diff options
Diffstat (limited to 'drivers/watchdog/digicolor_wdt.c')
| -rw-r--r-- | drivers/watchdog/digicolor_wdt.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/drivers/watchdog/digicolor_wdt.c b/drivers/watchdog/digicolor_wdt.c new file mode 100644 index 000000000000..31d8e4936611 --- /dev/null +++ b/drivers/watchdog/digicolor_wdt.c @@ -0,0 +1,205 @@ +/* + * Watchdog driver for Conexant Digicolor + * + * Copyright (C) 2015 Paradox Innovation Ltd. + * + * 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/types.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/clk.h> +#include <linux/watchdog.h> +#include <linux/reboot.h> +#include <linux/platform_device.h> +#include <linux/of_address.h> + +#define TIMER_A_CONTROL 0 +#define TIMER_A_COUNT 4 + +#define TIMER_A_ENABLE_COUNT BIT(0) +#define TIMER_A_ENABLE_WATCHDOG BIT(1) + +struct dc_wdt { + void __iomem *base; + struct clk *clk; + struct notifier_block restart_handler; + spinlock_t lock; +}; + +static unsigned timeout; +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); + +static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks) +{ + unsigned long flags; + + spin_lock_irqsave(&wdt->lock, flags); + + writel_relaxed(0, wdt->base + TIMER_A_CONTROL); + writel_relaxed(ticks, wdt->base + TIMER_A_COUNT); + writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG, + wdt->base + TIMER_A_CONTROL); + + spin_unlock_irqrestore(&wdt->lock, flags); +} + +static int dc_restart_handler(struct notifier_block *this, unsigned long mode, + void *cmd) +{ + struct dc_wdt *wdt = container_of(this, struct dc_wdt, restart_handler); + + dc_wdt_set(wdt, 1); + /* wait for reset to assert... */ + mdelay(500); + + return NOTIFY_DONE; +} + +static int dc_wdt_start(struct watchdog_device *wdog) +{ + struct dc_wdt *wdt = watchdog_get_drvdata(wdog); + + dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); + + return 0; +} + +static int dc_wdt_stop(struct watchdog_device *wdog) +{ + struct dc_wdt *wdt = watchdog_get_drvdata(wdog); + + writel_relaxed(0, wdt->base + TIMER_A_CONTROL); + + return 0; +} + +static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) +{ + struct dc_wdt *wdt = watchdog_get_drvdata(wdog); + + dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); + wdog->timeout = t; + + return 0; +} + +static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) +{ + struct dc_wdt *wdt = watchdog_get_drvdata(wdog); + uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); + + return count / clk_get_rate(wdt->clk); +} + +static struct watchdog_ops dc_wdt_ops = { + .owner = THIS_MODULE, + .start = dc_wdt_start, + .stop = dc_wdt_stop, + .set_timeout = dc_wdt_set_timeout, + .get_timeleft = dc_wdt_get_timeleft, +}; + +static struct watchdog_info dc_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE + | WDIOF_KEEPALIVEPING, + .identity = "Conexant Digicolor Watchdog", +}; + +static struct watchdog_device dc_wdt_wdd = { + .info = &dc_wdt_info, + .ops = &dc_wdt_ops, + .min_timeout = 1, +}; + +static int dc_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct dc_wdt *wdt; + int ret; + + wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + platform_set_drvdata(pdev, wdt); + + wdt->base = of_iomap(np, 0); + if (!wdt->base) { + dev_err(dev, "Failed to remap watchdog regs"); + return -ENODEV; + } + + wdt->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(wdt->clk)) { + ret = PTR_ERR(wdt->clk); + goto err_iounmap; + } + dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); + dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; + + spin_lock_init(&wdt->lock); + + watchdog_set_drvdata(&dc_wdt_wdd, wdt); + watchdog_init_timeout(&dc_wdt_wdd, timeout, dev); + ret = watchdog_register_device(&dc_wdt_wdd); + if (ret) { + dev_err(dev, "Failed to register watchdog device"); + goto err_iounmap; + } + + wdt->restart_handler.notifier_call = dc_restart_handler; + wdt->restart_handler.priority = 128; + ret = register_restart_handler(&wdt->restart_handler); + if (ret) + dev_warn(&pdev->dev, "cannot register restart handler\n"); + + return 0; + +err_iounmap: + iounmap(wdt->base); + return ret; +} + +static int dc_wdt_remove(struct platform_device *pdev) +{ + struct dc_wdt *wdt = platform_get_drvdata(pdev); + + unregister_restart_handler(&wdt->restart_handler); + watchdog_unregister_device(&dc_wdt_wdd); + iounmap(wdt->base); + + return 0; +} + +static void dc_wdt_shutdown(struct platform_device *pdev) +{ + dc_wdt_stop(&dc_wdt_wdd); +} + +static const struct of_device_id dc_wdt_of_match[] = { + { .compatible = "cnxt,cx92755-wdt", }, + {}, +}; +MODULE_DEVICE_TABLE(of, dc_wdt_of_match); + +static struct platform_driver dc_wdt_driver = { + .probe = dc_wdt_probe, + .remove = dc_wdt_remove, + .shutdown = dc_wdt_shutdown, + .driver = { + .name = "digicolor-wdt", + .of_match_table = dc_wdt_of_match, + }, +}; +module_platform_driver(dc_wdt_driver); + +MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); +MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer"); +MODULE_LICENSE("GPL"); |