Am Dienstag, den 21.03.2017, 06:42 -0700 schrieb Andrey Smirnov: > As can be seen from [1]: > > "...the different behavior between iMX6Q PCIe and iMX7D PCIe maybe > caused by the different controller version. > > Regarding to the DOC description, the DIRECT_SPEED_CHANGE should be > cleared after the speed change from GEN1 to GEN2. Unfortunately, when > GEN1 device is used, the behavior is not documented. > > So, IC design guys run the simulation and > find out the following behaviors: > > 1. DIRECT_SPEED_CHANGE will be cleared in 7D after speed change > from GEN1 to GEN2. This matches doc’s description > > 2. set MAX link speed(PCIE_CAP_TARGET_LINK_SPEED=0x01) as GEN1 and > re-run the simulation, DIRECT_SPEED_CHANGE will not be cleared; > remain as 1, this matches your result, but function test is > passed, so this bit should not affect the normal PCIe function. > ..." > > imx6_pcie_wait_for_speed_change will report false failures for Gen1 -> > Gen1 speed transition, so avoid doing that check and just rely on > imx6_pcie_wait_for_link only. > > [1] https://community.nxp.com/message/867943 > > Cc: yurovsky@xxxxxxxxx > Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Cc: Fabio Estevam <fabio.estevam@xxxxxxx> > Cc: Dong Aisheng <dongas86@xxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx> Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > --- > drivers/pci/dwc/pci-imx6.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c > index 64de9bb..c731e41 100644 > --- a/drivers/pci/dwc/pci-imx6.c > +++ b/drivers/pci/dwc/pci-imx6.c > @@ -545,10 +545,21 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie) > tmp |= PORT_LOGIC_SPEED_CHANGE; > dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp); > > - ret = imx6_pcie_wait_for_speed_change(imx6_pcie); > - if (ret) { > - dev_err(dev, "Failed to bring link up!\n"); > - goto err_reset_phy; > + if (imx6_pcie->variant != IMX7D) { > + /* > + * On i.MX7, DIRECT_SPEED_CHANGE behaves differently > + * from i.MX6 family when no link speed transition > + * occurs and we go Gen1 -> yep, Gen1. The difference > + * is that, in such case, it will not be cleared by HW > + * which will cause the following code to report false > + * failure. > + */ > + > + ret = imx6_pcie_wait_for_speed_change(imx6_pcie); > + if (ret) { > + dev_err(dev, "Failed to bring link up!\n"); > + goto err_reset_phy; > + } > } > > /* Make sure link training is finished as well! */
