Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755022AbbFKQ2X (ORCPT ); Thu, 11 Jun 2015 12:28:23 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:51524 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbbFKQ2S (ORCPT ); Thu, 11 Jun 2015 12:28:18 -0400 Date: Thu, 11 Jun 2015 09:28:10 -0700 From: Guenter Roeck To: fu.wei@linaro.org Cc: Suravee.Suthikulpanit@amd.com, linaro-acpi@lists.linaro.org, linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, tekkamanninja@gmail.com, graeme.gregory@linaro.org, al.stone@linaro.org, hanjun.guo@linaro.org, timur@codeaurora.org, ashwin.chaugule@linaro.org, arnd@arndb.de, vgandhi@codeaurora.org, wim@iguana.be, jcm@redhat.com, leo.duran@amd.com, corbet@lwn.net, mark.rutland@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, rjw@rjwysocki.net Subject: Re: [non-pretimeout,4/7] Watchdog: introduce ARM SBSA watchdog driver Message-ID: <20150611162810.GA22711@roeck-us.net> References: <1433958452-23721-5-git-send-email-fu.wei@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433958452-23721-5-git-send-email-fu.wei@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=0.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 15965 Lines: 516 On Thu, Jun 11, 2015 at 01:47:29AM +0800, fu.wei@linaro.org wrote: > From: Fu Wei > > This driver bases on linux kernel watchdog framework. > It supports getting timeout from parameter and FDT > at the driver init stage. > The first timeout period expires, the interrupt routine > got another timeout period to run panic for saving > system context. > Comments inline. Thanks, Guenter > Signed-off-by: Fu Wei > --- > drivers/watchdog/Kconfig | 11 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/sbsa_gwdt.c | 383 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 395 insertions(+) > create mode 100644 drivers/watchdog/sbsa_gwdt.c > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index e5e7c55..554f18a 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -152,6 +152,17 @@ config ARM_SP805_WATCHDOG > ARM Primecell SP805 Watchdog timer. This will reboot your system when > the timeout is reached. > > +config ARM_SBSA_WATCHDOG > + tristate "ARM SBSA Generic Watchdog" > + depends on ARM64 > + depends on ARM_ARCH_TIMER > + select WATCHDOG_CORE > + help > + ARM SBSA Generic Watchdog. This watchdog has two Watchdog timeouts. > + The first timeout will trigger a panic; the second timeout will > + trigger a system reset. > + More details: ARM DEN0029B - Server Base System Architecture (SBSA) > + To compile this driver as module, choose M here: The module will be called sbsa_gwdt. > config AT91RM9200_WATCHDOG > tristate "AT91RM9200 watchdog" > depends on SOC_AT91RM9200 && MFD_SYSCON > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 5c19294..471f1b7c 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -30,6 +30,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o > > # ARM Architecture > obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o > +obj-$(CONFIG_ARM_SBSA_WATCHDOG) += sbsa_gwdt.o > obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o > obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o > obj-$(CONFIG_CADENCE_WATCHDOG) += cadence_wdt.o > diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c > new file mode 100644 > index 0000000..1ddc10f > --- /dev/null > +++ b/drivers/watchdog/sbsa_gwdt.c > @@ -0,0 +1,383 @@ > +/* > + * SBSA(Server Base System Architecture) Generic Watchdog driver > + * > + * Copyright (c) 2015, Linaro Ltd. > + * Author: Fu Wei > + * Suravee Suthikulpanit > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License 2 as published > + * by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * Note: This SBSA Generic watchdog has two stage timeouts, s/This/The/ "has two stages". I would suggest to drop "Note:", but that is up to you. > + * When the first timeout occurs, WS0(SPI or LPI) is