| Message ID | 1392190075-23204-1-git-send-email-s.hauer@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wednesday, February 12, 2014 at 08:27:55 AM, Sascha Hauer wrote: +CC Troy Kisky, since I think he submitted something similar some time ago already. Otherwise I agree this happens. > This is broken since: > | commit e6daf4a5e1b813bc7f85507ec83b8c2452c121e6 > | Author: Marek Vasut <marex@denx.de> > | 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@denx.de> > | Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > | Acked-by: Shawn Guo <shawn.guo@linaro.org> > > 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@pengutronix.de> > Cc: Richard Zhu <r65037@freescale.com> (maintainer:PCI DRIVER FOR IMX6) > Cc: Shawn Guo <shawn.guo@linaro.org> (maintainer:PCI DRIVER FOR IMX6) > Cc: Bjorn Helgaas <bhelgaas@google.com> (supporter:PCI SUBSYSTEM) > Cc: linux-pci@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: Marek Vasut <marex@denx.de> > --- > 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; > > /*
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; /*
This is broken since: | commit e6daf4a5e1b813bc7f85507ec83b8c2452c121e6 | Author: Marek Vasut <marex@denx.de> | 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@denx.de> | Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> | Acked-by: Shawn Guo <shawn.guo@linaro.org> 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@pengutronix.de> Cc: Richard Zhu <r65037@freescale.com> (maintainer:PCI DRIVER FOR IMX6) Cc: Shawn Guo <shawn.guo@linaro.org> (maintainer:PCI DRIVER FOR IMX6) Cc: Bjorn Helgaas <bhelgaas@google.com> (supporter:PCI SUBSYSTEM) Cc: linux-pci@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: Marek Vasut <marex@denx.de> --- drivers/pci/host/pci-imx6.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)