Subject: Re: [PATCH V2 2/6] powerpc/powernv: simplify the calculation of iov resource

From: Wei Yang <[email-masked]>
Date: Thu, 6 Aug 2015 21:49:02 +0800

On Thu, Aug 06, 2015 at 02:51:40PM +1000, Gavin Shan wrote:
>On Wed, Aug 05, 2015 at 09:24:59AM +0800, Wei Yang wrote:
>>The alignment of IOV BAR on PowerNV platform is the total size of the IOV
>>BAR. No matter whether the IOV BAR is truncated or not, the total size
>>could be calculated by (vfs_expanded * VF size).
>>
>
>s/VF size/VF BAR size
>
>I think the changelog would be more explicit:
>
>The alignment of IOV BAR on PowerNV platform is the total size of the
>IOV BAR, no matter whether the IOV BAR is extended with number of max
>VFs or number of max PE number (256). The alignment can be calculated

number of max VFs is not correct. This should be
roundup_pow_of_two(total_vfs).

Others looks good to me.

>by (vfs_expaned * VF_BAR_size).
>
>>This patch simplifies the pnv_pci_iov_resource_alignment() by removing the
>>first case.
>>
>>Signed-off-by: Wei Yang <[email-masked]>
>
>Reviewed-by: Gavin Shan <[email-masked]>
>
>>---
>> arch/powerpc/platforms/powernv/pci-ioda.c |   14 +++++++++-----
>> 1 file changed, 9 insertions(+), 5 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>index 9b41dba..7192e62 100644
>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>@@ -2987,12 +2987,16 @@ static resource_size_t pnv_pci_iov_resource_alignment(struct pci_dev *pdev,
>> 						      int resno)
>> {
>> 	struct pci_dn *pdn = pci_get_pdn(pdev);
>>-	resource_size_t align, iov_align;
>>-
>>-	iov_align = resource_size(&pdev->resource[resno]);
>>-	if (iov_align)
>>-		return iov_align;
>>+	resource_size_t align;
>>
>>+	/*
>>+	 * On PowerNV platform, IOV BAR is mapped by M64 BAR to enable the
>>+	 * SR-IOV. While from hardware perspective, the range mapped by M64
>>+	 * BAR should be size aligned.
>>+	 *
>>+	 * This function return the total IOV BAR size if expanded or just the
>>+	 * individual size if not.
>>+	 */
>> 	align = pci_iov_resource_size(pdev, resno);
>> 	if (pdn->vfs_expanded)
>> 		return pdn->vfs_expanded * align;
>>-- 
>>1.7.9.5
>>

-- 
Richard Yang
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