Logo Search packages:      
Sourcecode: linux version File versions  Download package

iommu_common.c

/* $Id: iommu_common.c,v 1.9 2001/12/17 07:05:09 davem Exp $
 * iommu_common.c: UltraSparc SBUS/PCI common iommu code.
 *
 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
 */

#include "iommu_common.h"

/* You are _strongly_ advised to enable the following debugging code
 * any time you make changes to the sg code below, run it for a while
 * with filesystems mounted read-only before buying the farm... -DaveM
 */

#ifdef VERIFY_SG
static int verify_lengths(struct scatterlist *sglist, int nents, int npages)
{
      int sg_len, dma_len;
      int i, pgcount;
      struct scatterlist *sg;

      sg_len = 0;
      for_each_sg(sglist, sg, nents, i)
            sg_len += sg->length;

      dma_len = 0;
      for_each_sg(sglist, sg, nents, i) {
            if (!sg->dma_length)
                  break;
            dma_len += sg->dma_length;
      }

      if (sg_len != dma_len) {
            printk("verify_lengths: Error, different, sg[%d] dma[%d]\n",
                   sg_len, dma_len);
            return -1;
      }

      pgcount = 0;
      for_each_sg(sglist, sg, nents, i) {
            unsigned long start, end;

            if (!sg->dma_length)
                  break;

            start = sg->dma_address;
            start = start & IO_PAGE_MASK;

            end = sg->dma_address + sg->dma_length;
            end = (end + (IO_PAGE_SIZE - 1)) & IO_PAGE_MASK;

            pgcount += ((end - start) >> IO_PAGE_SHIFT);
      }

      if (pgcount != npages) {
            printk("verify_lengths: Error, page count wrong, "
                   "npages[%d] pgcount[%d]\n",
                   npages, pgcount);
            return -1;
      }

      /* This test passes... */
      return 0;
}

static int verify_one_map(struct scatterlist *dma_sg, struct scatterlist **__sg, int nents, iopte_t **__iopte)
{
      struct scatterlist *sg = *__sg;
      iopte_t *iopte = *__iopte;
      u32 dlen = dma_sg->dma_length;
      u32 daddr;
      unsigned int sglen;
      unsigned long sgaddr;

      daddr = dma_sg->dma_address;
      sglen = sg->length;
      sgaddr = (unsigned long) sg_virt(sg);
      while (dlen > 0) {
            unsigned long paddr;

            /* SG and DMA_SG must begin at the same sub-page boundary. */
            if ((sgaddr & ~IO_PAGE_MASK) != (daddr & ~IO_PAGE_MASK)) {
                  printk("verify_one_map: Wrong start offset "
                         "sg[%08lx] dma[%08x]\n",
                         sgaddr, daddr);
                  nents = -1;
                  goto out;
            }

            /* Verify the IOPTE points to the right page. */
            paddr = iopte_val(*iopte) & IOPTE_PAGE;
            if ((paddr + PAGE_OFFSET) != (sgaddr & IO_PAGE_MASK)) {
                  printk("verify_one_map: IOPTE[%08lx] maps the "
                         "wrong page, should be [%08lx]\n",
                         iopte_val(*iopte), (sgaddr & IO_PAGE_MASK) - PAGE_OFFSET);
                  nents = -1;
                  goto out;
            }

            /* If this SG crosses a page, adjust to that next page
             * boundary and loop.
             */
            if ((sgaddr & IO_PAGE_MASK) ^ ((sgaddr + sglen - 1) & IO_PAGE_MASK)) {
                  unsigned long next_page, diff;

                  next_page = (sgaddr + IO_PAGE_SIZE) & IO_PAGE_MASK;
                  diff = next_page - sgaddr;
                  sgaddr += diff;
                  daddr += diff;
                  sglen -= diff;
                  dlen -= diff;
                  if (dlen > 0)
                        iopte++;
                  continue;
            }

