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Wysocki" References: <20210605205317.GA2254430@bjorn-Precision-5520> Message-ID: <5d1b9b9b-568a-d581-8938-cac174a22f7a@nvidia.com> Date: Sat, 5 Jun 2021 19:04:05 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210605205317.GA2254430@bjorn-Precision-5520> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [172.20.187.6] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 81617498-62a6-4fd4-307b-08d9287e9c0e X-MS-TrafficTypeDiagnostic: DM6PR12MB4747: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:597; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.112.34;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:schybrid03.nvidia.com;CAT:NONE;SFS:(4636009)(396003)(346002)(376002)(39860400002)(136003)(46966006)(36840700001)(26005)(2906002)(16576012)(316002)(53546011)(30864003)(16526019)(54906003)(110136005)(5660300002)(186003)(47076005)(31686004)(31696002)(36860700001)(86362001)(7416002)(82740400003)(336012)(7636003)(4326008)(8936002)(36756003)(478600001)(8676002)(2616005)(36906005)(70206006)(70586007)(356005)(82310400003)(426003)(83380400001)(43740500002);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Jun 2021 00:04:09.7698 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 81617498-62a6-4fd4-307b-08d9287e9c0e X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.112.34];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT034.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4747 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bjorn, On 6/5/21 3:53 PM, Bjorn Helgaas wrote: > Mention ACPI in the subject, e.g., > > PCI: Add support for ACPI _RST reset method Will change in the next patch. > On Sun, May 30, 2021 at 12:55:25AM +0530, Amey Narkhede wrote: >> From: Shanker Donthineni >> >> The _RST is a standard method specified in the ACPI specification. It >> provides a function level reset when it is described in the acpi_device >> context associated with PCI-device. >> >> Implement a new reset function pci_dev_acpi_reset() for probing RST >> method and execute if it is defined in the firmware. The ACPI binding >> information is available only after calling device_add(). To consider >> _RST method, move pci_init_reset_methods() to end of pci_device_add() >> and craete two sysfs entries reset & reset_methond from >> pci_create_sysfs_dev_files() > s/craete/create/ > s/reset_methond/reset_method/ Will fix it. >> The default priority of the acpi reset is set to below device-specific >> and above hardware resets. > s/acpi/ACPI/ Will fix it. >> Signed-off-by: Shanker Donthineni >> Reviewed-by: Sinan Kaya >> --- >> drivers/pci/pci-sysfs.c | 23 ++++++++++++++++++++--- >> drivers/pci/pci.c | 30 ++++++++++++++++++++++++++++++ >> drivers/pci/probe.c | 2 +- >> include/linux/pci.h | 2 +- >> 4 files changed, 52 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c >> index 04b3d6565..b332d7923 100644 >> --- a/drivers/pci/pci-sysfs.c >> +++ b/drivers/pci/pci-sysfs.c >> @@ -1482,12 +1482,30 @@ static const struct attribute_group pci_dev_reset_attr_group = { >> .is_visible = pci_dev_reset_attr_is_visible, >> }; >> >> +const struct attribute_group *pci_dev_reset_groups[] = { >> + &pci_dev_reset_attr_group, >> + &pci_dev_reset_method_attr_group, >> + NULL, >> +}; > These should be static sysfs attributes if possible, e.g., see > e1d3f3268b0e ("PCI/sysfs: Convert "config" to static attribute"). > pci_create_sysfs_dev_files() will soon be removed completely. > >> int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev) >> { >> + int retval; >> + >> if (!sysfs_initialized) >> return -EACCES; >> >> - return pci_create_resource_files(pdev); >> + retval = pci_create_resource_files(pdev); >> + if (retval) >> + return retval; >> + >> + retval = device_add_groups(&pdev->dev, pci_dev_reset_groups); >> + if (retval) { >> + pci_remove_resource_files(pdev); >> + return retval; >> + } >> + >> + return 0; >> } >> >> /** >> @@ -1501,6 +1519,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev) >> if (!sysfs_initialized) >> return; >> >> + device_remove_groups(&pdev->dev, pci_dev_reset_groups); >> pci_remove_resource_files(pdev); >> } >> >> @@ -1594,8 +1613,6 @@ const struct attribute_group *pci_dev_groups[] = { >> &pci_dev_group, >> &pci_dev_config_attr_group, >> &pci_dev_rom_attr_group, >> - &pci_dev_reset_attr_group, >> - &pci_dev_reset_method_attr_group, >> &pci_dev_vpd_attr_group, >> #ifdef