arch/sparc64/kernel/iommu_common.c

   1 /* $Id: iommu_common.c,v 1.9 2001/12/17 07:05:09 davem 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 <linux/dma-mapping.h>
   8 #include "iommu_common.h"
   9
  10 /* You are _strongly_ advised to enable the following debugging code
  11  * any time you make changes to the sg code below, run it for a while
  12  * with filesystems mounted read-only before buying the farm... -DaveM
  13  */
  14
  15 #ifdef VERIFY_SG
  16 static int verify_lengths(struct scatterlist *sglist, int nents, int npages)
  17 {
  18         int sg_len, dma_len;
  19         int i, pgcount;
  20         struct scatterlist *sg;
  21
  22         sg_len = 0;
  23         for_each_sg(sglist, sg, nents, i)
  24                 sg_len += sg->length;
  25
  26         dma_len = 0;
  27         for_each_sg(sglist, sg, nents, i) {
  28                 if (!sg->dma_length)
  29                         break;
  30                 dma_len += sg->dma_length;
  31         }
  32
  33         if (sg_len != dma_len) {
  34                 printk("verify_lengths: Error, different, sg[%d] dma[%d]\n",
  35                        sg_len, dma_len);
  36                 return -1;
  37         }
  38
  39         pgcount = 0;
  40         for_each_sg(sglist, sg, nents, i) {
  41                 unsigned long start, end;
  42
  43                 if (!sg->dma_length)
  44                         break;
  45
  46                 start = sg->dma_address;
  47                 start = start & IO_PAGE_MASK;
  48
  49                 end = sg->dma_address + sg->dma_length;
  50                 end = (end + (IO_PAGE_SIZE - 1)) & IO_PAGE_MASK;
  51
  52                 pgcount += ((end - start) >> IO_PAGE_SHIFT);
  53         }
  54
  55         if (pgcount != npages) {
  56                 printk("verify_lengths: Error, page count wrong, "
  57                        "npages[%d] pgcount[%d]\n",
  58                        npages, pgcount);
  59                 return -1;
  60         }
  61
  62         /* This test passes... */
  63         return 0;
  64 }
  65
  66 static int verify_one_map(struct scatterlist *dma_sg, struct scatterlist **__sg, int nents, iopte_t **__iopte)
  67 {
  68         struct scatterlist *sg = *__sg;
  69         iopte_t *iopte = *__iopte;
  70         u32 dlen = dma_sg->dma_length;
  71         u32 daddr;
  72         unsigned int sglen;
  73         unsigned long sgaddr;
  74
  75         daddr = dma_sg->dma_address;
  76         sglen = sg->length;
  77         sgaddr = (unsigned long) sg_virt(sg);
  78         while (dlen > 0) {
  79                 unsigned long paddr;
  80
  81                 /* SG and DMA_SG must begin at the same sub-page boundary. */
  82                 if ((sgaddr & ~IO_PAGE_MASK) != (daddr & ~IO_PAGE_MASK)) {
  83                         printk("verify_one_map: Wrong start offset "
  84                                "sg[%08lx] dma[%08x]\n",
  85                                sgaddr, daddr);
  86                         nents = -1;
  87                         goto out;
  88                 }
  89
  90                 /* Verify the IOPTE points to the right page. */
  91                 paddr = iopte_val(*iopte) & IOPTE_PAGE;
  92                 if ((paddr + PAGE_OFFSET) != (sgaddr & IO_PAGE_MASK)) {
  93                         printk("verify_one_map: IOPTE[%08lx] maps the "
  94                                "wrong page, should be [%08lx]\n",
  95                                iopte_val(*iopte), (sgaddr & IO_PAGE_MASK) - PAGE_OFFSET);
  96                         nents = -1;
  97                         goto out;
  98                 }
  99
 100                 /* If this SG crosses a page, adjust to that next page
 101                  * boundary and loop.
 102                  */
 103                 if ((sgaddr & IO_PAGE_MASK) ^ ((sgaddr + sglen - 1) & IO_PAGE_MASK)) {
 104                         unsigned long next_page, diff;
 105
 106                         next_page = (sgaddr + IO_PAGE_SIZE) & IO_PAGE_MASK;
 107                         diff = next_page - sgaddr;
 108                         sgaddr += diff;
 109                         daddr += diff;
 110                         sglen -= diff;
 111                         dlen -= diff;
 112                         if (dlen > 0)
 113                                 iopte++;
 114                         continue;
 115                 }
 116
 117                 /* SG wholly consumed within this page. */
 118                 daddr += sglen;
 119                 dlen -= sglen;
 120
 121                 if (dlen > 0 && ((daddr & ~IO_PAGE_MASK) == 0))
 122                         iopte++;
 123
 124                 sg = sg_next(sg);
 125                 if (--nents <= 0)
 126                         break;
 127                 sgaddr = (unsigned long) sg_virt(sg);
 128                 sglen = sg->length;
 129         }
 130         if (dlen < 0) {
 131                 /* Transfer overrun, big problems. */
 132                 printk("verify_one_map: Transfer overrun by %d bytes.\n",
 133                        -dlen);
 134                 nents = -1;
 135         } else {
 136                 /* Advance to next dma_sg implies that the next iopte will
 137                  * begin it.
