diff options
Diffstat (limited to 'drivers/watchdog/meson_gxbb_wdt.c')
| -rw-r--r-- | drivers/watchdog/meson_gxbb_wdt.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c new file mode 100644 index 000000000..981a2f7c3 --- /dev/null +++ b/drivers/watchdog/meson_gxbb_wdt.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +/* + * Copyright (c) 2016 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + * + */ +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/watchdog.h> + +#define DEFAULT_TIMEOUT 30 /* seconds */ + +#define GXBB_WDT_CTRL_REG 0x0 +#define GXBB_WDT_TCNT_REG 0x8 +#define GXBB_WDT_RSET_REG 0xc + +#define GXBB_WDT_CTRL_CLKDIV_EN BIT(25) +#define GXBB_WDT_CTRL_CLK_EN BIT(24) +#define GXBB_WDT_CTRL_EE_RESET BIT(21) +#define GXBB_WDT_CTRL_EN BIT(18) +#define GXBB_WDT_CTRL_DIV_MASK (BIT(18) - 1) + +#define GXBB_WDT_TCNT_SETUP_MASK (BIT(16) - 1) +#define GXBB_WDT_TCNT_CNT_SHIFT 16 + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static unsigned int timeout; +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds=" + __MODULE_STRING(DEFAULT_TIMEOUT) ")"); + +struct meson_gxbb_wdt { + void __iomem *reg_base; + struct watchdog_device wdt_dev; + struct clk *clk; +}; + +static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev) +{ + struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); + + writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN, + data->reg_base + GXBB_WDT_CTRL_REG); + + return 0; +} + +static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev) +{ + struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); + + writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN, + data->reg_base + GXBB_WDT_CTRL_REG); + + return 0; +} + +static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev) +{ + struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); + + writel(0, data->reg_base + GXBB_WDT_RSET_REG); + + return 0; +} + +static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) +{ + struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); + unsigned long tcnt = timeout * 1000; + + if (tcnt > GXBB_WDT_TCNT_SETUP_MASK) + tcnt = GXBB_WDT_TCNT_SETUP_MASK; + + wdt_dev->timeout = timeout; + + meson_gxbb_wdt_ping(wdt_dev); + + writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG); + + return 0; +} + +static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev) +{ + struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev); + unsigned long reg; + + reg = readl(data->reg_base + GXBB_WDT_TCNT_REG); + + return ((reg & GXBB_WDT_TCNT_SETUP_MASK) - + (reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000; +} + +static const struct watchdog_ops meson_gxbb_wdt_ops = { + .start = meson_gxbb_wdt_start, + .stop = meson_gxbb_wdt_stop, + .ping = meson_gxbb_wdt_ping, + .set_timeout = meson_gxbb_wdt_set_timeout, + .get_timeleft = meson_gxbb_wdt_get_timeleft, +}; + +static const struct watchdog_info meson_gxbb_wdt_info = { + .identity = "Meson GXBB Watchdog", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, +}; + +static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev) +{ + struct meson_gxbb_wdt *data = dev_get_drvdata(dev); + + if (watchdog_active(&data->wdt_dev)) + meson_gxbb_wdt_start(&data->wdt_dev); + + return 0; +} + +static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev) +{ + struct meson_gxbb_wdt *data = dev_get_drvdata(dev); + + if (watchdog_active(&data->wdt_dev)) + meson_gxbb_wdt_stop(&data->wdt_dev); + + return 0; +} + +static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume) +}; + +static const struct of_device_id meson_gxbb_wdt_dt_ids[] = { + { .compatible = "amlogic,meson-gxbb-wdt", }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids); + +static void meson_clk_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +static int meson_gxbb_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct meson_gxbb_wdt *data; + int ret; + u32 ctrl_reg; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->reg_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(data->reg_base)) + return PTR_ERR(data->reg_base); + + data->clk = devm_clk_get(dev, NULL); + if (IS_ERR(data->clk)) + return PTR_ERR(data->clk); + + ret = clk_prepare_enable(data->clk); + if (ret) + return ret; + ret = devm_add_action_or_reset(dev, meson_clk_disable_unprepare, + data->clk); + if (ret) + return ret; + + platform_set_drvdata(pdev, data); + + data->wdt_dev.parent = dev; + data->wdt_dev.info = &meson_gxbb_wdt_info; + data->wdt_dev.ops = &meson_gxbb_wdt_ops; + data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK; + data->wdt_dev.min_timeout = 1; + data->wdt_dev.timeout = DEFAULT_TIMEOUT; + watchdog_init_timeout(&data->wdt_dev, timeout, dev); + watchdog_set_nowayout(&data->wdt_dev, nowayout); + watchdog_set_drvdata(&data->wdt_dev, data); + + ctrl_reg = readl(data->reg_base + GXBB_WDT_CTRL_REG) & + GXBB_WDT_CTRL_EN; + + if (ctrl_reg) { + /* Watchdog is running - keep it running but extend timeout + * to the maximum while setting the timebase + */ + set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status); + meson_gxbb_wdt_set_timeout(&data->wdt_dev, + GXBB_WDT_TCNT_SETUP_MASK / 1000); + } + + /* Setup with 1ms timebase */ + ctrl_reg |= ((clk_get_rate(data->clk) / 1000) & + GXBB_WDT_CTRL_DIV_MASK) | + GXBB_WDT_CTRL_EE_RESET | + GXBB_WDT_CTRL_CLK_EN | + GXBB_WDT_CTRL_CLKDIV_EN; + + writel(ctrl_reg, data->reg_base + GXBB_WDT_CTRL_REG); + meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout); + + return devm_watchdog_register_device(dev, &data->wdt_dev); +} + +static struct platform_driver meson_gxbb_wdt_driver = { + .probe = meson_gxbb_wdt_probe, + .driver = { + .name = "meson-gxbb-wdt", + .pm = &meson_gxbb_wdt_pm_ops, + .of_match_table = meson_gxbb_wdt_dt_ids, + }, +}; + +module_platform_driver(meson_gxbb_wdt_driver); + +MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); +MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver"); +MODULE_LICENSE("Dual BSD/GPL"); |