triggered, > + * the second timeout period(as long as the first timeout period) starts. no longer accurate if WOR is used for the second period. > + * In WS0 interrupt routine, panic() will be called for collecting > + * crashdown info. > + * If system can not recover from WS0 interrupt routine, then second > + * timeout occurs, WS1(reset or higher level interrupt) is triggered. > + * The two timeout period can be set by WOR(32bit). The second timeout period is determined by ... > + * WOR gives a maximum watch period of around 10s at the maximum > + * system counter frequency. > + * The System Counter shall run at maximum of 400MHz. "... at the maximum system counter frequency of 400 MHz.", and drop the last sentence. Please uses spaces before '('. > + * > + * But If we need a larger timeout period, this driver will programme WCV s/But // s/this/the/ s/programme/program/ > + * directly. That can support more than 10s timeout at the maximum > + * system counter frequency. Drop the last sentence. > + * More details: ARM DEN0029B - Server Base System Architecture (SBSA) > + * > + * SBSA GWDT: |---WOR(or WCV)---WS0---WOR(or WCV)---WS1 > + * |-----timeout-----WS0-----timeout-----WS1 > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* SBSA Generic Watchdog register definitions */ > +/* refresh frame */ > +#define SBSA_GWDT_WRR 0x000 > + > +/* control frame */ > +#define SBSA_GWDT_WCS 0x000 > +#define SBSA_GWDT_WOR 0x008 > +#define SBSA_GWDT_WCV_LO 0x010 > +#define SBSA_GWDT_WCV_HI 0x014 > + > +/* refresh/control frame */ > +#define SBSA_GWDT_W_IIDR 0xfcc > +#define SBSA_GWDT_IDR 0xfd0 > + > +/* Watchdog Control and Status Register */ > +#define SBSA_GWDT_WCS_EN BIT(0) > +#define SBSA_GWDT_WCS_WS0 BIT(1) > +#define SBSA_GWDT_WCS_WS1 BIT(2) > + > +/** > + * struct sbsa_gwdt - Internal representation of the SBSA GWDT > + * @wdd: kernel watchdog_device structure > + * @clk: store the System Counter clock frequency, in Hz. > + * @max_wor_timeout: the maximum timeout value for WOR (in seconds). > + * @refresh_base: Virtual address of the watchdog refresh frame > + * @control_base: Virtual address of the watchdog control frame > + */ > +struct sbsa_gwdt { > + struct watchdog_device wdd; > + u32 clk; > + int max_wor_timeout; > + void __iomem *refresh_base; > + void __iomem *control_base; > +}; > + > +#define to_sbsa_gwdt(e) container_of(e, struct sbsa_gwdt, wdd) > + > +#define DEFAULT_TIMEOUT 30 /* seconds */ > + > +static unsigned int timeout; > +module_param(timeout, uint, 0); > +MODULE_PARM_DESC(timeout, > + "Watchdog timeout in seconds. (>=0, default=" > + __MODULE_STRING(DEFAULT_TIMEOUT) ")"); > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +module_param(nowayout, bool, S_IRUGO); > +MODULE_PARM_DESC(nowayout, > + "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +/* > + * help functions for accessing 64bit WCV register > + */ > +static u64 sbsa_gwdt_get_wcv(struct watchdog_device *wdd) > +{ > + u32 wcv_lo, wcv_hi; > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + do { > + wcv_hi = readl_relaxed(gwdt->control_base + SBSA_GWDT_WCV_HI); > + wcv_lo = readl_relaxed(gwdt->control_base + SBSA_GWDT_WCV_LO); > + } while (wcv_hi != readl_relaxed(gwdt->control_base + > + SBSA_GWDT_WCV_HI)); > + > + return (((u64)wcv_hi << 32) | wcv_lo); > +} > + > +static void reload_timeout_to_wcv(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + u64 wcv; > + > + wcv = arch_counter_get_cntvct() + (u64)wdd->timeout * gwdt->clk; > + > + writel_relaxed(upper_32_bits(wcv), > + gwdt->control_base + SBSA_GWDT_WCV_HI); > + writel_relaxed(lower_32_bits(wcv), > + gwdt->control_base + SBSA_GWDT_WCV_LO); > +} > + > +static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd, > + unsigned int timeout) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + wdd->timeout = timeout; > + > + if (timeout <= gwdt->max_wor_timeout) > + writel_relaxed(timeout * gwdt->clk, > + gwdt->control_base + SBSA_GWDT_WOR); > + else > + writel_relaxed(gwdt->max_wor_timeout * gwdt->clk, > + gwdt->control_base + SBSA_GWDT_WOR); > + This can be simplified a bit to if (timeout > gwdt->max_wor_timeout) timeout = gwdt->max_wor_timeout; writel_relaxed(timeout * gwdt->clk, gwdt->control_base + SBSA_GWDT_WOR); > + return 0; > +} > + > +static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + u64 timeleft = sbsa_gwdt_get_wcv(wdd) - arch_counter_get_cntvct(); > + > + do_div(timeleft, gwdt->clk); > + > + return timeleft; > +} > + > +static int sbsa_gwdt_keepalive(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + if (wdd->timeout <= gwdt->max_wor_timeout) > + /* > + * Writing WRR for an explicit watchdog refresh. > + * You can write anyting(like 0xc0ffee). > + */ > + writel_relaxed(0xc0ffee, gwdt->refresh_base + SBSA_GWDT_WRR); > + else > + reload_timeout_to_wcv(wdd); > + > + return 0; > +} > + > +static int sbsa_gwdt_start(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + /* Force refresh due to hardware bug found in certain Soc. */ Can you specify which SOC(s) are known to need this, and explain the bug a bit better ? > + writel_relaxed(0xc0ffee, gwdt->refresh_base + SBSA_GWDT_WRR); > + /* writing WCS will cause an explicit watchdog refresh */ > + writel_relaxed(SBSA_GWDT_WCS_EN, gwdt->control_base + SBSA_GWDT_WCS); > + > + return sbsa_gwdt_keepalive(wdd); > +} > + > +static int sbsa_gwdt_stop(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + writel_relaxed(0, gwdt->control_base + SBSA_GWDT_WCS); > + > + return 0; > +} > + > +static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id) > +{ > + struct sbsa_gwdt *gwdt = (struct sbsa_gwdt *)dev_id; > + struct watchdog_device *wdd = &gwdt->wdd; > + > + if (wdd->timeout > gwdt->max_wor_timeout) > + reload_timeout_to_wcv(wdd); > + Please drop the above. > + panic("SBSA Watchdog pre-timeout"); > + > + return IRQ_HANDLED; > +} > + > +static struct watchdog_info sbsa_gwdt_info = { > + .identity = "SBSA Generic Watchdog", > + .options = WDIOF_SETTIMEOUT | > + WDIOF_KEEPALIVEPING | > + WDIOF_MAGICCLOSE | > + WDIOF_CARDRESET, > +}; > + > +static struct watchdog_ops sbsa_gwdt_ops = { > + .owner = THIS_MODULE, > + .start = sbsa_gwdt_start, > + .stop = sbsa_gwdt_stop, > + .ping = sbsa_gwdt_keepalive, > + .set_timeout = sbsa_gwdt_set_timeout, > + .get_timeleft = sbsa_gwdt_get_timeleft, > +}; > + > +static int sbsa_gwdt_probe(struct platform_device *pdev) > +{ > + u64 first_period_max = U64_MAX; > + struct device *dev = &pdev->dev; > + struct watchdog_device *wdd; > + struct sbsa_gwdt *gwdt; > + struct resource *res; > + void *rf_base, *cf_base; > + int ret, irq; > + u32 status; > + > + gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL); > + if (!gwdt) > + return -ENOMEM; > + platform_set_drvdata(pdev, gwdt); > + > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "refresh"); > + rf_base = devm_ioremap_resource(dev, res); > + if (IS_ERR(rf_base)) > + return PTR_ERR(rf_base); > + > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "control"); > + cf_base = devm_ioremap_resource(dev, res); > + if (IS_ERR(cf_base)) > + return PTR_ERR(cf_base); > + > + irq = platform_get_irq_byname(pdev, "ws0"); > + if (irq < 0) { > + dev_err(dev, "unable to get ws0 interrupt.