/*
* Copyright 2016 IBM Corporation
*
* Joel Stanley <joel@jms.id.au>
*
* 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/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
struct aspeed_wdt {
struct watchdog_device wdd;
void __iomem *base;
u32 ctrl;
};
static const struct of_device_id aspeed_wdt_of_table[] = {
{ .compatible = "aspeed,ast2400-wdt" },
{ .compatible = "aspeed,ast2500-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_1MHZ_CLK BIT(4)
#define WDT_CTRL_WDT_EXT BIT(3)
#define WDT_CTRL_WDT_INTR BIT(2)
#define WDT_CTRL_RESET_SYSTEM BIT(1)
#define WDT_CTRL_ENABLE BIT(0)
#define WDT_RESTART_MAGIC 0x4755
/* 32 bits at 1MHz, in milliseconds */
#define WDT_MAX_TIMEOUT_MS 4294967
#define WDT_DEFAULT_TIMEOUT 30
#define WDT_RATE_1MHZ 1000000
static struct aspeed_wdt *to_aspeed_wdt(struct watchdog_device *wdd)
{
return container_of(wdd, struct aspeed_wdt, wdd);
}
static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
{
wdt->ctrl |= 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(wdt->ctrl, wdt->base + WDT_CTRL);
}
static int aspeed_wdt_start(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
aspeed_wdt_enable(wdt, wdd->timeout * WDT_RATE_1MHZ);
return 0;
}
static int aspeed_wdt_stop(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
wdt->ctrl &= ~WDT_CTRL_ENABLE;
writel(wdt->ctrl, wdt->base + WDT_CTRL);
return 0;
}
static int aspeed_wdt_ping(struct watchdog_device *wdd)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
return 0;
}
static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
u32 actual;
wdd->timeout = timeout;
actual = min(timeout, wdd->max_hw_heartbeat_ms * 1000);
writel(actual * WDT_RATE_1MHZ, wdt->base + WDT_RELOAD_VALUE);
writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
return 0;
}
static int aspeed_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
aspeed_wdt_enable(wdt, 128 * WDT_RATE_1MHZ / 1000);
mdelay(1000);
return 0;
}
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,
.restart = aspeed_wdt_restart,
.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);
watchdog_unregister_device(&wdt->wdd);
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);
/*
* The ast2400 wdt can run at PCLK, or 1MHz. The ast2500 only
* runs at 1MHz. We chose to always run at 1MHz, as there's no
* good reason to have a faster watchdog counter.
*/
wdt->wdd.info = &aspeed_wdt_info;
wdt->wdd.ops = &aspeed_wdt_ops;
wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
wdt->wdd.parent = &pdev->dev;
wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
/*
* Control reset on a per-device basis to ensure the
* host is not affected by a BMC reboot, so only reset
* the SOC and not the full chip
*/
wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
WDT_CTRL_1MHZ_CLK |
WDT_CTRL_RESET_SYSTEM;
if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE) {
aspeed_wdt_start(&wdt->wdd);
set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
}
ret = watchdog_register_device(&wdt->wdd);
if (ret) {
dev_err(&pdev->dev, "failed to register\n");
return ret;
}
platform_set_drvdata(pdev, wdt);
return 0;
}
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 Watchdog Driver");
MODULE_LICENSE("GPL");
