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ahci: retry enabling AHCI a few times before spitting out WARN_ON()

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Some chips need AHCI_EN set more than once to actually set it.  Try a
few times before giving up and spitting out WARN_ON().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Peer Chen <pchen@nvidia.com>
Cc: Volker Armin Hemmann <volker.armin.hemmann@tu-clausthal.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Tejun Heo 2008-04-23 20:52:58 +09:00 committed by Jeff Garzik
parent 411cb3869a
commit 15fe982e42
1 changed files with 13 additions and 2 deletions
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15
drivers/ata/ahci.c
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@ -556,16 +556,27 @@ static inline void __iomem *ahci_port_base(struct ata_port *ap)
static void ahci_enable_ahci(void __iomem *mmio)
{
int i;
u32 tmp;
/* turn on AHCI_EN */
tmp = readl(mmio + HOST_CTL);
if (!(tmp & HOST_AHCI_EN)) {
if (tmp & HOST_AHCI_EN)
return;
/* Some controllers need AHCI_EN to be written multiple times.
* Try a few times before giving up.
*/
for (i = 0; i < 5; i++) {
tmp |= HOST_AHCI_EN;
writel(tmp, mmio + HOST_CTL);
tmp = readl(mmio + HOST_CTL); /* flush && sanity check */
WARN_ON(!(tmp & HOST_AHCI_EN));
if (tmp & HOST_AHCI_EN)
return;
msleep(10);
}
WARN_ON(1);
}
/**