 138                  */
 139                 iopte++;
 140         }
 141
 142 out:
 143         *__sg = sg;
 144         *__iopte = iopte;
 145         return nents;
 146 }
 147
 148 static int verify_maps(struct scatterlist *sg, int nents, iopte_t *iopte)
 149 {
 150         struct scatterlist *dma_sg = sg;
 151         struct scatterlist *orig_dma_sg = dma_sg;
 152         int orig_nents = nents;
 153
 154         for (;;) {
 155                 nents = verify_one_map(dma_sg, &sg, nents, &iopte);
 156                 if (nents <= 0)
 157                         break;
 158                 dma_sg = sg_next(dma_sg);
 159                 if (dma_sg->dma_length == 0)
 160                         break;
 161         }
 162
 163         if (nents > 0) {
 164                 printk("verify_maps: dma maps consumed by some sgs remain (%d)\n",
 165                        nents);
 166                 return -1;
 167         }
 168
 169         if (nents < 0) {
 170                 printk("verify_maps: Error, messed up mappings, "
 171                        "at sg %d dma_sg %d\n",
 172                        (int) (orig_nents + nents), (int) (dma_sg - orig_dma_sg));
 173                 return -1;
 174         }
 175
 176         /* This test passes... */
 177         return 0;
 178 }
 179
 180 void verify_sglist(struct scatterlist *sglist, int nents, iopte_t *iopte, int npages)
 181 {
 182         struct scatterlist *sg;
 183
 184         if (verify_lengths(sglist, nents, npages) < 0 ||
 185             verify_maps(sglist, nents, iopte) < 0) {
 186                 int i;
 187
 188                 printk("verify_sglist: Crap, messed up mappings, dumping, iodma at ");
 189                 printk("%016lx.\n", sglist->dma_address & IO_PAGE_MASK);
 190
 191                 for_each_sg(sglist, sg, nents, i) {
 192                         printk("sg(%d): page_addr(%p) off(%x) length(%x) "
 193                                "dma_address[%016x] dma_length[%016x]\n",
 194                                i,
 195                                page_address(sg_page(sg)), sg->offset,
 196                                sg->length,
 197                                sg->dma_address, sg->dma_length);
 198                 }
 199         }
 200
 201         /* Seems to be ok */
 202 }
 203 #endif
 204
 205 unsigned long prepare_sg(struct device *dev, struct scatterlist *sg, int nents)
 206 {
 207         struct scatterlist *dma_sg = sg;
 208         unsigned long prev;
 209         u32 dent_addr, dent_len;
 210         unsigned int max_seg_size;
 211
 212         prev  = (unsigned long) sg_virt(sg);
 213         prev += (unsigned long) (dent_len = sg->length);
 214         dent_addr = (u32) ((unsigned long)(sg_virt(sg)) & (IO_PAGE_SIZE - 1UL));
 215         max_seg_size = dma_get_max_seg_size(dev);
 216         while (--nents) {
 217                 unsigned long addr;
 218
 219                 sg = sg_next(sg);
 220                 addr = (unsigned long) sg_virt(sg);
 221                 if (! VCONTIG(prev, addr) ||
 222                         dent_len + sg->length > max_seg_size) {
 223                         dma_sg->dma_address = dent_addr;
 224                         dma_sg->dma_length = dent_len;
 225                         dma_sg = sg_next(dma_sg);
 226
 227                         dent_addr = ((dent_addr +
 228                                       dent_len +
 229                                       (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT);
 230                         dent_addr <<= IO_PAGE_SHIFT;
 231                         dent_addr += addr & (IO_PAGE_SIZE - 1UL);
 232                         dent_len = 0;
 233                 }
 234                 dent_len += sg->length;
 235                 prev = addr + sg->length;
 236         }
 237         dma_sg->dma_address = dent_addr;
 238         dma_sg->dma_length = dent_len;
 239
 240         if (dma_sg != sg) {
 241                 dma_sg = sg_next(dma_sg);
 242                 dma_sg->dma_length = 0;
 243         }
 244
 245         return ((unsigned long) dent_addr +
 246                 (unsigned long) dent_len +
 247                 (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT;
 248 }