This is broken since:
| commit e6daf4a5e1b813bc7f85507ec83b8c2452c121e6
| Author: Marek Vasut <marex@xxxxxxx>
| Date: Thu Dec 12 22:49:59 2013 +0100
|
| 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@xxxxxxx>
| Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
| Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
The problem is: Before the above commit only the PCIE_PHY_DEBUG_R1_XMLH_LINK_UP
bit was used to determine whether the link is up or not. Since the above commit
also the PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING is used. This means a link
still being trained is as link down.
The designware driver changes the PORT_LOGIC_SPEED_CHANGE bit in
dw_pcie_host_init() which causes the link to be retrained. During the next call
to dw_pcie_rd_conf() the link is then reported being down and the function
returns PCIBIOS_DEVICE_NOT_FOUND resulting in nonfunctioning PCIe.
This patch fixes this by waiting until the link training has finished before
testing the PCIE_PHY_DEBUG_R1_XMLH_LINK_UP bit. This is hardly the correct
solution, but I don't know what should be done instead.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: Richard Zhu <r65037@xxxxxxxxxxxxx> (maintainer:PCI DRIVER FOR IMX6)
Cc: Shawn Guo <shawn.guo@xxxxxxxxxx> (maintainer:PCI DRIVER FOR IMX6)
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> (supporter:PCI SUBSYSTEM)
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: Marek Vasut <marex@xxxxxxx>
---
drivers/pci/host/pci-imx6.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 866bdc7..9b6b501 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -449,6 +449,7 @@ 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;
+ int count = 1000;
/*
* Test if the PHY reports that the link is up and also that
@@ -458,8 +459,13 @@ static int imx6_pcie_link_up(struct pcie_port *pp)
* 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))
+ while (rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING) {
+ if (!count--)
+ return 0;
+ rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);
+ }
+
+ if (rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP)
return 1;
/*
--
1.8.5.3
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