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@@ -153,8 +153,11 @@ EXPORT_SYMBOL_GPL(ide_build_sglist);
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*
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* ide_build_dmatable() prepares a dma request. We map the command
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* to get the pci bus addresses of the buffers and then build up
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- * the PRD table that the IDE layer wants to be fed. The code
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- * knows about the 64K wrap bug in the CS5530.
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+ * the PRD table that the IDE layer wants to be fed.
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+ *
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+ * Most chipsets correctly interpret a length of 0x0000 as 64KB,
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+ * but at least one (e.g. CS5530) misinterprets it as zero (!).
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+ * So we break the 64KB entry into two 32KB entries instead.
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*
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* Returns the number of built PRD entries if all went okay,
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* returns 0 otherwise.
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@@ -171,15 +174,12 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
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int i;
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struct scatterlist *sg;
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- hwif->sg_nents = i = ide_build_sglist(drive, rq);
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-
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- if (!i)
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+ hwif->sg_nents = ide_build_sglist(drive, rq);
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+ if (hwif->sg_nents == 0)
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return 0;
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- sg = hwif->sg_table;
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- while (i) {
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- u32 cur_addr;
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- u32 cur_len;
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+ for_each_sg(hwif->sg_table, sg, hwif->sg_nents, i) {
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+ u32 cur_addr, cur_len, xcount, bcount;
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cur_addr = sg_dma_address(sg);
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cur_len = sg_dma_len(sg);
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@@ -191,40 +191,27 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
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*/
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while (cur_len) {
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- if (count++ >= PRD_ENTRIES) {
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- printk(KERN_ERR "%s: DMA table too small\n", drive->name);
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+ if (count++ >= PRD_ENTRIES)
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goto use_pio_instead;
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- } else {
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- u32 xcount, bcount = 0x10000 - (cur_addr & 0xffff);
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-
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- if (bcount > cur_len)
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- bcount = cur_len;
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- *table++ = cpu_to_le32(cur_addr);
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- xcount = bcount & 0xffff;
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- if (is_trm290)
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- xcount = ((xcount >> 2) - 1) << 16;
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- else if (xcount == 0x0000) {
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- /*
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- * Most chipsets correctly interpret a length of 0x0000 as 64KB,
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- * but at least one (e.g. CS5530) misinterprets it as zero (!).
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- * So here we break the 64KB entry into two 32KB entries instead.
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- */
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- if (count++ >= PRD_ENTRIES) {
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- printk(KERN_ERR "%s: DMA table too small\n", drive->name);
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- goto use_pio_instead;
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- }
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- *table++ = cpu_to_le32(0x8000);
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- *table++ = cpu_to_le32(cur_addr + 0x8000);
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- xcount = 0x8000;
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- }
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- *table++ = cpu_to_le32(xcount);
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- cur_addr += bcount;
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- cur_len -= bcount;
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+
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+ bcount = 0x10000 - (cur_addr & 0xffff);
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+ if (bcount > cur_len)
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+ bcount = cur_len;
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+ *table++ = cpu_to_le32(cur_addr);
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+ xcount = bcount & 0xffff;
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+ if (is_trm290)
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+ xcount = ((xcount >> 2) - 1) << 16;
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+ if (xcount == 0x0000) {
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+ if (count++ >= PRD_ENTRIES)
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+ goto use_pio_instead;
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+ *table++ = cpu_to_le32(0x8000);
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+ *table++ = cpu_to_le32(cur_addr + 0x8000);
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+ xcount = 0x8000;
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}
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+ *table++ = cpu_to_le32(xcount);
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+ cur_addr += bcount;
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+ cur_len -= bcount;
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}
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-
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- sg = sg_next(sg);
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- i--;
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}
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if (count) {
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@@ -233,14 +220,14 @@ int ide_build_dmatable (ide_drive_t *drive, struct request *rq)
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return count;
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}
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- printk(KERN_ERR "%s: empty DMA table?\n", drive->name);
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-
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use_pio_instead:
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+ printk(KERN_ERR "%s: %s\n", drive->name,
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+ count ? "DMA table too small" : "empty DMA table?");
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+
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ide_destroy_dmatable(drive);
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return 0; /* revert to PIO for this request */
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}
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-
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EXPORT_SYMBOL_GPL(ide_build_dmatable);
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#endif
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