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path: root/drivers/pci/host/pci-imx6.c
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Diffstat (limited to 'drivers/pci/host/pci-imx6.c')
-rw-r--r--drivers/pci/host/pci-imx6.c47
1 files changed, 34 insertions, 13 deletions
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index e8663a8c3406..ee082509b0ba 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -424,20 +424,40 @@ static void imx6_pcie_reset_phy(struct pcie_port *pp)
static int imx6_pcie_link_up(struct pcie_port *pp)
{
- u32 rc, ltssm, rx_valid;
+ u32 rc, debug_r0, rx_valid;
+ int count = 5;
/*
- * 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.
+ * Test if the PHY reports that the link is up and also that the LTSSM
+ * training finished. There are three possible states of the link when
+ * this code is called:
+ * 1) The link is DOWN (unlikely)
+ * The link didn't come up yet for some reason. This usually means
+ * we have a real problem somewhere. Reset the PHY and exit. This
+ * state calls for inspection of the DEBUG registers.
+ * 2) The link is UP, but still in LTSSM training
+ * Wait for the training to finish, which should take a very short
+ * time. If the training does not finish, we have a problem and we
+ * need to inspect the DEBUG registers. If the training does finish,
+ * the link is up and operating correctly.
+ * 3) The link is UP and no longer in LTSSM training
+ * The link is up and operating correctly.
*/
- 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;
-
+ while (1) {
+ rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);
+ if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP))
+ break;
+ if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING))
+ return 1;
+ if (!count--)
+ break;
+ dev_dbg(pp->dev, "Link is up, but still in training\n");
+ /*
+ * Wait a little bit, then re-check if the link finished
+ * the training.
+ */
+ usleep_range(1000, 2000);
+ }
/*
* From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
* Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
@@ -446,15 +466,16 @@ static int imx6_pcie_link_up(struct pcie_port *pp)
* to gen2 is stuck
*/
pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
- ltssm = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0) & 0x3F;
+ debug_r0 = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0);
if (rx_valid & 0x01)
return 0;
- if (ltssm != 0x0d)
+ if ((debug_r0 & 0x3f) != 0x0d)
return 0;
dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n");
+ dev_dbg(pp->dev, "debug_r0=%08x debug_r1=%08x\n", debug_r0, rc);
imx6_pcie_reset_phy(pp);