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/*
* Copyright 2015 IBM Corp.
*
* Joel Stanley <joel@jms.id.au>
*
* Based on the qcom-watchdog driver
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/io.h>
struct aspeed_wdt {
struct watchdog_device wdd;
struct clk *clk;
unsigned long rate;
struct notifier_block restart_nb;
void __iomem *base;
};
static const struct of_device_id aspeed_wdt_of_table[] = {
{ .compatible = "aspeed,wdt", },
{ },
};
MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
#define WDT_STATUS 0x00
#define WDT_RELOAD_VALUE 0x04
#define WDT_RESTART 0x08
#define WDT_CTRL 0x0C
#define WDT_CTRL_RESET_MODE_SOC (0x00 << 5)
#define WDT_CTRL_RESET_MODE_FULL_CHIP (0x01 << 5)
#define WDT_CTRL_RESET_SYSTEM (0x1 << 1)
#define WDT_CTRL_ENABLE (0x1 << 0)
#define WDT_RESTART_MAGIC 0x4755
static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
{
u32 ctrl = WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM |
WDT_CTRL_ENABLE;
writel(0, wdt->base + WDT_CTRL);
writel(count, wdt->base + WDT_RELOAD_VALUE);
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
writel(ctrl, wdt->base + WDT_CTRL);
}
static int aspeed_wdt_start(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = container_of(wdd, struct aspeed_wdt, wdd);
dev_dbg(wdd->dev, "starting with timeout of %d (rate %lu)\n",
wdd->timeout, wdt->rate);
aspeed_wdt_enable(wdt, wdd->timeout * wdt->rate);
return 0;
}
static int aspeed_wdt_stop(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = container_of(wdd, struct aspeed_wdt, wdd);
writel(0, wdt->base + WDT_CTRL);
return 0;
}
static int aspeed_wdt_ping(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = container_of(wdd, struct aspeed_wdt, wdd);
dev_dbg(wdd->dev, "ping\n");
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
return 0;
}
static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
dev_dbg(wdd->dev, "timeout set to %u\n", timeout);
wdd->timeout = timeout;
return aspeed_wdt_start(wdd);
}
static int aspeed_wdt_restart(struct notifier_block *nb, unsigned long action,
void *data)
{
struct aspeed_wdt *wdt = container_of(nb,
struct aspeed_wdt, restart_nb);
/*
* Trigger watchdog bite:
* Setup reload count to be 128ms, and enable WDT.
*/
aspeed_wdt_enable(wdt, 128 * wdt->rate / 1000);
return NOTIFY_DONE;
}
static const struct watchdog_ops aspeed_wdt_ops = {
.start = aspeed_wdt_start,
.stop = aspeed_wdt_stop,
.ping = aspeed_wdt_ping,
.set_timeout = aspeed_wdt_set_timeout,
.owner = THIS_MODULE,
};
static const struct watchdog_info aspeed_wdt_info = {
.options = WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
| WDIOF_SETTIMEOUT,
.identity = KBUILD_MODNAME,
};
static int aspeed_wdt_remove(struct platform_device *pdev)
{
struct aspeed_wdt *wdt = platform_get_drvdata(pdev);
unregister_restart_handler(&wdt->restart_nb);
watchdog_unregister_device(&wdt->wdd);
clk_disable_unprepare(wdt->clk);
return 0;
}
static int aspeed_wdt_probe(struct platform_device *pdev)
{
struct aspeed_wdt *wdt;
struct resource *res;
int ret;
wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
wdt->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(wdt->clk)) {
dev_err(&pdev->dev, "failed to get input clock\n");
return PTR_ERR(wdt->clk);
}
ret = clk_prepare_enable(wdt->clk);
if (ret) {
dev_err(&pdev->dev, "failed to setup clock\n");
goto err;
}
/*
* We use the clock rate to calculate the max timeout, so ensure it's
* not zero to avoid a divide-by-zero exception.
*
* WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
* that it would bite before a second elapses it's usefulness is
* limited. Bail if this is the case.
*/
wdt->rate = clk_get_rate(wdt->clk);
if (wdt->rate == 0 ||
wdt->rate > 0x10000000U) {
dev_err(&pdev->dev, "invalid clock rate\n");
ret = -EINVAL;
goto err;
}
wdt->wdd.dev = &pdev->dev;
wdt->wdd.info = &aspeed_wdt_info;
wdt->wdd.ops = &aspeed_wdt_ops;
wdt->wdd.min_timeout = 1;
wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
/*
* If 'timeout-sec' unspecified in devicetree, assume a 30 second
* default, unless the max timeout is less than 30 seconds, then use
* the max instead.
*/
wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
ret = watchdog_register_device(&wdt->wdd);
if (ret) {
dev_err(&pdev->dev, "failed to register\n");
goto err;
}
/*
* WDT restart notifier has priority 0 (use as a last resort)
*/
wdt->restart_nb.notifier_call = aspeed_wdt_restart;
ret = register_restart_handler(&wdt->restart_nb);
if (ret)
dev_err(&pdev->dev, "failed to setup restart handler\n");
dev_info(&pdev->dev, "rate %lu, max timeout %u, timeout %d\n",
wdt->rate, wdt->wdd.max_timeout, wdt->wdd.timeout);
platform_set_drvdata(pdev, wdt);
return 0;
err:
clk_disable_unprepare(wdt->clk);
return ret;
}
static struct platform_driver aspeed_watchdog_driver = {
.probe = aspeed_wdt_probe,
.remove = aspeed_wdt_remove,
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = of_match_ptr(aspeed_wdt_of_table),
},
};
module_platform_driver(aspeed_watchdog_driver);
MODULE_DESCRIPTION("Aspeed AST23/4xx Watchdog Driver");
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