PCI: rockchip-dwc: Reset core at driver probe

The PCIe controller is in an unknown state at driver probe. This can
lead to undesireable effects when the driver attempts to configure the
controller.

Prevent issues in the future by resetting the core during probe.

Link: https://lore.kernel.org/r/20220429123832.2376381-3-pgwipeout@gmail.comTested-by: NNicolas Frattaroli <frattaroli.nicolas@gmail.com>
Signed-off-by: NPeter Geis <pgwipeout@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/controller/dwc/pcie-dw-rockchip.c

@@ -152,6 +152,11 @@ static int rockchip_pcie_resource_get(struct platform_device *pdev,
 	if (IS_ERR(rockchip->rst_gpio))
 		return PTR_ERR(rockchip->rst_gpio);
 
+	rockchip->rst = devm_reset_control_array_get_exclusive(&pdev->dev);
+	if (IS_ERR(rockchip->rst))
+		return dev_err_probe(&pdev->dev, PTR_ERR(rockchip->rst),
+				     "failed to get reset lines\n");
+
 	return 0;
 }
 
@@ -182,18 +187,6 @@ static void rockchip_pcie_phy_deinit(struct rockchip_pcie *rockchip)
 	phy_power_off(rockchip->phy);
 }
 
-static int rockchip_pcie_reset_control_release(struct rockchip_pcie *rockchip)
-{
-	struct device *dev = rockchip->pci.dev;
-
-	rockchip->rst = devm_reset_control_array_get_exclusive(dev);
-	if (IS_ERR(rockchip->rst))
-		return dev_err_probe(dev, PTR_ERR(rockchip->rst),
-				     "failed to get reset lines\n");
-
-	return reset_control_deassert(rockchip->rst);
-}
-
 static const struct dw_pcie_ops dw_pcie_ops = {
 	.link_up = rockchip_pcie_link_up,
 	.start_link = rockchip_pcie_start_link,
@@ -222,6 +215,10 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = reset_control_assert(rockchip->rst);
+	if (ret)
+		return ret;
+
 	/* DON'T MOVE ME: must be enable before PHY init */
 	rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
 	if (IS_ERR(rockchip->vpcie3v3)) {
@@ -241,7 +238,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		goto disable_regulator;
 
-	ret = rockchip_pcie_reset_control_release(rockchip);
+	ret = reset_control_deassert(rockchip->rst);
 	if (ret)
 		goto deinit_phy;