/*
* sunxi Watchdog Driver
*
* Copyright (c) 2013 Carlo Caione
* 2012 Henrik Nordstrom
*
* 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.
*
* Based on xen_wdt.c
* (c) Copyright 2010 Novell, Inc.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define WDT_MAX_TIMEOUT 16
#define WDT_MIN_TIMEOUT 1
#define WDT_TIMEOUT_MASK 0x0F
#define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1))
#define WDT_MODE_EN (1 << 0)
#define DRV_NAME "sunxi-wdt"
#define DRV_VERSION "1.0"
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int timeout = WDT_MAX_TIMEOUT;
/*
* This structure stores the register offsets for different variants
* of Allwinner's watchdog hardware.
*/
struct sunxi_wdt_reg {
u8 wdt_ctrl;
u8 wdt_cfg;
u8 wdt_mode;
u8 wdt_timeout_shift;
u8 wdt_reset_mask;
u8 wdt_reset_val;
};
struct sunxi_wdt_dev {
struct watchdog_device wdt_dev;
void __iomem *wdt_base;
const struct sunxi_wdt_reg *wdt_regs;
};
/*
* wdt_timeout_map maps the watchdog timer interval value in seconds to
* the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
*
* [timeout seconds] = register value
*
*/
static const int wdt_timeout_map[] = {
[1] = 0x1, /* 1s */
[2] = 0x2, /* 2s */
[3] = 0x3, /* 3s */
[4] = 0x4, /* 4s */
[5] = 0x5, /* 5s */
[6] = 0x6, /* 6s */
[8] = 0x7, /* 8s */
[10] = 0x8, /* 10s */
[12] = 0x9, /* 12s */
[14] = 0xA, /* 14s */
[16] = 0xB, /* 16s */
};
static int sunxi_wdt_restart(struct watchdog_device *wdt_dev,
unsigned long action, void *data)
{
struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = sunxi_wdt->wdt_base;
const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
u32 val;
/* Set system reset function */
val = readl(wdt_base + regs->wdt_cfg);
val &= ~(regs->wdt_reset_mask);
val |= regs->wdt_reset_val;
writel(val, wdt_base + regs->wdt_cfg);
/* Set lowest timeout and enable watchdog */
val = readl(wdt_base + regs->wdt_mode);
val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
val |= WDT_MODE_EN;
writel(val, wdt_base + regs->wdt_mode);
/*
* Restart the watchdog. The default (and lowest) interval
* value for the watchdog is 0.5s.
*/
writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
while (1) {
mdelay(5);
val = readl(wdt_base + regs->wdt_mode);
val |= WDT_MODE_EN;
writel(val, wdt_base + regs->wdt_mode);
}
return 0;
}
static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
{
struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = sunxi_wdt->wdt_base;
const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
return 0;
}
static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = sunxi_wdt->wdt_base;
const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
u32 reg;
if (wdt_timeout_map[timeout] == 0)
timeout++;
sunxi_wdt->wdt_dev.timeout = timeout;
reg = readl(wdt_base + regs->wdt_mode);
reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
writel(reg, wdt_base + regs->wdt_mode);
sunxi_wdt_ping(wdt_dev);
return 0;
}
static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
{
struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = sunxi_wdt->wdt_base;
const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
writel(0, wdt_base + regs->wdt_mode);
return 0;
}
static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
{
u32 reg;
struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base = sunxi_wdt->wdt_base;
const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
int ret;
ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
sunxi_wdt->wdt_dev.timeout);
if (ret < 0)
return ret;
/* Set system reset function */
reg = readl(wdt_base + regs->wdt_cfg);
reg &= ~(regs->wdt_reset_mask);
reg |= regs->wdt_reset_val;
writel(reg, wdt_base + regs->wdt_cfg);
/* Enable watchdog */
reg = readl(wdt_base + regs->wdt_mode);
reg |= WDT_MODE_EN;
writel(reg, wdt_base + regs->wdt_mode);
return 0;
}
static const struct watchdog_info sunxi_wdt_info = {
.identity = DRV_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops sunxi_wdt_ops = {
.owner = THIS_MODULE,
.start = sunxi_wdt_start,
.stop = sunxi_wdt_stop,
.ping = sunxi_wdt_ping,
.set_timeout = sunxi_wdt_set_timeout,
.restart = sunxi_wdt_restart,
};
static const struct sunxi_wdt_reg sun4i_wdt_reg = {
.wdt_ctrl = 0x00,
.wdt_cfg = 0x04,
.wdt_mode = 0x04,
.wdt_timeout_shift = 3,
.wdt_reset_mask = 0x02,
.wdt_reset_val = 0x02,
};
static const struct sunxi_wdt_reg sun6i_wdt_reg = {
.wdt_ctrl = 0x10,
.wdt_cfg = 0x14,
.wdt_mode = 0x18,
.wdt_timeout_shift = 4,
.wdt_reset_mask = 0x03,
.wdt_reset_val = 0x01,
};
static const struct of_device_id sunxi_wdt_dt_ids[] = {
{ .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
{ .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
static int sunxi_wdt_probe(struct platform_device *pdev)
{
struct sunxi_wdt_dev *sunxi_wdt;
const struct of_device_id *device;
struct resource *res;
int err;
sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
if (!sunxi_wdt)
return -EINVAL;
device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
if (!device)
return -ENODEV;
sunxi_wdt->wdt_regs = device->data;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(sunxi_wdt->wdt_base))
return PTR_ERR(sunxi_wdt->wdt_base);
sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
sunxi_wdt->wdt_dev.parent = &pdev->dev;
watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128);
watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
watchdog_stop_on_reboot(&sunxi_wdt->wdt_dev);
err = devm_watchdog_register_device(&pdev->dev, &sunxi_wdt->wdt_dev);
if (unlikely(err))
return err;
dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
sunxi_wdt->wdt_dev.timeout, nowayout);
return 0;
}
static struct platform_driver sunxi_wdt_driver = {
.probe = sunxi_wdt_probe,
.driver = {
.name = DRV_NAME,
.of_match_table = sunxi_wdt_dt_ids,
},
};
module_platform_driver(sunxi_wdt_driver);
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
MODULE_VERSION(DRV_VERSION);
