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[198.54.128.46]) by smtp.googlemail.com with ESMTPSA id o2sm2489730oom.26.2021.06.07.22.49.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Jun 2021 22:49:16 -0700 (PDT) From: Amey Narkhede To: Bjorn Helgaas Cc: alex.williamson@redhat.com, Raphael Norwitz , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kw@linux.com, Shanker Donthineni , Sinan Kaya , Len Brown , "Rafael J . Wysocki" , Amey Narkhede Subject: [PATCH v7 2/8] PCI: Add new array for keeping track of ordering of reset methods Date: Tue, 8 Jun 2021 11:18:51 +0530 Message-Id: <20210608054857.18963-3-ameynarkhede03@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210608054857.18963-1-ameynarkhede03@gmail.com> References: <20210608054857.18963-1-ameynarkhede03@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Introduce a new array reset_methods in struct pci_dev to keep track of reset mechanisms supported by the device and their ordering. Also refactor probing and reset functions to take advantage of calling convention of reset functions. Reviewed-by: Alex Williamson Reviewed-by: Raphael Norwitz Co-developed-by: Alex Williamson Signed-off-by: Alex Williamson Signed-off-by: Amey Narkhede Tested-by: Shanker Donthineni --- drivers/pci/pci.c | 108 ++++++++++++++++++++++++++------------------ drivers/pci/pci.h | 8 +++- drivers/pci/probe.c | 5 +- include/linux/pci.h | 7 +++ 4 files changed, 81 insertions(+), 47 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 3bf36924c..39a9ea8bb 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -72,6 +72,14 @@ static void pci_dev_d3_sleep(struct pci_dev *dev) msleep(delay); } +bool pci_reset_supported(struct pci_dev *dev) +{ + u8 null_reset_methods[PCI_RESET_METHODS_NUM] = { 0 }; + + return memcmp(null_reset_methods, + dev->reset_methods, PCI_RESET_METHODS_NUM); +} + #ifdef CONFIG_PCI_DOMAINS int pci_domains_supported = 1; #endif @@ -5107,6 +5115,18 @@ static void pci_dev_restore(struct pci_dev *dev) err_handler->reset_done(dev); } +/* + * The ordering for functions in pci_reset_fn_methods is required for + * reset_methods byte array defined in struct pci_dev. + */ +const struct pci_reset_fn_method pci_reset_fn_methods[] = { + { &pci_dev_specific_reset, .name = "device_specific" }, + { &pcie_reset_flr, .name = "flr" }, + { &pci_af_flr, .name = "af_flr" }, + { &pci_pm_reset, .name = "pm" }, + { &pci_reset_bus_function, .name = "bus" }, +}; + /** * __pci_reset_function_locked - reset a PCI device function while holding * the @dev mutex lock. @@ -5129,65 +5149,67 @@ static void pci_dev_restore(struct pci_dev *dev) */ int __pci_reset_function_locked(struct pci_dev *dev) { - int rc; + int i, rc = -ENOTTY; + u8 prio; might_sleep(); - /* - * A reset method returns -ENOTTY if it doesn't support this device - * and we should try the next method. - * - * If it returns 0 (success), we're finished. If it returns any - * other error, we're also finished: this indicates that further - * reset mechanisms might be broken on the device. - */ - rc = pci_dev_specific_reset(dev, 0); - if (rc != -ENOTTY) - return rc; - rc = pcie_reset_flr(dev, 0); - if (rc != -ENOTTY) - return rc; - rc = pci_af_flr(dev, 0); - if (rc != -ENOTTY) - return rc; - rc = pci_pm_reset(dev, 0); - if (rc != -ENOTTY) - return rc; - return pci_reset_bus_function(dev, 0); + for (prio = PCI_RESET_METHODS_NUM; prio; prio--) { + for (i = 0; i < PCI_RESET_METHODS_NUM; i++) { + if (dev->reset_methods[i] == prio) { + /* + * A reset method returns -ENOTTY if it doesn't + * support this device and we should try the + * next method. + * + * If it returns 0 (success), we're finished. + * If it returns any other error, we're also + * finished: this indicates that further reset + * mechanisms might be broken on the device. + */ + rc = pci_reset_fn_methods[i].reset_fn(dev, 0); + if (rc != -ENOTTY) + return rc; + break; + } + } + if (i == PCI_RESET_METHODS_NUM) + break; + } + return