linux/drivers/watchdog/davinci_wdt.c
Guenter Roeck cecda01051 watchdog: davinci_wdt: Convert to use device managed functions and other improvements
Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.
Other improvements as listed below.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Drop assignments to otherwise unused variables
- Drop unnecessary braces around conditional return statements
- Drop empty remove function
- Use devm_add_action_or_reset() for calls to clk_disable_unprepare
- Use local variable 'struct device *dev' consistently
- Use devm_watchdog_register_driver() to register watchdog device

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:18 +02:00

286 lines
7.6 KiB
C

/*
* drivers/char/watchdog/davinci_wdt.c
*
* Watchdog driver for DaVinci DM644x/DM646x processors
*
* Copyright (C) 2006-2013 Texas Instruments.
*
* 2007 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mod_devicetable.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/err.h>
#define MODULE_NAME "DAVINCI-WDT: "
#define DEFAULT_HEARTBEAT 60
#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/
/* Timer register set definition */
#define PID12 (0x0)
#define EMUMGT (0x4)
#define TIM12 (0x10)
#define TIM34 (0x14)
#define PRD12 (0x18)
#define PRD34 (0x1C)
#define TCR (0x20)
#define TGCR (0x24)
#define WDTCR (0x28)
/* TCR bit definitions */
#define ENAMODE12_DISABLED (0 << 6)
#define ENAMODE12_ONESHOT (1 << 6)
#define ENAMODE12_PERIODIC (2 << 6)
/* TGCR bit definitions */
#define TIM12RS_UNRESET (1 << 0)
#define TIM34RS_UNRESET (1 << 1)
#define TIMMODE_64BIT_WDOG (2 << 2)
/* WDTCR bit definitions */
#define WDEN (1 << 14)
#define WDFLAG (1 << 15)
#define WDKEY_SEQ0 (0xa5c6 << 16)
#define WDKEY_SEQ1 (0xda7e << 16)
static int heartbeat;
/*
* struct to hold data for each WDT device
* @base - base io address of WD device
* @clk - source clock of WDT
* @wdd - hold watchdog device as is in WDT core
*/
struct davinci_wdt_device {
void __iomem *base;
struct clk *clk;
struct watchdog_device wdd;
};
static int davinci_wdt_start(struct watchdog_device *wdd)
{
u32 tgcr;
u32 timer_margin;
unsigned long wdt_freq;
struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
wdt_freq = clk_get_rate(davinci_wdt->clk);
/* disable, internal clock source */
iowrite32(0, davinci_wdt->base + TCR);
/* reset timer, set mode to 64-bit watchdog, and unreset */
iowrite32(0, davinci_wdt->base + TGCR);
tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
iowrite32(tgcr, davinci_wdt->base + TGCR);
/* clear counter regs */
iowrite32(0, davinci_wdt->base + TIM12);
iowrite32(0, davinci_wdt->base + TIM34);
/* set timeout period */
timer_margin = (((u64)wdd->timeout * wdt_freq) & 0xffffffff);
iowrite32(timer_margin, davinci_wdt->base + PRD12);
timer_margin = (((u64)wdd->timeout * wdt_freq) >> 32);
iowrite32(timer_margin, davinci_wdt->base + PRD34);
/* enable run continuously */
iowrite32(ENAMODE12_PERIODIC, davinci_wdt->base + TCR);
/* Once the WDT is in pre-active state write to
* TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
* write protected (except for the WDKEY field)
*/
/* put watchdog in pre-active state */
iowrite32(WDKEY_SEQ0 | WDEN, davinci_wdt->base + WDTCR);
/* put watchdog in active state */
iowrite32(WDKEY_SEQ1 | WDEN, davinci_wdt->base + WDTCR);
return 0;
}
static int davinci_wdt_ping(struct watchdog_device *wdd)
{
struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
/* put watchdog in service state */
iowrite32(WDKEY_SEQ0, davinci_wdt->base + WDTCR);
/* put watchdog in active state */
iowrite32(WDKEY_SEQ1, davinci_wdt->base + WDTCR);
return 0;
}
static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd)
{
u64 timer_counter;
unsigned long freq;
