FRV
   *
   * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   * Written by David Woodhouse (dwmw2@infradead.org)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #include <linux/types.h>
  #include <linux/slab.h>
  #include <linux/export.h>
  #include <linux/dma-mapping.h>
  #include <linux/list.h>
  #include <linux/pci.h>
  #include <asm/io.h>
  
  #if 1
  #define DMA_SRAM_START	dma_coherent_mem_start
  #define DMA_SRAM_END	dma_coherent_mem_end
  #else // Use video RAM on Matrox
  #define DMA_SRAM_START	0xe8900000
  #define DMA_SRAM_END	0xe8a00000
  #endif
  
  struct dma_alloc_record {
  	struct list_head	list;
  	unsigned long		ofs;
  	unsigned long		len;
  };
  
  static DEFINE_SPINLOCK(dma_alloc_lock);
  static LIST_HEAD(dma_alloc_list);
  
  void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
  {
  	struct dma_alloc_record *new;
  	struct list_head *this = &dma_alloc_list;
  	unsigned long flags;
  	unsigned long start = DMA_SRAM_START;
  	unsigned long end;
  
  	if (!DMA_SRAM_START) {
  		printk("%s called without any DMA area reserved!
  ", __func__);
  		return NULL;
  	}
  
  	new = kmalloc(sizeof (*new), GFP_ATOMIC);
  	if (!new)
  		return NULL;
  
  	/* Round up to a reasonable alignment */
  	new->len = (size + 31) & ~31;
  
  	spin_lock_irqsave(&dma_alloc_lock, flags);
  
  	list_for_each (this, &dma_alloc_list) {
  		struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
  		end = this_r->ofs;
  
  		if (end - start >= size)
  			goto gotone;
  
  		start = this_r->ofs + this_r->len;
  	}
  	/* Reached end of list. */
  	end = DMA_SRAM_END;
  	this = &dma_alloc_list;
  
  	if (end - start >= size) {
  	gotone:
  		new->ofs = start;
  		list_add_tail(&new->list, this);
  		spin_unlock_irqrestore(&dma_alloc_lock, flags);
  
  		*dma_handle = start;
  		return (void *)start;
  	}
  
  	kfree(new);
  	spin_unlock_irqrestore(&dma_alloc_lock, flags);
  	return NULL;
  }
  
  EXPORT_SYMBOL(dma_alloc_coherent);
  
  void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
  {
  	struct dma_alloc_record *rec;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dma_alloc_lock, flags);
  
  	list_for_each_entry(rec, &dma_alloc_list, list) {
  		if (rec->ofs == dma_handle) {
  			list_del(&rec->list);
  			kfree(rec);
  			spin_unlock_irqrestore(&dma_alloc_lock, flags);
  			return;
  		}
  	}
  	spin_unlock_irqrestore(&dma_alloc_lock, flags);
  	BUG();
  }
  
  EXPORT_SYMBOL(dma_free_coherent);
  
  dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
  			  enum dma_data_direction direction)
  {
  	BUG_ON(direction == DMA_NONE);
  
  	frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
  
  	return virt_to_bus(ptr);
  }
  
  EXPORT_SYMBOL(dma_map_single);
  
  int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
  	       enum dma_data_direction direction)
  {
  	int i;
  
  	for (i=0; i<nents; i++)
  		frv_cache_wback_inv(sg_dma_address(&sg[i]),
  				    sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]));
  
  	BUG_ON(direction == DMA_NONE);
  
  	return nents;
  }
  
  EXPORT_SYMBOL(dma_map_sg);
  
  dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
  			size_t size, enum dma_data_direction direction)
  {
  	BUG_ON(direction == DMA_NONE);
  	flush_dcache_page(page);
  	return (dma_addr_t) page_to_phys(page) + offset;
  }
  
  EXPORT_SYMBOL(dma_map_page);