linux-kernel - Re: [tip:x86/urgent] x86/quirks: Add early quirk to reset Apple AirPort card

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Date:	Wed, 8 Jun 2016 11:56:14 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>, cmilsted@...hat.com,
	Rafał Miłecki <zajec5@...il.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Peter Zijlstra <peterz@...radead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	lukas@...ner.de, Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Garrett <mjg59@...f.ucam.org>, m@...s.ch
Cc:	"linux-tip-commits@...r.kernel.org" 
	<linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:x86/urgent] x86/quirks: Add early quirk to reset Apple
 AirPort card

On Wed, Jun 8, 2016 at 7:23 AM, tip-bot for Lukas Wunner
<tipbot@...or.com> wrote:
> Commit-ID:  625a99d9bfd038ea492f57308555bf4e607ce591
> Gitweb:     http://git.kernel.org/tip/625a99d9bfd038ea492f57308555bf4e607ce591
> Author:     Lukas Wunner <lukas@...ner.de>
> AuthorDate: Sun, 29 May 2016 01:35:28 +0200
...
> ---
>  arch/x86/kernel/early-quirks.c | 95 ++++++++++++++++++++++++++++++++++++------
>  drivers/bcma/bcma_private.h    |  2 -
>  include/linux/bcma/bcma.h      |  1 +
>  3 files changed, 83 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
> index bca14c8..4e4e499 100644
> --- a/arch/x86/kernel/early-quirks.c
> +++ b/arch/x86/kernel/early-quirks.c
...

Extend bus scan range part should be in separated patch?

and put apple_airport_reset() related in second patch.

> -/*
> - * Only works for devices on the root bus. If you add any devices
> - * not on bus 0 readd another loop level in early_quirks(). But
> - * be careful because at least the Nvidia quirk here relies on
> - * only matching on bus 0.
> - */
>  static struct chipset early_qrk[] __initdata = {
>         { PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
>           PCI_CLASS_BRIDGE_PCI, PCI_ANY_ID, QFLAG_APPLY_ONCE, nvidia_bugs },
> @@ -638,9 +692,13 @@ static struct chipset early_qrk[] __initdata = {
>          */
>         { PCI_VENDOR_ID_INTEL, 0x0f00,
>                 PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
> +       { PCI_VENDOR_ID_BROADCOM, 0x4331,
> +         PCI_CLASS_NETWORK_OTHER, PCI_ANY_ID, 0, apple_airport_reset},
>         {}
>  };
>
> +static void __init early_pci_scan_bus(int bus);
> +
>  /**
>   * check_dev_quirk - apply early quirks to a given PCI device
>   * @num: bus number
> @@ -649,7 +707,7 @@ static struct chipset early_qrk[] __initdata = {
>   *
>   * Check the vendor & device ID against the early quirks table.
>   *
> - * If the device is single function, let early_quirks() know so we don't
> + * If the device is single function, let early_pci_scan_bus() know so we don't
>   * poke at this device again.
>   */
>  static int __init check_dev_quirk(int num, int slot, int func)
> @@ -658,6 +716,7 @@ static int __init check_dev_quirk(int num, int slot, int func)
>         u16 vendor;
>         u16 device;
>         u8 type;
> +       u8 sec;
>         int i;
>
>         class = read_pci_config_16(num, slot, func, PCI_CLASS_DEVICE);
> @@ -685,25 +744,35 @@ static int __init check_dev_quirk(int num, int slot, int func)
>
>         type = read_pci_config_byte(num, slot, func,
>                                     PCI_HEADER_TYPE);
> +
> +       if ((type & 0x7f) == PCI_HEADER_TYPE_BRIDGE) {
> +               sec = read_pci_config_byte(num, slot, func, PCI_SECONDARY_BUS);
> +               early_pci_scan_bus(sec);

How do you know that sec is valid ?

How about on the system that have one bridge that still have sec num register 0?

it will be get into dead loop.

> +       }
> +
>         if (!(type & 0x80))
>                 return -1;
>
>         return 0;
>  }
>
> -void __init early_quirks(void)
> +static void __init early_pci_scan_bus(int bus)
>  {
>         int slot, func;
>
> -       if (!early_pci_allowed())
> -               return;
> -
>         /* Poor man's PCI discovery */
> -       /* Only scan the root bus */
>         for (slot = 0; slot < 32; slot++)
>                 for (func = 0; func < 8; func++) {
>                         /* Only probe function 0 on single fn devices */
> -                       if (check_dev_quirk(0, slot, func))
> +                       if (check_dev_quirk(bus, slot, func))
>                                 break;
>                 }
>  }
> +
> +void __init early_quirks(void)
> +{
> +       if (!early_pci_allowed())
> +               return;
> +
> +       early_pci_scan_bus(0);
> +}

Would just revert to scan domain 0, bus 0 to 255.

Thanks

Yinghai