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=-8.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT 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 1A7EAC43381 for ; Mon, 11 Mar 2019 17:34:52 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E7E88206BA for ; Mon, 11 Mar 2019 17:34:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="okhJpuuG"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="YDzdVQQH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E7E88206BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7VAbLlsYTaSWAttzWdKMb6EvYn+tRD4djFCYCnqgQfY=; b=okhJpuuGmayKKC zm8fiDv87GTGaaK4BclnedPwJKwgo4EDHExtS3n1p/DLCMgHITEygzRIKQywzphXNg+hlPflU+1qJ AfzAbJWKhQ4Ox+3ho3Hf6FKY28RkSXAvpdR/aVuHpBwV2YVpJSRkDGOkJBFmXb0E5PhI2gEpzjSJ3 xrk3tZS/vpE3xT8jg2vRlCA4pp8wZzrmM+7AEw9uKecyy0e5YMGRWHXfFISpH59eTam+HmdUFUahR pUsVbfORwC+TwhK9ejfhAN3ChcAp1ZN22B9F3KgpMhFdvFPJIy9lqJ/8mHkRQC/0+qNM2i1lGYfyq Ox2mBi3tZ0e9zOpj3PAA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h3Op2-0005I5-H4; Mon, 11 Mar 2019 17:34:44 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h3Ooz-0005He-6G for linux-arm-kernel@lists.infradead.org; Mon, 11 Mar 2019 17:34:42 +0000 Received: from localhost (odyssey.drury.edu [64.22.249.253]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98F112063F; Mon, 11 Mar 2019 17:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552325680; bh=UWtPlmQaR7sliraYATCPtyacTIPkYHDDo6g3z7Ae5y4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YDzdVQQHeJh7nwyApH4FA64nn5k9aF9+stPGjn8AyPvjxGV8jp9MZ7VL5osRVHEDS 5rr3RH9T/8SfxM0GVpSftsYLJLxJBFBl1xe5f3KE6+V51yk9cu0kSpt0GDqeclwXAI 39kz/lOBNnGemQHSaHY0CgGPNmvUgNfaAFM1D+Dw= Date: Mon, 11 Mar 2019 12:34:39 -0500 From: Bjorn Helgaas To: "Z.q. Hou" Subject: Re: [PATCHv4 26/28] PCI: mobiveil: ls_pcie_g4: add Workaround for A-011451 Message-ID: <20190311173439.GH214730@google.com> References: <20190311093130.7209-1-Zhiqiang.Hou@nxp.com> <20190311093130.7209-27-Zhiqiang.Hou@nxp.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190311093130.7209-27-Zhiqiang.Hou@nxp.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190311_103441_264726_60A9572A X-CRM114-Status: GOOD ( 22.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "lorenzo.pieralisi@arm.com" , Xiaowei Bao , "linux-pci@vger.kernel.org" , "l.subrahmanya@mobiveil.co.in" , "will.deacon@arm.com" , "linux-kernel@vger.kernel.org" , Leo Li , "M.h. Lian" , "robh+dt@kernel.org" , Mingkai Hu , "catalin.marinas@arm.com" , "shawnguo@kernel.org" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Mar 11, 2019 at 09:33:32AM +0000, Z.q. Hou wrote: > From: Hou Zhiqiang > > When LX2 PCIe controller is sending multiple split completions and > ACK latency expires indicating that ACK should be send at priority. > But because of large number of split completions and FC update DLLP, > the controller does not give priority to ACK transmission. This > results into ACK latency timer timeout error at the link partner and > the pending TLPs are replayed by the link partner again. > > Workaround: > 1. Reduce the ACK latency timeout value to a very small value. > 2. Restrict the number of completions from the LX2 PCIe controller > to 1, by changing the Max Read Request Size (MRRS) of link partner > to the same value as Max Packet size (MPS). > > This patch implemented part 1, the part 2 can be set by kernel parameter > 'pci=pcie_bus_perf' If I understand correctly, you're saying that LX2160A Rev1.0 will only work correctly if you have this patch applied AND you boot with "pci=pcie_bus_perf". That might be OK if these rev 1.0 parts are only used in the lab and are never shipped to customers. But if these parts are ever shipped to customers, I don't think it's acceptable for them to have to figure out that they must boot with "pci=pcie_bus_perf". Yes, you can document that in release notes, but it's still a poor user experience, and users will forget, and they will see mysterious hard-to-debug issues. Maybe there's a way for you to automatically set that pcie_bus_perf mode? With a dmesg note to indicate that you're overriding any mode the user may have selected? > This ERRATA is only for LX2160A Rev1.0, and it will be fixed > in Rev2.0. > > Signed-off-by: Hou Zhiqiang > --- > V4: > - no change > > .../pci/controller/mobiveil/pci-layerscape-gen4.c | 15 +++++++++++++++ > drivers/pci/controller/mobiveil/pcie-mobiveil.h | 4 ++++ > 2 files changed, 19 insertions(+) > > diff --git a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c > index d2c5dbbd5e3c..20ce146788ca 100644 > --- a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c > +++ b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c > @@ -82,12 +82,27 @@ static bool ls_pcie_g4_is_bridge(struct ls_pcie_g4 *pcie) > return header_type == PCI_HEADER_TYPE_BRIDGE; > } > > +static void workaround_A011451(struct ls_pcie_g4 *pcie) > +{ > + struct mobiveil_pcie *mv_pci = pcie->pci; > + u32 val; > + > + /* Set ACK latency timeout */ > + val = csr_readl(mv_pci, GPEX_ACK_REPLAY_TO); > + val &= ~(ACK_LAT_TO_VAL_MASK << ACK_LAT_TO_VAL_SHIFT); > + val |= (4 << ACK_LAT_TO_VAL_SHIFT); > + csr_writel(mv_pci, val, GPEX_ACK_REPLAY_TO); > +} > + > static int ls_pcie_g4_host_init(struct mobiveil_pcie *pci) > { > struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci); > > pcie->rev = csr_readb(pci, PCI_REVISION_ID); > > + if (pcie->rev == REV_1_0) > + workaround_A011451(pcie); > + > return 0; > } > > diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil.h b/drivers/pci/controller/mobiveil/pcie-mobiveil.h > index ab43de5e4b2b..f0e2e4ae09b5 100644 > --- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h > +++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h > @@ -85,6 +85,10 @@ > #define PAB_AXI_AMAP_PEX_WIN_H(win) PAB_REG_ADDR(0x0bac, win) > #define PAB_INTP_AXI_PIO_CLASS 0x474 > > +#define GPEX_ACK_REPLAY_TO 0x438 > +#define ACK_LAT_TO_VAL_MASK 0x1fff > +#define ACK_LAT_TO_VAL_SHIFT 0 > + > #define PAB_PEX_AMAP_CTRL(win) PAB_REG_ADDR(0x4ba0, win) > #define AMAP_CTRL_EN_SHIFT 0 > #define AMAP_CTRL_TYPE_SHIFT 1 > -- > 2.17.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel