Peer Chen wrote:
According to the description of section 5.2.2.1 and 10.1.2 of AHCI specification rev1_1/rev1_2, GHC.HR shall only be set to ¡®1¡¯
by software when GHC.AE is set to ¡®1¡¯.
Signed-off-by: Peer Chen <peerchen@xxxxxxxxx>
---
--- linux-2.6.23-rc7/drivers/ata/ahci.c.orig 2007-09-20 11:01:55.000000000 -0400
+++ linux-2.6.23-rc7/drivers/ata/ahci.c 2007-09-20 11:07:31.000000000 -0400
@@ -834,6 +834,10 @@ static int ahci_reset_controller(struct
void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
u32 tmp;
+ /* turn on AHCI mode before controller reset*/
+ writel(HOST_AHCI_EN, mmio + HOST_CTL);
+ (void) readl(mmio + HOST_CTL); /* flush */
applied the attached patch, inspired by yours.
commit 5fca365d6109b51cfeb3515ca660cd2dc6e8822c
Author: Jeff Garzik <jeff@xxxxxxxxxx>
Date: Wed Sep 26 00:02:41 2007 -0400
[libata] AHCI: enable AHCI mode, before using AHCI reset
AHCI spec says host-reset bit may only be set when the ahci-enable bit
is also set.
Noticed by Peer Chen <peerchen@xxxxxxxxx>
Signed-off-by: Jeff Garzik <jeff@xxxxxxxxxx>
drivers/ata/ahci.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
5fca365d6109b51cfeb3515ca660cd2dc6e8822c
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 9f3c591..b615390 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -827,8 +827,14 @@ static int ahci_reset_controller(struct ata_host *host)
void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
u32 tmp;
- /* global controller reset */
+ /* we must be in AHCI mode, before using anything
+ * AHCI-specific, such as HOST_RESET.
+ */
tmp = readl(mmio + HOST_CTL);
+ if (!(tmp & HOST_AHCI_EN))
+ writel(tmp | HOST_AHCI_EN, mmio + HOST_CTL);
+
+ /* global controller reset */
if ((tmp & HOST_RESET) == 0) {
writel(tmp | HOST_RESET, mmio + HOST_CTL);
readl(mmio + HOST_CTL); /* flush */
