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 const 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 unsigned long attrs) 38 { 39 void *ret, *ret_nocache; 40 int order = get_order(size); 41 42 gfp |= __GFP_ZERO; 43 44 ret = (void *)__get_free_pages(gfp, order); 45 if (!ret) 46 return NULL; 47 48 /* 49 * Pages from the page allocator may have data present in 50 * cache. So flush the cache before using uncached memory. 51 */ 52 dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL); 53 54 ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size); 55 if (!ret_nocache) { 56 free_pages((unsigned long)ret, order); 57 return NULL; 58 } 59 60 split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order); 61 62 *dma_handle = virt_to_phys(ret); 63 64 return ret_nocache; 65 } 66 67 void dma_generic_free_coherent(struct device *dev, size_t size, 68 void *vaddr, dma_addr_t dma_handle, 69 unsigned long attrs) 70 { 71 int order = get_order(size); 72 unsigned long pfn = dma_handle >> PAGE_SHIFT; 73 int k; 74 75 for (k = 0; k < (1 << order); k++) 76 __free_pages(pfn_to_page(pfn + k), 0); 77 78 iounmap(vaddr); 79 } 80 81 void dma_cache_sync(struct device *dev, void *vaddr, size_t size, 82 enum dma_data_direction direction) 83 { 84 void *addr; 85 86 addr = __in_29bit_mode() ? 87 (void *)CAC_ADDR((unsigned long)vaddr) : vaddr; 88 89 switch (direction) { 90 case DMA_FROM_DEVICE: /* invalidate only */ 91 __flush_invalidate_region(addr, size); 92 break; 93 case DMA_TO_DEVICE: /* writeback only */ 94 __flush_wback_region(addr, size); 95 break; 96 case DMA_BIDIRECTIONAL: /* writeback and invalidate */ 97 __flush_purge_region(addr, size); 98 break; 99 default: 100 BUG(); 101 } 102 } 103 EXPORT_SYMBOL(dma_cache_sync); 104 105 static int __init memchunk_setup(char *str) 106 { 107 return 1; /* accept anything that begins with "memchunk." */ 108 } 109 __setup("memchunk.", memchunk_setup); 110 111 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep) 112 { 113 char *p = boot_command_line; 114 int k = strlen(name); 115 116 while ((p = strstr(p, "memchunk."))) { 117 p += 9; /* strlen("memchunk.") */ 118 if (!strncmp(name, p, k) && p[k] == '=') { 119 p += k + 1; 120 *sizep = memparse(p, NULL); 121 pr_info("%s: forcing memory chunk size to 0x%08lx\n", 122 name, *sizep); 123 break; 124 } 125 } 126 } 127 128 int __init platform_resource_setup_memory(struct platform_device *pdev, 129 char *name, unsigned long memsize) 130 { 131 struct resource *r; 132 dma_addr_t dma_handle; 133 void *buf; 134 135 r = pdev->resource + pdev->num_resources - 1; 136 if (r->flags) { 137 pr_warning("%s: unable to find empty space for resource\n", 138 name); 139 return -EINVAL; 140 } 141 142 memchunk_cmdline_override(name, &memsize); 143 if (!memsize) 144 return 0; 145 146 buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL); 147 if (!buf) { 148 pr_warning("%s: unable to allocate memory\n", name); 149 return -ENOMEM; 150 } 151 152 memset(buf, 0, memsize); 153 154 r->flags = IORESOURCE_MEM; 155 r->start = dma_handle; 156 r->end = r->start + memsize - 1; 157 r->name = name; 158 return 0; 159 } 160