Under certain circumstances (SSP turned off by the BIOS) and for
debugging purposes, skipping global controller reset is helpful. Add
a kernel parameter for it.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/ata/ahci.c | 48 +++++++++++++++++++++++++++++-------------------
1 file changed, 29 insertions(+), 19 deletions(-)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 70a0f07..fb1af0f 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -49,6 +49,10 @@
#define DRV_NAME "ahci"
#define DRV_VERSION "3.0"
+static int ahci_skip_host_reset;
+module_param_named(skip_host_reset, ahci_skip_host_reset, int, 0444);
+MODULE_PARM_DESC(skip_host_reset, "skip global host reset (0=don't skip, 1=skip)");
+
static int ahci_enable_alpm(struct ata_port *ap,
enum link_pm policy);
static void ahci_disable_alpm(struct ata_port *ap);
@@ -1057,29 +1061,35 @@ static int ahci_reset_controller(struct ata_host *host)
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 */
- }
+ if (!ahci_skip_host_reset) {
+ tmp = readl(mmio + HOST_CTL);
+ if ((tmp & HOST_RESET) == 0) {
+ writel(tmp | HOST_RESET, mmio + HOST_CTL);
+ readl(mmio + HOST_CTL); /* flush */
+ }
- /* reset must complete within 1 second, or
- * the hardware should be considered fried.
- */
- ssleep(1);
+ /* reset must complete within 1 second, or
+ * the hardware should be considered fried.
+ */
+ ssleep(1);
- tmp = readl(mmio + HOST_CTL);
- if (tmp & HOST_RESET) {
- dev_printk(KERN_ERR, host->dev,
- "controller reset failed (0x%x)\n", tmp);
- return -EIO;
- }
+ tmp = readl(mmio + HOST_CTL);
+ if (tmp & HOST_RESET) {
+ dev_printk(KERN_ERR, host->dev,
+ "controller reset failed (0x%x)\n", tmp);
+ return -EIO;
+ }
- /* turn on AHCI mode */
- ahci_enable_ahci(mmio);
+ /* turn on AHCI mode */
+ ahci_enable_ahci(mmio);
- /* some registers might be cleared on reset. restore initial values */
- ahci_restore_initial_config(host);
+ /* Some registers might be cleared on reset. Restore
+ * initial values.
+ */
+ ahci_restore_initial_config(host);
+ } else
+ dev_printk(KERN_INFO, host->dev,
+ "skipping global host reset\n");
if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
u16 tmp16;
--
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