linux-kernel - [PATCH v7 5/8] PCI: Setup ACPI

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Date:   Tue,  8 Jun 2021 11:18:54 +0530
From:   Amey Narkhede <ameynarkhede03@...il.com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     alex.williamson@...hat.com,
        Raphael Norwitz <raphael.norwitz@...anix.com>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        kw@...ux.com, Shanker Donthineni <sdonthineni@...dia.com>,
        Sinan Kaya <okaya@...nel.org>, Len Brown <lenb@...nel.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>
Subject: [PATCH v7 5/8] PCI: Setup ACPI_COMPANION early

From: Shanker Donthineni <sdonthineni@...dia.com>

Currently, the ACPI_COMPANION is not available until device_add().
The software features which have dependency on ACPI fwnode properties
and needs to be handled before device_add() will not work. One use
case, software has to check the existence of _RST method to support
ACPI based reset mechanism.

This patch adds a new function pci_set_acpi_fwnode() for setting the
ACPI_COMPANION, same code which is available in acpi_pci_bridge_d3().

Call pci_set_acpi_fwnode() from pci_scan_device() to fix the issue.

Signed-off-by: Shanker Donthineni <sdonthineni@...dia.com>
---
 drivers/pci/pci-acpi.c | 12 ++++++++----
 drivers/pci/pci.h      |  2 ++
 drivers/pci/probe.c    |  2 ++
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 36bc23e21..eaddbf701 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -934,6 +934,13 @@ static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
 
 static struct acpi_device *acpi_pci_find_companion(struct device *dev);
 
+void pci_set_acpi_fwnode(struct pci_dev *dev)
+{
+	if (!ACPI_COMPANION(&dev->dev) && !pci_dev_is_added(dev))
+		ACPI_COMPANION_SET(&dev->dev,
+				   acpi_pci_find_companion(&dev->dev));
+}
+
 static bool acpi_pci_bridge_d3(struct pci_dev *dev)
 {
 	const struct fwnode_handle *fwnode;
@@ -945,11 +952,8 @@ static bool acpi_pci_bridge_d3(struct pci_dev *dev)
 		return false;
 
 	/* Assume D3 support if the bridge is power-manageable by ACPI. */
+	pci_set_acpi_fwnode(dev);
 	adev = ACPI_COMPANION(&dev->dev);
-	if (!adev && !pci_dev_is_added(dev)) {
-		adev = acpi_pci_find_companion(&dev->dev);
-		ACPI_COMPANION_SET(&dev->dev, adev);
-	}
 
 	if (adev && acpi_device_power_manageable(adev))
 		return true;
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 13ec6bd6f..d22da6d3c 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -703,7 +703,9 @@ static inline int pci_aer_raw_clear_status(struct pci_dev *dev) { return -EINVAL
 #ifdef CONFIG_ACPI
 int pci_acpi_program_hp_params(struct pci_dev *dev);
 extern const struct attribute_group pci_dev_acpi_attr_group;
+void pci_set_acpi_fwnode(struct pci_dev *dev);
 #else
+static inline void pci_set_acpi_fwnode(struct pci_dev *dev) {}
 static inline int pci_acpi_program_hp_params(struct pci_dev *dev)
 {
 	return -ENODEV;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 90fd4f61f..dfefa5ed0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2359,6 +2359,8 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
 		return NULL;
 	}
 
+	pci_set_acpi_fwnode(dev);
+
 	return dev;
 }
 
-- 
2.31.1