[PATCH 16/18] PCI: aardvark: Add suspend to RAM support

["Marek Behún" <kabel@kernel.org>]

From: Miquel Raynal <miquel.raynal@bootlin.com>

Add suspend and resume callbacks. The priority of these are
"_noirq()", to workaround early access to the registers done by the
PCI core through the ->read()/->write() callbacks at resume time.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
---
 drivers/pci/controller/pci-aardvark.c | 39 +++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 3b51f47abd72..8c9ac7766ac7 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1896,6 +1896,44 @@ static int advk_pcie_setup_phy(struct advk_pcie *pcie)
 	return ret;
 }
 
+static int __maybe_unused advk_pcie_suspend(struct device *dev)
+{
+	struct advk_pcie *pcie = dev_get_drvdata(dev);
+
+	advk_pcie_disable_phy(pcie);
+
+	clk_disable_unprepare(pcie->clk);
+
+	return 0;
+}
+
+static int __maybe_unused advk_pcie_resume(struct device *dev)
+{
+	struct advk_pcie *pcie = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(pcie->clk);
+	if (ret)
+		return ret;
+
+	ret = advk_pcie_enable_phy(pcie);
+	if (ret)
+		return ret;
+
+	advk_pcie_setup_hw(pcie);
+
+	return 0;
+}
+
+/*
+ * The PCI core will try to reconfigure the bus quite early in the resume path.
+ * We must use the _noirq() alternatives to ensure the controller is ready when
+ * the core uses the ->read()/->write() callbacks.
+ */
+static const struct dev_pm_ops advk_pcie_dev_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(advk_pcie_suspend, advk_pcie_resume)
+};
+
 static int advk_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -2171,6 +2209,7 @@ static struct platform_driver advk_pcie_driver = {
 	.driver = {
 		.name = "advk-pcie",
 		.of_match_table = advk_pcie_of_match_table,
+		.pm = &advk_pcie_dev_pm_ops,
 	},
 	.probe = advk_pcie_probe,
 	.remove = advk_pcie_remove,
-- 
2.34.1