This driver adds support for the Altera Timer in the Watchdog Timer configuration. This component is usually found on SOPC (System on Programmable Chip) for Altera FPGAs.
Signed-off-by: Tobias Klauser <[email protected]> Reviewed-by: Jamie Iles <[email protected]> --- Thanks a lot to Jamie Iles and Walter Goossens for their feedback on v2. changes for v3: - Make altera_wdt_setup static void (as suggested by Jamie) - Use const __be32 * for devicetree properties (as suggested by Walter) changes for v2: - Get driver properties from devicetree (and document them), thus the driver depends on OF - Do not select WATCHDOG_NOWAYOUT, but instead implement a software timer resetting the watchdog timer when the device is not open - Only support a single instance of the watchdog, so the private data can be kept in static data - Use devm_* functions in altera_wdt_probe to simplify cleanup and error handling - Remove empty altera_wdt_shutdown function - Add MODULE_LICENSE (GPL) .../devicetree/bindings/watchdog/altera_wdt.txt | 7 + drivers/watchdog/Kconfig | 8 + drivers/watchdog/Makefile | 1 + drivers/watchdog/altera_wdt.c | 309 ++++++++++++++++++++ 4 files changed, 325 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/watchdog/altera_wdt.txt create mode 100644 drivers/watchdog/altera_wdt.c diff --git a/Documentation/devicetree/bindings/watchdog/altera_wdt.txt b/Documentation/devicetree/bindings/watchdog/altera_wdt.txt new file mode 100644 index 0000000..16ac949 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/altera_wdt.txt @@ -0,0 +1,7 @@ +Altera Watchdog Timer + +Required properties: +- compatible : should be "ALTR,wdt-1.0" +- clock-frequency : frequency of the clock input +- timeout : load value of the timer (number of clock ticks until watchdog + resets) diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index bd6a33d..ebcafb0 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -69,6 +69,14 @@ config WM8350_WATCHDOG Support for the watchdog in the WM8350 AudioPlus PMIC. When the watchdog triggers the system will be reset. +config ALTERA_WDT + tristate "Altera Watchdog Timer" + depends on OF + help + Support for the Altera Timer in the Watchdog Timer configuration. This + component is found on SOPC (System on Programmable Chip) for Altera + FPGAs. + # ALPHA Architecture # ARM Architecture diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index fd9c8c0..48a2167 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -153,4 +153,5 @@ obj-$(CONFIG_WATCHDOG_CP1XXX) += cpwd.o obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o +obj-$(CONFIG_ALTERA_WDT) += altera_wdt.o obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o diff --git a/drivers/watchdog/altera_wdt.c b/drivers/watchdog/altera_wdt.c new file mode 100644 index 0000000..2a7f14a --- /dev/null +++ b/drivers/watchdog/altera_wdt.c @@ -0,0 +1,309 @@ +/* + * Driver for the Altera Watchdog Timer + * + * Copyright (C) 2011 Tobias Klauser <[email protected]> + * Copyright (C) 2005 Walter Goossens + * + * Originally based on wdt.c which is + * + * Copyright (C) 1995-1997 Alan Cox <[email protected]> + * + * Software timeout heartbeat code based on pika_wdt.c which is + * + * Copyright (c) 2008 PIKA Technologies + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/jiffies.h> +#include <linux/timer.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <linux/of_platform.h> + +#define WATCHDOG_NAME "altera_wdt" + +/* Register offsets */ +#define ALTERA_WDT_STATUS 0x00 +#define ALTERA_WDT_CONTROL 0x04 +#define ALTERA_WDT_PERIODL 0x08 +#define ALTERA_WDT_PERIODH 0x0C + +#define ALTERA_WDT_RUN_BIT 0x04 + +/* User land timeout */ +#define WDT_HEARTBEAT 15 +static int heartbeat = WDT_HEARTBEAT; +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " + "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); + +static int nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " + "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static struct { + void __iomem *base; + unsigned long wdt_timeout; /* timeout of the hardware timer */ + + unsigned long next_heartbeat; /* the next_heartbeat for the timer */ + unsigned long is_open; + char expect_close; + struct timer_list timer; /* software timer that pings the watchdog */ +} altera_wdt_priv; + +/* + * Start the watchdog. Once it has been started, it cannot be stopped anymore. + */ +static void altera_wdt_setup(void) +{ + u32 control = readl(altera_wdt_priv.base + ALTERA_WDT_CONTROL); + + writel(control | ALTERA_WDT_RUN_BIT, altera_wdt_priv.base + ALTERA_WDT_CONTROL); +} + +/* + * Tickle the watchdog (reset the watchdog timer) + */ +static void altera_wdt_reset(void) +{ + /* It doesn't matter what value we write */ + writel(1, altera_wdt_priv.base + ALTERA_WDT_PERIODL); +} + +/* + * Software timer tick + */ +static void altera_wdt_ping(unsigned long data) +{ + if (time_before(jiffies, altera_wdt_priv.next_heartbeat) || + (!nowayout && !altera_wdt_priv.is_open)) { + altera_wdt_reset(); + mod_timer(&altera_wdt_priv.timer, jiffies + altera_wdt_priv.wdt_timeout); + } else + pr_crit(WATCHDOG_NAME ": I will reset your machine!