PCI: imx6: Report "link up" only after link training completes

While waiting for the PHY to report the PCIe link is up, we might hit a
situation where the link training is still in progress, while the PHY
already reports the link is up.  Add additional check for this condition.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Frank Li <lznuaa@gmail.com>
Cc: Harro Haan <hrhaan@gmail.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Mohit KUMAR <Mohit.KUMAR@st.com>
Cc: Pratyush Anand <pratyush.anand@st.com>
Cc: Richard Zhu <r65037@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Sean Cross <xobs@kosagi.com>
Cc: Siva Reddy Kallam <siva.kallam@samsung.com>
Cc: Srikanth T Shivanand <ts.srikanth@samsung.com>
Cc: Tim Harvey <tharvey@gateworks.com>
Cc: Troy Kisky <troy.kisky@boundarydevices.com>
Cc: Yinghai Lu <yinghai@kernel.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 1176bddee1cc..5634a33ea642 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -48,6 +48,8 @@ struct imx6_pcie {
 #define PL_OFFSET 0x700
 #define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
 #define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
+#define PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING (1 << 29)
+#define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP          (1 << 4)
 
 #define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
 #define PCIE_PHY_CTRL_DATA_LOC 0
@@ -338,10 +340,17 @@ static int imx6_pcie_link_up(struct pcie_port *pp)
 {
         u32 rc, ltssm, rx_valid, temp;
 
-        /* link is debug bit 36, debug register 1 starts at bit 32 */
-        rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32));
-        if (rc)
-                return -EAGAIN;
+        /*
+         * Test if the PHY reports that the link is up and also that
+         * the link training finished.  It might happen that the PHY
+         * reports the link is already up, but the link training bit
+         * is still set, so make sure to check the training is done
+         * as well here.
+         */
+        rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);
+        if ((rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP) &&
+            !(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING))
+                return 1;
 
         /*
          * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.