ahci: retry enabling AHCI a few times before spitting out WARN_ON()
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>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 986e332..7c4f886 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -556,16 +556,27 @@
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);
}
/**