From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Date: Thu, 16 Jan 2025 14:09:13 +0000 (+0530)
Subject: PCI/pwrctrl: Skip scanning for the device further if pwrctrl device is created
X-Git-Tag: v6.15-rc1~119^2~24^2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2489eeb777aff943cb93b287385f2e8c68978db0;p=thirdparty%2Flinux.git

PCI/pwrctrl: Skip scanning for the device further if pwrctrl device is created

The pwrctrl core will rescan the bus once the device is powered on. So
there is no need to continue scanning for the device further.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20250116-pci-pwrctrl-slot-v3-3-827473c8fbf4@linaro.org
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
---

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 95a91778bb5d4..1191b02ae9f80 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2495,11 +2495,7 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
 }
 EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);
 
-/*
- * Create pwrctrl device (if required) for the PCI device to handle the power
- * state.
- */
-static void pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)
+static struct platform_device *pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)
 {
 	struct pci_host_bridge *host = pci_find_host_bridge(bus);
 	struct platform_device *pdev;
@@ -2507,7 +2503,7 @@ static void pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)
 
 	np = of_pci_find_child_device(dev_of_node(&bus->dev), devfn);
 	if (!np || of_find_device_by_node(np))
-		return;
+		return NULL;
 
 	/*
 	 * First check whether the pwrctrl device really needs to be created or
@@ -2516,13 +2512,17 @@ static void pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)
 	 */
 	if (!of_pci_supply_present(np)) {
 		pr_debug("PCI/pwrctrl: Skipping OF node: %s\n", np->name);
-		return;
+		return NULL;
 	}
 
 	/* Now create the pwrctrl device */
 	pdev = of_platform_device_create(np, NULL, &host->dev);
-	if (!pdev)
-		pr_err("PCI/pwrctrl: Failed to create pwrctrl device for OF node: %s\n", np->name);
+	if (!pdev) {
+		pr_err("PCI/pwrctrl: Failed to create pwrctrl device for node: %s\n", np->name);
+		return NULL;
+	}
+
+	return pdev;
 }
 
 /*
@@ -2534,7 +2534,14 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
 	struct pci_dev *dev;
 	u32 l;
 
-	pci_pwrctrl_create_device(bus, devfn);
+	/*
+	 * Create pwrctrl device (if required) for the PCI device to handle the
+	 * power state. If the pwrctrl device is created, then skip scanning
+	 * further as the pwrctrl core will rescan the bus after powering on
+	 * the device.
+	 */
+	if (pci_pwrctrl_create_device(bus, devfn))
+		return NULL;
 
 	if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000))
 		return NULL;