dma-alloc.c revision 6e0c64f4ddf4a76a04108c1e24132d5d7dea8872
1/* MN10300 Dynamic DMA mapping support 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * Derived from: arch/i386/kernel/pci-dma.c 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public Licence 9 * as published by the Free Software Foundation; either version 10 * 2 of the Licence, or (at your option) any later version. 11 */ 12 13#include <linux/types.h> 14#include <linux/mm.h> 15#include <linux/string.h> 16#include <linux/pci.h> 17#include <linux/gfp.h> 18#include <asm/io.h> 19 20static unsigned long pci_sram_allocated = 0xbc000000; 21 22void *dma_alloc_coherent(struct device *dev, size_t size, 23 dma_addr_t *dma_handle, int gfp) 24{ 25 unsigned long addr; 26 void *ret; 27 28 pr_debug("dma_alloc_coherent(%s,%zu,%x)\n", 29 dev ? dev_name(dev) : "?", size, gfp); 30 31 if (0xbe000000 - pci_sram_allocated >= size) { 32 size = (size + 255) & ~255; 33 addr = pci_sram_allocated; 34 pci_sram_allocated += size; 35 ret = (void *) addr; 36 goto done; 37 } 38 39 /* ignore region specifiers */ 40 gfp &= ~(__GFP_DMA | __GFP_HIGHMEM); 41 42 if (dev == NULL || dev->coherent_dma_mask < 0xffffffff) 43 gfp |= GFP_DMA; 44 45 addr = __get_free_pages(gfp, get_order(size)); 46 if (!addr) 47 return NULL; 48 49 /* map the coherent memory through the uncached memory window */ 50 ret = (void *) (addr | 0x20000000); 51 52 /* fill the memory with obvious rubbish */ 53 memset((void *) addr, 0xfb, size); 54 55 /* write back and evict all cache lines covering this region */ 56 mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE); 57 58done: 59 *dma_handle = virt_to_bus((void *) addr); 60 printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle); 61 return ret; 62} 63EXPORT_SYMBOL(dma_alloc_coherent); 64 65void dma_free_coherent(struct device *dev, size_t size, void *vaddr, 66 dma_addr_t dma_handle) 67{ 68 unsigned long addr = (unsigned long) vaddr & ~0x20000000; 69 70 if (addr >= 0x9c000000) 71 return; 72 73 free_pages(addr, get_order(size)); 74} 75EXPORT_SYMBOL(dma_free_coherent); 76