1/* $Id: iommu_common.c,v 1.1.1.1 2007/08/03 18:52:18 Exp $ 2 * iommu_common.c: UltraSparc SBUS/PCI common iommu code. 3 * 4 * Copyright (C) 1999 David S. Miller (davem@redhat.com) 5 */ 6 7#include "iommu_common.h" 8 9/* You are _strongly_ advised to enable the following debugging code 10 * any time you make changes to the sg code below, run it for a while 11 * with filesystems mounted read-only before buying the farm... -DaveM 12 */ 13 14#ifdef VERIFY_SG 15static int verify_lengths(struct scatterlist *sg, int nents, int npages) 16{ 17 int sg_len, dma_len; 18 int i, pgcount; 19 20 sg_len = 0; 21 for (i = 0; i < nents; i++) 22 sg_len += sg[i].length; 23 24 dma_len = 0; 25 for (i = 0; i < nents && sg[i].dma_length; i++) 26 dma_len += sg[i].dma_length; 27 28 if (sg_len != dma_len) { 29 printk("verify_lengths: Error, different, sg[%d] dma[%d]\n", 30 sg_len, dma_len); 31 return -1; 32 } 33 34 pgcount = 0; 35 for (i = 0; i < nents && sg[i].dma_length; i++) { 36 unsigned long start, end; 37 38 start = sg[i].dma_address; 39 start = start & IO_PAGE_MASK; 40 41 end = sg[i].dma_address + sg[i].dma_length; 42 end = (end + (IO_PAGE_SIZE - 1)) & IO_PAGE_MASK; 43 44 pgcount += ((end - start) >> IO_PAGE_SHIFT); 45 } 46 47 if (pgcount != npages) { 48 printk("verify_lengths: Error, page count wrong, " 49 "npages[%d] pgcount[%d]\n", 50 npages, pgcount); 51 return -1; 52 } 53 54 /* This test passes... */ 55 return 0; 56} 57 58static int verify_one_map(struct scatterlist *dma_sg, struct scatterlist **__sg, int nents, iopte_t **__iopte) 59{ 60 struct scatterlist *sg = *__sg; 61 iopte_t *iopte = *__iopte; 62 u32 dlen = dma_sg->dma_length; 63 u32 daddr; 64 unsigned int sglen; 65 unsigned long sgaddr; 66 67 daddr = dma_sg->dma_address; 68 sglen = sg->length; 69 sgaddr = (unsigned long) (page_address(sg->page) + sg->offset); 70 while (dlen > 0) { 71 unsigned long paddr; 72 73 /* SG and DMA_SG must begin at the same sub-page boundary. */ 74 if ((sgaddr & ~IO_PAGE_MASK) != (daddr & ~IO_PAGE_MASK)) { 75 printk("verify_one_map: Wrong start offset " 76 "sg[%08lx] dma[%08x]\n", 77 sgaddr, daddr); 78 nents = -1; 79 goto out; 80 } 81 82 /* Verify the IOPTE points to the right page. */ 83 paddr = iopte_val(*iopte) & IOPTE_PAGE; 84 if ((paddr + PAGE_OFFSET) != (sgaddr & IO_PAGE_MASK)) { 85 printk("verify_one_map: IOPTE[%08lx] maps the " 86 "wrong page, should be [%08lx]\n", 87 iopte_val(*iopte), (sgaddr & IO_PAGE_MASK) - PAGE_OFFSET); 88 nents = -1; 89 goto out; 90 } 91 92 /* If this SG crosses a page, adjust to that next page 93 * boundary and loop. 94 */ 95 if ((sgaddr & IO_PAGE_MASK) ^ ((sgaddr + sglen - 1) & IO_PAGE_MASK)) { 96 unsigned long next_page, diff; 97 98 next_page = (sgaddr + IO_PAGE_SIZE) & IO_PAGE_MASK; 99 diff = next_page - sgaddr; 100 sgaddr += diff; 101 daddr += diff; 102 sglen -= diff; 103 dlen -= diff; 104 if (dlen > 0) 105 iopte++; 106 continue; 107 } 108 109 /* SG wholly consumed within this page. */ 110 daddr += sglen; 111 dlen -= sglen; 112 113 if (dlen > 0 && ((daddr & ~IO_PAGE_MASK) == 0)) 114 iopte++; 115 116 sg++; 117 if (--nents <= 0) 118 break; 119 sgaddr = (unsigned long) (page_address(sg->page) + sg->offset); 120 sglen = sg->length; 121 } 122 if (dlen < 0) { 123 /* Transfer overrun, big problems. */ 124 printk("verify_one_map: Transfer overrun by %d bytes.