On Mon, Aug 27, 2018 at 02:28:37PM +0300, Leonard Crestez wrote: > On imx7d the pcie-phy power domain is turned off in suspend and this can > make the system hang after resume when attempting any read from PCI. > > Fix this by adding minimal suspend/resume code from the nxp internal > tree. This will prepare for powering down on suspend and reset the block > on resume. > > Code is only for imx7d but a very similar sequence can be used for > other socs. > > The original author is mostly Richard Zhu <hongxing.zhu@xxxxxxx>, this > patch adjusts the code to the upstream imx7d implemention using reset > controls and power domains. I will add a Suggested-by: replacing this paragraph, it is always better to add proper tags rather than credit hidden in commit logs messages. > Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx> > Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > --- > drivers/pci/controller/dwc/pci-imx6.c | 97 +++++++++++++++++++++++++-- > 1 file changed, 92 insertions(+), 5 deletions(-) > > Resending after RC1 as suggested here: https://lkml.org/lkml/2018/8/8/496 > > This was initially sent together with a dts fix, that was already > accepted by Shawn: https://lkml.org/lkml/2018/8/21/529 > > Some dependencies in this area are complicated but as far as I know > including this patch without others should not break anything that was > not already broken. Since this is a patch for something that has never > worked before it should be treated as a feature not a bugfix. Ok, so I consider this v4.20 material, please shout if it has to be sent as a fix, I do not think so given what we discussed above. Lorenzo > I have a few other patches for imx pci but it's better to deal with them > separately. This initial patch adding suspend support is useful by > itself. > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c > index 4a9a673b4777..65b6d1015723 100644 > --- a/drivers/pci/controller/dwc/pci-imx6.c > +++ b/drivers/pci/controller/dwc/pci-imx6.c > @@ -540,10 +540,28 @@ static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie) > > dev_err(dev, "Speed change timeout\n"); > return -EINVAL; > } > > +static void imx6_pcie_ltssm_enable(struct device *dev) > +{ > + struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); > + > + switch (imx6_pcie->variant) { > + case IMX6Q: > + case IMX6SX: > + case IMX6QP: > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > + IMX6Q_GPR12_PCIE_CTL_2, > + IMX6Q_GPR12_PCIE_CTL_2); > + break; > + case IMX7D: > + reset_control_deassert(imx6_pcie->apps_reset); > + break; > + } > +} > + > static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie) > { > struct dw_pcie *pci = imx6_pcie->pci; > struct device *dev = pci->dev; > u32 tmp; > @@ -558,15 +576,11 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie) > tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; > tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1; > dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp); > > /* Start LTSSM. */ > - if (imx6_pcie->variant == IMX7D) > - reset_control_deassert(imx6_pcie->apps_reset); > - else > - regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > - IMX6Q_GPR12_PCIE_CTL_2, 1 << 10); > + imx6_pcie_ltssm_enable(dev); > > ret = imx6_pcie_wait_for_link(imx6_pcie); > if (ret) > goto err_reset_phy; > > @@ -680,10 +694,82 @@ 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, > }; > > +#ifdef CONFIG_PM_SLEEP > +static void imx6_pcie_ltssm_disable(struct device *dev) > +{ > + struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); > + > + switch (imx6_pcie->variant) { > + case IMX6SX: > + case IMX6QP: > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > + IMX6Q_GPR12_PCIE_CTL_2, 0); > + break; > + case IMX7D: > + reset_control_assert(imx6_pcie->apps_reset); > + break; > + default: > + dev_err(dev, "ltssm_disable not supported\n"); > + } > +} > + > +static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie) > +{ > + clk_disable_unprepare(imx6_pcie->pcie); > + clk_disable_unprepare(imx6_pcie->pcie_phy); > + clk_disable_unprepare(imx6_pcie->pcie_bus); > + > + if (imx6_pcie->variant == IMX7D) { > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > + IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, > + IMX7D_GPR12_PCIE_PHY_REFCLK_SEL); > + } > +} > + > +static int imx6_pcie_suspend_noirq(struct device *dev) > +{ > + struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); > + > + if (imx6_pcie->variant != IMX7D) > + return 0; > + > + imx6_pcie_clk_disable(imx6_pcie); > + imx6_pcie_ltssm_disable(dev); > + > + return 0; > +} > + > +static int imx6_pcie_resume_noirq(struct device *dev) > +{ > + int ret; > + struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); > + struct pcie_port *pp = &imx6_pcie->pci->pp; > + > + if (imx6_pcie->variant != IMX7D) > + return 0; > + > + imx6_pcie_assert_core_reset(imx6_pcie); > + imx6_pcie_init_phy(imx6_pcie); > + imx6_pcie_deassert_core_reset(imx6_pcie); > + dw_pcie_setup_rc(pp); > + > + ret = imx6_pcie_establish_link(imx6_pcie); > + if (ret < 0) > + dev_info(dev, "pcie link is down after resume.\n"); > + > + return 0; > +} > +#endif > + > +static const struct dev_pm_ops imx6_pcie_pm_ops = { > + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq, > + imx6_pcie_resume_noirq) > +}; > + > static int imx6_pcie_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > struct dw_pcie *pci; > struct imx6_pcie *imx6_pcie; > @@ -846,10 +932,11 @@ static const struct of_device_id imx6_pcie_of_match[] = { > static struct platform_driver imx6_pcie_driver = { > .driver = { > .name = "imx6q-pcie", > .of_match_table = imx6_pcie_of_match, > .suppress_bind_attrs = true, > + .pm = &imx6_pcie_pm_ops, > }, > .probe = imx6_pcie_probe, > .shutdown = imx6_pcie_shutdown, > }; > > -- > 2.17.1 >
