1 /* 2 * arch/sh/mm/consistent.c 3 * 4 * Copyright (C) 2004 - 2007 Paul Mundt 5 * 6 * Declared coherent memory functions based on arch/x86/kernel/pci-dma_32.c 7 * 8 * This file is subject to the terms and conditions of the GNU General Public 9 * License. See the file "COPYING" in the main directory of this archive 10 * for more details. 11 */ 12 #include <linux/mm.h> 13 #include <linux/init.h> 14 #include <linux/platform_device.h> 15 #include <linux/dma-mapping.h> 16 #include <linux/dma-debug.h> 17 #include <linux/io.h> 18 #include <linux/module.h> 19 #include <linux/gfp.h> 20 #include <asm/cacheflush.h> 21 #include <asm/addrspace.h> 22 23 #define PREALLOC_DMA_DEBUG_ENTRIES 4096 24 25 struct dma_map_ops *dma_ops; 26 EXPORT_SYMBOL(dma_ops); 27 28 static int __init dma_init(void) 29 { 30 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 31 return 0; 32 } 33 fs_initcall(dma_init); 34 35 void *dma_generic_alloc_coherent(struct device *dev, size_t size, 36 dma_addr_t *dma_handle, gfp_t gfp) 37 { 38 void *ret, *ret_nocache; 39 int order = get_order(size); 40 41 gfp |= __GFP_ZERO; 42 43 ret = (void *)__get_free_pages(gfp, order); 44 if (!ret) 45 return NULL; 46 47 /* 48 * Pages from the page allocator may have data present in 49 * cache. So flush the cache before using uncached memory. 50 */ 51 dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL); 52 53 ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size); 54 if (!ret_nocache) { 55 free_pages((unsigned long)ret, order); 56 return NULL; 57 } 58 59 split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order); 60 61 *dma_handle = virt_to_phys(ret); 62 63 return ret_nocache; 64 } 65 66 void dma_generic_free_coherent(struct device *dev, size_t size, 67 void *vaddr, dma_addr_t dma_handle) 68 { 69 int order = get_order(size); 70 unsigned long pfn = dma_handle >> PAGE_SHIFT; 71 int k; 72 73 for (k = 0; k < (1 << order); k++) 74 __free_pages(pfn_to_page(pfn + k), 0); 75 76 iounmap(vaddr); 77 } 78 79 void dma_cache_sync(struct device *dev, void *vaddr, size_t size, 80 enum dma_data_direction direction) 81 { 82 void *addr; 83 84 addr = __in_29bit_mode() ? 85 (void *)P1SEGADDR((unsigned long)vaddr) : vaddr; 86 87 switch (direction) { 88 case DMA_FROM_DEVICE: /* invalidate only */ 89 __flush_invalidate_region(addr, size); 90 break; 91 case DMA_TO_DEVICE: /* writeback only */ 92 __flush_wback_region(addr, size); 93 break; 94 case DMA_BIDIRECTIONAL: /* writeback and invalidate */ 95 __flush_purge_region(addr, size); 96 break; 97 default: 98 BUG(); 99 } 100 } 101 EXPORT_SYMBOL(dma_cache_sync); 102 103 static int __init memchunk_setup(char *str) 104 { 105 return 1; /* accept anything that begins with "memchunk." */ 106 } 107 __setup("memchunk.", memchunk_setup); 108 109 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep) 110 { 111 char *p = boot_command_line; 112 int k = strlen(name); 113 114 while ((p = strstr(p, "memchunk."))) { 115 p += 9; /* strlen("memchunk.") */ 116 if (!strncmp(name, p, k) && p[k] == '=') { 117 p += k + 1; 118 *sizep = memparse(p, NULL); 119 pr_info("%s: forcing memory chunk size to 0x%08lx\n", 120 name, *sizep); 121 break; 122 } 123 } 124 } 125 126 int __init platform_resource_setup_memory(struct platform_device *pdev, 127 char *name, unsigned long memsize) 128 { 129 struct resource *r; 130 dma_addr_t dma_handle; 131 void *buf; 132 133 r = pdev->resource + pdev->num_resources - 1; 134 if (r->flags) { 135 pr_warning("%s: unable to find empty space for resource\n", 136 name); 137 return -EINVAL; 138 } 139 140 memchunk_cmdline_override(name, &memsize); 141 if (!memsize) 142 return 0; 143 144 buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL); 145 if (!buf) { 146 pr_warning("%s: unable to allocate memory\n", name); 147 return -ENOMEM; 148 } 149 150 memset(buf, 0, memsize); 151 152 r->flags = IORESOURCE_MEM; 153 r->start = dma_handle; 154 r->end = r->start + memsize - 1; 155 r->name = name; 156 return 0; 157 } 158