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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26686EB64DB for ; Thu, 22 Jun 2023 13:13:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231569AbjFVNND (ORCPT ); Thu, 22 Jun 2023 09:13:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229437AbjFVNNA (ORCPT ); Thu, 22 Jun 2023 09:13:00 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC4D51BD7; Thu, 22 Jun 2023 06:12:58 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Qn1212SWGz67k9Y; Thu, 22 Jun 2023 21:10:17 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Thu, 22 Jun 2023 14:12:56 +0100 Date: Thu, 22 Jun 2023 14:12:55 +0100 From: Jonathan Cameron To: Terry Bowman CC: , , , , , , , , , Subject: Re: [PATCH v6 25/27] cxl/pci: Disable root port interrupts in RCH mode Message-ID: <20230622141255.00006d13@Huawei.com> In-Reply-To: <20230622035126.4130151-26-terry.bowman@amd.com> References: <20230622035126.4130151-1-terry.bowman@amd.com> <20230622035126.4130151-26-terry.bowman@amd.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500001.china.huawei.com (7.191.163.213) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Jun 2023 22:51:24 -0500 Terry Bowman wrote: > The RCH root port contains root command AER registers that should not be > enabled.[1] Disable these to prevent root port interrupts. I'm a little dubious about a 'because the spec says' so argument. If we can describe the path by which spurious interrupts turn up then great - if not then fair enough. One trivial spelling thing inline. With that fixed. Reviewed-by: Jonathan Cameron > > [1] CXL 3.0 - 12.2.1.1 RCH Downstream Port-detected Errors > > Signed-off-by: Terry Bowman > Signed-off-by: Robert Richter > --- > drivers/cxl/core/core.h | 6 ++++++ > drivers/cxl/core/pci.c | 29 +++++++++++++++++++++++++++++ > drivers/cxl/core/port.c | 3 +++ > 3 files changed, 38 insertions(+) > > diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h > index 87467c633123..880bac9db376 100644 > --- a/drivers/cxl/core/core.h > +++ b/drivers/cxl/core/core.h > @@ -86,4 +86,10 @@ enum cxl_poison_trace_type { > CXL_POISON_TRACE_CLEAR, > }; > > +#ifdef CONFIG_PCIEAER_CXL > +void cxl_disable_rch_root_ints(struct cxl_dport *dport); > +#else > +static inline void cxl_disable_rch_root_ints(struct cxl_dport *dport) { }; > +#endif > + > #endif /* __CXL_CORE_H__ */ > diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c > index 9e0eba5ccfc4..39a2f9f4f115 100644 > --- a/drivers/cxl/core/pci.c > +++ b/drivers/cxl/core/pci.c > @@ -838,6 +838,35 @@ static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) > cxl_handle_rdport_ras(cxlds, dport); > } > > +void cxl_disable_rch_root_ints(struct cxl_dport *dport) > +{ > + void __iomem *aer_base = dport->regs.dport_aer; > + struct pci_host_bridge *bridge; > + u32 aer_cmd_mask, aer_cmd; > + > + if (!aer_base) > + return; > + > + bridge = to_pci_host_bridge(dport->dport_dev); > + > + /* > + * Disable RCH root port command interrupts. > + * CXL 3.0 12.2.1.1 - RCH Downstream Port-detected Errors > + * > + * This sequnce may not be necessary. CXL spec states disabling Spell check. (I often forget as well :( > + * the root cmd register's interrupts is required. But, PCI spec > + * shows these are disabled by default on reset. > + */ > + if (bridge->native_cxl_error) { > + aer_cmd_mask = (PCI_ERR_ROOT_CMD_COR_EN | > + PCI_ERR_ROOT_CMD_NONFATAL_EN | > + PCI_ERR_ROOT_CMD_FATAL_EN); > + aer_cmd = readl(aer_base + PCI_ERR_ROOT_COMMAND); > + aer_cmd &= ~aer_cmd_mask; > + writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND); > + } > +} > + > #else > static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { } > #endif > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > index 87a12e69aa8e..2d812bbaf05f 100644 > --- a/drivers/cxl/core/port.c > +++ b/drivers/cxl/core/port.c > @@ -1035,6 +1035,9 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev, > > cxl_dport_map_regs(dport); > > + if (dport->rch) > + cxl_disable_rch_root_ints(dport); > + > cond_cxl_root_lock(port); > rc = add_dport(port, dport); > cond_cxl_root_unlock(port);