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Subject[PATCH v16 7/9] PCI: Setup ACPI fwnode early and at the same time with OF
Date
From: Shanker Donthineni <sdonthineni@nvidia.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@nvidia.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.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
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