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Release 4.14 drivers/watchdog/uniphier_wdt.c

Directory: drivers/watchdog
/*
 * 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; }

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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; }

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static int __uniphier_watchdog_stop(struct regmap *regmap) { /* Disable and stop watchdog */ return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0); }

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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); }

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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); }

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static int uniphier_watchdog_stop(struct watchdog_device *w) { struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); return __uniphier_watchdog_stop(wdev->regmap); }

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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; }

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/* * 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; }

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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");

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Directory: drivers/watchdog
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