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 DD6AFC433F5 for ; Wed, 18 May 2022 22:18:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229630AbiERWSe (ORCPT ); Wed, 18 May 2022 18:18:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229612AbiERWSe (ORCPT ); Wed, 18 May 2022 18:18:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2423C209B7B; Wed, 18 May 2022 15:18:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B592261624; Wed, 18 May 2022 22:18:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0345C385A9; Wed, 18 May 2022 22:18:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652912312; bh=1BE7QoEPoRv0SPcn20p4AnFm8hcFxjR8MT1AIyyGM5E=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=eWelHZ0gWDLOdAb4yIc8otFLq/7/SstVjEPMrNM5OY/ixhWrfGsLoOJrA7cqGaUc+ OOT5LJFUhIh39Uadm23ojBqe1kIz33mRCBucZOj7kwEw89qf9l8rJfsZyL00MEg8fw EBMDxY0/0QDdEvOnzrGp5EAIq4hielcEeJFD33evSn0R05BHwx7yLaEBlyPRMMjzBA dgWHntw69PJYQFVW0xsALZ6gdsFX//zK3JfsSKSlfc4UPynE0zoilgGi3pRS2622Kb 8gPrWUiA3mkQuKBpCVNc/ye/2FLPe1/lq47+1fyLWxioFrTVfZ0mI/OUJd/A3JRGU/ H9KOU66/TWDsA== Date: Wed, 18 May 2022 17:18:30 -0500 From: Bjorn Helgaas To: Cyril Brulebois , Jim Quinlan Cc: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Bjorn Helgaas , james.dutton@gmail.com, bcm-kernel-feedback-list@broadcom.com, james.quinlan@broadcom.com, Florian Fainelli , Lorenzo Pieralisi , Rob Herring , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , open list Subject: Re: [PATCH v1] PCI: brcmstb: Fix regression regarding missing PCIe linkup Message-ID: <20220518221830.GA12467@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220518194211.20143-1-jim2101024@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+to Cyril] Cyril, if you have a chance to test this and verify that it fixes the regression, we may still be able to squeeze this into v5.18. I can add the Reported-by and Tested-by tags myself. On Wed, May 18, 2022 at 03:42:11PM -0400, Jim Quinlan wrote: > commit 93e41f3fca3d ("PCI: brcmstb: Add control of subdevice voltage regulators") > > introduced a regression on the PCIe RPi4 Compute Module. If the PCIe > endpoint node described in [2] was missing, no linkup would be attempted, > and subsequent accesses would cause a panic because this particular PCIe HW > causes a CPU abort on illegal accesses (instead of returning 0xffffffff). > > We fix this by allowing the DT endpoint subnode to be missing. This is > important for platforms like the CM4 which have a standard PCIe socket and > the endpoint device is unknown. > > Please do not accept this commit until someone with a CM4 has tested > this solution; I have only emulated the problem and fix on different > platform. > > Note that a bisection identified > > commit 830aa6f29f07 ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs") > > as the first failing commit. This commit is a regression, but is unrelated > and was fixed by a subsequent commit in the original patchset. > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=215925 > [2] Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > > Fixes: 93e41f3fca3d ("PCI: brcmstb: Add control of subdevice voltage regulators") > Fixes: 830aa6f29f07 ("PCI: brcmstb: Split brcm_pcie_setup() into two funcs") > Link: https://bugzilla.kernel.org/show_bug.cgi?id=215925 > Signed-off-by: Jim Quinlan > --- > drivers/pci/controller/pcie-brcmstb.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c > index ba5c120816b2..adca74e235cb 100644 > --- a/drivers/pci/controller/pcie-brcmstb.c > +++ b/drivers/pci/controller/pcie-brcmstb.c > @@ -540,16 +540,18 @@ static int pci_subdev_regulators_add_bus(struct pci_bus *bus) > > static int brcm_pcie_add_bus(struct pci_bus *bus) > { > - struct device *dev = &bus->dev; > struct brcm_pcie *pcie = (struct brcm_pcie *) bus->sysdata; > int ret; > > - if (!dev->of_node || !bus->parent || !pci_is_root_bus(bus->parent)) > + /* Only busno==1 requires us to linkup */ > + if ((int)bus->number != 1) > return 0; > > ret = pci_subdev_regulators_add_bus(bus); > - if (ret) > + if (ret) { > + pcie->refusal_mode = true; > return ret; > + } > > /* Grab the regulators for suspend/resume */ > pcie->sr = bus->dev.driver_data; > > base-commit: ef1302160bfb19f804451d0e919266703501c875 > prerequisite-patch-id: 23a425390a4226bd70bbff459148c80f5e28379c > prerequisite-patch-id: e3f2875124b46b2b1cf9ea28883bf0c864b79479 > prerequisite-patch-id: 9cdd706ee2038c7b393c4d65ff76a1873df1ca03 > prerequisite-patch-id: 332ac90be6e4e4110e27bdd1caaff212c129f547 > prerequisite-patch-id: 32a74f87cbfe9e8d52c34a4edeee6d271925665a > prerequisite-patch-id: f57cdf7ec7080bb8c95782bc7c3ec672db8ec1ce > prerequisite-patch-id: 18dc9236aed47f708f5c854afd832f3c80be5ea7 > prerequisite-patch-id: dd147c6854c4ca12a9a8bd4f5714968a59d60e4e > -- > 2.17.1 >