[PATCH v4] PCI: mediatek: Add system pm support for MT2712

[<honghui.zhang@xxxxxxxxxxxx>]

From: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>

The MTCMOS of PCIe Host for MT2712 will be off when system suspend, and all
the internal control register will be reset after system resume. The PCIe
link should be re-established and the related control register values
should be re-set after system resume.

Signed-off-by: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>
CC: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
---
 drivers/pci/controller/pcie-mediatek.c | 60 ++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

Change since v3:
 - rebase to v4.18-rc1.

diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 0baabe3..1ed2ef0 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -134,12 +134,14 @@ struct mtk_pcie_port;
 /**
  * struct mtk_pcie_soc - differentiate between host generations
  * @need_fix_class_id: whether this host's class ID needed to be fixed or not
+ * @pm_support: whether the host's MTCMOS will be off when suspend
  * @ops: pointer to configuration access functions
  * @startup: pointer to controller setting functions
  * @setup_irq: pointer to initialize IRQ functions
  */
 struct mtk_pcie_soc {
 	bool need_fix_class_id;
+	bool pm_support;
 	struct pci_ops *ops;
 	int (*startup)(struct mtk_pcie_port *port);
 	int (*setup_irq)(struct mtk_pcie_port *port, struct device_node *node);
@@ -1181,12 +1183,69 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	return err;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int mtk_pcie_suspend_noirq(struct device *dev)
+{
+	struct mtk_pcie *pcie = dev_get_drvdata(dev);
+	const struct mtk_pcie_soc *soc = pcie->soc;
+	struct mtk_pcie_port *port;
+
+	if (!soc->pm_support)
+		return 0;
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		clk_disable_unprepare(port->ahb_ck);
+		clk_disable_unprepare(port->sys_ck);
+		phy_power_off(port->phy);
+	}
+
+	return 0;
+}
+
+static int mtk_pcie_resume_noirq(struct device *dev)
+{
+	struct mtk_pcie *pcie = dev_get_drvdata(dev);
+	const struct mtk_pcie_soc *soc = pcie->soc;
+	struct mtk_pcie_port *port;
+	int ret;
+
+	if (!soc->pm_support)
+		return 0;
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		phy_power_on(port->phy);
+		clk_prepare_enable(port->sys_ck);
+		clk_prepare_enable(port->ahb_ck);
+
+		ret = soc->startup(port);
+		if (ret) {
+			dev_err(dev, "Port%d link down\n", port->slot);
+			phy_power_off(port->phy);
+			clk_disable_unprepare(port->sys_ck);
+			clk_disable_unprepare(port->ahb_ck);
+			return ret;
+		}
+
+		if (IS_ENABLED(CONFIG_PCI_MSI))
+			mtk_pcie_enable_msi(port);
+	}
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops mtk_pcie_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mtk_pcie_suspend_noirq,
+				      mtk_pcie_resume_noirq)
+};
+
 static const struct mtk_pcie_soc mtk_pcie_soc_v1 = {
 	.ops = &mtk_pcie_ops,
 	.startup = mtk_pcie_startup_port,
 };
 
 static const struct mtk_pcie_soc mtk_pcie_soc_mt2712 = {
+	.pm_support = true,
 	.ops = &mtk_pcie_ops_v2,
 	.startup = mtk_pcie_startup_port_v2,
 	.setup_irq = mtk_pcie_setup_irq,
@@ -1213,6 +1272,7 @@ static struct platform_driver mtk_pcie_driver = {
 		.name = "mtk-pcie",
 		.of_match_table = mtk_pcie_ids,
 		.suppress_bind_attrs = true,
+		.pm = &mtk_pcie_pm_ops,
 	},
 };
 builtin_platform_driver(mtk_pcie_driver);
-- 
2.6.4