\n"); +} + +static void altera_wdt_keepalive(void) +{ + altera_wdt_priv.next_heartbeat = jiffies + heartbeat * HZ; +} + +static void altera_wdt_start(void) +{ + altera_wdt_keepalive(); + mod_timer(&altera_wdt_priv.timer, jiffies + altera_wdt_priv.wdt_timeout); +} + +static int altera_wdt_open(struct inode *inode, struct file *file) +{ + /* /dev/watchdog can only be opened once */ + if (test_and_set_bit(0, &altera_wdt_priv.is_open)) + return -EBUSY; + + altera_wdt_start(); + + return nonseekable_open(inode, file); +} + +static int altera_wdt_release(struct inode *inode, struct file *file) +{ + /* stop internal ping */ + if (!altera_wdt_priv.expect_close) + del_timer(&altera_wdt_priv.timer); + + clear_bit(0, &altera_wdt_priv.is_open); + altera_wdt_priv.expect_close = 0; + + return 0; +} + +static ssize_t altera_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + if (!len) + return 0; + + /* Scan for magic character */ + if (!nowayout) { + size_t i; + + altera_wdt_priv.expect_close = 0; + + for (i = 0; i < len; i++) { + char c; + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') { + altera_wdt_priv.expect_close = 42; + break; + } + } + } + + altera_wdt_keepalive(); + + return len; +} + +static const struct watchdog_info altera_wdt_info = { + .identity = "Altera Watchdog", + .options = WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, + .firmware_version = 1, +}; + +static long altera_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *) arg; + int __user *p = argp; + int new_value; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &altera_wdt_info, sizeof(altera_wdt_info)); + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + + case WDIOC_KEEPALIVE: + altera_wdt_keepalive(); + return 0; + + case WDIOC_SETTIMEOUT: + if (get_user(new_value, p)) + return -EFAULT; + + heartbeat = new_value; + altera_wdt_keepalive(); + + return put_user(new_value, p); /* return current value */ + + case WDIOC_GETTIMEOUT: + return put_user(heartbeat, p); + + default: + return -ENOTTY; + } +} + +static const struct file_operations altera_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .open = altera_wdt_open, + .release = altera_wdt_release, + .write = altera_wdt_write, + .unlocked_ioctl = altera_wdt_ioctl, +}; + +static struct miscdevice altera_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &altera_wdt_fops, +}; + +static int __devinit altera_wdt_probe(struct platform_device *pdev) +{ + struct resource *res, *mem; + const __be32 *freq_prop, *timeout_prop; + unsigned long timeout; + int ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENOENT; + + mem = devm_request_mem_region(&pdev->dev, res->start, + resource_size(res), pdev->name); + if (!mem) + return -EBUSY; + + altera_wdt_priv.base = devm_ioremap_nocache(&pdev->dev, mem->start, + resource_size(mem)); + if (!altera_wdt_priv.base) + return -ENOMEM; + + freq_prop = of_get_property(pdev->dev.of_node, "clock-frequency", NULL); + if (!freq_prop) + return -ENODEV; + + timeout_prop = of_get_property(pdev->dev.of_node, "timeout", NULL); + if (!timeout_prop) + return -ENODEV; + + /* Add 1 as the timeout property actually holds the load value */ + timeout = be32_to_cpup(timeout_prop) + 1; + /* Convert timeout to msecs */ + timeout = timeout / (be32_to_cpup(freq_prop) / MSEC_PER_SEC); + /* Tickle the watchdog twice per timeout period */ + altera_wdt_priv.wdt_timeout = msecs_to_jiffies(timeout / 2); + + ret = misc_register(&altera_wdt_miscdev); + if (ret) + return ret; + + altera_wdt_setup(); + altera_wdt_priv.next_heartbeat = jiffies + heartbeat * HZ; + setup_timer(&altera_wdt_priv.timer, altera_wdt_ping, 0); + mod_timer(&altera_wdt_priv.timer, jiffies + altera_wdt_priv.wdt_timeout); + + pr_info(WATCHDOG_NAME " enabled (heartbeat=%d sec, nowayout=%d)\n", + heartbeat, nowayout); + + return 0; +} + +static int __devexit altera_wdt_remove(struct platform_device *pdev) +{ + misc_deregister(&altera_wdt_miscdev); + return 0; +} + +static struct of_device_id altera_wdt_match[] = { + { .compatible = "altr,wdt-1.0", }, + {}, +}; +MODULE_DEVICE_TABLE(of, altera_wdt_match); + +static struct platform_driver altera_wdt_driver = { + .probe = altera_wdt_probe, + .remove = __devexit_p(altera_wdt_remove), + .driver = { + .owner = THIS_MODULE, + .name = WATCHDOG_NAME, + .of_match_table = altera_wdt_match, + }, +}; + +static int __init altera_wdt_init(void) +{ + return platform_driver_register(&altera_wdt_driver); +} + +static void __exit altera_wdt_exit(void) +{ + platform_driver_unregister(&altera_wdt_driver); +} + +module_init(altera_wdt_init); +module_exit(altera_wdt_exit); + +MODULE_AUTHOR("Walter Goossens, Tobias Klauser <[email protected]>"); +MODULE_DESCRIPTION("Driver for Altera Watchdog Timer"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); +MODULE_ALIAS("platform:" WATCHDOG_NAME); -- 1.7.0.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
