[PATCH v3 1/3] PCI: Disable parity checking if broken_parity is set

[Bjorn Helgaas]

On Wed, Jan 06, 2021 at 06:50:22PM +0100, Heiner Kallweit wrote:
> If we know that a device has broken parity checking, then disable it.
> This avoids quirks like in r8169 where on the first parity error
> interrupt parity checking will be disabled if broken_parity_status
> is set. Make pci_quirk_broken_parity() public so that it can be used
> by platform code, e.g. for Thecus N2100.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
> Reviewed-by: Leon Romanovsky <leonro at nvidia.com>

Acked-by: Bjorn Helgaas <bhelgaas at google.com>

This series should all go together.  Let me know if you want me to do
anything more (would require acks for arm and r8169, of course).

> ---
>  drivers/pci/quirks.c | 17 +++++++++++------
>  include/linux/pci.h  |  2 ++
>  2 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 653660e3b..ab54e26b8 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -205,17 +205,22 @@ static void quirk_mmio_always_on(struct pci_dev *dev)
>  DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID,
>  				PCI_CLASS_BRIDGE_HOST, 8, quirk_mmio_always_on);
>  
> +void pci_quirk_broken_parity(struct pci_dev *dev)
> +{
> +	u16 cmd;
> +
> +	dev->broken_parity_status = 1;	/* This device gives false positives */
> +	pci_read_config_word(dev, PCI_COMMAND, &cmd);
> +	pci_write_config_word(dev, PCI_COMMAND, cmd & ~PCI_COMMAND_PARITY);
> +}
> +
>  /*
>   * The Mellanox Tavor device gives false positive parity errors.  Mark this
>   * device with a broken_parity_status to allow PCI scanning code to "skip"
>   * this now blacklisted device.
>   */
> -static void quirk_mellanox_tavor(struct pci_dev *dev)
> -{
> -	dev->broken_parity_status = 1;	/* This device gives false positives */
> -}
> -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR, quirk_mellanox_tavor);
> -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR_BRIDGE, quirk_mellanox_tavor);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR, pci_quirk_broken_parity);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_DEVICE_ID_MELLANOX_TAVOR_BRIDGE, pci_quirk_broken_parity);
>  
>  /*
>   * Deal with broken BIOSes that neglect to enable passive release,
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index b32126d26..161dcc474 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1916,6 +1916,8 @@ enum pci_fixup_pass {
>  	pci_fixup_suspend_late,	/* pci_device_suspend_late() */
>  };
>  
> +void pci_quirk_broken_parity(struct pci_dev *dev);
> +
>  #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
>  #define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
>  				    class_shift, hook)			\
> -- 
> 2.30.0
> 
> 
>