u32 val;
struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
/* if timeout has occured then return 0 */
val = ioread32(davinci_wdt->base + WDTCR);
if (val & WDFLAG)
return 0;
freq = clk_get_rate(davinci_wdt->clk);
if (!freq)
return 0;
timer_counter = ioread32(davinci_wdt->base + TIM12);
timer_counter |= ((u64)ioread32(davinci_wdt->base + TIM34) << 32);
do_div(timer_counter, freq);
return wdd->timeout - timer_counter;
}
static int davinci_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
u32 tgcr, wdtcr;
/* disable, internal clock source */
iowrite32(0, davinci_wdt->base + TCR);
/* reset timer, set mode to 64-bit watchdog, and unreset */
tgcr = 0;
iowrite32(tgcr, davinci_wdt->base + TGCR);
tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
iowrite32(tgcr, davinci_wdt->base + TGCR);
/* clear counter and period regs */
iowrite32(0, davinci_wdt->base + TIM12);
iowrite32(0, davinci_wdt->base + TIM34);
iowrite32(0, davinci_wdt->base + PRD12);
iowrite32(0, davinci_wdt->base + PRD34);
/* put watchdog in pre-active state */
wdtcr = WDKEY_SEQ0 | WDEN;
iowrite32(wdtcr, davinci_wdt->base + WDTCR);
/* put watchdog in active state */
wdtcr = WDKEY_SEQ1 | WDEN;
iowrite32(wdtcr, davinci_wdt->base + WDTCR);
/* write an invalid value to the WDKEY field to trigger a restart */
wdtcr = 0x00004000;
iowrite32(wdtcr, davinci_wdt->base + WDTCR);
return 0;
}
static const struct watchdog_info davinci_wdt_info = {
.options = WDIOF_KEEPALIVEPING,
.identity = "DaVinci/Keystone Watchdog",
};
static const struct watchdog_ops davinci_wdt_ops = {
.owner = THIS_MODULE,
.start = davinci_wdt_start,
.stop = davinci_wdt_ping,
.ping = davinci_wdt_ping,
.get_timeleft = davinci_wdt_get_timeleft,
.restart = davinci_wdt_restart,
};
static void davinci_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int davinci_wdt_probe(struct platform_device *pdev)
{
int ret = 0;
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
struct davinci_wdt_device *davinci_wdt;
davinci_wdt = devm_kzalloc(dev, sizeof(*davinci_wdt), GFP_KERNEL);
if (!davinci_wdt)
return -ENOMEM;
davinci_wdt->clk = devm_clk_get(dev, NULL);
if (IS_ERR(davinci_wdt->clk)) {
if (PTR_ERR(davinci_wdt->clk) != -EPROBE_DEFER)
dev_err(dev, "failed to get clock node\n");
return PTR_ERR(davinci_wdt->clk);
}
ret = clk_prepare_enable(davinci_wdt->clk);
if (ret) {
dev_err(dev, "failed to prepare clock\n");
return ret;
}
ret = devm_add_action_or_reset(dev, davinci_clk_disable_unprepare,
davinci_wdt->clk);
if (ret)
return ret;
platform_set_drvdata(pdev, davinci_wdt);
wdd = &davinci_wdt->wdd;
wdd->info = &davinci_wdt_info;
wdd->ops = &davinci_wdt_ops;
wdd->min_timeout = 1;
wdd->max_timeout = MAX_HEARTBEAT;
wdd->timeout = DEFAULT_HEARTBEAT;
wdd->parent = dev;
watchdog_init_timeout(wdd, heartbeat, dev);
dev_info(dev, "heartbeat %d sec\n", wdd->timeout);
watchdog_set_drvdata(wdd, davinci_wdt);
watchdog_set_nowayout(wdd, 1);
watchdog_set_restart_priority(wdd, 128);
davinci_wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(davinci_wdt->base))
return PTR_ERR(davinci_wdt->base);
ret = devm_watchdog_register_device(dev, wdd);
if (ret) {
dev_err(dev, "cannot register watchdog device\n");
return ret;
}
return 0;
}
static const struct of_device_id davinci_wdt_of_match[] = {
{ .compatible = "ti,davinci-wdt", },
{},
};
MODULE_DEVICE_TABLE(of, davinci_wdt_of_match);
static struct platform_driver platform_wdt_driver = {
.driver = {
.name = "davinci-wdt",
.of_match_table = davinci_wdt_of_match,
},
.probe = davinci_wdt_probe,
};
module_platform_driver(platform_wdt_driver);
MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("DaVinci Watchdog Driver");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:davinci-wdt");