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ea104a9e4d
The restart handler is missing two things, first, the registers
has to be unlocked and second there is no synchronization for the
write_relaxed() calls.
This was tested on a custom board with the NXP LS1028A SoC.
Fixes: 6c5c0d48b6
("watchdog: sp805: add restart handler")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200327162450.28506-1-michael@walle.cc
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
365 lines
8.7 KiB
C
365 lines
8.7 KiB
C
/*
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* drivers/char/watchdog/sp805-wdt.c
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*
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* Watchdog driver for ARM SP805 watchdog module
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*
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* Copyright (C) 2010 ST Microelectronics
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* Viresh Kumar <vireshk@kernel.org>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2 or later. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/acpi.h>
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#include <linux/device.h>
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#include <linux/resource.h>
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#include <linux/amba/bus.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/math64.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/of.h>
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#include <linux/pm.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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/* default timeout in seconds */
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#define DEFAULT_TIMEOUT 60
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#define MODULE_NAME "sp805-wdt"
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/* watchdog register offsets and masks */
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#define WDTLOAD 0x000
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#define LOAD_MIN 0x00000001
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#define LOAD_MAX 0xFFFFFFFF
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#define WDTVALUE 0x004
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#define WDTCONTROL 0x008
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/* control register masks */
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#define INT_ENABLE (1 << 0)
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#define RESET_ENABLE (1 << 1)
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#define ENABLE_MASK (INT_ENABLE | RESET_ENABLE)
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#define WDTINTCLR 0x00C
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#define WDTRIS 0x010
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#define WDTMIS 0x014
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#define INT_MASK (1 << 0)
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#define WDTLOCK 0xC00
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#define UNLOCK 0x1ACCE551
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#define LOCK 0x00000001
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/**
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* struct sp805_wdt: sp805 wdt device structure
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* @wdd: instance of struct watchdog_device
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* @lock: spin lock protecting dev structure and io access
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* @base: base address of wdt
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* @clk: clock structure of wdt
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* @adev: amba device structure of wdt
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* @status: current status of wdt
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* @load_val: load value to be set for current timeout
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*/
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struct sp805_wdt {
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struct watchdog_device wdd;
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spinlock_t lock;
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void __iomem *base;
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struct clk *clk;
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u64 rate;
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struct amba_device *adev;
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unsigned int load_val;
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};
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Set to 1 to keep watchdog running after device release");
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/* returns true if wdt is running; otherwise returns false */
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static bool wdt_is_running(struct watchdog_device *wdd)
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{
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struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
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u32 wdtcontrol = readl_relaxed(wdt->base + WDTCONTROL);
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return (wdtcontrol & ENABLE_MASK) == ENABLE_MASK;
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}
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/* This routine finds load value that will reset system in required timout */
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static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
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{
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struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
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u64 load, rate;
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rate = wdt->rate;
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/*
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* sp805 runs counter with given value twice, after the end of first
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* counter it gives an interrupt and then starts counter again. If
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* interrupt already occurred then it resets the system. This is why
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* load is half of what should be required.
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*/
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load = div_u64(rate, 2) * timeout - 1;
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load = (load > LOAD_MAX) ? LOAD_MAX : load;
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load = (load < LOAD_MIN) ? LOAD_MIN : load;
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spin_lock(&wdt->lock);
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wdt->load_val = load;
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/* roundup timeout to closest positive integer value */
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wdd->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
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spin_unlock(&wdt->lock);
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return 0;
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}
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/* returns number of seconds left for reset to occur */
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static unsigned int wdt_timeleft(struct watchdog_device *wdd)
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{
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struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
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u64 load;
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spin_lock(&wdt->lock);
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load = readl_relaxed(wdt->base + WDTVALUE);
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/*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
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if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
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load += wdt->load_val + 1;
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spin_unlock(&wdt->lock);
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return div_u64(load, wdt->rate);
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}
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static int
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wdt_restart(struct watchdog_device *wdd, unsigned long mode, void *cmd)
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{
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struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
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writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
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writel_relaxed(0, wdt->base + WDTCONTROL);
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writel_relaxed(0, wdt->base + WDTLOAD);
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writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
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/* Flush posted writes. */
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readl_relaxed(wdt->base + WDTLOCK);
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return 0;
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}
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static int wdt_config(struct watchdog_device *wdd, bool ping)
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{
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struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
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int ret;
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if (!ping) {
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ret = clk_prepare_enable(wdt->clk);
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if (ret) {
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dev_err(&wdt->adev->dev, "clock enable fail");
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return ret;
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}
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}
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spin_lock(&wdt->lock);
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writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
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writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
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writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
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if (!ping)
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writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
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WDTCONTROL);
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writel_relaxed(LOCK, wdt->base + WDTLOCK);
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/* Flush posted writes. */
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readl_relaxed(wdt->base + WDTLOCK);
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spin_unlock(&wdt->lock);
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return 0;
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}
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static int wdt_ping(struct watchdog_device *wdd)
