[+cc Ben, Mika]
On Thu, Aug 05, 2021 at 09:59:15PM +0530, Amey Narkhede wrote:
> From: Shanker Donthineni <sdonthineni@xxxxxxxxxx>
>
> 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().
> - Remove pci_set_acpi_fwnode() in acpi_pci_bridge_d3().
>
> 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@xxxxxxxxxx>
> Reviewed-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> ---
> drivers/pci/pci-acpi.c | 1 -
> drivers/pci/probe.c | 7 ++++---
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index eaddbf701759..dae021322b3f 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -952,7 +952,6 @@ 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);
I *think* the Root Port code farther down in this function is also now
unnecessary:
acpi_pci_bridge_d3(...)
{
...
root = pcie_find_root_port(dev);
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);
}
Since we're now setting the ACPI_COMPANION for every pci_dev long
before we get here, I think this could now be simplified to something
like this:
acpi_pci_bridge_d3(...)
{
if (!dev->is_hotplug_bridge)
return false;
adev = ACPI_COMPANION(&dev->dev);
if (adev && acpi_device_power_manageable(adev))
return true;
root = pcie_find_root_port(dev);
if (!root)
return false;
adev = ACPI_COMPANION(&root->dev);
if (!adev)
return false;
rc = acpi_dev_get_property(dev, "HotPlugSupportInD3",
ACPI_TYPE_INTEGER, &val);
if (rc < 0)
return false;
return val == 1;
}
acpi_pci_bridge_d3() was added by 26ad34d510a8 ("PCI / ACPI: Whitelist
D3 for more PCIe hotplug ports") [1], so I cc'd Mika in case he has
any comment.
> if (adev && acpi_device_power_manageable(adev))
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 379e85037d9b..15a6975d3757 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);
Is there a reason why you moved pci_set_of_node() from
pci_scan_device() to here? I think it's a good change; I'm just
curious if you tripped over something that required it.
The pci_set_of_node() was added to pci_scan_device() by 98d9f30c820d
("pci/of: Match PCI devices to OF nodes dynamically") [2], so I cc'd
Ben just in case there's some reason he didn't put it in
pci_setup_device() in the first place.
> 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;
[1] https://git.kernel.org/linus/26ad34d510a8
[2] https://git.kernel.org/linus/98d9f30c820d
