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@xxxxxxx> --- drivers/pci/controller/dwc/pci-imx6.c | 40 ++++++++++++++++++--- include/linux/mfd/syscon/imx6q-iomuxc-gpr.h | 1 + 2 files changed, 36 insertions(+), 5 deletions(-) Patch is again linux-next, meant to apply here: https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/log/?h=pci/dwc This is quite an old patch, mostly did it to prove that imx7d suspend support is indeed generic. diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 2cbef2d7c207..6171171db1fc 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -771,12 +771,29 @@ 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 while + * others poke at iomuxc registers. + */ + if (imx6_pcie->turnoff_reset) { + reset_control_assert(imx6_pcie->turnoff_reset); + reset_control_deassert(imx6_pcie->turnoff_reset); + } else if (imx6_pcie->variant == 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); + } else { + 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. * @@ -790,22 +807,35 @@ 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 +847,11 @@ 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
