commit 5fca365d6109b51cfeb3515ca660cd2dc6e8822c Author: Jeff Garzik 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 Signed-off-by: Jeff Garzik 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 */