linux-kernel - [PATCH v6 7/9] PCI: mediatek: Add system pm support for MT2712 and MT7622

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Date:   Mon, 8 Oct 2018 11:24:46 +0800
From:   <honghui.zhang@...iatek.com>
To:     <lorenzo.pieralisi@....com>, <bhelgaas@...gle.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <linux-pci@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <ryder.lee@...iatek.com>
CC:     <ulf.hansson@...aro.org>, <marc.zyngier@....com>,
        <matthias.bgg@...il.com>, <devicetree@...r.kernel.org>,
        <yingjoe.chen@...iatek.com>, <eddie.huang@...iatek.com>,
        <honghui.zhang@...iatek.com>, <youlin.pei@...iatek.com>,
        <yt.shen@...iatek.com>, <sean.wang@...iatek.com>
Subject: [PATCH v6 7/9] PCI: mediatek: Add system pm support for MT2712 and MT7622

From: Honghui Zhang <honghui.zhang@...iatek.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.zhang@...iatek.com>
Acked-by: Ryder Lee <ryder.lee@...iatek.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 d3f4694..42cf2a4 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -1168,6 +1168,55 @@ 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,
@@ -1200,6 +1249,7 @@ 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