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SubjectRE: [PATCH 1/7] powerpc: Add interface to get msi region information
Date


> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Wednesday, October 09, 2013 4:27 AM
> To: Bhushan Bharat-R65777
> Cc: alex.williamson@redhat.com; joro@8bytes.org; benh@kernel.crashing.org;
> galak@kernel.crashing.org; linux-kernel@vger.kernel.org; linuxppc-
> dev@lists.ozlabs.org; linux-pci@vger.kernel.org; agraf@suse.de;
> iommu@lists.linux-foundation.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 1/7] powerpc: Add interface to get msi region information
>
> On Thu, 2013-09-19 at 12:59 +0530, Bharat Bhushan wrote:
> > @@ -376,6 +405,7 @@ static int fsl_of_msi_probe(struct platform_device *dev)
> > int len;
> > u32 offset;
> > static const u32 all_avail[] = { 0, NR_MSI_IRQS };
> > + static int bank_index;
> >
> > match = of_match_device(fsl_of_msi_ids, &dev->dev);
> > if (!match)
> > @@ -419,8 +449,8 @@ static int fsl_of_msi_probe(struct platform_device *dev)
> > dev->dev.of_node->full_name);
> > goto error_out;
> > }
> > - msi->msiir_offset =
> > - features->msiir_offset + (res.start & 0xfffff);
> > + msi->msiir = res.start + features->msiir_offset;
> > + printk("msi->msiir = %llx\n", msi->msiir);
>
> dev_dbg or remove

Oops, sorry it was leftover of debugging :(

>
> > }
> >
> > msi->feature = features->fsl_pic_ip; @@ -470,6 +500,7 @@ static int
> > fsl_of_msi_probe(struct platform_device *dev)
> > }
> > }
> >
> > + msi->bank_index = bank_index++;
>
> What if multiple MSIs are boing probed in parallel?

Ohh, I have not thought that it can be called in parallel

> bank_index is not atomic.

Will declare bank_intex as atomic_t and use atomic_inc_return(&bank_index)

>
> > diff --git a/arch/powerpc/sysdev/fsl_msi.h
> > b/arch/powerpc/sysdev/fsl_msi.h index 8225f86..6bd5cfc 100644
> > --- a/arch/powerpc/sysdev/fsl_msi.h
> > +++ b/arch/powerpc/sysdev/fsl_msi.h
> > @@ -29,12 +29,19 @@ struct fsl_msi {
> > struct irq_domain *irqhost;
> >
> > unsigned long cascade_irq;
> > -
> > - u32 msiir_offset; /* Offset of MSIIR, relative to start of CCSR */
> > + dma_addr_t msiir; /* MSIIR Address in CCSR */
>
> Are you sure dma_addr_t is right here, versus phys_addr_t? It implies that it's
> the output of the DMA API, but I don't think the DMA API is used in the MSI
> driver. Perhaps it should be, but we still want the raw physical address to
> pass on to VFIO.

Looking through the conversation I will make this phys_addr_t

>
> > void __iomem *msi_regs;
> > u32 feature;
> > int msi_virqs[NR_MSI_REG];
> >
> > + /*
> > + * During probe each bank is assigned a index number.
> > + * index number ranges from 0 to 2^32.
> > + * Example MSI bank 1 = 0
> > + * MSI bank 2 = 1, and so on.
> > + */
> > + int bank_index;
>
> 2^32 doesn't fit in "int" (nor does 2^32 - 1).

Right :(

>
> Just say that indices start at 0.

Will correct this

Thanks
-Bharat

>
> -Scott
>

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