Re: [PATCH 2/5] PCI: Add mask bit definition for MSI-X table

[Hidetoshi Seto]

(2010/11/04 15:15), Sheng Yang wrote:
> Then we can use it instead of magic number 1.
> 
> Cc: Matthew Wilcox <wi...@linux.intel.com>
> Cc: Jesse Barnes <jbar...@virtuousgeek.org>
> Cc: linux-...@vger.kernel.org
> Signed-off-by: Sheng Yang <sh...@linux.intel.com>
> ---
>  drivers/pci/msi.c        |    4 ++--
>  include/linux/pci_regs.h |    1 +
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 69b7be3..673e7dc 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -158,7 +158,7 @@ static u32 __msix_mask_irq(struct msi_desc *desc, u32 
> flag)
>       u32 mask_bits = desc->masked;
>       unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
>                                               PCI_MSIX_ENTRY_VECTOR_CTRL;
> -     mask_bits &= ~1;
> +     mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
>       mask_bits |= flag;
>       writel(mask_bits, desc->mask_base + offset);
>  
> @@ -185,7 +185,7 @@ static void msi_set_mask_bit(unsigned irq, u32 flag)
>  
>  void mask_msi_irq(unsigned int irq)
>  {
> -     msi_set_mask_bit(irq, 1);
> +     msi_set_mask_bit(irq, PCI_MSIX_ENTRY_CTRL_MASKBIT);
>  }
>  
>  void unmask_msi_irq(unsigned int irq)

This hunk is not good, because the function msi_set_mask_bit() is
not only for MSI-X but also for MSI, so the number 0/1 here works
as like as false/true:

 static void msi_set_mask_bit(struct irq_data *data, u32 flag)
 {
        struct msi_desc *desc = irq_data_get_msi(data);

        if (desc->msi_attrib.is_msix) {
                msix_mask_irq(desc, flag);
                readl(desc->mask_base);         /* Flush write to device */
        } else {
                unsigned offset = data->irq - desc->dev->irq;
                msi_mask_irq(desc, 1 << offset, flag << offset);
        }
 }

> diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
> index acfc224..ff51632 100644
> --- a/include/linux/pci_regs.h
> +++ b/include/linux/pci_regs.h
> @@ -313,6 +313,7 @@
>  #define  PCI_MSIX_ENTRY_UPPER_ADDR   4
>  #define  PCI_MSIX_ENTRY_DATA         8
>  #define  PCI_MSIX_ENTRY_VECTOR_CTRL  12
> +#define   PCI_MSIX_ENTRY_CTRL_MASKBIT        1
>  
>  /* CompactPCI Hotswap Register */
>  

So I recommend you to have a patch with the above hunk for header
plus a change like:

 -      mask_bits &= ~1;
 -      mask_bits |= flag;
 +      mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
 +      mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT & !!flag;

Anyway thank you very much for doing this work.

Reviewed-by: Hidetoshi Seto <seto.hideto...@jp.fujitsu.com>

Thanks,
H.Seto

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