diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/ide/ide-dma.c | 73 |
1 files changed, 30 insertions, 43 deletions
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c index 83885ba0496c..4d212b867c35 100644 --- a/drivers/ide/ide-dma.c +++ b/drivers/ide/ide-dma.c @@ -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 |