CONFIG_DMI >> &pci_dev_smbios_attr_group, >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index bbed852d9..4a7019d0b 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -5115,6 +5115,35 @@ static void pci_dev_restore(struct pci_dev *dev) >> err_handler->reset_done(dev); >> } >> >> +/** >> + * pci_dev_acpi_reset - do a function level reset using _RST method >> + * @dev: device to reset >> + * @probe: check if _RST method is included in the acpi_device context. >> + */ >> +static int pci_dev_acpi_reset(struct pci_dev *dev, int probe) >> +{ >> +#ifdef CONFIG_ACPI >> + acpi_handle handle = ACPI_HANDLE(&dev->dev); >> + >> + /* Return -ENOTTY if _RST method is not included in the dev context */ >> + if (!handle || !acpi_has_method(handle, "_RST")) >> + return -ENOTTY; >> + >> + /* Return 0 for probe phase indicating that we can reset this device */ >> + if (probe) >> + return 0; >> + >> + /* Invoke _RST() method to perform a function level reset */ > Superfluous comment. Actually all the single-line comments here are > superfluous. Will remove in the next patch. >> + if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) { >> + pci_warn(dev, "Failed to reset the device\n"); > The message should mention the type of reset, e.g., "ACPI _RST failed ..." > Will change to pci_warn(dev, "ACPI _RST failed\n"); >> + return -EINVAL; >> + } >> + return 0; >> +#else >> + return -ENOTTY; >> +#endif >> +} >> + >> /* >> * The ordering for functions in pci_reset_fn_methods >> * is required for reset_methods byte array defined >> @@ -5122,6 +5151,7 @@ static void pci_dev_restore(struct pci_dev *dev) >> */ >> const struct pci_reset_fn_method pci_reset_fn_methods[] = { >> { &pci_dev_specific_reset, .name = "device_specific" }, >> + { &pci_dev_acpi_reset, .name = "acpi" }, >> { &pcie_reset_flr, .name = "flr" }, >> { &pci_af_flr, .name = "af_flr" }, >> { &pci_pm_reset, .name = "pm" }, >> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c >> index 90fd4f61f..eeab791a0 100644 >> --- a/drivers/pci/probe.c >> +++ b/drivers/pci/probe.c >> @@ -2404,7 +2404,6 @@ static void pci_init_capabilities(struct pci_dev *dev) >> pci_rcec_init(dev); /* Root Complex Event Collector */ >> >> pcie_report_downtraining(dev); >> - pci_init_reset_methods(dev); >> } >> >> /* >> @@ -2495,6 +2494,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus) >> dev->match_driver = false; >> ret = device_add(&dev->dev); >> WARN_ON(ret < 0); >> + pci_init_reset_methods(dev); > This is a little sketchy. We shouldn't be doing device config stuff > after device_add() because that's when it becomes available for > drivers to bind to the device. If we do anything with the device > after that point, we may interfere with a driver. The reason I did PCI driver attach/bind is happening from pci_bus_add_device() after setting 'dev->match_driver = true'. I thought it's safe to update reset methods after calling device_add() and before driver bind happens. void pci_bus_add_device(struct pci_dev *dev) {     int retval;     /*      * Can not put in pci_device_add yet because resources      * are not assigned yet for some devices.      */     pcibios_bus_add_device(dev);     pci_fixup_device(pci_fixup_final, dev);     pci_create_sysfs_dev_files(dev);     pci_proc_attach_device(dev);     pci_bridge_d3_update(dev);     dev->match_driver = true;          retval = device_attach(&dev->dev);  ---- > PCI driver bind call > I think the problem is that we don't call acpi_bind_one() until > device_add(). There's some hackery in pci-acpi.c to deal with a > similar problem for something else -- see acpi_pci_bridge_d3(). > > I don't know how to fix this yet. Here's the call graph that I think > is relevant: > > pci_scan_single_device > pci_scan_device > pci_set_of_node > dev->dev.of_node = of_pci_find_child_device() <-- set OF stuff > pci_device_add > device_add > device_platform_notify > acpi_platform_notify > case KOBJ_ADD: > acpi_device_notify > acpi_bind_one > ACPI_COMPANION_SET() <-- sets ACPI_COMPANION > pci_init_reset_methods > pci_dev_acpi_reset(PCI_RESET_PROBE) > handle = ACPI_HANDLE(&dev->dev) <-- uses ACPI_COMPANION > > I think it's kind of a general problem that we currently don't have > access to the ACPI stuff until *after* device_add(). I included > pci_set_of_node() in the graph above because that seems sort of > like an OF analogue of what acpi_bind_one() is doing. > > I would really