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Subject[14/66] libahci: fix result_tf handling after an ATA PIO data-in command
2.6.36-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Tejun Heo <tj@kernel.org>

commit 6ad601955315b010a117306b994f2204fae85fdc upstream.

ATA devices don't send D2H Reg FIS after an successful ATA PIO data-in
command. The host is supposed to take the TF and E_Status of the
preceding PIO Setup FIS. Update ahci_qc_fill_rtf() such that it takes
TF + E_Status from PIO Setup FIS after a successful ATA PIO data-in
command.

Without this patch, result_tf for such a command is filled with the
content of the previous D2H Reg FIS which belongs to a previous
command, which can make the command incorrectly seen as failed.

* Patch updated to grab the whole TF + E_Status from PIO Setup FIS
instead of just E_Status as suggested by Robert Hancock.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Mark Lord <kernel@teksavvy.com>
Cc: Robert Hancock <hancockrwd@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/ata/ahci.h | 1 +
drivers/ata/libahci.c | 18 +++++++++++++++---
2 files changed, 16 insertions(+), 3 deletions(-)

--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -72,6 +72,7 @@ enum {
AHCI_CMD_RESET = (1 << 8),
AHCI_CMD_CLR_BUSY = (1 << 10),

+ RX_FIS_PIO_SETUP = 0x20, /* offset of PIO Setup FIS data */
RX_FIS_D2H_REG = 0x40, /* offset of D2H Register FIS data */
RX_FIS_SDB = 0x58, /* offset of SDB FIS data */
RX_FIS_UNK = 0x60, /* offset of Unknown FIS data */
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1830,12 +1830,24 @@ static unsigned int ahci_qc_issue(struct
static bool ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
{
struct ahci_port_priv *pp = qc->ap->private_data;
- u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
+ u8 *rx_fis = pp->rx_fis;

if (pp->fbs_enabled)
- d2h_fis += qc->dev->link->pmp * AHCI_RX_FIS_SZ;
+ rx_fis += qc->dev->link->pmp * AHCI_RX_FIS_SZ;
+
+ /*
+ * After a successful execution of an ATA PIO data-in command,
+ * the device doesn't send D2H Reg FIS to update the TF and
+ * the host should take TF and E_Status from the preceding PIO
+ * Setup FIS.
+ */
+ if (qc->tf.protocol == ATA_PROT_PIO && qc->dma_dir == DMA_FROM_DEVICE &&
+ !(qc->flags & ATA_QCFLAG_FAILED)) {
+ ata_tf_from_fis(rx_fis + RX_FIS_PIO_SETUP, &qc->result_tf);
+ qc->result_tf.command = (rx_fis + RX_FIS_PIO_SETUP)[15];
+ } else
+ ata_tf_from_fis(rx_fis + RX_FIS_D2H_REG, &qc->result_tf);

- ata_tf_from_fis(d2h_fis, &qc->result_tf);
return true;
}




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