rc; } EXPORT_SYMBOL_GPL(__pci_reset_function_locked); /** - * pci_probe_reset_function - check whether the device can be safely reset - * @dev: PCI device to reset + * pci_init_reset_methods - check whether device can be safely reset + * and store supported reset mechanisms. + * @dev: PCI device to check for reset mechanisms * * Some devices allow an individual function to be reset without affecting * other functions in the same device. The PCI device must be responsive - * to PCI config space in order to use this function. + * to reads and writes to its PCI config space in order to use this function. * - * Returns 0 if the device function can be reset or negative if the - * device doesn't support resetting a single function. + * Stores reset mechanisms supported by device in reset_methods byte array + * which is a member of struct pci_dev. */ -int pci_probe_reset_function(struct pci_dev *dev) +void pci_init_reset_methods(struct pci_dev *dev) { - int rc; + int i, rc; + u8 prio = PCI_RESET_METHODS_NUM; + u8 reset_methods[PCI_RESET_METHODS_NUM] = { 0 }; - might_sleep(); + BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_RESET_METHODS_NUM); - rc = pci_dev_specific_reset(dev, 1); - if (rc != -ENOTTY) - return rc; - rc = pcie_reset_flr(dev, 1); - if (rc != -ENOTTY) - return rc; - rc = pci_af_flr(dev, 1); - if (rc != -ENOTTY) - return rc; - rc = pci_pm_reset(dev, 1); - if (rc != -ENOTTY) - return rc; + might_sleep(); - return pci_reset_bus_function(dev, 1); + for (i = 0; i < PCI_RESET_METHODS_NUM; i++) { + rc = pci_reset_fn_methods[i].reset_fn(dev, 1); + if (!rc) + reset_methods[i] = prio--; + else if (rc != -ENOTTY) + break; + } + memcpy(dev->reset_methods, reset_methods, sizeof(reset_methods)); } /** diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 37c913bbc..13ec6bd6f 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); -int pci_probe_reset_function(struct pci_dev *dev); +void 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); @@ -606,6 +606,12 @@ struct pci_dev_reset_methods { int (*reset)(struct pci_dev *dev, int probe); }; +struct pci_reset_fn_method { + int (*reset_fn)(struct pci_dev *pdev, int probe); + char *name; +}; + +extern const struct pci_reset_fn_method pci_reset_fn_methods[]; #ifdef CONFIG_PCI_QUIRKS int pci_dev_specific_reset(struct pci_dev *dev, int probe); #else diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 3a62d09b8..8cf532681 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2404,9 +2404,8 @@ static void pci_init_capabilities(struct pci_dev *dev) pci_rcec_init(dev); /* Root Complex Event Collector */ pcie_report_downtraining(dev); - - if (pci_probe_reset_function(dev) == 0) - dev->reset_fn = 1; + pci_init_reset_methods(dev); + dev->reset_fn = pci_reset_supported(dev); } /* diff --git a/include/linux/pci.h b/include/linux/pci.h index 20b90c205..0955246f8 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -49,6 +49,8 @@ PCI_STATUS_SIG_TARGET_ABORT | \ PCI_STATUS_PARITY) +#define PCI_RESET_METHODS_NUM 5 + /* * The PCI interface treats multi-function devices as independent * devices. The slot/function address of each device is encoded @@ -505,6 +507,10 @@ struct pci_dev { char *driver_override; /* Driver name to force a match */ unsigned long priv_flags; /* Private flags for the PCI driver */ + /* + * See pci_reset_fn_methods array in pci.c for ordering. + */ + u8 reset_methods[PCI_RESET_METHODS_NUM]; /* Reset methods ordered by priority */ }; static inline struct pci_dev *pci_physfn(struct pci_dev *dev) @@ -1227,6 +1233,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, void pcie_print_link_status(struct pci_dev *dev); int pcie_reset_flr(struct pci_dev *dev, int probe); int pcie_flr(struct pci_dev *dev); +bool pci_reset_supported(struct pci_dev *dev); int __pci_reset_function_locked(struct pci_dev *dev); int pci_reset_function(struct pci_dev *dev); int pci_reset_function_locked(struct pci_dev *dev);