From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51817C4320A for ; Wed, 4 Aug 2021 10:53:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A9E060F94 for ; Wed, 4 Aug 2021 10:53:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237668AbhHDKxl (ORCPT ); Wed, 4 Aug 2021 06:53:41 -0400 Received: from foss.arm.com ([217.140.110.172]:59188 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237653AbhHDKxj (ORCPT ); Wed, 4 Aug 2021 06:53:39 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3BF2013A1; Wed, 4 Aug 2021 03:53:26 -0700 (PDT) Received: from lpieralisi (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AF84F3F719; Wed, 4 Aug 2021 03:53:23 -0700 (PDT) Date: Wed, 4 Aug 2021 11:53:18 +0100 From: Lorenzo Pieralisi To: Kishon Vijay Abraham I Cc: Bjorn Helgaas , Rob Herring , Tom Joseph , Jingoo Han , Gustavo Pimentel , Marek Vasut , Yoshihiro Shimoda , Shawn Lin , Heiko Stuebner , Jonathan Corbet , Arnd Bergmann , Greg Kroah-Hartman , linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Lokesh Vutla Subject: Re: [PATCH v7 5/7] PCI: cadence: Add support to configure virtual functions Message-ID: <20210804105318.GA31443@lpieralisi> References: <20210803050310.27122-1-kishon@ti.com> <20210803050310.27122-6-kishon@ti.com> <20210803114530.GE11252@lpieralisi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Aug 03, 2021 at 08:26:42PM +0530, Kishon Vijay Abraham I wrote: > Hi Lorenzo, > > On 03/08/21 5:15 pm, Lorenzo Pieralisi wrote: > > On Tue, Aug 03, 2021 at 10:33:08AM +0530, Kishon Vijay Abraham I wrote: > >> Now that support for SR-IOV is added in PCIe endpoint core, add support > >> to configure virtual functions in the Cadence PCIe EP driver. > >> > >> Signed-off-by: Kishon Vijay Abraham I > >> Acked-by: Tom Joseph > >> --- > >> .../pci/controller/cadence/pcie-cadence-ep.c | 241 +++++++++++++++--- > >> drivers/pci/controller/cadence/pcie-cadence.h | 7 + > >> 2 files changed, 217 insertions(+), 31 deletions(-) > >> > >> diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c > >> index 912a15be8bfd..791915054ff4 100644 > >> --- a/drivers/pci/controller/cadence/pcie-cadence-ep.c > >> +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c > >> @@ -20,7 +20,18 @@ static int cdns_pcie_ep_write_header(struct pci_epc *epc, u8 fn, u8 vfn, > >> struct pci_epf_header *hdr) > >> { > >> struct cdns_pcie_ep *ep = epc_get_drvdata(epc); > >> + u32 cap = CDNS_PCIE_EP_FUNC_SRIOV_CAP_OFFSET; > >> struct cdns_pcie *pcie = &ep->pcie; > >> + u32 reg; > >> + > >> + if (vfn > 1) { > >> + dev_dbg(&epc->dev, "Only Virtual Function #1 has deviceID\n"); > >> + return 0; > > > > Shouldn't this return an error ? > > Since the same function driver could be used for physical function and > virtual function, I tried to avoid adding any additional case specific > for virtual function in the function driver. > > If we want to return an error here, then the function driver should be > modified to not invoke writeheader for vfn > 1. Well, I see it the other way around. If writing the header for vfn > 1 is an error it must be reported as such and handled accordingly. As it stands - it looks like we do nothing and everything is just fine, which is weird. Thanks, Lorenzo > >> + } else if (vfn == 1) { > >> + reg = cap + PCI_SRIOV_VF_DID; > >> + cdns_pcie_ep_fn_writew(pcie, fn, reg, hdr->deviceid); > >> + return 0; > >> + } > >> > >> cdns_pcie_ep_fn_writew(pcie, fn, PCI_DEVICE_ID, hdr->deviceid); > >> cdns_pcie_ep_fn_writeb(pcie, fn, PCI_REVISION_ID, hdr->revid); > >> @@ -51,12 +62,14 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, u8 vfn, > >> struct pci_epf_bar *epf_bar) > >> { > >> struct cdns_pcie_ep *ep = epc_get_drvdata(epc); > >> + u32 cap = CDNS_PCIE_EP_FUNC_SRIOV_CAP_OFFSET; > >> struct cdns_pcie_epf *epf = &ep->epf[fn]; > >> struct cdns_pcie *pcie = &ep->pcie; > >> dma_addr_t bar_phys = epf_bar->phys_addr; > >> enum pci_barno bar = epf_bar->barno; > >> int flags = epf_bar->flags; > >> u32 addr0, addr1, reg, cfg, b, aperture, ctrl; > >> + u32 first_vf_offset, stride; > >> u64 sz; > >> > >> /* BAR size is 2^(aperture + 7) */ > >> @@ -92,26 +105,50 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, u8 vfn, > >> > >> addr0 = lower_32_bits(bar_phys); > >> addr1 = upper_32_bits(bar_phys); > >> + > >> + if (vfn == 1) { > >> + /* All virtual functions use the same BAR config */ > >> + if (bar < BAR_4) { > >> + reg = CDNS_PCIE_LM_EP_VFUNC_BAR_CFG0(fn); > >> + b = bar; > >> + } else { > >> + reg = CDNS_PCIE_LM_EP_VFUNC_BAR_CFG1(fn); > >> + b = bar - BAR_4; > >> + } > >> + } else if (vfn == 0) { > >> + /* BAR configuration for physical function */ > >> + if (bar < BAR_4) { > >> + reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG0(fn); > >> + b = bar; > >> + } else { > >> + reg = CDNS_PCIE_LM_EP_FUNC_BAR_CFG1(fn); > >> + b = bar - BAR_4; > >> + } > >> + } > > > > Code in both branches is almost identical except for what is > > assigned to reg, it is not fundamental but maybe it can be rewritten > > more concisely. > > okay.. let me think. > > Thanks > Kishon