libata: Support chips with 64K PRD quirk
Add ata_dumb_qc_prep and supporting logic so that a driver can just
specify it needs to be helped in this area. 64K entries are split
as with drivers/ide.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 74c4cd9..5b25311 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4103,6 +4103,68 @@
}
/**
+ * ata_fill_sg_dumb - Fill PCI IDE PRD table
+ * @qc: Metadata associated with taskfile to be transferred
+ *
+ * Fill PCI IDE PRD (scatter-gather) table with segments
+ * associated with the current disk command. Perform the fill
+ * so that we avoid writing any length 64K records for
+ * controllers that don't follow the spec.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host lock)
+ *
+ */
+static void ata_fill_sg_dumb(struct ata_queued_cmd *qc)
+{
+ struct ata_port *ap = qc->ap;
+ struct scatterlist *sg;
+ unsigned int idx;
+
+ WARN_ON(qc->__sg == NULL);
+ WARN_ON(qc->n_elem == 0 && qc->pad_len == 0);
+
+ idx = 0;
+ ata_for_each_sg(sg, qc) {
+ u32 addr, offset;
+ u32 sg_len, len, blen;
+
+ /* determine if physical DMA addr spans 64K boundary.
+ * Note h/w doesn't support 64-bit, so we unconditionally
+ * truncate dma_addr_t to u32.
+ */
+ addr = (u32) sg_dma_address(sg);
+ sg_len = sg_dma_len(sg);
+
+ while (sg_len) {
+ offset = addr & 0xffff;
+ len = sg_len;
+ if ((offset + sg_len) > 0x10000)
+ len = 0x10000 - offset;
+
+ blen = len & 0xffff;
+ ap->prd[idx].addr = cpu_to_le32(addr);
+ if (blen == 0) {
+ /* Some PATA chipsets like the CS5530 can't
+ cope with 0x0000 meaning 64K as the spec says */
+ ap->prd[idx].flags_len = cpu_to_le32(0x8000);
+ blen = 0x8000;
+ ap->prd[++idx].addr = cpu_to_le32(addr + 0x8000);
+ }
+ ap->prd[idx].flags_len = cpu_to_le32(blen);
+ VPRINTK("PRD[%u] = (0x%X, 0x%X)\n", idx, addr, len);
+
+ idx++;
+ sg_len -= len;
+ addr += len;
+ }
+ }
+
+ if (idx)
+ ap->prd[idx - 1].flags_len |= cpu_to_le32(ATA_PRD_EOT);
+}
+
+/**
* ata_check_atapi_dma - Check whether ATAPI DMA can be supported
* @qc: Metadata associated with taskfile to check
*
@@ -4149,6 +4211,23 @@
ata_fill_sg(qc);
}
+/**
+ * ata_dumb_qc_prep - Prepare taskfile for submission
+ * @qc: Metadata associated with taskfile to be prepared
+ *
+ * Prepare ATA taskfile for submission.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host lock)
+ */
+void ata_dumb_qc_prep(struct ata_queued_cmd *qc)
+{
+ if (!(qc->flags & ATA_QCFLAG_DMAMAP))
+ return;
+
+ ata_fill_sg_dumb(qc);
+}
+
void ata_noop_qc_prep(struct ata_queued_cmd *qc) { }
/**
@@ -6821,6 +6900,7 @@
EXPORT_SYMBOL_GPL(ata_data_xfer);
EXPORT_SYMBOL_GPL(ata_data_xfer_noirq);
EXPORT_SYMBOL_GPL(ata_qc_prep);
+EXPORT_SYMBOL_GPL(ata_dumb_qc_prep);
EXPORT_SYMBOL_GPL(ata_noop_qc_prep);
EXPORT_SYMBOL_GPL(ata_bmdma_setup);
EXPORT_SYMBOL_GPL(ata_bmdma_start);