linux-kernel - [PATCH v16 7/9] PCI: Setup ACPI fwnode early and at the same time with OF

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Message-Id: <20210817180937.3123-8-ameynarkhede03@gmail.com>
Date:   Tue, 17 Aug 2021 23:39:35 +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 v16 7/9] PCI: Setup ACPI fwnode early and at the same time with OF

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

The pci_dev objects are created through two mechanisms 1) during PCI
bus scan and 2) from I/O Virtualization. The fwnode in pci_dev object
is being set at different places depends on the type of firmware used,
device creation mechanism, and acpi_pci_bridge_d3().

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

This patch does the two changes in order to provide fwnode consistently.
 - Set ACPI and OF fwnodes from pci_setup_device().
 - Cleanup acpi_pci_bridge_d3() since FWNODE is available long before
   it's being called.

After this patch, ACPI/OF firmware properties are visible at the same
time during the early stage of pci_dev setup. And also call sites should
be able to use firmware agnostic functions device_property_xxx() for the
early PCI quirks in the future.

Signed-off-by: Shanker Donthineni <sdonthineni@...dia.com>
Reviewed-by: Alex Williamson <alex.williamson@...hat.com>
---
 drivers/pci/pci-acpi.c | 49 ++++++++++++++++--------------------------
 drivers/pci/probe.c    |  7 +++---
 2 files changed, 23 insertions(+), 33 deletions(-)

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index eaddbf701..e9a403191 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -941,55 +941,44 @@ void pci_set_acpi_fwnode(struct pci_dev *dev)
 				   acpi_pci_find_companion(&dev->dev));
 }
 
+static bool acpi_pci_power_manageable(struct pci_dev *dev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
+	return adev ? acpi_device_power_manageable(adev) : false;
+}
+
 static bool acpi_pci_bridge_d3(struct pci_dev *dev)
 {
-	const struct fwnode_handle *fwnode;
+	const union acpi_object *obj;
 	struct acpi_device *adev;
-	struct pci_dev *root;
-	u8 val;
+	struct pci_dev *rpdev;
 
 	if (!dev->is_hotplug_bridge)
 		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 && acpi_device_power_manageable(adev))
+	if (acpi_pci_power_manageable(dev))
 		return true;
 
 	/*
-	 * Look for a special _DSD property for the root port and if it
-	 * is set we know the hierarchy behind it supports D3 just fine.
+	 * The ACPI firmware will provide the device-specific properties through
+	 * _DSD configuration object. Look for the 'HotPlugSupportInD3' property
+	 * for the root port and if it is set we know the hierarchy behind it
+	 * supports D3 just fine.
 	 */
-	root = pcie_find_root_port(dev);
-	if (!root)
+	rpdev = pcie_find_root_port(dev);
+	if (!rpdev)
 		return false;
 
-	adev = ACPI_COMPANION(&root->dev);
-	if (root == dev) {
-		/*
-		 * It is possible that the ACPI companion is not yet bound
-		 * for the root port so look it up manually here.
-		 */
-		if (!adev && !pci_dev_is_added(root))
-			adev = acpi_pci_find_companion(&root->dev);
-	}
-
+	adev = ACPI_COMPANION(&rpdev->dev);
 	if (!adev)
 		return false;
 
-	fwnode = acpi_fwnode_handle(adev);
-	if (fwnode_property_read_u8(fwnode, "HotPlugSupportInD3", &val))
+	if (acpi_dev_get_property(adev, "HotPlugSupportInD3",
+				   ACPI_TYPE_INTEGER, &obj) < 0)
 		return false;
 
-	return val == 1;
-}
-
-static bool acpi_pci_power_manageable(struct pci_dev *dev)
-{
-	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
-	return adev ? acpi_device_power_manageable(adev) : false;
+	return obj->integer.value == 1;
 }
 
 static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 379e85037..15a6975d3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1789,6 +1789,9 @@ int pci_setup_device(struct pci_dev *dev)
 	dev->error_state = pci_channel_io_normal;
 	set_pcie_port_type(dev);
 
+	pci_set_of_node(dev);
+	pci_set_acpi_fwnode(dev);
+
 	pci_dev_assign_slot(dev);
 
 	/*
@@ -1924,6 +1927,7 @@ int pci_setup_device(struct pci_dev *dev)
 	default:				    /* unknown header */
 		pci_err(dev, "unknown header type %02x, ignoring device\n",
 			dev->hdr_type);
+		pci_release_of_node(dev);
 		return -EIO;
 
 	bad:
@@ -2351,10 +2355,7 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
 	dev->vendor = l & 0xffff;
 	dev->device = (l >> 16) & 0xffff;
 
-	pci_set_of_node(dev);
-
 	if (pci_setup_device(dev)) {
-		pci_release_of_node(dev);
 		pci_bus_put(dev->bus);
 		kfree(dev);
 		return NULL;
-- 
2.32.0