1 files changed, 47 insertions, 14 deletions

diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c
index c6962300b93c..f03aab187f4d 100644
--- a/drivers/ata/ahci_xgene.c
+++ b/drivers/ata/ahci_xgene.c
@@ -78,6 +78,9 @@
 #define CFG_MEM_RAM_SHUTDOWN            0x00000070
 #define BLOCK_MEM_RDY                   0x00000074
 
+/* Max retry for link down */
+#define MAX_LINK_DOWN_RETRY 3
+
 struct xgene_ahci_context {
         struct ahci_host_priv *hpriv;
         struct device *dev;
@@ -145,6 +148,14 @@ static unsigned int xgene_ahci_qc_issue(struct ata_queued_cmd *qc)
         return rc;
 }
 
+static bool xgene_ahci_is_memram_inited(struct xgene_ahci_context *ctx)
+{
+        void __iomem *diagcsr = ctx->csr_diag;
+
+        return (readl(diagcsr + CFG_MEM_RAM_SHUTDOWN) == 0 &&
+                readl(diagcsr + BLOCK_MEM_RDY) == 0xFFFFFFFF);
+}
+
 /**
  * xgene_ahci_read_id - Read ID data from the specified device
  * @dev: device
@@ -229,8 +240,11 @@ static void xgene_ahci_set_phy_cfg(struct xgene_ahci_context *ctx, int channel)
  * and Gen1 (1.5Gbps). Otherwise during long IO stress test, the PHY will
  * report disparity error and etc. In addition, during COMRESET, there can
  * be error reported in the register PORT_SCR_ERR. For SERR_DISPARITY and
- * SERR_10B_8B_ERR, the PHY receiver line must be reseted. The following
- * algorithm is followed to proper configure the hardware PHY during COMRESET:
+ * SERR_10B_8B_ERR, the PHY receiver line must be reseted. Also during long
+ * reboot cycle regression, sometimes the PHY reports link down even if the
+ * device is present because of speed negotiation failure. so need to retry
+ * the COMRESET to get the link up. The following algorithm is followed to
+ * proper configure the hardware PHY during COMRESET:
  *
  * Alg Part 1:
  * 1. Start the PHY at Gen3 speed (default setting)
@@ -246,9 +260,15 @@ static void xgene_ahci_set_phy_cfg(struct xgene_ahci_context *ctx, int channel)
  * Alg Part 2:
  * 1. On link up, if there are any SERR_DISPARITY and SERR_10B_8B_ERR error
  *    reported in the register PORT_SCR_ERR, then reset the PHY receiver line
- * 2. Go to Alg Part 3
+ * 2. Go to Alg Part 4
  *
  * Alg Part 3:
+ * 1. Check the PORT_SCR_STAT to see whether device presence detected but PHY
+ *    communication establishment failed and maximum link down attempts are
+ *    less than Max attempts 3 then goto Alg Part 1.
+ * 2. Go to Alg Part 4.
+ *
+ * Alg Part 4:
  * 1. Clear any pending from register PORT_SCR_ERR.
  *
  * NOTE: For the initial version, we will NOT support Gen1/Gen2. In addition
@@ -267,19 +287,27 @@ static int xgene_ahci_do_hardreset(struct ata_link *link,
         u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
         void __iomem *port_mmio = ahci_port_base(ap);
         struct ata_taskfile tf;
+        int link_down_retry = 0;
         int rc;
-        u32 val;
-
-        /* clear D2H reception area to properly wait for D2H FIS */
-        ata_tf_init(link->device, &tf);
-        tf.command = ATA_BUSY;
-        ata_tf_to_fis(&tf, 0, 0, d2h_fis);
-        rc = sata_link_hardreset(link, timing, deadline, online,
+        u32 val, sstatus;
+
+        do {
+                /* clear D2H reception area to properly wait for D2H FIS */
+                ata_tf_init(link->device, &tf);
+                tf.command = ATA_BUSY;
+                ata_tf_to_fis(&tf, 0, 0, d2h_fis);
+                rc = sata_link_hardreset(link, timing, deadline, online,
                                  ahci_check_ready);
+                if (*online) {
+                        val = readl(port_mmio + PORT_SCR_ERR);
+                        if (val & (SERR_DISPARITY | SERR_10B_8B_ERR))
+                                dev_warn(ctx->dev, "link has error\n");
+                        break;
+                }
 
-        val = readl(port_mmio + PORT_SCR_ERR);
-        if (val & (SERR_DISPARITY | SERR_10B_8B_ERR))
-                dev_warn(ctx->dev, "link has error\n");
+                sata_scr_read(link, SCR_STATUS, &sstatus);
+        } while (link_down_retry++ < MAX_LINK_DOWN_RETRY &&
+                 (sstatus & 0xff) == 0x1);
 
         /* clear all errors if any pending */
         val = readl(port_mmio + PORT_SCR_ERR);
@@ -467,6 +495,11 @@ static int xgene_ahci_probe(struct platform_device *pdev)
                 return -ENODEV;
         }
 
+        if (xgene_ahci_is_memram_inited(ctx)) {
+                dev_info(dev, "skip clock and PHY initialization\n");
+                goto skip_clk_phy;
+        }
+
         /* Due to errata, HW requires full toggle transition */
         rc = ahci_platform_enable_clks(hpriv);
         if (rc)
@@ -479,7 +512,7 @@ static int xgene_ahci_probe(struct platform_device *pdev)
 
         /* Configure the host controller */
         xgene_ahci_hw_init(hpriv);
-
+skip_clk_phy:
         hpriv->flags = AHCI_HFLAG_NO_PMP | AHCI_HFLAG_NO_NCQ;
 
         rc = ahci_platform_init_host(pdev, hpriv, &xgene_ahci_port_info);