[lkml]   [2018]   [Dec]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH AUTOSEL 4.19 045/123] PCI: imx6: Fix link training status detection in link up check
From: Trent Piepho <>

[ Upstream commit 68bc10bf992180f269816ff3d22eb30383138577 ]

This bug was introduced in the interaction for two commits on either
branch of the merge commit 562df5c8521e ("Merge branch
'pci/host-designware' into next").

Commit 4d107d3b5a68 ("PCI: imx6: Move link up check into
imx6_pcie_wait_for_link()"), changed imx6_pcie_wait_for_link() to poll
the link status register directly, checking for link up and not
training, and made imx6_pcie_link_up() only check the link up bit (once,
not a polling loop).

While commit 886bc5ceb5cc ("PCI: designware: Add generic
dw_pcie_wait_for_link()"), replaced the loop in
imx6_pcie_wait_for_link() with a call to a new dwc core function, which
polled imx6_pcie_link_up(), which still checked both link up and not
training in a loop.

When these two commits were merged, the version of
imx6_pcie_wait_for_link() from 886bc5ceb5cc was kept, which eliminated
the link training check placed there by 4d107d3b5a68. However, the
version of imx6_pcie_link_up() from 4d107d3b5a68 was kept, which
eliminated the link training check that had been there and was moved to

The result was the link training check got lost for the imx6 driver.

Eliminate imx6_pcie_link_up() so that the default handler,
dw_pcie_link_up(), is used instead. The default handler has the correct
code, which checks for link up and also that it still is not training,
fixing the regression.

Fixes: 562df5c8521e ("Merge branch 'pci/host-designware' into next")
Signed-off-by: Trent Piepho <>
[ rewrote the commit log]
Signed-off-by: Lorenzo Pieralisi <>
Reviewed-by: Lucas Stach <>
Cc: Bjorn Helgaas <>
Cc: Joao Pinto <>
Cc: Lorenzo Pieralisi <>
Cc: Richard Zhu <>
Signed-off-by: Sasha Levin <>
drivers/pci/controller/dwc/pci-imx6.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 4a9a673b4777..975050a69494 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -80,8 +80,6 @@ struct imx6_pcie {
#define PCIE_PL_PFLR_FORCE_LINK (1 << 15)
#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
-#define PCIE_PHY_DEBUG_R1_XMLH_LINK_UP (1 << 4)

#define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
@@ -641,12 +639,6 @@ static int imx6_pcie_host_init(struct pcie_port *pp)
return 0;

-static int imx6_pcie_link_up(struct dw_pcie *pci)
- return dw_pcie_readl_dbi(pci, PCIE_PHY_DEBUG_R1) &
static const struct dw_pcie_host_ops imx6_pcie_host_ops = {
.host_init = imx6_pcie_host_init,
@@ -679,7 +671,7 @@ static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,

static const struct dw_pcie_ops dw_pcie_ops = {
- .link_up = imx6_pcie_link_up,
+ /* No special ops needed, but pcie-designware still expects this struct */

static int imx6_pcie_probe(struct platform_device *pdev)
 \ /
  Last update: 2018-12-05 11:11    [W:0.282 / U:2.424 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site