\n", 125 -dlen); 126 nents = -1; 127 } else { 128 /* Advance to next dma_sg implies that the next iopte will 129 * begin it. 130 */ 131 iopte++; 132 } 133 134out: 135 *__sg = sg; 136 *__iopte = iopte; 137 return nents; 138} 139 140static int verify_maps(struct scatterlist *sg, int nents, iopte_t *iopte) 141{ 142 struct scatterlist *dma_sg = sg; 143 struct scatterlist *orig_dma_sg = dma_sg; 144 int orig_nents = nents; 145 146 for (;;) { 147 nents = verify_one_map(dma_sg, &sg, nents, &iopte); 148 if (nents <= 0) 149 break; 150 dma_sg++; 151 if (dma_sg->dma_length == 0) 152 break; 153 } 154 155 if (nents > 0) { 156 printk("verify_maps: dma maps consumed by some sgs remain (%d)\n", 157 nents); 158 return -1; 159 } 160 161 if (nents < 0) { 162 printk("verify_maps: Error, messed up mappings, " 163 "at sg %d dma_sg %d\n", 164 (int) (orig_nents + nents), (int) (dma_sg - orig_dma_sg)); 165 return -1; 166 } 167 168 /* This test passes... */ 169 return 0; 170} 171 172void verify_sglist(struct scatterlist *sg, int nents, iopte_t *iopte, int npages) 173{ 174 if (verify_lengths(sg, nents, npages) < 0 || 175 verify_maps(sg, nents, iopte) < 0) { 176 int i; 177 178 printk("verify_sglist: Crap, messed up mappings, dumping, iodma at "); 179 printk("%016lx.\n", sg->dma_address & IO_PAGE_MASK); 180 181 for (i = 0; i < nents; i++) { 182 printk("sg(%d): page_addr(%p) off(%x) length(%x) " 183 "dma_address[%016lx] dma_length[%016lx]\n", 184 i, 185 page_address(sg[i].page), sg[i].offset, 186 sg[i].length, 187 sg[i].dma_address, sg[i].dma_length); 188 } 189 } 190 191 /* Seems to be ok */ 192} 193#endif 194 195unsigned long prepare_sg(struct scatterlist *sg, int nents) 196{ 197 struct scatterlist *dma_sg = sg; 198 unsigned long prev; 199 u32 dent_addr, dent_len; 200 201 prev = (unsigned long) (page_address(sg->page) + sg->offset); 202 prev += (unsigned long) (dent_len = sg->length); 203 dent_addr = (u32) ((unsigned long)(page_address(sg->page) + sg->offset) 204 & (IO_PAGE_SIZE - 1UL)); 205 while (--nents) { 206 unsigned long addr; 207 208 sg++; 209 addr = (unsigned long) (page_address(sg->page) + sg->offset); 210 if (! VCONTIG(prev, addr)) { 211 dma_sg->dma_address = dent_addr; 212 dma_sg->dma_length = dent_len; 213 dma_sg++; 214 215 dent_addr = ((dent_addr + 216 dent_len + 217 (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT); 218 dent_addr <<= IO_PAGE_SHIFT; 219 dent_addr += addr & (IO_PAGE_SIZE - 1UL); 220 dent_len = 0; 221 } 222 dent_len += sg->length; 223 prev = addr + sg->length; 224 } 225 dma_sg->dma_address = dent_addr; 226 dma_sg->dma_length = dent_len; 227 228 return ((unsigned long) dent_addr + 229 (unsigned long) dent_len + 230 (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT; 231} 232