watchdog: digicolor: driver for Conexant Digicolor CX92755 SoC
This commit add a driver for the watchdog functionality of the Conexant CX92755 SoC, from the Digicolor series of SoCs. Of 8 system timers provided by the CX92755, the first one, timer A, can reset the chip when its counter reaches zero. This driver uses this capability to provide userspace with a standard watchdog, using the watchdog timer driver core framework. This driver also implements a reboot handler for the reboot(2) system call. The watchdog driver shares the timer registers with the CX92755 timer driver (drivers/clocksource/timer-digicolor.c). The timer driver, however, uses only timers other than A, so both drivers should coexist. Signed-off-by: Baruch Siach <baruch@tkos.co.il> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Baruch Siach
Wim Van Sebroeck
parent
b0abc8ff75
commit
336694a01d
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@ -526,6 +526,16 @@ config MEDIATEK_WATCHDOG
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To compile this driver as a module, choose M here: the
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module will be called mtk_wdt.
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config DIGICOLOR_WATCHDOG
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tristate "Conexant Digicolor SoCs watchdog support"
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depends on ARCH_DIGICOLOR
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select WATCHDOG_CORE
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help
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Say Y here to include support for the watchdog timer
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in Conexant Digicolor SoCs.
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To compile this driver as a module, choose M here: the
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module will be called digicolor_wdt.
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# AVR32 Architecture
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config AT32AP700X_WDT
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@ -65,6 +65,7 @@ obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
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obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
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obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
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obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
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obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
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# AVR32 Architecture
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obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
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@ -0,0 +1,205 @@
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/*
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* Watchdog driver for Conexant Digicolor
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*
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* Copyright (C) 2015 Paradox Innovation Ltd.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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#include <linux/clk.h>
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#include <linux/watchdog.h>
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#include <linux/reboot.h>
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#include <linux/platform_device.h>
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#include <linux/of_address.h>
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#define TIMER_A_CONTROL 0
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#define TIMER_A_COUNT 4
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#define TIMER_A_ENABLE_COUNT BIT(0)
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#define TIMER_A_ENABLE_WATCHDOG BIT(1)
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struct dc_wdt {
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void __iomem *base;
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struct clk *clk;
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struct notifier_block restart_handler;
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spinlock_t lock;
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};
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static unsigned timeout;
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
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static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
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{
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unsigned long flags;
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spin_lock_irqsave(&wdt->lock, flags);
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writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
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writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
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writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
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wdt->base + TIMER_A_CONTROL);
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spin_unlock_irqrestore(&wdt->lock, flags);
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}
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static int dc_restart_handler(struct notifier_block *this, unsigned long mode,
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void *cmd)
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{
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struct dc_wdt *wdt = container_of(this, struct dc_wdt, restart_handler);
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dc_wdt_set(wdt, 1);
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/* wait for reset to assert... */
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mdelay(500);
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return NOTIFY_DONE;
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}
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static int dc_wdt_start(struct watchdog_device *wdog)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
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return 0;
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}
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static int dc_wdt_stop(struct watchdog_device *wdog)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
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return 0;
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}
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static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
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wdog->timeout = t;
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return 0;
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}
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static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
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return count / clk_get_rate(wdt->clk);
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}
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static struct watchdog_ops dc_wdt_ops = {
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.owner = THIS_MODULE,
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.start = dc_wdt_start,
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.stop = dc_wdt_stop,
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.set_timeout = dc_wdt_set_timeout,
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.get_timeleft = dc_wdt_get_timeleft,
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};
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static struct watchdog_info dc_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
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| WDIOF_KEEPALIVEPING,
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.identity = "Conexant Digicolor Watchdog",
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};
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static struct watchdog_device dc_wdt_wdd = {
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.info = &dc_wdt_info,
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.ops = &dc_wdt_ops,
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.min_timeout = 1,
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};
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static int dc_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct dc_wdt *wdt;
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int ret;
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wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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platform_set_drvdata(pdev, wdt);
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wdt->base = of_iomap(np, 0);
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if (!wdt->base) {
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dev_err(dev, "Failed to remap watchdog regs");
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return -ENODEV;
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}
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wdt->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(wdt->clk)) {
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ret = PTR_ERR(wdt->clk);
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goto err_iounmap;
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}
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dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
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dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
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spin_lock_init(&wdt->lock);
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watchdog_set_drvdata(&dc_wdt_wdd, wdt);
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watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
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ret = watchdog_register_device(&dc_wdt_wdd);
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if (ret) {
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dev_err(dev, "Failed to register watchdog device");
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goto err_iounmap;
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}
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wdt->restart_handler.notifier_call = dc_restart_handler;
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wdt->restart_handler.priority = 128;
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ret = register_restart_handler(&wdt->restart_handler);
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if (ret)
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dev_warn(&pdev->dev, "cannot register restart handler\n");
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return 0;
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err_iounmap:
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iounmap(wdt->base);
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return ret;
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}
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static int dc_wdt_remove(struct platform_device *pdev)
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{
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struct dc_wdt *wdt = platform_get_drvdata(pdev);
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unregister_restart_handler(&wdt->restart_handler);
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watchdog_unregister_device(&dc_wdt_wdd);
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iounmap(wdt->base);
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return 0;
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}
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static void dc_wdt_shutdown(struct platform_device *pdev)
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{
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dc_wdt_stop(&dc_wdt_wdd);
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}
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static const struct of_device_id dc_wdt_of_match[] = {
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{ .compatible = "cnxt,cx92755-wdt", },
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{},
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};
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MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
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static struct platform_driver dc_wdt_driver = {
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.probe = dc_wdt_probe,
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.remove = dc_wdt_remove,
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.shutdown = dc_wdt_shutdown,
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.driver = {
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.name = "digicolor-wdt",
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.of_match_table = dc_wdt_of_match,
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},
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};
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module_platform_driver(dc_wdt_driver);
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MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
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MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
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MODULE_LICENSE("GPL");
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