From 0ee2c1f2429f74328c82ea559b127c96d5224ccd Mon Sep 17 00:00:00 2001 From: Leonard Crestez Date: Mon, 27 Aug 2018 14:28:37 +0300 Subject: 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: Richard Zhu Signed-off-by: Leonard Crestez [lorenzo.pieralisi@arm.com: commit log update] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Lucas Stach --- drivers/pci/controller/dwc/pci-imx6.c | 97 +++++++++++++++++++++++++++++++++-- 1 file changed, 92 insertions(+), 5 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 21e03c6567da..d13dae50dc99 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -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, -- cgit v1.2.1