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{
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return wdt_config(wdd, true);
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}
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/* enables watchdog timers reset */
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static int wdt_enable(struct watchdog_device *wdd)
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{
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return wdt_config(wdd, false);
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}
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/* disables watchdog timers reset */
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static int wdt_disable(struct watchdog_device *wdd)
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{
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struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
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spin_lock(&wdt->lock);
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writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
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writel_relaxed(0, wdt->base + WDTCONTROL);
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writel_relaxed(LOCK, wdt->base + WDTLOCK);
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/* Flush posted writes. */
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readl_relaxed(wdt->base + WDTLOCK);
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spin_unlock(&wdt->lock);
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clk_disable_unprepare(wdt->clk);
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return 0;
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}
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static const struct watchdog_info wdt_info = {
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.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
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.identity = MODULE_NAME,
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};
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static const struct watchdog_ops wdt_ops = {
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.owner = THIS_MODULE,
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.start = wdt_enable,
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.stop = wdt_disable,
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.ping = wdt_ping,
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.set_timeout = wdt_setload,
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.get_timeleft = wdt_timeleft,
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.restart = wdt_restart,
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};
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static int
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sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
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{
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struct sp805_wdt *wdt;
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int ret = 0;
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wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
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if (!wdt) {
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ret = -ENOMEM;
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goto err;
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}
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wdt->base = devm_ioremap_resource(&adev->dev, &adev->res);
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if (IS_ERR(wdt->base))
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return PTR_ERR(wdt->base);
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if (adev->dev.of_node) {
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wdt->clk = devm_clk_get(&adev->dev, NULL);
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if (IS_ERR(wdt->clk)) {
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dev_err(&adev->dev, "Clock not found\n");
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return PTR_ERR(wdt->clk);
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}
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wdt->rate = clk_get_rate(wdt->clk);
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} else if (has_acpi_companion(&adev->dev)) {
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/*
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* When Driver probe with ACPI device, clock devices
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* are not available, so watchdog rate get from
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* clock-frequency property given in _DSD object.
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*/
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device_property_read_u64(&adev->dev, "clock-frequency",
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&wdt->rate);
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if (!wdt->rate) {
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dev_err(&adev->dev, "no clock-frequency property\n");
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return -ENODEV;
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}
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}
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wdt->adev = adev;
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wdt->wdd.info = &wdt_info;
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wdt->wdd.ops = &wdt_ops;
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wdt->wdd.parent = &adev->dev;
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spin_lock_init(&wdt->lock);
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watchdog_set_nowayout(&wdt->wdd, nowayout);
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watchdog_set_drvdata(&wdt->wdd, wdt);
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watchdog_set_restart_priority(&wdt->wdd, 128);
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/*
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* If 'timeout-sec' devicetree property is specified, use that.
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* Otherwise, use DEFAULT_TIMEOUT
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*/
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wdt->wdd.timeout = DEFAULT_TIMEOUT;
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watchdog_init_timeout(&wdt->wdd, 0, &adev->dev);
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wdt_setload(&wdt->wdd, wdt->wdd.timeout);
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/*
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* If HW is already running, enable/reset the wdt and set the running
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* bit to tell the wdt subsystem
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*/
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if (wdt_is_running(&wdt->wdd)) {
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wdt_enable(&wdt->wdd);
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set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
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}
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ret = watchdog_register_device(&wdt->wdd);
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if (ret)
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goto err;
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amba_set_drvdata(adev, wdt);
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dev_info(&adev->dev, "registration successful\n");
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return 0;
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err:
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dev_err(&adev->dev, "Probe Failed!!!\n");
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return ret;
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}
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static int sp805_wdt_remove(struct amba_device *adev)
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{
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struct sp805_wdt *wdt = amba_get_drvdata(adev);
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watchdog_unregister_device(&wdt->wdd);
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watchdog_set_drvdata(&wdt->wdd, NULL);
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return 0;
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}
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static int __maybe_unused sp805_wdt_suspend(struct device *dev)
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{
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struct sp805_wdt *wdt = dev_get_drvdata(dev);
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if (watchdog_active(&wdt->wdd))
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return wdt_disable(&wdt->wdd);
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return 0;
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}
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static int __maybe_unused sp805_wdt_resume(struct device *dev)
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{
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struct sp805_wdt *wdt = dev_get_drvdata(dev);
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if (watchdog_active(&wdt->wdd))
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return wdt_enable(&wdt->wdd);
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return 0;
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}
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static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
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sp805_wdt_resume);
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static const struct amba_id sp805_wdt_ids[] = {
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{
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.id = 0x00141805,
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.mask = 0x00ffffff,
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},
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{ 0, 0 },
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};
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MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
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static struct amba_driver sp805_wdt_driver = {
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.drv = {
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.name = MODULE_NAME,
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.pm = &sp805_wdt_dev_pm_ops,
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},
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.id_table = sp805_wdt_ids,
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.probe = sp805_wdt_probe,
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.remove = sp805_wdt_remove,
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};
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module_amba_driver(sp805_wdt_driver);
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MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
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MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
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MODULE_LICENSE("GPL");
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