On 04/23/2011 02:58 AM, Jian Peng wrote:
At the end of section 10.1 of AHCI spec (rev 1.3), it states Software shall not set PxCMD.ST to 1 until it is determined that a functoinal device is present on the port as determined by PxTFD.STS.BSY=0, PxTFD.STS.DRQ=0 and PxSSTS.DET=3h Even though most AHCI host controller works without this check, specific controller will fail under this condition. Signed-off-by: Jian Peng<jipeng2005@xxxxxxxxx> --- drivers/ata/libahci.c | 21 +++++++++++++++++++++ 1 files changed, 21 insertions(+), 0 deletions(-) diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 26d4523..83ed544 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -539,6 +539,27 @@ void ahci_start_engine(struct ata_port *ap) { void __iomem *port_mmio = ahci_port_base(ap); u32 tmp; + u8 status; + + status = readl(port_mmio + PORT_TFDATA)& 0xFF; + + /* + * At end of section 10.1 of AHCI spec (rev 1.3), it states + * Software shall not set PxCMD.ST to 1 until it is determined + * that a functoinal device is present on the port as determined by + * PxTFD.STS.BSY=0, PxTFD.STS.DRQ=0 and PxSSTS.DET=3h + * + * Even though most AHCI host controllers work without this check, + * specific controller will fail under this condition + */ + if (status& (ATA_BUSY | ATA_DRQ)) + return; + else { + ahci_scr_read(&ap->link, SCR_STATUS,&tmp); + + if ((tmp& 0xf) != 0x3) + return; + }
Looks good, I'll get this queued up... -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html