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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 32394C43613 for ; Fri, 21 Jun 2019 20:07:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07BAE2084E for ; Fri, 21 Jun 2019 20:07:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561147657; bh=ukqowutmuU9gyBHIE/U8gJR8BfHRqDbWkLUfnaFsZmA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=w7OXOFmRnnlIRlYz3CMh39KfVedMWM84Fsh/oaFYWif/PzE/kTvr8j1cjawZDmcaq YMblYm5fZOCecsacNrXqozbbjaVe6yd2VfeZzrPo9Gx2eGlXfK3hKS4+/1F5c4XKeL A7FHJioJcpsmg9jYH20T5goKCnWZfgRwt5ZpdnUY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726049AbfFUUHg (ORCPT ); Fri, 21 Jun 2019 16:07:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:44802 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726010AbfFUUHg (ORCPT ); Fri, 21 Jun 2019 16:07:36 -0400 Received: from localhost (unknown [69.71.4.100]) (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 E41EC20673; Fri, 21 Jun 2019 20:07:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561147655; bh=ukqowutmuU9gyBHIE/U8gJR8BfHRqDbWkLUfnaFsZmA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EjqIYCl4osDDBf7dIOMPMUNFIkc5UKLXN07I6qSsORITlGdgHlWmPe/r9hq7bmf06 NFIngFeCQK8wC1v8XkpZV3XdF2L0BiUVgBegsGHqNCctUT1j07to9jvh94CBqQUeU2 iZuNAcuWuSWfx8TvmqGZMBaNLCxSl/rRcYv0UAUo= Date: Fri, 21 Jun 2019 15:07:33 -0500 From: Bjorn Helgaas To: Benjamin Herrenschmidt Cc: linux-pci@vger.kernel.org, Ard Biesheuvel , Lorenzo Pieralisi , Sinan Kaya , Ali Saidi , Zeev Zilberman , linux-arm-kernel Subject: Re: [PATCH 2/4] pci: acpi: Read _DSM #5 from ACPI on root bridges Message-ID: <20190621200733.GC127746@google.com> References: <20190615002359.29577-1-benh@kernel.crashing.org> <20190615002359.29577-2-benh@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190615002359.29577-2-benh@kernel.crashing.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Match the subject line convention for this file, e.g., PCI/ACPI: Evaluate PCI Boot Configuration _DSM On Sat, Jun 15, 2019 at 10:23:57AM +1000, Benjamin Herrenschmidt wrote: > This reads _DSM #5 value on root bridges, and when 0, sets a "preserve_config" > flag in the host bridge structure indicating that the FW has requested that > the existing configuration be preserved. Wrap to 75 or so, so this doesn't overflow 80 columns when "git log" adds its indentation. > The upcoming spec change to define _DSM #5 for host bridges states that > this should be the default behaviour, however doing so would be very > intrusive and break existing setups. So we leave the default to be > the existing behaviour. This paragraph is incorrect. Just remove it completely. I would silently fix stuff like this if I applied these, but you can do it if you repost these. > Signed-off-by: Benjamin Herrenschmidt > --- > drivers/acpi/pci_root.c | 23 +++++++++++++++++++++++ > include/linux/pci-acpi.h | 7 ++++--- > include/linux/pci.h | 2 ++ > 3 files changed, 29 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > index 39f5d172e84f..217b3916f0f1 100644 > --- a/drivers/acpi/pci_root.c > +++ b/drivers/acpi/pci_root.c > @@ -881,6 +881,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, > int node = acpi_get_node(device->handle); > struct pci_bus *bus; > struct pci_host_bridge *host_bridge; > + union acpi_object *obj; > > info->root = root; > info->bridge = device; > @@ -917,6 +918,28 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root, > if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL)) > host_bridge->native_ltr = 0; > > + /* > + * Invoke the PCI device specific method (_DSM) #5 'Ignore PCI Boot > + * Configuration', on the host bridge. This tells us whether the > + * firmware wants us to preserve or reassign the configuration of > + * the PCI resource tree for this root bridge. > + * > + * For now, we only care about the function being present and returning > + * 0, which we use to set a flag indicating that we'll preserve the > + * FW configuration. > + * > + * This diverges from the spec which states that 0 is also the default > + * in absence of _DSM #5. We do that today to work around the fact that > + * our arm64 code doesn't implement the right defaults otherwise. This > + * will be superseeded by a more thorough handling of _DSM #5 once the > + * resource survey code has been consolidated further. > + */ > + obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1, > + IGNORE_PCI_BOOT_CONFIG_DSM, NULL); > + if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0) > + host_bridge->preserve_config = 1; > + ACPI_FREE(obj); > + > pci_scan_child_bus(bus); > pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info, > info); > diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h > index 8082b612f561..62b7fdcc661c 100644 > --- a/include/linux/pci-acpi.h > +++ b/include/linux/pci-acpi.h > @@ -107,9 +107,10 @@ static inline void acpiphp_check_host_bridge(struct acpi_device *adev) { } > #endif > > extern const guid_t pci_acpi_dsm_guid; > -#define DEVICE_LABEL_DSM 0x07 > -#define RESET_DELAY_DSM 0x08 > -#define FUNCTION_DELAY_DSM 0x09 > +#define IGNORE_PCI_BOOT_CONFIG_DSM 0x05 > +#define DEVICE_LABEL_DSM 0x07 > +#define RESET_DELAY_DSM 0x08 > +#define FUNCTION_DELAY_DSM 0x09 > > #else /* CONFIG_ACPI */ > static inline void acpi_pci_add_bus(struct pci_bus *bus) { } > diff --git a/include/linux/pci.h b/include/linux/pci.h > index dd436da7eccc..c50389b8df3c 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -506,6 +506,8 @@ struct pci_host_bridge { > unsigned int native_shpc_hotplug:1; /* OS may use SHPC hotplug */ > unsigned int native_pme:1; /* OS may use PCIe PME */ > unsigned int native_ltr:1; /* OS may use PCIe LTR */ > + unsigned int preserve_config:1; /* Preserve FW resources setup */ > + > /* Resource alignment requirements */ > resource_size_t (*align_resource)(struct pci_dev *dev, > const struct resource *res, > -- > 2.17.1 >