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kernel/linux-rt-4.4.41/arch/mn10300/mm/dma-alloc.c 2 KB
5113f6f70   김현기   kernel add
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  /* MN10300 Dynamic DMA mapping support
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   * Derived from: arch/i386/kernel/pci-dma.c
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public Licence
   * as published by the Free Software Foundation; either version
   * 2 of the Licence, or (at your option) any later version.
   */
  
  #include <linux/types.h>
  #include <linux/mm.h>
  #include <linux/string.h>
  #include <linux/pci.h>
  #include <linux/gfp.h>
  #include <linux/export.h>
  #include <asm/io.h>
  
  static unsigned long pci_sram_allocated = 0xbc000000;
  
  void *dma_alloc_coherent(struct device *dev, size_t size,
  			 dma_addr_t *dma_handle, int gfp)
  {
  	unsigned long addr;
  	void *ret;
  
  	pr_debug("dma_alloc_coherent(%s,%zu,%x)
  ",
  		 dev ? dev_name(dev) : "?", size, gfp);
  
  	if (0xbe000000 - pci_sram_allocated >= size) {
  		size = (size + 255) & ~255;
  		addr = pci_sram_allocated;
  		pci_sram_allocated += size;
  		ret = (void *) addr;
  		goto done;
  	}
  
  	/* ignore region specifiers */
  	gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  
  	if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
  		gfp |= GFP_DMA;
  
  	addr = __get_free_pages(gfp, get_order(size));
  	if (!addr)
  		return NULL;
  
  	/* map the coherent memory through the uncached memory window */
  	ret = (void *) (addr | 0x20000000);
  
  	/* fill the memory with obvious rubbish */
  	memset((void *) addr, 0xfb, size);
  
  	/* write back and evict all cache lines covering this region */
  	mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
  
  done:
  	*dma_handle = virt_to_bus((void *) addr);
  	printk("dma_alloc_coherent() = %p [%x]
  ", ret, *dma_handle);
  	return ret;
  }
  EXPORT_SYMBOL(dma_alloc_coherent);
  
  void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
  		       dma_addr_t dma_handle)
  {
  	unsigned long addr = (unsigned long) vaddr & ~0x20000000;
  
  	if (addr >= 0x9c000000)
  		return;
  
  	free_pages(addr, get_order(size));
  }
  EXPORT_SYMBOL(dma_free_coherent);