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Commit 0ee2c1f2 authored by Leonard Crestez's avatar Leonard Crestez Committed by Lorenzo Pieralisi
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PCI: imx: Initial imx7d pm support 



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. 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.

Original-by: default avatarRichard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: default avatarLeonard Crestez <leonard.crestez@nxp.com>
[lorenzo.pieralisi@arm.com: commit log update]
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: default avatarLucas Stach <l.stach@pengutronix.de>
parent f18f42d7

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

+92 −5
Original line number Diff line number Diff line
@@ -596,6 +596,24 @@ static int imx6_pcie_wait_for_speed_change(struct imx6_pcie *imx6_pcie) 
	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;
@@ -614,11 +632,7 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie) 
	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)
@@ -737,6 +751,78 @@ 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;
@@ -903,6 +989,7 @@ static struct platform_driver imx6_pcie_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,