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Wysocki" , Amey Narkhede Subject: [PATCH v16 3/9] PCI: Add new array for keeping track of ordering of reset methods Date: Tue, 17 Aug 2021 23:39:31 +0530 Message-Id: <20210817180937.3123-4-ameynarkhede03@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210817180937.3123-1-ameynarkhede03@gmail.com> References: <20210817180937.3123-1-ameynarkhede03@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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. Co-developed-by: Alex Williamson Signed-off-by: Alex Williamson Signed-off-by: Amey Narkhede Reviewed-by: Raphael Norwitz --- drivers/pci/pci.c | 95 ++++++++++++++++++++++++++------------------- drivers/pci/pci.h | 8 +++- drivers/pci/probe.c | 5 +-- include/linux/pci.h | 7 ++++ 4 files changed, 71 insertions(+), 44 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7d1d96711..67eab3d29 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -73,6 +73,11 @@ static void pci_dev_d3_sleep(struct pci_dev *dev) msleep(delay); } +bool pci_reset_supported(struct pci_dev *dev) +{ + return dev->reset_methods[0] != 0; +} + #ifdef CONFIG_PCI_DOMAINS int pci_domains_supported = 1; #endif @@ -5117,6 +5122,16 @@ static void pci_dev_restore(struct pci_dev *dev) err_handler->reset_done(dev); } +/* dev->reset_methods[] is a 0-terminated list of indices into this array */ +static 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. @@ -5139,65 +5154,65 @@ static void pci_dev_restore(struct pci_dev *dev) */ int __pci_reset_function_locked(struct pci_dev *dev) { - int rc; + int i, m, rc = -ENOTTY; might_sleep(); /* - * A reset method returns -ENOTTY if it doesn't support this device - * and we should try the next method. + * 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. + * 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 (i = 0; i < PCI_NUM_RESET_METHODS; i++) { + m = dev->reset_methods[i]; + if (!m) + return -ENOTTY; + + rc = pci_reset_fn_methods[m].reset_fn(dev, 0); + if (!rc) + return 0; + if (rc != -ENOTTY) + return rc; + } + + return -ENOTTY; } 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. + * other functions in the same device. The PCI device must be in D0-D3hot + * state. * - * 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 m, i, rc; + + BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_NUM_RESET_METHODS); might_sleep(); - 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; + i = 0; + + for (m = 1; m < PCI_NUM_RESET_METHODS; m++) { + rc = pci_reset_fn_methods[m].reset_fn(dev, 1); + if (!rc) + dev->reset_methods[i++] = m; + else if (rc != -ENOTTY) + break; + } - return pci_reset_bus_function(dev, 1); + dev->reset_methods[i] = 0; } /** diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 37c913bbc..743895374 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -33,7 +33,8 @@ 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); +bool pci_reset_supported(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 +607,11 @@ 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; +}; + #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 df3f9db6e..5d8ad230f 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2405,9 +2405,8 @@ 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 aa85e7d31..d1a9a232d 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -49,6 +49,9 @@ PCI_STATUS_SIG_TARGET_ABORT | \ PCI_STATUS_PARITY) +/* Number of reset methods used in pci_reset_fn_methods array in pci.c */ +#define PCI_NUM_RESET_METHODS 6 + /* * The PCI interface treats multi-function devices as independent * devices. The slot/function address of each device is encoded @@ -506,6 +509,10 @@ 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_NUM_RESET_METHODS]; /* Reset methods ordered by priority */ }; static inline struct pci_dev *pci_physfn(struct pci_dev *dev) -- 2.32.0