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/* $Id: iommu_common.c,v 1.2 1999/12/19 09:17:53 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
int verify_lengths(struct scatterlist *sg, int nents, int npages)
{
int sg_len, dma_len;
int i, pgcount;
sg_len = 0;
for (i = 0; i < nents; i++)
sg_len += sg[i].length;
dma_len = 0;
for (i = 0; i < nents && sg[i].dvma_length; i++)
dma_len += sg[i].dvma_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 (i = 0; i < nents && sg[i].dvma_length; i++) {
unsigned long start, end;
start = sg[i].dvma_address;
start = start & PAGE_MASK;
end = sg[i].dvma_address + sg[i].dvma_length;
end = (end + (PAGE_SIZE - 1)) & PAGE_MASK;
pgcount += ((end - start) >> PAGE_SHIFT);
}
if (pgcount != npages) {
printk("verify_langths: Error, page count wrong, "
"npages[%d] pgcount[%d]\n",
npages, pgcount);
return -1;
}
/* This test passes... */
return 0;
}
int verify_one_map(struct scatterlist *dma_sg, struct scatterlist **__sg, int nents, iopte_t **__iopte)
{
struct scatterlist *sg = *__sg;
iopte_t *iopte = *__iopte;
int retval = 0;
u32 dlen = dma_sg->dvma_length;
u32 daddr = dma_sg->dvma_address;
unsigned int sglen;
unsigned long sgaddr;
sglen = sg->length;
sgaddr = (unsigned long) sg->address;
while (dlen > 0) {
unsigned long paddr;
/* SG and DMA_SG must begin at the same sub-page boundary. */
if ((sgaddr & ~PAGE_MASK) != (daddr & ~PAGE_MASK)) {
printk("verify_one_map: Wrong start offset "
"sg[%08lx] dma[%08x]\n",
sgaddr, daddr);
retval = -nents;
goto out;
}
/* Verify the IOPTE points to the right page. */
paddr = iopte_val(*iopte) & IOPTE_PAGE;
if ((paddr + PAGE_OFFSET) != (sgaddr & PAGE_MASK)) {
printk("verify_one_map: IOPTE[%08lx] maps the "
"wrong page, should be [%08lx]\n",
iopte_val(*iopte), (sgaddr & PAGE_MASK) - PAGE_OFFSET);
retval = -nents;
goto out;
}
/* If this SG crosses a page, adjust to that next page
* boundary and loop.
*/
if ((sgaddr & PAGE_MASK) ^ ((sgaddr + sglen - 1) & PAGE_MASK)) {
unsigned long next_page, diff;
next_page = (sgaddr + PAGE_SIZE) & 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 & ~PAGE_MASK) == 0))
iopte++;
sg++;
sgaddr = (unsigned long) sg->address;
sglen = sg->length;
}
if (dlen < 0) {
/* Transfer overrun, big problems. */
printk("verify_one_map: Transfer overrun by %d bytes.\n",
-dlen);
retval = -nents;
} else {
/* Advance to next dma_sg implies that the next iopte will
* begin it.
*/
iopte++;
}
out:
*__sg = sg;
*__iopte = iopte;
return retval;
}
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++;
if (dma_sg->dvma_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 *sg, int nents, iopte_t *iopte, int npages)
{
if (verify_lengths(sg, nents, npages) < 0 ||
verify_maps(sg, nents, iopte) < 0) {
int i;
printk("verify_sglist: Crap, messed up mappings, dumping, iodma at %08x.\n",
(u32) (sg->dvma_address & PAGE_MASK));
for (i = 0; i < nents; i++) {
printk("sg(%d): address(%p) length(%x) "
"dma_address[%08x] dma_length[%08x]\n",
i,
sg[i].address, sg[i].length,
sg[i].dvma_address, sg[i].dvma_length);
}
}
/* Seems to be ok */
}
#endif
/* Two addresses are "virtually contiguous" if and only if:
* 1) They are equal, or...
* 2) They are both on a page boundry
*/
#define VCONTIG(__X, __Y) (((__X) == (__Y)) || \
(((__X) | (__Y)) << (64UL - PAGE_SHIFT)) == 0UL)
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->address;
prev += (unsigned long) (dent_len = sg->length);
dent_addr = (u32) ((unsigned long)sg->address & (PAGE_SIZE - 1UL));
while (--nents) {
unsigned long addr;
sg++;
addr = (unsigned long) sg->address;
if (! VCONTIG(prev, addr)) {
dma_sg->dvma_address = dent_addr;
dma_sg->dvma_length = dent_len;
dma_sg++;
dent_addr = ((dent_addr +
dent_len +
(PAGE_SIZE - 1UL)) >> PAGE_SHIFT);
dent_addr <<= PAGE_SHIFT;
dent_addr += addr & (PAGE_SIZE - 1UL);
dent_len = 0;
}
dent_len += sg->length;
prev = addr + sg->length;
}
dma_sg->dvma_address = dent_addr;
dma_sg->dvma_length = dent_len;
return ((unsigned long) dent_addr +
(unsigned long) dent_len +
(PAGE_SIZE - 1UL)) >> PAGE_SHIFT;
}
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