diff options
Diffstat (limited to 'drivers/watchdog/meson_wdt.c')
| -rw-r--r-- | drivers/watchdog/meson_wdt.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/watchdog/meson_wdt.c b/drivers/watchdog/meson_wdt.c new file mode 100644 index 000000000..459f3ae02 --- /dev/null +++ b/drivers/watchdog/meson_wdt.c @@ -0,0 +1,232 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Meson Watchdog Driver + * + * Copyright (c) 2014 Carlo Caione + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/types.h> +#include <linux/watchdog.h> + +#define DRV_NAME "meson_wdt" + +#define MESON_WDT_TC 0x00 +#define MESON_WDT_DC_RESET (3 << 24) + +#define MESON_WDT_RESET 0x04 + +#define MESON_WDT_TIMEOUT 30 +#define MESON_WDT_MIN_TIMEOUT 1 + +#define MESON_SEC_TO_TC(s, c) ((s) * (c)) + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned int timeout; + +struct meson_wdt_data { + unsigned int enable; + unsigned int terminal_count_mask; + unsigned int count_unit; +}; + +static struct meson_wdt_data meson6_wdt_data = { + .enable = BIT(22), + .terminal_count_mask = 0x3fffff, + .count_unit = 100000, /* 10 us */ +}; + +static struct meson_wdt_data meson8b_wdt_data = { + .enable = BIT(19), + .terminal_count_mask = 0xffff, + .count_unit = 7812, /* 128 us */ +}; + +struct meson_wdt_dev { + struct watchdog_device wdt_dev; + void __iomem *wdt_base; + const struct meson_wdt_data *data; +}; + +static int meson_wdt_restart(struct watchdog_device *wdt_dev, + unsigned long action, void *data) +{ + struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); + u32 tc_reboot = MESON_WDT_DC_RESET; + + tc_reboot |= meson_wdt->data->enable; + + while (1) { + writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); + mdelay(5); + } + + return 0; +} + +static int meson_wdt_ping(struct watchdog_device *wdt_dev) +{ + struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); + + writel(0, meson_wdt->wdt_base + MESON_WDT_RESET); + + return 0; +} + +static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) +{ + struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); + u32 reg; + + reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); + reg &= ~meson_wdt->data->terminal_count_mask; + reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit); + writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); +} + +static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) +{ + wdt_dev->timeout = timeout; + + meson_wdt_change_timeout(wdt_dev, timeout); + meson_wdt_ping(wdt_dev); + + return 0; +} + +static int meson_wdt_stop(struct watchdog_device *wdt_dev) +{ + struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); + u32 reg; + + reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); + reg &= ~meson_wdt->data->enable; + writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); + + return 0; +} + +static int meson_wdt_start(struct watchdog_device *wdt_dev) +{ + struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); + u32 reg; + + meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout); + meson_wdt_ping(wdt_dev); + + reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); + reg |= meson_wdt->data->enable; + writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); + + return 0; +} + +static const struct watchdog_info meson_wdt_info = { + .identity = DRV_NAME, + .options = WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, +}; + +static const struct watchdog_ops meson_wdt_ops = { + .owner = THIS_MODULE, + .start = meson_wdt_start, + .stop = meson_wdt_stop, + .ping = meson_wdt_ping, + .set_timeout = meson_wdt_set_timeout, + .restart = meson_wdt_restart, +}; + +static const struct of_device_id meson_wdt_dt_ids[] = { + { .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data }, + { .compatible = "amlogic,meson8-wdt", .data = &meson6_wdt_data }, + { .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data }, + { .compatible = "amlogic,meson8m2-wdt", .data = &meson8b_wdt_data }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); + +static int meson_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct meson_wdt_dev *meson_wdt; + const struct of_device_id *of_id; + int err; + + meson_wdt = devm_kzalloc(dev, sizeof(*meson_wdt), GFP_KERNEL); + if (!meson_wdt) + return -ENOMEM; + + meson_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(meson_wdt->wdt_base)) + return PTR_ERR(meson_wdt->wdt_base); + + of_id = of_match_device(meson_wdt_dt_ids, dev); + if (!of_id) { + dev_err(dev, "Unable to initialize WDT data\n"); + return -ENODEV; + } + meson_wdt->data = of_id->data; + + meson_wdt->wdt_dev.parent = dev; + meson_wdt->wdt_dev.info = &meson_wdt_info; + meson_wdt->wdt_dev.ops = &meson_wdt_ops; + meson_wdt->wdt_dev.max_timeout = + meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit; + meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; + meson_wdt->wdt_dev.timeout = min_t(unsigned int, + MESON_WDT_TIMEOUT, + meson_wdt->wdt_dev.max_timeout); + + watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt); + + watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, dev); + watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout); + watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128); + + meson_wdt_stop(&meson_wdt->wdt_dev); + + watchdog_stop_on_reboot(&meson_wdt->wdt_dev); + err = devm_watchdog_register_device(dev, &meson_wdt->wdt_dev); + if (err) + return err; + + dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", + meson_wdt->wdt_dev.timeout, nowayout); + + return 0; +} + +static struct platform_driver meson_wdt_driver = { + .probe = meson_wdt_probe, + .driver = { + .name = DRV_NAME, + .of_match_table = meson_wdt_dt_ids, + }, +}; + +module_platform_driver(meson_wdt_driver); + +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); +MODULE_DESCRIPTION("Meson Watchdog Timer Driver"); |