PCI: dra7xx: Clear MSE bit during suspend so clocks will idle

DRA7xx requires the MSE bit to be cleared to set the master in standby
mode.  (In DRA7xx TRM_vE, section 24.9.4.5.2.2.1 PCIe Controller Master
Standby Behavior advises to use the clearing of the local MSE bit to set
the master in standby.  Without this some of the clocks do not idle).

Clear the MSE bit on suspend and enable it on resume.  Clearing MSE bit is
required to get clocks to be idled after suspend.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jingoo Han <jingoohan1@gmail.com>

drivers/pci/host/pci-dra7xx.c

@@ -83,6 +83,17 @@ static inline void dra7xx_pcie_writel(struct dra7xx_pcie *pcie, u32 offset,
 	writel(value, pcie->base + offset);
 }
 
+static inline u32 dra7xx_pcie_readl_rc(struct pcie_port *pp, u32 offset)
+{
+	return readl(pp->dbi_base + offset);
+}
+
+static inline void dra7xx_pcie_writel_rc(struct pcie_port *pp, u32 offset,
+					 u32 value)
+{
+	writel(value, pp->dbi_base + offset);
+}
+
 static int dra7xx_pcie_link_up(struct pcie_port *pp)
 {
 	struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pp);
@@ -434,6 +445,34 @@ static int __exit dra7xx_pcie_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_PM_SLEEP
+static int dra7xx_pcie_suspend(struct device *dev)
+{
+	struct dra7xx_pcie *dra7xx = dev_get_drvdata(dev);
+	struct pcie_port *pp = &dra7xx->pp;
+	u32 val;
+
+	/* clear MSE */
+	val = dra7xx_pcie_readl_rc(pp, PCI_COMMAND);
+	val &= ~PCI_COMMAND_MEMORY;
+	dra7xx_pcie_writel_rc(pp, PCI_COMMAND, val);
+
+	return 0;
+}
+
+static int dra7xx_pcie_resume(struct device *dev)
+{
+	struct dra7xx_pcie *dra7xx = dev_get_drvdata(dev);
+	struct pcie_port *pp = &dra7xx->pp;
+	u32 val;
+
+	/* set MSE */
+	val = dra7xx_pcie_readl_rc(pp, PCI_COMMAND);
+	val |= PCI_COMMAND_MEMORY;
+	dra7xx_pcie_writel_rc(pp, PCI_COMMAND, val);
+
+	return 0;
+}
+
 static int dra7xx_pcie_suspend_noirq(struct device *dev)
 {
 	struct dra7xx_pcie *dra7xx = dev_get_drvdata(dev);
@@ -479,6 +518,7 @@ err_phy:
 #endif
 
 static const struct dev_pm_ops dra7xx_pcie_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dra7xx_pcie_suspend, dra7xx_pcie_resume)
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(dra7xx_pcie_suspend_noirq,
 				      dra7xx_pcie_resume_noirq)
 };