Message-ID: <CAJZ5v0iCgQxxuoCB9B4-Ho3xeLwb4v99Xyw-9e-tT53mRD+YVQ@mail.gmail.com>
Date:   Mon, 20 Aug 2018 10:23:13 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Linux PCI <linux-pci@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Christoph Hellwig <hch@...radead.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>
Subject: Re: [RFC 07/15] PCI/ACPI: clean up acpi_pci_root_create()

On Fri, Aug 17, 2018 at 12:33 PM Arnd Bergmann <arnd@...db.de> wrote:
>
> The acpi_pci_create_root_bus() can be fully integrated into
> acpi_pci_root_create(), improving a few things:
>
> * We can call pci_scan_root_bus_bridge(), which registers and
>   scans the bridge in one step.
> * After a failure in pci_register_host_bridge(), we correctly
>   clean up the resources.
> * The bridge settings (release function, flags, operations etc)
>   can get set up before registering the bridge.
> * Further cleanup would be possible, removing duplication between
>   pci_host_bridge and some ACPI structures.
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/acpi/pci_root.c | 68 +++++++++++++++--------------------------
>  1 file changed, 24 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 85dbcf47015b..5f73de3b67c8 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -873,34 +873,6 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
>         __acpi_pci_root_release_info(bridge->release_data);
>  }
>
> -static struct pci_bus *acpi_pci_create_root_bus(struct device *parent, int bus,
> -               struct pci_ops *ops, void *sysdata, struct list_head *resources)
> -{
> -       int error;
> -       struct pci_host_bridge *bridge;
> -
> -       bridge = pci_alloc_host_bridge(0);
> -       if (!bridge)
> -               return NULL;
> -
> -       bridge->dev.parent = parent;
> -
> -       list_splice_init(resources, &bridge->windows);
> -       bridge->sysdata = sysdata;
> -       bridge->busnr = bus;
> -       bridge->ops = ops;
> -
> -       error = pci_register_host_bridge(bridge);
> -       if (error < 0)
> -               goto err_out;
> -
> -       return bridge->bus;
> -
> -err_out:
> -       kfree(bridge);
> -       return NULL;
> -}
> -
>  struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>                                      struct acpi_pci_root_ops *ops,
>                                      struct acpi_pci_root_info *info,
> @@ -909,8 +881,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>         int ret, busnum = root->secondary.start;
>         struct acpi_device *device = root->device;
>         int node = acpi_get_node(device->handle);
> -       struct pci_bus *bus;
> -       struct pci_host_bridge *host_bridge;
> +       struct pci_host_bridge *bridge;

Why "bridge" and not "host" or even something to stand for "root complex"?

Or maybe it can still be "host_bridge"?

>
>         info->root = root;
>         info->bridge = device;
> @@ -930,30 +901,39 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>
>         pci_acpi_root_add_resources(info);
>         pci_add_resource(&info->resources, &root->secondary);
> -       bus = acpi_pci_create_root_bus(NULL, busnum, ops->pci_ops,
> -                                 sysdata, &info->resources);
> -       if (!bus)
> +
> +       bridge = pci_alloc_host_bridge(0);
> +       if (!bridge)
>                 goto out_release_info;
>
> -       host_bridge = to_pci_host_bridge(bus->bridge);
> +       list_splice_init(&info->resources, &bridge->windows);
> +       bridge->sysdata = sysdata;
> +       bridge->busnr = busnum;
> +       bridge->ops = ops->pci_ops;
> +       pci_set_host_bridge_release(bridge, acpi_pci_root_release_info,
> +                                   info);
> +
>         if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
> -               host_bridge->native_pcie_hotplug = 0;
> +               bridge->native_pcie_hotplug = 0;
>         if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
> -               host_bridge->native_shpc_hotplug = 0;
> +               bridge->native_shpc_hotplug = 0;
>         if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
> -               host_bridge->native_aer = 0;
> +               bridge->native_aer = 0;
>         if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
> -               host_bridge->native_pme = 0;
> +               bridge->native_pme = 0;
>         if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
> -               host_bridge->native_ltr = 0;
> +               bridge->native_ltr = 0;
> +
> +       ret = pci_scan_root_bus_bridge(bridge);
> +       if (ret < 0)
> +               goto out_release_bridge;
>
> -       pci_scan_child_bus(bus);
> -       pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info,
> -                                   info);
>         if (node != NUMA_NO_NODE)
> -               dev_printk(KERN_DEBUG, &bus->dev, "on NUMA node %d\n", node);
> -       return bus;
> +               dev_printk(KERN_DEBUG, &bridge->bus->dev, "on NUMA node %d\n", node);
> +       return bridge->bus;
>
> +out_release_bridge:
> +       pci_free_host_bridge(bridge);
>  out_release_info:
>         __acpi_pci_root_release_info(info);
>         return NULL;
> --
> 2.18.0
>

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