diff options
Diffstat (limited to 'drivers/watchdog/uniphier_wdt.c')
| -rw-r--r-- | drivers/watchdog/uniphier_wdt.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/watchdog/uniphier_wdt.c b/drivers/watchdog/uniphier_wdt.c new file mode 100644 index 000000000000..0ea2339d9702 --- /dev/null +++ b/drivers/watchdog/uniphier_wdt.c @@ -0,0 +1,268 @@ +/* + * Watchdog driver for the UniPhier watchdog timer + * + * (c) Copyright 2014 Panasonic Corporation + * (c) Copyright 2016 Socionext Inc. + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/bitops.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/watchdog.h> + +/* WDT timer setting register */ +#define WDTTIMSET 0x3004 +#define WDTTIMSET_PERIOD_MASK (0xf << 0) +#define WDTTIMSET_PERIOD_1_SEC (0x3 << 0) + +/* WDT reset selection register */ +#define WDTRSTSEL 0x3008 +#define WDTRSTSEL_RSTSEL_MASK (0x3 << 0) +#define WDTRSTSEL_RSTSEL_BOTH (0x0 << 0) +#define WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0) + +/* WDT control register */ +#define WDTCTRL 0x300c +#define WDTCTRL_STATUS BIT(8) +#define WDTCTRL_CLEAR BIT(1) +#define WDTCTRL_ENABLE BIT(0) + +#define SEC_TO_WDTTIMSET_PRD(sec) \ + (ilog2(sec) + WDTTIMSET_PERIOD_1_SEC) + +#define WDTST_TIMEOUT 1000 /* usec */ + +#define WDT_DEFAULT_TIMEOUT 64 /* Default is 64 seconds */ +#define WDT_PERIOD_MIN 1 +#define WDT_PERIOD_MAX 128 + +static unsigned int timeout = 0; +static bool nowayout = WATCHDOG_NOWAYOUT; + +struct uniphier_wdt_dev { + struct watchdog_device wdt_dev; + struct regmap *regmap; +}; + +/* + * UniPhier Watchdog operations + */ +static int uniphier_watchdog_ping(struct watchdog_device *w) +{ + struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); + unsigned int val; + int ret; + + /* Clear counter */ + ret = regmap_write_bits(wdev->regmap, WDTCTRL, + WDTCTRL_CLEAR, WDTCTRL_CLEAR); + if (!ret) + /* + * As SoC specification, after clear counter, + * it needs to wait until counter status is 1. + */ + ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val, + (val & WDTCTRL_STATUS), + 0, WDTST_TIMEOUT); + + return ret; +} + +static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec) +{ + unsigned int val; + int ret; + + ret = regmap_read_poll_timeout(regmap, WDTCTRL, val, + !(val & WDTCTRL_STATUS), + 0, WDTST_TIMEOUT); + if (ret) + return ret; + + /* Setup period */ + ret = regmap_write(regmap, WDTTIMSET, + SEC_TO_WDTTIMSET_PRD(sec)); + if (ret) + return ret; + + /* Enable and clear watchdog */ + ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR); + if (!ret) + /* + * As SoC specification, after clear counter, + * it needs to wait until counter status is 1. + */ + ret = regmap_read_poll_timeout(regmap, WDTCTRL, val, + (val & WDTCTRL_STATUS), + 0, WDTST_TIMEOUT); + + return ret; +} + +static int __uniphier_watchdog_stop(struct regmap *regmap) +{ + /* Disable and stop watchdog */ + return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0); +} + +static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec) +{ + int ret; + + ret = __uniphier_watchdog_stop(regmap); + if (ret) + return ret; + + return __uniphier_watchdog_start(regmap, sec); +} + +static int uniphier_watchdog_start(struct watchdog_device *w) +{ + struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); + unsigned int tmp_timeout; + + tmp_timeout = roundup_pow_of_two(w->timeout); + + return __uniphier_watchdog_start(wdev->regmap, tmp_timeout); +} + +static int uniphier_watchdog_stop(struct watchdog_device *w) +{ + struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); + + return __uniphier_watchdog_stop(wdev->regmap); +} + +static int uniphier_watchdog_set_timeout(struct watchdog_device *w, + unsigned int t) +{ + struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); + unsigned int tmp_timeout; + int ret; + + tmp_timeout = roundup_pow_of_two(t); + if (tmp_timeout == w->timeout) + return 0; + + if (watchdog_active(w)) { + ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout); + if (ret) + return ret; + } + + w->timeout = tmp_timeout; + + return 0; +} + +/* + * Kernel Interfaces + */ +static const struct watchdog_info uniphier_wdt_info = { + .identity = "uniphier-wdt", + .options = WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE | + WDIOF_OVERHEAT, +}; + +static const struct watchdog_ops uniphier_wdt_ops = { + .owner = THIS_MODULE, + .start = uniphier_watchdog_start, + .stop = uniphier_watchdog_stop, + .ping = uniphier_watchdog_ping, + .set_timeout = uniphier_watchdog_set_timeout, +}; + +static int uniphier_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct uniphier_wdt_dev *wdev; + struct regmap *regmap; + struct device_node *parent; + int ret; + + wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL); + if (!wdev) + return -ENOMEM; + + platform_set_drvdata(pdev, wdev); + + parent = of_get_parent(dev->of_node); /* parent should be syscon node */ + regmap = syscon_node_to_regmap(parent); + of_node_put(parent); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + wdev->regmap = regmap; + wdev->wdt_dev.info = &uniphier_wdt_info; + wdev->wdt_dev.ops = &uniphier_wdt_ops; + wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX; + wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN; + wdev->wdt_dev.parent = dev; + + if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) { + wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT; + } + watchdog_set_nowayout(&wdev->wdt_dev, nowayout); + watchdog_stop_on_reboot(&wdev->wdt_dev); + + watchdog_set_drvdata(&wdev->wdt_dev, wdev); + + uniphier_watchdog_stop(&wdev->wdt_dev); + ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH); + if (ret) + return ret; + + ret = devm_watchdog_register_device(dev, &wdev->wdt_dev); + if (ret) + return ret; + + dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n", + wdev->wdt_dev.timeout, nowayout); + + return 0; +} + +static const struct of_device_id uniphier_wdt_dt_ids[] = { + { .compatible = "socionext,uniphier-wdt" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids); + +static struct platform_driver uniphier_wdt_driver = { + .probe = uniphier_wdt_probe, + .driver = { + .name = "uniphier-wdt", + .of_match_table = uniphier_wdt_dt_ids, + }, +}; + +module_platform_driver(uniphier_wdt_driver); + +module_param(timeout, uint, 0000); +MODULE_PARM_DESC(timeout, + "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default=" + __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")"); + +module_param(nowayout, bool, 0000); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>"); +MODULE_DESCRIPTION("UniPhier Watchdog Device Driver"); +MODULE_LICENSE("GPL v2"); |