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SubjectRe: [PATCH v2] PCI: imx: Add imx6sx suspend/resume support
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Am Donnerstag, den 22.11.2018, 11:38 +0000 schrieb Lorenzo Pieralisi:
> On Wed, Nov 07, 2018 at 01:57:03PM +0000, Leonard Crestez wrote:
> > Enable PCI suspend/resume support on imx6sx socs. This is similar to
> > imx7d with a few differences:
> >
> > * The PM_Turn_Off bit is exposed through an IOMUX GPR, like all other
> > pcie control bits on 6sx.
> > * The pcie_inbound_axi clk needs to be turned off in suspend. On resume
> > it is restored via resume -> deassert_core_reset -> enable_ref_clk.
> >
> > Most of the resume logic is shared with the initial reset after probe.
> >
> > > > Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> >
> > ---
> > Changes since v1:
> > * Use a switch statement in imx6_pcie_pm_turnoff. The DT-based turnoff
> > path is still an if statement.
> > * Did not split imx6_pcie_clk_disable or call it from other paths, this
> > would bring complications and is somewhat unrelated.
> > * See v1 comments: https://lore.kernel.org/patchwork/patch/996806/
> >
> >  drivers/pci/controller/dwc/pci-imx6.c       | 44 ++++++++++++++++++---
> >  include/linux/mfd/syscon/imx6q-iomuxc-gpr.h |  1 +
> >  2 files changed, 40 insertions(+), 5 deletions(-)
>
> I request Richard/Lucas ACK in order to merge this patch.

I'm fine with this patch.

Acked-by: Lucas Stach <l.stach@pengutronix.de>


> Thanks,
> Lorenzo
>
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> > index 2cbef2d7c207..54625569d0bc 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -771,41 +771,75 @@ static void imx6_pcie_ltssm_disable(struct device *dev)
> > > >   }
> >  }
> >  
> >  static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie)
> >  {
> > > > - reset_control_assert(imx6_pcie->turnoff_reset);
> > > > - reset_control_deassert(imx6_pcie->turnoff_reset);
> > > > + struct device *dev = imx6_pcie->pci->dev;
> > +
> > > > + /* Some variants have a turnoff reset in DT */
> > > > + if (imx6_pcie->turnoff_reset) {
> > > > + reset_control_assert(imx6_pcie->turnoff_reset);
> > > > + reset_control_deassert(imx6_pcie->turnoff_reset);
> > > > + goto pm_turnoff_sleep;
> > > > + }
> > +
> > > > + /* Others poke directly at IOMUXC registers */
> > > > + switch (imx6_pcie->variant) {
> > > > + case IMX6SX:
> > > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> > > > + IMX6SX_GPR12_PCIE_PM_TURN_OFF,
> > > > + IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> > > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> > > > + IMX6SX_GPR12_PCIE_PM_TURN_OFF, 0);
> > > > + break;
> > > > + default:
> > > > + dev_err(dev, "PME_Turn_Off not implemented\n");
> > > > + return;
> > > > + }
> >  
> > > >   /*
> > > >    * Components with an upstream port must respond to
> > > >    * PME_Turn_Off with PME_TO_Ack but we can't check.
> > > >    *
> > > >    * The standard recommends a 1-10ms timeout after which to
> > > >    * proceed anyway as if acks were received.
> > > >    */
> > +pm_turnoff_sleep:
> > > >   usleep_range(1000, 10000);
> >  }
> >  
> >  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) {
> > > > + switch (imx6_pcie->variant) {
> > > > + case IMX6SX:
> > > > + clk_disable_unprepare(imx6_pcie->pcie_inbound_axi);
> > > > + break;
> > > > + case IMX7D:
> > > >   regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> > > >      IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
> > > >      IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
> > > > + break;
> > > > + default:
> > > > + break;
> > > >   }
> >  }
> >  
> > +static inline bool imx6_pcie_supports_suspend(struct imx6_pcie *imx6_pcie)
> > +{
> > > > + return (imx6_pcie->variant == IMX7D ||
> > > > + imx6_pcie->variant == IMX6SX);
> > +}
> > +
> >  static int imx6_pcie_suspend_noirq(struct device *dev)
> >  {
> > > >   struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
> >  
> > > > - if (imx6_pcie->variant != IMX7D)
> > > > + if (!imx6_pcie_supports_suspend(imx6_pcie))
> > > >   return 0;
> >  
> > > >   imx6_pcie_pm_turnoff(imx6_pcie);
> > > >   imx6_pcie_clk_disable(imx6_pcie);
> > > >   imx6_pcie_ltssm_disable(dev);
> > @@ -817,11 +851,11 @@ 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)
> > > > + if (!imx6_pcie_supports_suspend(imx6_pcie))
> > > >   return 0;
> >  
> > > >   imx6_pcie_assert_core_reset(imx6_pcie);
> > > >   imx6_pcie_init_phy(imx6_pcie);
> > > >   imx6_pcie_deassert_core_reset(imx6_pcie);
> > diff --git a/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h b/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
> > index 6c1ad160ed87..c1b25f5e386d 100644
> > --- a/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
> > +++ b/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
> > @@ -438,10 +438,11 @@
> > > >  #define IMX6SX_GPR5_DISP_MUX_DCIC1_LCDIF1 (0x0 << 1)
> > > >  #define IMX6SX_GPR5_DISP_MUX_DCIC1_LVDS (0x1 << 1)
> > > >  #define IMX6SX_GPR5_DISP_MUX_DCIC1_MASK (0x1 << 1)
> >  
> > > >  #define IMX6SX_GPR12_PCIE_TEST_POWERDOWN BIT(30)
> > > > +#define IMX6SX_GPR12_PCIE_PM_TURN_OFF BIT(16)
> > > >  #define IMX6SX_GPR12_PCIE_RX_EQ_MASK (0x7 << 0)
> > > >  #define IMX6SX_GPR12_PCIE_RX_EQ_2 (0x2 << 0)
> >  
> >  /* For imx6ul iomux gpr register field define */
> > > >  #define IMX6UL_GPR1_ENET1_CLK_DIR (0x1 << 17)
> > -- 
> > 2.17.1
> >

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