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PCI: imx: Initial imx7d pm support

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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 <hongxing.zhu@nxp.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
[lorenzo.pieralisi@arm.com: commit log update]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
This commit is contained in:
Leonard Crestez 2018-08-27 14:28:37 +03:00 committed by Lorenzo Pieralisi
parent f18f42d749
commit 0ee2c1f242
1 changed files with 92 additions and 5 deletions
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97
drivers/pci/controller/dwc/pci-imx6.c
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@ -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,