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

[Sheng Yang <sheng@linux.intel.com>]

On Friday 05 November 2010 08:48:43 Hidetoshi Seto wrote:
> (2010/11/04 15:15), Sheng Yang wrote:
> > Then we can use it instead of magic number 1.
> > 
> > Cc: Matthew Wilcox <willy@linux.intel.com>
> > Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> > Cc: linux-pci@vger.kernel.org
> > Signed-off-by: Sheng Yang <sheng@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.

Good suggestion. Would update it.
> 
> Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

--
regards
Yang, Sheng

> 
> Thanks,
> H.Seto