From: Honghui Zhang <honghui.zh...@mediatek.com>

In order to reduce the PCIe power consuming while system suspend,
the physical layer should be gated. And the PCIe link should be
re-established and the related control register values should be
re-initialized after system resume.

Register suspend_noirq & resume_noirq callback functions to allow
PCIe to come up after resume from RAM.

Signed-off-by: Honghui Zhang <honghui.zh...@mediatek.com>
---
 drivers/pci/controller/pcie-mediatek.c | 50 ++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/pci/controller/pcie-mediatek.c 
b/drivers/pci/controller/pcie-mediatek.c
index be38b38..bd1bde3 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -1172,6 +1172,55 @@ static int mtk_pcie_probe(struct platform_device *pdev)
        return err;
 }
 
+static int __maybe_unused mtk_pcie_suspend_noirq(struct device *dev)
+{
+       struct mtk_pcie *pcie = dev_get_drvdata(dev);
+       struct mtk_pcie_port *port;
+
+       if (list_empty(&pcie->ports))
+               return 0;
+
+       list_for_each_entry(port, &pcie->ports, list) {
+               clk_disable_unprepare(port->pipe_ck);
+               clk_disable_unprepare(port->obff_ck);
+               clk_disable_unprepare(port->axi_ck);
+               clk_disable_unprepare(port->aux_ck);
+               clk_disable_unprepare(port->ahb_ck);
+               clk_disable_unprepare(port->sys_ck);
+               phy_power_off(port->phy);
+               phy_exit(port->phy);
+       }
+
+       clk_disable_unprepare(pcie->free_ck);
+
+       return 0;
+}
+
+static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev)
+{
+       struct mtk_pcie *pcie = dev_get_drvdata(dev);
+       struct mtk_pcie_port *port, *tmp;
+
+       if (list_empty(&pcie->ports))
+               return 0;
+
+       clk_prepare_enable(pcie->free_ck);
+
+       list_for_each_entry_safe(port, tmp, &pcie->ports, list)
+               mtk_pcie_enable_port(port);
+
+       /* In case of EP was removed while system suspend. */
+       if (list_empty(&pcie->ports))
+               clk_disable_unprepare(pcie->free_ck);
+
+       return 0;
+}
+
+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,
@@ -1204,6 +1253,7 @@ 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

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