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drivers/watchdog/max63xx_wdt.c
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/* * drivers/char/watchdog/max63xx_wdt.c * * Driver for max63{69,70,71,72,73,74} watchdog timers * * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org> * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. * * This driver assumes the watchdog pins are memory mapped (as it is * the case for the Arcom Zeus). Should it be connected over GPIOs or * another interface, some abstraction will have to be introduced. */ |
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#include <linux/err.h> |
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#include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/kernel.h> |
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#include <linux/watchdog.h> |
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#include <linux/bitops.h> #include <linux/platform_device.h> #include <linux/spinlock.h> |
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#include <linux/io.h> |
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#include <linux/slab.h> |
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#define DEFAULT_HEARTBEAT 60 #define MAX_HEARTBEAT 60 |
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static unsigned int heartbeat = DEFAULT_HEARTBEAT; |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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/* * Memory mapping: a single byte, 3 first lower bits to select bit 3 * to ping the watchdog. */ #define MAX6369_WDSET (7 << 0) |
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#define MAX6369_WDI (1 << 3) |
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static DEFINE_SPINLOCK(io_lock); |
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static int nodelay; |
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static void __iomem *wdt_base; |
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/* * The timeout values used are actually the absolute minimum the chip * offers. Typical values on my board are slightly over twice as long * (10s setting ends up with a 25s timeout), and can be up to 3 times * the nominal setting (according to the datasheet). So please take * these values with a grain of salt. Same goes for the initial delay * "feature". Only max6373/74 have a few settings without this initial * delay (selected with the "nodelay" parameter). * * I also decided to remove from the tables any timeout smaller than a * second, as it looked completly overkill... */ /* Timeouts in second */ struct max63xx_timeout { u8 wdset; u8 tdelay; u8 twd; }; static struct max63xx_timeout max6369_table[] = { { 5, 1, 1 }, { 6, 10, 10 }, { 7, 60, 60 }, { }, }; static struct max63xx_timeout max6371_table[] = { { 6, 60, 3 }, { 7, 60, 60 }, { }, }; static struct max63xx_timeout max6373_table[] = { { 2, 60, 1 }, { 5, 0, 1 }, { 1, 3, 3 }, { 7, 60, 10 }, { 6, 0, 10 }, { }, }; static struct max63xx_timeout *current_timeout; static struct max63xx_timeout * max63xx_select_timeout(struct max63xx_timeout *table, int value) { while (table->twd) { if (value <= table->twd) { if (nodelay && table->tdelay == 0) return table; if (!nodelay) return table; } table++; } return NULL; } |
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static int max63xx_wdt_ping(struct watchdog_device *wdd) |
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{ u8 val; spin_lock(&io_lock); val = __raw_readb(wdt_base); __raw_writeb(val | MAX6369_WDI, wdt_base); __raw_writeb(val & ~MAX6369_WDI, wdt_base); spin_unlock(&io_lock); |
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return 0; |
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} |
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static int max63xx_wdt_start(struct watchdog_device *wdd) |
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{ |
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struct max63xx_timeout *entry = watchdog_get_drvdata(wdd); |
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u8 val; |
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spin_lock(&io_lock); val = __raw_readb(wdt_base); val &= ~MAX6369_WDSET; val |= entry->wdset; __raw_writeb(val, wdt_base); spin_unlock(&io_lock); /* check for a edge triggered startup */ if (entry->tdelay == 0) |
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max63xx_wdt_ping(wdd); return 0; |
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} |
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static int max63xx_wdt_stop(struct watchdog_device *wdd) |
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{ |
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u8 val; |
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spin_lock(&io_lock); |
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val = __raw_readb(wdt_base); val &= ~MAX6369_WDSET; val |= 3; __raw_writeb(val, wdt_base); |
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spin_unlock(&io_lock); |
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return 0; |
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} |
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static const struct watchdog_info max63xx_wdt_info = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
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.identity = "max63xx Watchdog", }; |
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static const struct watchdog_ops max63xx_wdt_ops = { .owner = THIS_MODULE, .start = max63xx_wdt_start, .stop = max63xx_wdt_stop, .ping = max63xx_wdt_ping, |
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}; |
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static struct watchdog_device max63xx_wdt_dev = { .info = &max63xx_wdt_info, .ops = &max63xx_wdt_ops, |
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}; |
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static int max63xx_wdt_probe(struct platform_device *pdev) |
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{ |
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struct resource *wdt_mem; |
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struct max63xx_timeout *table; table = (struct max63xx_timeout *)pdev->id_entry->driver_data; if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) heartbeat = DEFAULT_HEARTBEAT; |
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dev_info(&pdev->dev, "requesting %ds heartbeat ", heartbeat); |
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current_timeout = max63xx_select_timeout(table, heartbeat); if (!current_timeout) { |
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dev_err(&pdev->dev, "unable to satisfy heartbeat request "); |
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return -EINVAL; } |
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dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay ", |
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current_timeout->twd, current_timeout->tdelay); heartbeat = current_timeout->twd; |
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wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem); if (IS_ERR(wdt_base)) return PTR_ERR(wdt_base); |
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max63xx_wdt_dev.timeout = heartbeat; watchdog_set_nowayout(&max63xx_wdt_dev, nowayout); watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout); |
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return watchdog_register_device(&max63xx_wdt_dev); |
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} |
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static int max63xx_wdt_remove(struct platform_device *pdev) |
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{ |
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watchdog_unregister_device(&max63xx_wdt_dev); |
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return 0; } static struct platform_device_id max63xx_id_table[] = { { "max6369_wdt", (kernel_ulong_t)max6369_table, }, { "max6370_wdt", (kernel_ulong_t)max6369_table, }, { "max6371_wdt", (kernel_ulong_t)max6371_table, }, { "max6372_wdt", (kernel_ulong_t)max6371_table, }, { "max6373_wdt", (kernel_ulong_t)max6373_table, }, { "max6374_wdt", (kernel_ulong_t)max6373_table, }, { }, }; MODULE_DEVICE_TABLE(platform, max63xx_id_table); static struct platform_driver max63xx_wdt_driver = { .probe = max63xx_wdt_probe, |
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.remove = max63xx_wdt_remove, |
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.id_table = max63xx_id_table, .driver = { .name = "max63xx_wdt", .owner = THIS_MODULE, }, }; |
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module_platform_driver(max63xx_wdt_driver); |
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MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>"); MODULE_DESCRIPTION("max63xx Watchdog Driver"); module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to " __MODULE_STRING(MAX_HEARTBEAT) ", default " __MODULE_STRING(DEFAULT_HEARTBEAT)); |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); module_param(nodelay, int, 0); MODULE_PARM_DESC(nodelay, "Force selection of a timeout setting without initial delay " "(max6373/74 only, default=0)"); MODULE_LICENSE("GPL"); |