From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 551231A0734 for ; Tue, 13 Oct 2015 14:56:49 +1100 (AEDT) Received: from e28smtp09.in.ibm.com (e28smtp09.in.ibm.com [122.248.162.9]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 8DA53140134 for ; Tue, 13 Oct 2015 14:56:48 +1100 (AEDT) Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 13 Oct 2015 09:26:46 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id 0C85D394005B for ; Tue, 13 Oct 2015 09:26:45 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay02.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t9D3ui4150397436 for ; Tue, 13 Oct 2015 09:26:44 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t9D3uirF003799 for ; Tue, 13 Oct 2015 09:26:44 +0530 Date: Tue, 13 Oct 2015 11:56:43 +0800 From: Wei Yang To: Gavin Shan Cc: Wei Yang , aik@ozlabs.ru, benh@kernel.crashing.org, linuxppc-dev@ozlabs.org, mpe@ellerman.id.au Subject: Re: [PATCH V5 2/6] powerpc/powernv: simplify the calculation of iov resource alignment Message-ID: <20151013035643.GB2858@richards-mbp.cn.ibm.com> Reply-To: Wei Yang References: <1444358816-8163-1-git-send-email-weiyang@linux.vnet.ibm.com> <1444358816-8163-3-git-send-email-weiyang@linux.vnet.ibm.com> <20151013001350.GA21778@gwshan> <20151013024545.GC1437@Richards-MacBook-Pro.local> <20151013032752.GB21017@gwshan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20151013032752.GB21017@gwshan> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Oct 13, 2015 at 02:27:52PM +1100, Gavin Shan wrote: >On Tue, Oct 13, 2015 at 10:45:45AM +0800, Wei Yang wrote: >>On Tue, Oct 13, 2015 at 11:13:50AM +1100, Gavin Shan wrote: >>>On Fri, Oct 09, 2015 at 10:46:52AM +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 extended with number of >>>>roundup_pow_of_two(total_vfs) or number of max PE number (256), the total >>>>size could be calculated by (vfs_expanded * VF_BAR_size). >>>> >>>>This patch simplifies the pnv_pci_iov_resource_alignment() by removing the >>>>first case. >>>> >>>>Signed-off-by: Wei Yang >>>>Reviewed-by: Gavin Shan >>>>Acked-by: Alexey Kardashevskiy >>>>--- >>>> arch/powerpc/platforms/powernv/pci-ioda.c | 20 ++++++++++++-------- >>>> 1 file changed, 12 insertions(+), 8 deletions(-) >>>> >>>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c >>>>index 8c031b5..7da476b 100644 >>>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c >>>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c >>>>@@ -2988,17 +2988,21 @@ 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 returns the total IOV BAR size if M64 BAR is in >>>>+ * Shared PE mode or just the individual size if not. >>>>+ */ >>> >>>s/the invidial size/VF BAR size >>> >>>> align = pci_iov_resource_size(pdev, resno); >>>>- if (pdn->vfs_expanded) >>>>- return pdn->vfs_expanded * align; >>>>+ if (!pdn->vfs_expanded) >>>>+ return align; >>>> >>>>- return align; >>>>+ return pdn->vfs_expanded * align; >>> >>>There is no difference before/after the changes. why this change is needed? >>> >> >>After change the logic is more clear. >> >>Alignment equals to the total size when IOV BAR is expanded or equals to the >>VF BAR size. We don't need to check whether IOV BAR is truncated. >> > >I didn't get what you're talking about with "IOV BAR is truncated". I also >didn't get what has been really changed from last 3 lines changes. > > if (pdn->vfs_expanded) if (!pdn->vfs_expanded) > return pdn->vfs_expanded * align; return align; > return align; return pdn->vfs_expanded * align; > Truncated IOV BAR resource happens during sizing state, since IOV BAR is optional. While we still need to get the correct alignment during this process. The code before and after change has the same meaning, while the later one is prepared for the single mode M64 BAR. You could look at the final version after single mode M64 is introduced. >>>> } >>>> #endif /* CONFIG_PCI_IOV */ >>>> >>>>-- >>>>2.5.0 >>>> >> >>-- >>Richard Yang >>Help you, Help me -- Richard Yang Help you, Help me