+/**
+ * k2_bmdma_setup_mmio - Set up PCI IDE BMDMA transaction (MMIO)
+ * @qc: Info associated with this ATA transaction.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ */
+
+void k2_bmdma_setup_mmio (struct ata_queued_cmd *qc)
+{
+ struct ata_port *ap = qc->ap;
+ unsigned int rw = (qc->tf.flags & ATA_TFLAG_WRITE);
+ u8 dmactl;
+ void *mmio = (void *) ap->ioaddr.bmdma_addr;
+ /* load PRD table addr. */
+ mb(); /* make sure PRD table writes are visible to controller */
+ writel(ap->prd_dma, mmio + ATA_DMA_TABLE_OFS);
+
+ /* specify data direction, triple-check start bit is clear */
+ dmactl = readb(mmio + ATA_DMA_CMD);
+ dmactl &= ~(ATA_DMA_WR | ATA_DMA_START);
+ if (!rw)
+ dmactl |= ATA_DMA_WR;
+ writeb(dmactl, mmio + ATA_DMA_CMD);
+
+ /* issue r/w command if this is not a ATA DMA command*/
+ if (qc->tf.protocol != ATA_PROT_DMA)
+ ap->ops->exec_command(ap, &qc->tf);
+}
+
+/**
+ * k2_bmdma_start_mmio - Start a PCI IDE BMDMA transaction (MMIO)
+ * @qc: Info associated with this ATA transaction.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ */
+
+void k2_bmdma_start_mmio (struct ata_queued_cmd *qc)
+{
+ struct ata_port *ap = qc->ap;
+ void *mmio = (void *) ap->ioaddr.bmdma_addr;
+ u8 dmactl;
+
+ /* start host DMA transaction */
+ dmactl = readb(mmio + ATA_DMA_CMD);
+ writeb(dmactl | ATA_DMA_START, mmio + ATA_DMA_CMD);
+ /* There is a race condition in certain SATA controllers that can
+ be seen when the r/w command is given to the controller before the
+ host DMA is started. On a Read command, the controller would initiate
+ the command to the drive even before it sees the DMA start. When there
+ are very fast drives connected to the controller, or when the data request
+ hits in the drive cache, there is the possibility that the drive returns a part
+ or all of the requested data to the controller before the DMA start is issued.
+ In this case, the controller would become confused as to what to do with the data.
+ In the worst case when all the data is returned back to the controller, the
+ controller could hang. In other cases it could return partial data returning
+ in data corruption. This problem has been seen in PPC systems and can also appear
+ on an system with very fast disks, where the SATA controller is sitting behind a
+ number of bridges, and hence there is significant latency between the r/w command
+ and the start command. */
+ /* issue r/w command if the access is to ATA*/
+ if (qc->tf.protocol == ATA_PROT_DMA)
+ ap->ops->exec_command(ap, &qc->tf);
+}