[PATCH v6] PCI: exynos: Handle PCIe PHY initialization errors

[Sreeraj S Kurup]

Check the return values of "phy_init()" and "phy_power_on()" to
avoid continuing PCIe host initialization when PHY setup fails.

Track the PHY initialization and power state to ensure cleanup is
performed only when appropriate, avoiding double calls to
"phy_exit()" on probe failure.

Also check the return value of "exynos_pcie_host_init()" during
resume and abort the resume sequence if PHY initialization fails.

Signed-off-by: Sreeraj S Kurup <sreekuttan2156239 at gmail.com>
---
v6:
 - Prevent state/reference count desynchronization in exynos_pcie_phy_exit()
 by ensuring both phy_power_off() and phy_exit() attempt cleanup even if one
 fails
 - Assert core reset on post-init probe failures in fail_probe if PHY/host
 initialization was reached
v5:
 - Avoid PM core state desynchronization in exynos_pcie_suspend_noirq()
 by logging teardown errors and returning 0 instead of aborting suspend
 on teardown failure
v4:
 - Fix invalid return in void exynos_pcie_remove() and ensure regulator cleanup
 - Add core reset deassertion on error in exynos_pcie_suspend_noirq()
 - Prevent regulator leaks in exynos_pcie_resume_noirq() error recovery path
v3:
 - Address review feedback on PHY and regulator state tracking
 - Avoid powering down the controller when link detection fails
v2:
 - Track PHY initialization and power state to prevent duplicate cleanup
 - Handle host initialization failures during resume

 drivers/pci/controller/dwc/pci-exynos.c | 115 +++++++++++++++++++++---
 1 file changed, 104 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
index e3c05ade381b..0085c3ed0c2f 100644
--- a/drivers/pci/controller/dwc/pci-exynos.c
+++ b/drivers/pci/controller/dwc/pci-exynos.c
@@ -11,6 +11,7 @@
 
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -55,8 +56,35 @@ struct exynos_pcie {
 	struct clk_bulk_data		*clks;
 	struct phy			*phy;
 	struct regulator_bulk_data	supplies[2];
+	bool phy_initialized;
+	bool phy_powered;
+	bool supplies_enabled;
 };
 
+static int exynos_pcie_phy_exit(struct exynos_pcie *ep)
+{
+	int ret = 0;
+	int err;
+
+	if (ep->phy_powered) {
+		err = phy_power_off(ep->phy);
+		if (err)
+			ret = err;
+		else
+			ep->phy_powered = false;
+	}
+
+	if (ep->phy_initialized) {
+		err = phy_exit(ep->phy);
+		if (err)
+			ret = err;
+		else
+			ep->phy_initialized = false;
+	}
+
+	return ret;
+}
+
 static void exynos_pcie_writel(void __iomem *base, u32 val, u32 reg)
 {
 	writel(val, base + reg);
@@ -225,13 +253,23 @@ static int exynos_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct exynos_pcie *ep = to_exynos_pcie(pci);
+	int ret;
 
 	pp->bridge->ops = &exynos_pci_ops;
 
 	exynos_pcie_assert_core_reset(ep);
 
-	phy_init(ep->phy);
-	phy_power_on(ep->phy);
+	ret = phy_init(ep->phy);
+	if (ret)
+		return ret;
+
+	ep->phy_initialized = true;
+
+	ret = phy_power_on(ep->phy);
+	if (ret)
+		return ret;
+
+	ep->phy_powered = true;
 
 	exynos_pcie_deassert_core_reset(ep);
 	exynos_pcie_enable_irq_pulse(ep);
@@ -314,6 +352,7 @@ static int exynos_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ep->supplies_enabled = true;
 	platform_set_drvdata(pdev, ep);
 
 	ret = exynos_add_pcie_port(ep, pdev);
@@ -323,8 +362,22 @@ static int exynos_pcie_probe(struct platform_device *pdev)
 	return 0;
 
 fail_probe:
-	phy_exit(ep->phy);
-	regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+	if (ep->phy_initialized || ep->phy_powered)
+		exynos_pcie_assert_core_reset(ep);
+
+	if (exynos_pcie_phy_exit(ep))
+		dev_err(&pdev->dev, "failed to exit PCIe PHY\n");
+
+	if (ep->supplies_enabled) {
+		int err;
+
+		err = regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+		if (err)
+			dev_err(&pdev->dev, "failed to disable regulators: %d\n", err);
+		else
+			ep->supplies_enabled = false;
+
+	}
 
 	return ret;
 }
@@ -332,22 +385,42 @@ static int exynos_pcie_probe(struct platform_device *pdev)
 static void exynos_pcie_remove(struct platform_device *pdev)
 {
 	struct exynos_pcie *ep = platform_get_drvdata(pdev);
+	int ret;
 
 	dw_pcie_host_deinit(&ep->pci.pp);
 	exynos_pcie_assert_core_reset(ep);
-	phy_power_off(ep->phy);
-	phy_exit(ep->phy);
-	regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+
+	ret = exynos_pcie_phy_exit(ep);
+	if (ret)
+		dev_err(&pdev->dev, "failed to exit PCIe PHY: %d\n", ret);
+
+	if (ep->supplies_enabled) {
+		ret = regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+		if (ret)
+			dev_err(&pdev->dev, "failed to disable regulators: %d\n", ret);
+		else
+			ep->supplies_enabled = false;
+	}
 }
 
 static int exynos_pcie_suspend_noirq(struct device *dev)
 {
 	struct exynos_pcie *ep = dev_get_drvdata(dev);
+	int ret;
 
 	exynos_pcie_assert_core_reset(ep);
-	phy_power_off(ep->phy);
-	phy_exit(ep->phy);
-	regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+
+	ret = exynos_pcie_phy_exit(ep);
+	if (ret)
+		dev_err(dev, "failed to exit PCIe PHY during suspend: %d\n", ret);
+
+	if (ep->supplies_enabled) {
+		ret = regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+		if (ret)
+			dev_err(dev, "failed to disable regulators during suspend: %d\n", ret);
+		else
+			ep->supplies_enabled = false;
+	}
 
 	return 0;
 }
@@ -358,13 +431,33 @@ static int exynos_pcie_resume_noirq(struct device *dev)
 	struct dw_pcie *pci = &ep->pci;
 	struct dw_pcie_rp *pp = &pci->pp;
 	int ret;
+	int err;
 
 	ret = regulator_bulk_enable(ARRAY_SIZE(ep->supplies), ep->supplies);
 	if (ret)
 		return ret;
 
+	ep->supplies_enabled = true;
+
 	/* exynos_pcie_host_init controls ep->phy */
-	exynos_pcie_host_init(pp);
+	ret = exynos_pcie_host_init(pp);
+	if (ret) {
+		err = exynos_pcie_phy_exit(ep);
+		if (err)
+			dev_err(dev, "failed to exit PCIe PHY during resume error: %d\n", err);
+
+		if (ep->supplies_enabled) {
+			err = regulator_bulk_disable(ARRAY_SIZE(ep->supplies), ep->supplies);
+			if (err)
+				dev_err(dev, "failed to disable regulators: %d\n", err);
+			else
+				ep->supplies_enabled = false;
+		}
+
+		return ret;
+
+	}
+
 	dw_pcie_setup_rc(pp);
 	exynos_pcie_start_link(pci);
 	return dw_pcie_wait_for_link(pci);
-- 
2.55.0