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Diffstat (limited to '')
-rw-r--r-- | drivers/watchdog/max63xx_wdt.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/watchdog/max63xx_wdt.c b/drivers/watchdog/max63xx_wdt.c new file mode 100644 index 0000000000..21935f9620 --- /dev/null +++ b/drivers/watchdog/max63xx_wdt.c @@ -0,0 +1,299 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 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. + */ + +#include <linux/err.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/mod_devicetable.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/watchdog.h> +#include <linux/bitops.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/property.h> + +#define DEFAULT_HEARTBEAT 60 +#define MAX_HEARTBEAT 60 + +static unsigned int heartbeat = DEFAULT_HEARTBEAT; +static bool nowayout = WATCHDOG_NOWAYOUT; + +/* + * Memory mapping: a single byte, 3 first lower bits to select bit 3 + * to ping the watchdog. + */ +#define MAX6369_WDSET (7 << 0) +#define MAX6369_WDI (1 << 3) + +#define MAX6369_WDSET_DISABLED 3 + +static int nodelay; + +struct max63xx_wdt { + struct watchdog_device wdd; + const struct max63xx_timeout *timeout; + + /* memory mapping */ + void __iomem *base; + spinlock_t lock; + + /* WDI and WSET bits write access routines */ + void (*ping)(struct max63xx_wdt *wdt); + void (*set)(struct max63xx_wdt *wdt, u8 set); +}; + +/* + * 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 { + const u8 wdset; + const u8 tdelay; + const u8 twd; +}; + +static const struct max63xx_timeout max6369_table[] = { + { 5, 1, 1 }, + { 6, 10, 10 }, + { 7, 60, 60 }, + { }, +}; + +static const struct max63xx_timeout max6371_table[] = { + { 6, 60, 3 }, + { 7, 60, 60 }, + { }, +}; + +static const struct max63xx_timeout max6373_table[] = { + { 2, 60, 1 }, + { 5, 0, 1 }, + { 1, 3, 3 }, + { 7, 60, 10 }, + { 6, 0, 10 }, + { }, +}; + +static const struct max63xx_timeout * +max63xx_select_timeout(const 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; +} + +static int max63xx_wdt_ping(struct watchdog_device *wdd) +{ + struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd); + + wdt->ping(wdt); + return 0; +} + +static int max63xx_wdt_start(struct watchdog_device *wdd) +{ + struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd); + + wdt->set(wdt, wdt->timeout->wdset); + + /* check for a edge triggered startup */ + if (wdt->timeout->tdelay == 0) + wdt->ping(wdt); + return 0; +} + +static int max63xx_wdt_stop(struct watchdog_device *wdd) +{ + struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd); + + wdt->set(wdt, MAX6369_WDSET_DISABLED); + return 0; +} + +static const struct watchdog_ops max63xx_wdt_ops = { + .owner = THIS_MODULE, + .start = max63xx_wdt_start, + .stop = max63xx_wdt_stop, + .ping = max63xx_wdt_ping, +}; + +static const struct watchdog_info max63xx_wdt_info = { + .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .identity = "max63xx Watchdog", +}; + +static void max63xx_mmap_ping(struct max63xx_wdt *wdt) +{ + u8 val; + + spin_lock(&wdt->lock); + + val = __raw_readb(wdt->base); + + __raw_writeb(val | MAX6369_WDI, wdt->base); + __raw_writeb(val & ~MAX6369_WDI, wdt->base); + + spin_unlock(&wdt->lock); +} + +static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set) +{ + u8 val; + + spin_lock(&wdt->lock); + + val = __raw_readb(wdt->base); + val &= ~MAX6369_WDSET; + val |= set & MAX6369_WDSET; + __raw_writeb(val, wdt->base); + + spin_unlock(&wdt->lock); +} + +static int max63xx_mmap_init(struct platform_device *p, struct max63xx_wdt *wdt) +{ + wdt->base = devm_platform_ioremap_resource(p, 0); + if (IS_ERR(wdt->base)) + return PTR_ERR(wdt->base); + + spin_lock_init(&wdt->lock); + + wdt->ping = max63xx_mmap_ping; + wdt->set = max63xx_mmap_set; + return 0; +} + +static int max63xx_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct max63xx_wdt *wdt; + const struct max63xx_timeout *table; + int err; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + /* Attempt to use fwnode first */ + table = device_get_match_data(dev); + if (!table) + table = (struct max63xx_timeout *)pdev->id_entry->driver_data; + + if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) + heartbeat = DEFAULT_HEARTBEAT; + + wdt->timeout = max63xx_select_timeout(table, heartbeat); + if (!wdt->timeout) { + dev_err(dev, "unable to satisfy %ds heartbeat request\n", + heartbeat); + return -EINVAL; + } + + err = max63xx_mmap_init(pdev, wdt); + if (err) + return err; + + platform_set_drvdata(pdev, &wdt->wdd); + watchdog_set_drvdata(&wdt->wdd, wdt); + + wdt->wdd.parent = dev; + wdt->wdd.timeout = wdt->timeout->twd; + wdt->wdd.info = &max63xx_wdt_info; + wdt->wdd.ops = &max63xx_wdt_ops; + + watchdog_set_nowayout(&wdt->wdd, nowayout); + + err = devm_watchdog_register_device(dev, &wdt->wdd); + if (err) + return err; + + dev_info(dev, "using %ds heartbeat with %ds initial delay\n", + wdt->timeout->twd, wdt->timeout->tdelay); + return 0; +} + +static const 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 const struct of_device_id max63xx_dt_id_table[] = { + { .compatible = "maxim,max6369", .data = max6369_table, }, + { .compatible = "maxim,max6370", .data = max6369_table, }, + { .compatible = "maxim,max6371", .data = max6371_table, }, + { .compatible = "maxim,max6372", .data = max6371_table, }, + { .compatible = "maxim,max6373", .data = max6373_table, }, + { .compatible = "maxim,max6374", .data = max6373_table, }, + { } +}; +MODULE_DEVICE_TABLE(of, max63xx_dt_id_table); + +static struct platform_driver max63xx_wdt_driver = { + .probe = max63xx_wdt_probe, + .id_table = max63xx_id_table, + .driver = { + .name = "max63xx_wdt", + .of_match_table = max63xx_dt_id_table, + }, +}; + +module_platform_driver(max63xx_wdt_driver); + +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)); + +module_param(nowayout, bool, 0); +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 v2"); |