1 files changed, 18 insertions, 2 deletions

diff --git a/drivers/ata/sata_highbank.c b/drivers/ata/sata_highbank.c
index b20aa96b958d..c846fd3c5c09 100644
--- a/drivers/ata/sata_highbank.c
+++ b/drivers/ata/sata_highbank.c
@@ -196,10 +196,26 @@ static int highbank_initialize_phys(struct device *dev, void __iomem *addr)
         return 0;
 }
 
+/*
+ * The Calxeda SATA phy intermittently fails to bring up a link with Gen3
+ * Retrying the phy hard reset can work around the issue, but the drive
+ * may fail again. In less than 150 out of 15000 test runs, it took more
+ * than 10 tries for the link to be established (but never more than 35).
+ * Triple the maximum observed retry count to provide plenty of margin for
+ * rare events and to guarantee that the link is established.
+ *
+ * Also, the default 2 second time-out on a failed drive is too long in
+ * this situation. The uboot implementation of the same driver function
+ * uses a much shorter time-out period and never experiences a time out
+ * issue. Reducing the time-out to 500ms improves the responsiveness.
+ * The other timing constants were kept the same as the stock AHCI driver.
+ * This change was also tested 15000 times on 24 drives and none of them
+ * experienced a time out.
+ */
 static int ahci_highbank_hardreset(struct ata_link *link, unsigned int *class,
                                 unsigned long deadline)
 {
-        const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
+        static const unsigned long timing[] = { 5, 100, 500};
         struct ata_port *ap = link->ap;
         struct ahci_port_priv *pp = ap->private_data;
         u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
@@ -207,7 +223,7 @@ static int ahci_highbank_hardreset(struct ata_link *link, unsigned int *class,
         bool online;
         u32 sstatus;
         int rc;
-        int retry = 10;
+        int retry = 100;
 
         ahci_stop_engine(ap);