| Message ID | 1407479800-6730-1-git-send-email-tharvey@gateworks.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Hi Tim: > -----Original Message----- > From: linux-pci-owner@vger.kernel.org [mailto:linux-pci-owner@vger.kernel.org] > On Behalf Of Tim Harvey > Sent: Friday, August 08, 2014 2:37 PM > To: l.stach@pengutronix.de > Cc: Fabio Estevam; Guo Shawn-R65073; stable@vger.kernel.org; marex@denx.de; > bhelgaas@google.com; linux-pci@vger.kernel.org > Subject: [PATCH] PCI: imx6: fix occasional link failure > > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable > for SS function) must remain deasserted until the reference clock is running > at the appropriate frequency. > > Without this patch we find a high link failure rate (>5%) on certain > IMX6 boards at various temperatures. > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> > --- > drivers/pci/host/pci-imx6.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index > 1be6073..9b6bab9 100644 > --- a/drivers/pci/host/pci-imx6.c > +++ b/drivers/pci/host/pci-imx6.c > @@ -256,11 +256,6 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port > *pp) > struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); > int ret; > > - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > - IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > - IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); > - > ret = clk_prepare_enable(imx6_pcie->pcie_phy); > if (ret) { > dev_err(pp->dev, "unable to enable pcie_phy clock\n"); @@ -282,6 > +277,12 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) > /* allow the clocks to stabilize */ > usleep_range(200, 500); > > + /* power up core phy and enable ref clock */ > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); > + [Richard] It's better add some comments into the codes, why Enable_pcie_clock should be placed before ssp_en is set. For example: - enable_pcie_clock should be call before ssp_en is set, since that ssp_en control the phy_ref clk gate, turn on it after the source of the pcie clks are stable. Best Regards Richard Zhu > /* Some boards don't have PCIe reset GPIO. */ > if (gpio_is_valid(imx6_pcie->reset_gpio)) { > gpio_set_value(imx6_pcie->reset_gpio, 0); > -- > 1.8.3.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in the > body of a message to majordomo@vger.kernel.org More majordomo info at > http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Aug 07, 2014 at 11:36:40PM -0700, Tim Harvey wrote: > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable > for SS function) must remain deasserted until the reference clock is running > at the appropriate frequency. > > Without this patch we find a high link failure rate (>5%) on certain > IMX6 boards at various temperatures. > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> > --- > drivers/pci/host/pci-imx6.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) <formletter> This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read Documentation/stable_kernel_rules.txt for how to do this properly. </formletter> -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Aug 8, 2014 at 3:36 AM, Tim Harvey <tharvey@gateworks.com> wrote: > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable > for SS function) must remain deasserted until the reference clock is running > at the appropriate frequency. > > Without this patch we find a high link failure rate (>5%) on certain > IMX6 boards at various temperatures. > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> Thanks, Tim. Marek, Does this fix the PCI linkup failures you reported earlier? Regards, Fabio Estevam -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Aug 8, 2014 at 3:36 AM, Tim Harvey <tharvey@gateworks.com> wrote: > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable > for SS function) must remain deasserted until the reference clock is running > at the appropriate frequency. > > Without this patch we find a high link failure rate (>5%) on certain > IMX6 boards at various temperatures. > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> Thanks for the patch, Tim: Tested-by: Fabio Estevam <fabio.estevam@freescale.com> -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Friday, August 08, 2014 at 05:59:23 PM, Fabio Estevam wrote: > On Fri, Aug 8, 2014 at 3:36 AM, Tim Harvey <tharvey@gateworks.com> wrote: > > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock > > enable for SS function) must remain deasserted until the reference clock > > is running at the appropriate frequency. > > > > Without this patch we find a high link failure rate (>5%) on certain > > IMX6 boards at various temperatures. > > > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> > > Thanks, Tim. > > Marek, > > Does this fix the PCI linkup failures you reported earlier? I currently don't have the board available, so I will moan later if this is still broken. Please go ahead and apply, the patch looks good to me: Acked-by: Marek Vasut <marex@denx.de> Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Aug 07, 2014 at 11:36:40PM -0700, Tim Harvey wrote: > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable > for SS function) must remain deasserted until the reference clock is running > at the appropriate frequency. > > Without this patch we find a high link failure rate (>5%) on certain > IMX6 boards at various temperatures. > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> Applied to pci/host-imx6 for v3.18 with acks from Marek and Lucas, thanks! > --- > drivers/pci/host/pci-imx6.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c > index 1be6073..9b6bab9 100644 > --- a/drivers/pci/host/pci-imx6.c > +++ b/drivers/pci/host/pci-imx6.c > @@ -256,11 +256,6 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) > struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); > int ret; > > - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > - IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > - IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); > - > ret = clk_prepare_enable(imx6_pcie->pcie_phy); > if (ret) { > dev_err(pp->dev, "unable to enable pcie_phy clock\n"); > @@ -282,6 +277,12 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) > /* allow the clocks to stabilize */ > usleep_range(200, 500); > > + /* power up core phy and enable ref clock */ > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); > + > /* Some boards don't have PCIe reset GPIO. */ > if (gpio_is_valid(imx6_pcie->reset_gpio)) { > gpio_set_value(imx6_pcie->reset_gpio, 0); > -- > 1.8.3.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wednesday, September 17, 2014 at 01:28:59 AM, Bjorn Helgaas wrote: > On Thu, Aug 07, 2014 at 11:36:40PM -0700, Tim Harvey wrote: > > According to the IMX6 reference manuals, REF_SSP_EN (Reference clock > > enable for SS function) must remain deasserted until the reference clock > > is running at the appropriate frequency. > > > > Without this patch we find a high link failure rate (>5%) on certain > > IMX6 boards at various temperatures. > > > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> > > Applied to pci/host-imx6 for v3.18 with acks from Marek and Lucas, thanks! Thanks! Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 1be6073..9b6bab9 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -256,11 +256,6 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); int ret; - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, - IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, - IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); - ret = clk_prepare_enable(imx6_pcie->pcie_phy); if (ret) { dev_err(pp->dev, "unable to enable pcie_phy clock\n"); @@ -282,6 +277,12 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) /* allow the clocks to stabilize */ usleep_range(200, 500); + /* power up core phy and enable ref clock */ + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, + IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16); + /* Some boards don't have PCIe reset GPIO. */ if (gpio_is_valid(imx6_pcie->reset_gpio)) { gpio_set_value(imx6_pcie->reset_gpio, 0);
According to the IMX6 reference manuals, REF_SSP_EN (Reference clock enable for SS function) must remain deasserted until the reference clock is running at the appropriate frequency. Without this patch we find a high link failure rate (>5%) on certain IMX6 boards at various temperatures. Signed-off-by: Tim Harvey <tharvey@gateworks.com> --- drivers/pci/host/pci-imx6.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)