ahci: factor out AHCI enabling and enable AHCI before reading CAP
Factor out AHCI enabling into ahci_enable_ahci() and enabling AHCI
before reading CAP in ahci_save_initial_config() as the spec requires
enabling AHCI mode before accessing any other registers.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 49761bc..6f089b8 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -597,6 +597,20 @@
return __ahci_port_base(ap->host, ap->port_no);
}
+static void ahci_enable_ahci(void __iomem *mmio)
+{
+ u32 tmp;
+
+ /* turn on AHCI_EN */
+ tmp = readl(mmio + HOST_CTL);
+ if (!(tmp & HOST_AHCI_EN)) {
+ tmp |= HOST_AHCI_EN;
+ writel(tmp, mmio + HOST_CTL);
+ tmp = readl(mmio + HOST_CTL); /* flush && sanity check */
+ WARN_ON(!(tmp & HOST_AHCI_EN));
+ }
+}
+
/**
* ahci_save_initial_config - Save and fixup initial config values
* @pdev: target PCI device
@@ -619,6 +633,9 @@
u32 cap, port_map;
int i;
+ /* make sure AHCI mode is enabled before accessing CAP */
+ ahci_enable_ahci(mmio);
+
/* Values prefixed with saved_ are written back to host after
* reset. Values without are used for driver operation.
*/
@@ -1043,13 +1060,10 @@
/* 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)) {
- tmp |= HOST_AHCI_EN;
- writel(tmp, mmio + HOST_CTL);
- }
+ ahci_enable_ahci(mmio);
/* global controller reset */
+ tmp = readl(mmio + HOST_CTL);
if ((tmp & HOST_RESET) == 0) {
writel(tmp | HOST_RESET, mmio + HOST_CTL);
readl(mmio + HOST_CTL); /* flush */
@@ -1068,8 +1082,7 @@
}
/* turn on AHCI mode */
- writel(HOST_AHCI_EN, mmio + HOST_CTL);
- (void) readl(mmio + HOST_CTL); /* flush */
+ ahci_enable_ahci(mmio);
/* some registers might be cleared on reset. restore initial values */
ahci_restore_initial_config(host);