ide: cleanup ide_build_dmatable()
- use for_each_sg() - move printing 'DMA table too small' message below use_pio_instead label - merge '64KB bug' comment with function documentation - fix intendation There should be no functional changes caused by this patch. Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
This commit is contained in:
parent
c19f7f226b
commit
14c123f371
|
@ -153,8 +153,11 @@ EXPORT_SYMBOL_GPL(ide_build_sglist);
|
|||
*
|
||||
* ide_build_dmatable() prepares a dma request. We map the command
|
||||
* to get the pci bus addresses of the buffers and then build up
|
||||
* the PRD table that the IDE layer wants to be fed. The code
|
||||
* knows about the 64K wrap bug in the CS5530.
|
||||
* the PRD table that the IDE layer wants to be fed.
|
||||
*
|
||||
* Most chipsets correctly interpret a length of 0x0000 as 64KB,
|
||||
* but at least one (e.g. CS5530) misinterprets it as zero (!).
|
||||
* So we break the 64KB entry into two 32KB entries instead.
|
||||
*
|
||||
* Returns the number of built PRD entries if all went okay,
|
||||
* returns 0 otherwise.
|
||||
|
@ -171,15 +174,12 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
|
|||
int i;
|
||||
struct scatterlist *sg;
|
||||
|
||||
hwif->sg_nents = i = ide_build_sglist(drive, rq);
|
||||
|
||||
if (!i)
|
||||
hwif->sg_nents = ide_build_sglist(drive, rq);
|
||||
if (hwif->sg_nents == 0)
|
||||
return 0;
|
||||
|
||||
sg = hwif->sg_table;
|
||||
while (i) {
|
||||
u32 cur_addr;
|
||||
u32 cur_len;
|
||||
for_each_sg(hwif->sg_table, sg, hwif->sg_nents, i) {
|
||||
u32 cur_addr, cur_len, xcount, bcount;
|
||||
|
||||
cur_addr = sg_dma_address(sg);
|
||||
cur_len = sg_dma_len(sg);
|
||||
|
@ -191,40 +191,27 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
|
|||
*/
|
||||
|
||||
while (cur_len) {
|
||||
if (count++ >= PRD_ENTRIES) {
|
||||
printk(KERN_ERR "%s: DMA table too small\n", drive->name);
|
||||
if (count++ >= PRD_ENTRIES)
|
||||
goto use_pio_instead;
|
||||
} else {
|
||||
u32 xcount, bcount = 0x10000 - (cur_addr & 0xffff);
|
||||
|
||||
if (bcount > cur_len)
|
||||
bcount = cur_len;
|
||||
*table++ = cpu_to_le32(cur_addr);
|
||||
xcount = bcount & 0xffff;
|
||||
if (is_trm290)
|
||||
xcount = ((xcount >> 2) - 1) << 16;
|
||||
else if (xcount == 0x0000) {
|
||||
/*
|
||||
* Most chipsets correctly interpret a length of 0x0000 as 64KB,
|
||||
* but at least one (e.g. CS5530) misinterprets it as zero (!).
|
||||
* So here we break the 64KB entry into two 32KB entries instead.
|
||||
*/
|
||||
if (count++ >= PRD_ENTRIES) {
|
||||
printk(KERN_ERR "%s: DMA table too small\n", drive->name);
|
||||
goto use_pio_instead;
|
||||
}
|
||||
*table++ = cpu_to_le32(0x8000);
|
||||
*table++ = cpu_to_le32(cur_addr + 0x8000);
|
||||
xcount = 0x8000;
|
||||
}
|
||||
*table++ = cpu_to_le32(xcount);
|
||||
cur_addr += bcount;
|
||||
cur_len -= bcount;
|
||||
bcount = 0x10000 - (cur_addr & 0xffff);
|
||||
if (bcount > cur_len)
|
||||
bcount = cur_len;
|
||||
*table++ = cpu_to_le32(cur_addr);
|
||||
xcount = bcount & 0xffff;
|
||||
if (is_trm290)
|
||||
xcount = ((xcount >> 2) - 1) << 16;
|
||||
if (xcount == 0x0000) {
|
||||
if (count++ >= PRD_ENTRIES)
|
||||
goto use_pio_instead;
|
||||
*table++ = cpu_to_le32(0x8000);
|
||||
*table++ = cpu_to_le32(cur_addr + 0x8000);
|
||||
xcount = 0x8000;
|
||||
}
|
||||
*table++ = cpu_to_le32(xcount);
|
||||
cur_addr += bcount;
|
||||
cur_len -= bcount;
|
||||
}
|
||||
|
||||
sg = sg_next(sg);
|
||||
i--;
|
||||
}
|
||||
|
||||
if (count) {
|
||||
|
@ -233,14 +220,14 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
|
|||
return count;
|
||||
}
|
||||
|
||||
printk(KERN_ERR "%s: empty DMA table?\n", drive->name);
|
||||
|
||||
use_pio_instead:
|
||||
printk(KERN_ERR "%s: %s\n", drive->name,
|
||||
count ? "DMA table too small" : "empty DMA table?");
|
||||
|
||||
ide_destroy_dmatable(drive);
|
||||
|
||||
return 0; /* revert to PIO for this request */
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL_GPL(ide_build_dmatable);
|
||||
#endif
|
||||
|
||||
|
|
Loading…
Reference in New Issue
Block a user