            /* SG wholly consumed within this page. */
            daddr += sglen;
            dlen -= sglen;

            if (dlen > 0 && ((daddr & ~IO_PAGE_MASK) == 0))
                  iopte++;

            sg = sg_next(sg);
            if (--nents <= 0)
                  break;
            sgaddr = (unsigned long) sg_virt(sg);
            sglen = sg->length;
      }
      if (dlen < 0) {
            /* Transfer overrun, big problems. */
            printk("verify_one_map: Transfer overrun by %d bytes.\n",
                   -dlen);
            nents = -1;
      } else {
            /* Advance to next dma_sg implies that the next iopte will
             * begin it.
             */
            iopte++;
      }

out:
      *__sg = sg;
      *__iopte = iopte;
      return nents;
}

static int verify_maps(struct scatterlist *sg, int nents, iopte_t *iopte)
{
      struct scatterlist *dma_sg = sg;
      struct scatterlist *orig_dma_sg = dma_sg;
      int orig_nents = nents;

      for (;;) {
            nents = verify_one_map(dma_sg, &sg, nents, &iopte);
            if (nents <= 0)
                  break;
            dma_sg = sg_next(dma_sg);
            if (dma_sg->dma_length == 0)
                  break;
      }

      if (nents > 0) {
            printk("verify_maps: dma maps consumed by some sgs remain (%d)\n",
                   nents);
            return -1;
      }

      if (nents < 0) {
            printk("verify_maps: Error, messed up mappings, "
                   "at sg %d dma_sg %d\n",
                   (int) (orig_nents + nents), (int) (dma_sg - orig_dma_sg));
            return -1;
      }

      /* This test passes... */
      return 0;
}

void verify_sglist(struct scatterlist *sglist, int nents, iopte_t *iopte, int npages)
{
      struct scatterlist *sg;

      if (verify_lengths(sglist, nents, npages) < 0 ||
          verify_maps(sglist, nents, iopte) < 0) {
            int i;

            printk("verify_sglist: Crap, messed up mappings, dumping, iodma at ");
            printk("%016lx.\n", sglist->dma_address & IO_PAGE_MASK);

            for_each_sg(sglist, sg, nents, i) {
                  printk("sg(%d): page_addr(%p) off(%x) length(%x) "
                         "dma_address[%016x] dma_length[%016x]\n",
                         i,
                         page_address(sg_page(sg)), sg->offset,
                         sg->length,
                         sg->dma_address, sg->dma_length);
            }
      }

      /* Seems to be ok */
}
#endif

unsigned long prepare_sg(struct scatterlist *sg, int nents)
{
      struct scatterlist *dma_sg = sg;
      unsigned long prev;
      u32 dent_addr, dent_len;

      prev  = (unsigned long) sg_virt(sg);
      prev += (unsigned long) (dent_len = sg->length);
      dent_addr = (u32) ((unsigned long)(sg_virt(sg)) & (IO_PAGE_SIZE - 1UL));
      while (--nents) {
            unsigned long addr;

            sg = sg_next(sg);
            addr = (unsigned long) sg_virt(sg);
            if (! VCONTIG(prev, addr)) {
                  dma_sg->dma_address = dent_addr;
                  dma_sg->dma_length = dent_len;
                  dma_sg = sg_next(dma_sg);

                  dent_addr = ((dent_addr +
                              dent_len +
                              (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT);
                  dent_addr <<= IO_PAGE_SHIFT;
                  dent_addr += addr & (IO_PAGE_SIZE - 1UL);
                  dent_len = 0;
            }
            dent_len += sg->length;
            prev = addr + sg->length;
      }
      dma_sg->dma_address = dent_addr;
      dma_sg->dma_length = dent_len;

      if (dma_sg != sg) {
            dma_sg = sg_next(dma_sg);
            dma_sg->dma_length = 0;
      }

      return ((unsigned long) dent_addr +
            (unsigned long) dent_len +
            (IO_PAGE_SIZE - 1UL)) >> IO_PAGE_SHIFT;
}

Generated by  Doxygen 1.6.0   Back to index