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

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Thu, Aug 06, 2015 at 09:49:02PM +0800, Wei Yang wrote:
>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.
>

Yes, You're correct.

>>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 <weiyang@linux.vnet.ibm.com>
>>
>>Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>
>>>---
>>> 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
>Help you, Help me