[PATCH v2 05/12] PCI: aardvark: Add suspend to RAM support

Miquel Raynal
2018-12-12T10:23:00Z

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>
---
drivers/pci/controller/pci-aardvark.c | 52 +++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 108b3f15c410..7ecf1ac4036b 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1108,6 +1108,55 @@ static int advk_pcie_setup_clk(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;
+
+ /*
+ * Empirical delay needed after enabling the clock and before
+ * accessing any register.
+ */
+ msleep(10);
+
+ ret = advk_pcie_enable_phy(pcie);
+ if (ret)
+ return ret;
+
+ advk_pcie_hard_reset(pcie);
+
+ advk_pcie_setup_hw(pcie);
+
+ advk_sw_pci_bridge_init(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;
@@ -1188,6 +1237,8 @@ static int advk_pcie_probe(struct platform_device *pdev)
return ret;
}

+ dev_set_drvdata(dev, pcie);
+
return 0;
}

@@ -1200,6 +1251,7 @@ 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,
/* Driver unloading/unbinding currently not supported */
.suppress_bind_attrs = true,
},
--
2.19.1