From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 7632F1A084F for ; Thu, 6 Aug 2015 19:00:10 +1000 (AEST) Received: from mail-pa0-f49.google.com (mail-pa0-f49.google.com [209.85.220.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 925391402B7 for ; Thu, 6 Aug 2015 19:00:07 +1000 (AEST) Received: by pacrr5 with SMTP id rr5so22868633pac.3 for ; Thu, 06 Aug 2015 02:00:06 -0700 (PDT) Subject: Re: [PATCH V2 2/6] powerpc/powernv: simplify the calculation of iov resource To: Gavin Shan , Wei Yang References: <20150731020148.GA6151@richard> <1438737903-10399-1-git-send-email-weiyang@linux.vnet.ibm.com> <1438737903-10399-3-git-send-email-weiyang@linux.vnet.ibm.com> <20150806045139.GB28524@gwshan> Cc: benh@kernel.crashing.org, linuxppc-dev@ozlabs.org From: Alexey Kardashevskiy Message-ID: <55C32210.9090803@ozlabs.ru> Date: Thu, 6 Aug 2015 19:00:00 +1000 MIME-Version: 1.0 In-Reply-To: <20150806045139.GB28524@gwshan> Content-Type: text/plain; charset=koi8-r; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 08/06/2015 02:51 PM, 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 > by (vfs_expaned * VF_BAR_size). Is that really a PowerNV-specific requirement or it is valid for every platform (I suspect this is the case here)? Also, what is the exact meaning of "expanded" in @vfs_expanded? It is either 255 (if individual VF BARs are <= 64MB) or roundup_pow_of_two(total_vfs) (which is something like 4 or 16). What is expanded here? > >> This patch simplifies the pnv_pci_iov_resource_alignment() by removing the >> first case. >> >> Signed-off-by: Wei Yang > > Reviewed-by: Gavin Shan > >> --- >> 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 >> > -- Alexey