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Commit 1102407b authored by Suman Tripathi's avatar Suman Tripathi Committed by Tejun Heo
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ahci_xgene: Fix the DMA state machine lockup for the ATA_CMD_PACKET PIO mode command. 



This patch addresses the issue with ATA_CMD_PACKET pio mode
command for enumeration and device detection with ATAPI devices.
The X-Gene AHCI controller has an errata in which it cannot clear
the BSY bit after the PIO setup FIS. The dma state machine enters
CMFatalErrorUpdate state and locks up.

Signed-off-by: default avatarSuman Tripathi <stripathi@apm.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 5c0b8e0d

drivers/ata/ahci_xgene.c

+7 −5
Original line number Diff line number Diff line
@@ -125,10 +125,11 @@ static int xgene_ahci_restart_engine(struct ata_port *ap) 
 * xgene_ahci_qc_issue - Issue commands to the device

 * @qc: Command to issue

 *

 * Due to Hardware errata for IDENTIFY DEVICE command, the controller cannot

 * clear the BSY bit after receiving the PIO setup FIS. This results in the dma

 * state machine goes into the CMFatalErrorUpdate state and locks up. By

 * restarting the dma engine, it removes the controller out of lock up state.

 * Due to Hardware errata for IDENTIFY DEVICE command and PACKET

 * command of ATAPI protocol set, the controller cannot clear the BSY bit

 * after receiving the PIO setup FIS. This results in the DMA state machine

 * going into the CMFatalErrorUpdate state and locks up. By restarting the

 * DMA engine, it removes the controller out of lock up state.

 */

static unsigned int xgene_ahci_qc_issue(struct ata_queued_cmd *qc)

{
@@ -137,7 +138,8 @@ static unsigned int xgene_ahci_qc_issue(struct ata_queued_cmd *qc) 
	struct xgene_ahci_context *ctx = hpriv->plat_data;

	int rc = 0;



	if (unlikely(ctx->last_cmd[ap->port_no] == ATA_CMD_ID_ATA))

	if (unlikely((ctx->last_cmd[ap->port_no] == ATA_CMD_ID_ATA) ||

	    (ctx->last_cmd[ap->port_no] == ATA_CMD_PACKET)))

		xgene_ahci_restart_engine(ap);



	rc = ahci_qc_issue(qc);