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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 798E9C4743D for ; Sat, 5 Jun 2021 20:55:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60FA0613F1 for ; Sat, 5 Jun 2021 20:55:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230136AbhFEU5k (ORCPT ); Sat, 5 Jun 2021 16:57:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:60790 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230010AbhFEU5j (ORCPT ); Sat, 5 Jun 2021 16:57:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1E0CF613EF; Sat, 5 Jun 2021 20:55:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622926551; bh=h5BuiyZebUfAAsqkCt+uUT5aV8OBM4nk9UOqy4fM7wY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=I+XSN2YTdr0IF3PHhF0Km7MiWEcPXbQVzzL3DvODqho3xLCpgUcemoqk9oI9UenL6 nHqGjE09AS1HojJPEPziQkhE1HIrDFLghwZqCJtFs3ixvMIwtLE71VMVLk+fnQOGJG mdUpD7YWD27SxxuZ4Cdg2ARwzdwNNm45z1JhP5YnV9elIJsB8x6rA+6PfTCiS+OBx7 +D9k7whacFfLPDtVLeMPuCHBPslUaepgEXjKuE9RB916I3uCHqf1hsRY2CHIkl9bC+ lL/7/6apwr/1xZ6Pwib+KsNg5vDNWz7RHDVDXu5cZUHMh+WoCWPrecHCjLahuU3RFm fZuB/PjgwdzCw== Date: Sat, 5 Jun 2021 15:55:48 -0500 From: Bjorn Helgaas To: Amey Narkhede Cc: Bjorn Helgaas , alex.williamson@redhat.com, Raphael Norwitz , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kw@linux.com, Shanker Donthineni , Sinan Kaya Subject: Re: [PATCH v5 2/7] PCI: Add new array for keeping track of ordering of reset methods Message-ID: <20210605205548.GA2254180@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210529192527.2708-3-ameynarkhede03@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 30, 2021 at 12:55:22AM +0530, Amey Narkhede wrote: > 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. Rewrap above to use 75 columns. > Reviewed-by: Alex Williamson > Reviewed-by: Raphael Norwitz > Co-developed-by: Alex Williamson > Signed-off-by: Alex Williamson > Signed-off-by: Amey Narkhede > --- > drivers/pci/pci.c | 107 ++++++++++++++++++++++++++------------------ > drivers/pci/pci.h | 8 +++- > drivers/pci/probe.c | 5 +-- > include/linux/pci.h | 7 +++ > 4 files changed, 80 insertions(+), 47 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 3bf36924c..67a2605d4 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 +5115,19 @@ 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. Rewrap to fill 75-78 columns. > + */ > +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 +5150,65 @@ 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. Rewrap to fit in 80 columns. > + */ > + 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); > -- > 2.31.1 >