linux-kernel - Re: [PATCH v10 6/8] PCI: Setup ACPI fwnode early and at the same time with OF

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Date:   Tue, 27 Jul 2021 18:30:25 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Amey Narkhede <ameynarkhede03@...il.com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>, 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: Re: [PATCH v10 6/8] PCI: Setup ACPI fwnode early and at the same
 time with OF

On Fri, Jul 09, 2021 at 06:08:11PM +0530, Amey Narkhede wrote:
> 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() WAR.

WAR?

> 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@...dia.com>
> ---
>  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 eaddbf701..dae021322 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);
>  
>  	if (adev && acpi_device_power_manageable(adev))
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index c272e23db..c911d6a5c 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1790,6 +1790,9 @@ 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);
>  
>  	/*
> @@ -1925,6 +1928,7 @@ 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:
> @@ -2352,10 +2356,7 @@ 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
>