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Date:   Wed, 31 Aug 2022 11:11:39 +0100
From:   Jonathan Cameron <Jonathan.Cameron@huawei.com>
To:     Robert Richter <rrichter@amd.com>
CC:     Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Ben Widawsky <bwidawsk@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        "Bjorn Helgaas" <bhelgaas@google.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        <linux-cxl@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Len Brown <lenb@kernel.org>, <linux-pci@vger.kernel.org>,
        <linux-acpi@vger.kernel.org>
Subject: Re: [PATCH 06/15] PCI/ACPI: Link host bridge to its ACPI fw node
Message-ID: <20220831111139.0000560f@huawei.com>
In-Reply-To: <20220831081603.3415-7-rrichter@amd.com>
References: <20220831081603.3415-1-rrichter@amd.com>
        <20220831081603.3415-7-rrichter@amd.com>
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On Wed, 31 Aug 2022 10:15:54 +0200
Robert Richter <rrichter@amd.com> wrote:

> A lookup of a host bridge's corresponding acpi device (struct
> acpi_device) is not possible, for example:
> 
> 	adev = ACPI_COMPANION(&host_bridge->dev);
> 
> This could be useful to find a host bridge's fwnode handle and to
> determine and call additional host bridge ACPI parameters and methods
> such as HID/CID or _UID.
> 
> Make this work by linking the host bridge to its ACPI fw node.
> 
> Signed-off-by: Robert Richter <rrichter@amd.com>

Seems sensible to me, though I'm not an expert in this are of the code.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>


> ---
>  drivers/acpi/pci_root.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d57cf8454b93..846c979e4c29 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -1083,6 +1083,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>  		goto out_release_info;
>  
>  	host_bridge = to_pci_host_bridge(bus->bridge);
> +	host_bridge->dev.fwnode = acpi_fwnode_handle(device);
>  	if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
>  		host_bridge->native_pcie_hotplug = 0;
>  	if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))