like to do the ACPI_COMPANION setup earlier, maybe > at the same time as pci_set_of_node(). But I don't know enough about > what acpi_bind_one() does -- there's a lot going on in there. > Yes, it's a general problem ACPI binding information is available only after calling device_platform_notify(). There are no exported functions to set the ACPI_COMPANION like OF_NODE. Another approach: It simplifies the code logic if we update reset methods when creating sysfs entries 'reset' and 'reset_method'. I've verified this code and getting an expected behavior. root@jetson:~# cat /sys/bus/pci/devices/0009\:01\:00.0/reset_method acpi,flr --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1427,7 +1427,7 @@ static umode_t pci_dev_reset_method_attr_is_visible(struct kobject *kobj,  {         struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); -       if (!pci_reset_supported(pdev)) +       if (!pci_reset_supported(pdev) && !pci_init_reset_methods(pdev))                 return 0;         return a->mode; @@ -1471,7 +1471,7 @@ static umode_t pci_dev_reset_attr_is_visible(struct kobject *kobj,  {         struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); -       if (!pci_reset_supported(pdev)) +       if (!pci_reset_supported(pdev) && !pci_init_reset_methods(pdev))                 return 0;         return a->mode; diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index bbed852d977f1..13654255fa3dc 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5115,6 +5115,32 @@ static void pci_dev_restore(struct pci_dev *dev)                 err_handler->reset_done(dev);  } +/** + * pci_dev_acpi_reset - do a function level reset using _RST method + * @dev: device to reset + * @probe: check if _RST method is included in the acpi_device context. + */ +static int pci_dev_acpi_reset(struct pci_dev *dev, int probe) +{ +#ifdef CONFIG_ACPI +       acpi_handle handle = ACPI_HANDLE(&dev->dev); + +       if (!handle || !acpi_has_method(handle, "_RST")) +               return -ENOTTY; + +       if (probe) +               return 0; + +       if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) { +               pci_warn(dev, "ACPI _RST failed\n"); +               return -EINVAL; +       } +       return 0; +#else +       return -ENOTTY; +#endif +} +  /*   * The ordering for functions in pci_reset_fn_methods   * is required for reset_methods byte array defined @@ -5122,6 +5148,7 @@ static void pci_dev_restore(struct pci_dev *dev)   */  const struct pci_reset_fn_method pci_reset_fn_methods[] = {         { &pci_dev_specific_reset, .name = "device_specific" }, +       { &pci_dev_acpi_reset, .name = "acpi" },         { &pcie_reset_flr, .name = "flr" },         { &pci_af_flr, .name = "af_flr" },         { &pci_pm_reset, .name = "pm" }, @@ -5191,7 +5218,7 @@ EXPORT_SYMBOL_GPL(__pci_reset_function_locked);   * Stores reset mechanisms supported by device in reset_methods byte array   * which is a member of struct pci_dev.   */ -void pci_init_reset_methods(struct pci_dev *dev) +bool pci_init_reset_methods(struct pci_dev *dev)  {         int i, rc;         u8 prio = PCI_RESET_METHODS_NUM; @@ -5209,6 +5236,7 @@ void pci_init_reset_methods(struct pci_dev *dev)                         break;         }         memcpy(dev->reset_methods, reset_methods, sizeof(reset_methods)); +       return pci_reset_supported(dev);  }  /** diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 13ec6bd6f4f76..3e871a5a21bbd 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -33,7 +33,7 @@ enum pci_mmap_api {  int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai,                   enum pci_mmap_api mmap_api); -void pci_init_reset_methods(struct pci_dev *dev); +bool pci_init_reset_methods(struct pci_dev *dev);  int pci_bridge_secondary_bus_reset(struct pci_dev *dev);  int pci_bus_error_reset(struct pci_dev *dev); -void pci_init_reset_methods(struct pci_dev *dev); +bool pci_init_reset_methods(struct pci_dev *dev);  int pci_bridge_secondary_bus_reset(struct pci_dev *dev);  int pci_bus_error_reset(struct pci_dev *dev); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 90fd4f61f3802..275a067d7a282 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2404,7 +2404,6 @@ static void pci_init_capabilities(struct pci_dev *dev)         pci_rcec_init(dev);             /* Root Complex Event Collector */         pcie_report_downtraining(dev); -       pci_init_reset_methods(dev);  }