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: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Acked-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 4a307cd..25a2b76 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -817,8 +817,28 @@ static void imx6_pcie_ltssm_disable(struct device *dev)
static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie)
{
- reset_control_assert(imx6_pcie->turnoff_reset);
- reset_control_deassert(imx6_pcie->turnoff_reset);
+ 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);