1 /* 2 * DMA implementation for Hexagon 3 * 4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #include <linux/dma-mapping.h> 22 #include <linux/bootmem.h> 23 #include <linux/genalloc.h> 24 #include <asm/dma-mapping.h> 25 #include <linux/module.h> 26 27 struct dma_map_ops *dma_ops; 28 EXPORT_SYMBOL(dma_ops); 29 30 int bad_dma_address; /* globals are automatically initialized to zero */ 31 32 int dma_supported(struct device *dev, u64 mask) 33 { 34 if (mask == DMA_BIT_MASK(32)) 35 return 1; 36 else 37 return 0; 38 } 39 EXPORT_SYMBOL(dma_supported); 40 41 int dma_set_mask(struct device *dev, u64 mask) 42 { 43 if (!dev->dma_mask || !dma_supported(dev, mask)) 44 return -EIO; 45 46 *dev->dma_mask = mask; 47 48 return 0; 49 } 50 EXPORT_SYMBOL(dma_set_mask); 51 52 static struct gen_pool *coherent_pool; 53 54 55 /* Allocates from a pool of uncached memory that was reserved at boot time */ 56 57 static void *hexagon_dma_alloc_coherent(struct device *dev, size_t size, 58 dma_addr_t *dma_addr, gfp_t flag, 59 struct dma_attrs *attrs) 60 { 61 void *ret; 62 63 if (coherent_pool == NULL) { 64 coherent_pool = gen_pool_create(PAGE_SHIFT, -1); 65 66 if (coherent_pool == NULL) 67 panic("Can't create %s() memory pool!", __func__); 68 else 69 gen_pool_add(coherent_pool, 70 (PAGE_OFFSET + (max_low_pfn << PAGE_SHIFT)), 71 hexagon_coherent_pool_size, -1); 72 } 73 74 ret = (void *) gen_pool_alloc(coherent_pool, size); 75 76 if (ret) { 77 memset(ret, 0, size); 78 *dma_addr = (dma_addr_t) (ret - PAGE_OFFSET); 79 } else 80 *dma_addr = ~0; 81 82 return ret; 83 } 84 85 static void hexagon_free_coherent(struct device *dev, size_t size, void *vaddr, 86 dma_addr_t dma_addr, struct dma_attrs *attrs) 87 { 88 gen_pool_free(coherent_pool, (unsigned long) vaddr, size); 89 } 90 91 static int check_addr(const char *name, struct device *hwdev, 92 dma_addr_t bus, size_t size) 93 { 94 if (hwdev && hwdev->dma_mask && !dma_capable(hwdev, bus, size)) { 95 if (*hwdev->dma_mask >= DMA_BIT_MASK(32)) 96 printk(KERN_ERR 97 "%s: overflow %Lx+%zu of device mask %Lx\n", 98 name, (long long)bus, size, 99 (long long)*hwdev->dma_mask); 100 return 0; 101 } 102 return 1; 103 } 104 105 static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg, 106 int nents, enum dma_data_direction dir, 107 struct dma_attrs *attrs) 108 { 109 struct scatterlist *s; 110 int i; 111 112 WARN_ON(nents == 0 || sg[0].length == 0); 113 114 for_each_sg(sg, s, nents, i) { 115 s->dma_address = sg_phys(s); 116 if (!check_addr("map_sg", hwdev, s->dma_address, s->length)) 117 return 0; 118 119 s->dma_length = s->length; 120 121 flush_dcache_range(PAGE_OFFSET + s->dma_address, 122 PAGE_OFFSET + s->dma_address + s->length); 123 } 124 125 return nents; 126 } 127 128 /* 129 * address is virtual 130 */ 131 static inline void dma_sync(void *addr, size_t size, 132 enum dma_data_direction dir) 133 { 134 switch (dir) { 135 case DMA_TO_DEVICE: 136 hexagon_clean_dcache_range((unsigned long) addr, 137 (unsigned long) addr + size); 138 break; 139 case DMA_FROM_DEVICE: 140 hexagon_inv_dcache_range((unsigned long) addr, 141 (unsigned long) addr + size); 142 break; 143 case DMA_BIDIRECTIONAL: 144 flush_dcache_range((unsigned long) addr, 145 (unsigned long) addr + size); 146 break; 147 default: 148 BUG(); 149 } 150 } 151 152 static inline void *dma_addr_to_virt(dma_addr_t dma_addr) 153 { 154 return phys_to_virt((unsigned long) dma_addr); 155 } 156 157 /** 158 * hexagon_map_page() - maps an address for device DMA 159 * @dev: pointer to DMA device 160 * @page: pointer to page struct of DMA memory 161 * @offset: offset within page 162 * @size: size of memory to map 163 * @dir: transfer direction 164 * @attrs: pointer to DMA attrs (not used) 165 * 166 * Called to map a memory address to a DMA address prior 167 * to accesses to/from device. 168 * 169 * We don't particularly have many hoops to jump through 170 * so far. Straight translation between phys and virtual. 171 * 172 * DMA is not cache coherent so sync is necessary; this 173 * seems to be a convenient place to do it. 174 * 175 */ 176 static dma_addr_t hexagon_map_page(struct device *dev, struct page *page, 177 unsigned long offset, size_t size, 178 enum dma_data_direction dir, 179 struct dma_attrs *attrs) 180 { 181 dma_addr_t bus = page_to_phys(page) + offset; 182 WARN_ON(size == 0); 183 184 if (!check_addr("map_single", dev, bus, size)) 185 return bad_dma_address; 186 187 dma_sync(dma_addr_to_virt(bus), size, dir); 188 189 return bus; 190 } 191 192 static void hexagon_sync_single_for_cpu(struct device *dev, 193 dma_addr_t dma_handle, size_t size, 194 enum dma_data_direction dir) 195 { 196 dma_sync(dma_addr_to_virt(dma_handle), size, dir); 197 } 198 199 static void hexagon_sync_single_for_device(struct device *dev, 200 dma_addr_t dma_handle, size_t size, 201 enum dma_data_direction dir) 202 { 203 dma_sync(dma_addr_to_virt(dma_handle), size, dir); 204 } 205 206 struct dma_map_ops hexagon_dma_ops = { 207 .alloc = hexagon_dma_alloc_coherent, 208 .free = hexagon_free_coherent, 209 .map_sg = hexagon_map_sg, 210 .map_page = hexagon_map_page, 211 .sync_single_for_cpu = hexagon_sync_single_for_cpu, 212 .sync_single_for_device = hexagon_sync_single_for_device, 213 .is_phys = 1, 214 }; 215 216 void __init hexagon_dma_init(void) 217 { 218 if (dma_ops) 219 return; 220 221 dma_ops = &hexagon_dma_ops; 222 } 223