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@xxxxxxxxx>
Cc: Peer Chen <pchen@xxxxxxxxxx>
Cc: Volker Armin Hemmann <volker.armin.hemmann@xxxxxxxxxxxxxxx>
---
drivers/ata/ahci.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 739ba3f..711b5d7 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -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);
}
/**
--
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