\n"); > + return irq; > + } > + > + /* > + * Get the frequency of system counter from the cp15 interface of ARM > + * Generic timer. We don't need to check it, because if it returns "0", > + * system would panic in very early stage. > + */ > + gwdt->clk = arch_timer_get_cntfrq(); > + gwdt->refresh_base = rf_base; > + gwdt->control_base = cf_base; > + gwdt->max_wor_timeout = U32_MAX / gwdt->clk; > + > + wdd = &gwdt->wdd; > + wdd->parent = dev; > + wdd->info = &sbsa_gwdt_info; > + wdd->ops = &sbsa_gwdt_ops; > + watchdog_set_drvdata(wdd, gwdt); > + watchdog_set_nowayout(wdd, nowayout); > + > + wdd->min_timeout = 1; > + do_div(first_period_max, gwdt->clk); > + wdd->max_timeout = first_period_max; > + > + wdd->timeout = DEFAULT_TIMEOUT; > + watchdog_init_timeout(wdd, timeout, dev); > + > + status = readl_relaxed(gwdt->control_base + SBSA_GWDT_WCS); > + if (status & SBSA_GWDT_WCS_WS1) { > + dev_warn(dev, "System reset by WDT(WCV: %llx)\n", > + sbsa_gwdt_get_wcv(wdd)); WCV here only tells us how many clock cycles were executed since the system started (or something like that). So I still don't understand why it is valuable to print that number. > + wdd->bootstatus |= WDIOF_CARDRESET; > + } > + /* Check if watchdog is already enabled */ > + if (status & SBSA_GWDT_WCS_EN) { > + dev_warn(dev, "already enabled\n"); > + sbsa_gwdt_keepalive(wdd); > + } Can you merge the message with the info message below ? Something like dev_info(dev, "Initialized with %ds timeout @ %u Hz%s\n", wdd->timeout, gwdt->clk, status & SBSA_GWDT_WCS_EN ? " [enabled]" : ""); I don't think that should be a warning. > + > + /* update timeout to WOR */ > + sbsa_gwdt_set_timeout(wdd, wdd->timeout); > + That will trigger a refresh if the watchdog is active, meaning the timeout will occur at time + WOR, not at time + timeout. I think keepalive has to be called later, preferrably after calling watchdog_register_device(). > + ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0, > + pdev->name, gwdt); > + if (ret) { > + dev_err(dev, "unable to request IRQ %d\n", irq); > + return ret; > + } > + > + ret = watchdog_register_device(wdd); > + if (ret) > + return ret; > + > + dev_info(dev, "Initialized with %ds timeout @ %u Hz\n", wdd->timeout, > + gwdt->clk); > + > + return 0; > +} > + > +static void sbsa_gwdt_shutdown(struct platform_device *pdev) > +{ > + struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev); > + > + sbsa_gwdt_stop(&gwdt->wdd); > +} > + > +static int sbsa_gwdt_remove(struct platform_device *pdev) > +{ > + struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev); > + > + watchdog_unregister_device(&gwdt->wdd); > + > + return 0; > +} > + > +/* Disable watchdog if it is active during suspend */ > +static int __maybe_unused sbsa_gwdt_suspend(struct device *dev) > +{ > + struct sbsa_gwdt *gwdt = dev_get_drvdata(dev); > + > + if (watchdog_active(&gwdt->wdd)) > + sbsa_gwdt_stop(&gwdt->wdd); > + > + return 0; > +} > + > +/* Enable watchdog and configure it if necessary */ > +static int __maybe_unused sbsa_gwdt_resume(struct device *dev) > +{ > + struct sbsa_gwdt *gwdt = dev_get_drvdata(dev); > + > + if (watchdog_active(&gwdt->wdd)) > + sbsa_gwdt_start(&gwdt->wdd); > + > + return 0; > +} > + > +static const struct dev_pm_ops sbsa_gwdt_pm_ops = { > + SET_SYSTEM_SLEEP_PM_OPS(sbsa_gwdt_suspend, sbsa_gwdt_resume) > +}; > + > +static const struct of_device_id sbsa_gwdt_of_match[] = { > + { .compatible = "arm,sbsa-gwdt", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match); > + > +static const struct platform_device_id sbsa_gwdt_pdev_match[] = { > + { .name = "sbsa-gwdt", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(platform, sbsa_gwdt_pdev_match); > + > +static struct platform_driver sbsa_gwdt_driver = { > + .driver = { > + .name = "sbsa-gwdt", > + .pm = &sbsa_gwdt_pm_ops, > + .of_match_table = sbsa_gwdt_of_match, > + }, > + .probe = sbsa_gwdt_probe, > + .remove = sbsa_gwdt_remove, > + .shutdown = sbsa_gwdt_shutdown, > + .id_table = sbsa_gwdt_pdev_match, > +}; > + > +module_platform_driver(sbsa_gwdt_driver); > + > +MODULE_DESCRIPTION("SBSA Generic Watchdog Driver"); > +MODULE_VERSION("v1.0"); Version numbers tend to be out of date constantly, and there is no well defined mechanism or protocol when increase them. I would suggest to drop it. > +MODULE_AUTHOR("Fu Wei "); > +MODULE_AUTHOR("Suravee Suthikulpanit "); > +MODULE_LICENSE("GPL v2"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/