On Tue, Jan 07, 2014 at 12:45:42PM -0500, Santosh Shilimkar wrote:
> On Monday 06 January 2014 08:11 PM, Russell King - ARM Linux wrote:
> > /--------------------------------------------------------------
> > | > > Right, so, with Assabet, which has CONFIG_DMA_ZONE=y and
> > | > > CONFIG_ARM_PATCH_PHYS_VIRT=y:
> > | > >
> > | > > $ make O=../build/assabet arch/arm/mm/init.i
> > | > >
> > | > > gives:
> > | > > arm_dma_limit = __pv_phys_offset + arm_dma_zone_size - 1;
> > | > >
> > | > > with or without Santosh's patch.
> > \--------------------------------------------------------------
> >
> >> May be I missed your point but I ended up creating the patch because
> >> the CMA reservation was failing on Keystone since the arm_dma_limit
> >> wasn't right since it wasn't considering the actual __pv_phys_offset.
> >>
> >> Isn't that an issue ?
> >
> > See the above. Your patch has _no_ effect what so ever when
> > CONFIG_ARM_PATCH_PHYS_VIRT=y - which you have on the Keystone, right?
> >
> > If you don't believe me, ask make to produce arch/arm/mm/init.i, which
> > is the output from the preprocessor, comparing the resulting generated
> > file both with and without your patch applied.
> >
> Looks like you are right. I did two fixes to have right arm_dma_limit in
> below order.
>
> 1. 787b0d5 {ARM: 7908/1: mm: Fix the arm_dma_limit calculation}
> 2. 7c92732 {ARM: 7909/1: mm: Call setup_dma_zone() post early_paging_init()}
>
> But with 2 alone the issue gets fixed since with ARM_PATCH_PHYS_VIRT and
> below pre-processor, the PHYS_OFFSET also gets an updated value. I never
> realised that 1 becomes redundant after second patch while creating them.
>
> #define PHYS_OFFSET __pv_phys_offset
>
> So indeed, 787b0d5{ARM: 7908/1: mm: Fix the arm_dma_limit calculation}
> won't be needed anymore and can be reverted. Sorry it took some time
> for me to reach to your conclusion.
Okay, reverted.
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