Commit 9e56f0df authored by Leonard Crestez's avatar Leonard Crestez Committed by Lorenzo Pieralisi
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PCI: imx: Add imx6sx suspend/resume support 



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: default avatarLeonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: default avatarAndrey Smirnov <andrew.smirnov@gmail.com>
Acked-by: default avatarLucas Stach <l.stach@pengutronix.de>
parent 3d71746c

drivers/pci/controller/dwc/pci-imx6.c

+39 −5
Original line number Diff line number Diff line
@@ -817,8 +817,28 @@ static void imx6_pcie_ltssm_disable(struct device *dev) 


static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie)

{

	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
@@ -827,6 +847,7 @@ static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie) 
	 * The standard recommends a 1-10ms timeout after which to

	 * proceed anyway as if acks were received.

	 */

pm_turnoff_sleep:

	usleep_range(1000, 10000);

}
@@ -836,18 +857,31 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_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);
@@ -863,7 +897,7 @@ static int imx6_pcie_resume_noirq(struct device *dev) 
	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);

include/linux/mfd/syscon/imx6q-iomuxc-gpr.h

+1 −0
Original line number Diff line number Diff line
@@ -440,6 +440,7 @@ 
#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)

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