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 <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>
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 21e03c6..d13dae5 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,