linux/drivers/watchdog/bcm_kona_wdt.c
Uwe Kleine-König 0eddace462 watchdog: bcm_kona: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230303213716.2123717-10-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-04-22 12:53:43 +02:00

340 lines
8.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 Broadcom Corporation
*
*/
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define SECWDOG_CTRL_REG 0x00000000
#define SECWDOG_COUNT_REG 0x00000004
#define SECWDOG_RESERVED_MASK 0x1dffffff
#define SECWDOG_WD_LOAD_FLAG 0x10000000
#define SECWDOG_EN_MASK 0x08000000
#define SECWDOG_SRSTEN_MASK 0x04000000
#define SECWDOG_RES_MASK 0x00f00000
#define SECWDOG_COUNT_MASK 0x000fffff
#define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK
#define SECWDOG_CLKS_SHIFT 20
#define SECWDOG_MAX_RES 15
#define SECWDOG_DEFAULT_RESOLUTION 4
#define SECWDOG_MAX_TRY 1000
#define SECS_TO_TICKS(x, w) ((x) << (w)->resolution)
#define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution)
#define BCM_KONA_WDT_NAME "bcm_kona_wdt"
struct bcm_kona_wdt {
void __iomem *base;
/*
* One watchdog tick is 1/(2^resolution) seconds. Resolution can take
* the values 0-15, meaning one tick can be 1s to 30.52us. Our default
* resolution of 4 means one tick is 62.5ms.
*
* The watchdog counter is 20 bits. Depending on resolution, the maximum
* counter value of 0xfffff expires after about 12 days (resolution 0)
* down to only 32s (resolution 15). The default resolution of 4 gives
* us a maximum of about 18 hours and 12 minutes before the watchdog
* times out.
*/
int resolution;
spinlock_t lock;
#ifdef CONFIG_BCM_KONA_WDT_DEBUG
unsigned long busy_count;
struct dentry *debugfs;
#endif
};
static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
{
uint32_t val;
unsigned count = 0;
/*
* If the WD_LOAD_FLAG is set, the watchdog counter field is being
* updated in hardware. Once the WD timer is updated in hardware, it
* gets cleared.
*/
do {
if (unlikely(count > 1))
udelay(5);
val = readl_relaxed(wdt->base + offset);
count++;
} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
#ifdef CONFIG_BCM_KONA_WDT_DEBUG
/* Remember the maximum number iterations due to WD_LOAD_FLAG */
if (count > wdt->busy_count)
wdt->busy_count = count;
#endif
/* This is the only place we return a negative value. */
if (val & SECWDOG_WD_LOAD_FLAG)
return -ETIMEDOUT;
/* We always mask out reserved bits. */
val &= SECWDOG_RESERVED_MASK;
return val;
}
#ifdef CONFIG_BCM_KONA_WDT_DEBUG
static int bcm_kona_show(struct seq_file *s, void *data)
{
int ctl_val, cur_val;
unsigned long flags;
struct bcm_kona_wdt *wdt = s->private;
if (!wdt) {
seq_puts(s, "No device pointer\n");
return 0;
}
spin_lock_irqsave(&wdt->lock, flags);
ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);
cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);
spin_unlock_irqrestore(&wdt->lock, flags);
if (ctl_val < 0 || cur_val < 0) {
seq_puts(s, "Error accessing hardware\n");
} else {
int ctl, cur, ctl_sec, cur_sec, res;
ctl = ctl_val & SECWDOG_COUNT_MASK;
res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
cur = cur_val & SECWDOG_COUNT_MASK;
ctl_sec = TICKS_TO_SECS(ctl, wdt);
cur_sec = TICKS_TO_SECS(cur, wdt);
seq_printf(s,
"Resolution: %d / %d\n"
"Control: %d s / %d (%#x) ticks\n"
"Current: %d s / %d (%#x) ticks\n"
"Busy count: %lu\n",
res, wdt->resolution,
ctl_sec, ctl, ctl,
cur_sec, cur, cur,
wdt->busy_count);
}
return 0;
}
DEFINE_SHOW_ATTRIBUTE(bcm_kona);
static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
{
struct dentry *dir;
struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
if (!wdt)
return;
wdt->debugfs = NULL;
dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
&bcm_kona_fops);
wdt->debugfs = dir;
}
static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
{
struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
if (wdt)
debugfs_remove_recursive(wdt->debugfs);
}
#else
static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
#endif /* CONFIG_BCM_KONA_WDT_DEBUG */
static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
unsigned mask, unsigned newval)
{
int val;
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&wdt->lock, flags);
val = secure_register_read(wdt, SECWDOG_CTRL_REG);
if (val < 0) {
ret = val;
} else {
val &= ~mask;
val |= newval;
writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
}
spin_unlock_irqrestore(&wdt->lock, flags);
return ret;
}
static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
{
if (wdt->resolution > SECWDOG_MAX_RES)
return -EINVAL;
return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
wdt->resolution << SECWDOG_CLKS_SHIFT);
}
static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
unsigned watchdog_flags)
{
struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
SECS_TO_TICKS(wdog->timeout, wdt) |
watchdog_flags);
}
static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
unsigned int t)
{
wdog->timeout = t;
return 0;
}
static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
{
struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
int val;
unsigned long flags;
spin_lock_irqsave(&wdt->lock, flags);
val = secure_register_read(wdt, SECWDOG_COUNT_REG);
spin_unlock_irqrestore(&wdt->lock, flags);
if (val < 0)
return val;
return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
}
static int bcm_kona_wdt_start(struct watchdog_device *wdog)
{
return bcm_kona_wdt_set_timeout_reg(wdog,
SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
}
static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
{
struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
SECWDOG_SRSTEN_MASK, 0);
}
static const struct watchdog_ops bcm_kona_wdt_ops = {
.owner = THIS_MODULE,
.start = bcm_kona_wdt_start,
.stop = bcm_kona_wdt_stop,
.set_timeout = bcm_kona_wdt_set_timeout,
.get_timeleft = bcm_kona_wdt_get_timeleft,
};
static const struct watchdog_info bcm_kona_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
.identity = "Broadcom Kona Watchdog Timer",
};
static struct watchdog_device bcm_kona_wdt_wdd = {
.info = &bcm_kona_wdt_info,
.ops = &bcm_kona_wdt_ops,
.min_timeout = 1,
.max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
.timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
};
static int bcm_kona_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct bcm_kona_wdt *wdt;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
spin_lock_init(&wdt->lock);
wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
ret = bcm_kona_wdt_set_resolution_reg(wdt);
if (ret) {
dev_err(dev, "Failed to set resolution (error: %d)", ret);
return ret;
}
platform_set_drvdata(pdev, wdt);
watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
bcm_kona_wdt_wdd.parent = dev;
ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
if (ret) {
dev_err(dev, "Failed set watchdog timeout");
return ret;
}
watchdog_stop_on_reboot(&bcm_kona_wdt_wdd);
watchdog_stop_on_unregister(&bcm_kona_wdt_wdd);
ret = devm_watchdog_register_device(dev, &bcm_kona_wdt_wdd);
if (ret)
return ret;
bcm_kona_wdt_debug_init(pdev);
dev_dbg(dev, "Broadcom Kona Watchdog Timer");
return 0;
}
static void bcm_kona_wdt_remove(struct platform_device *pdev)
{
bcm_kona_wdt_debug_exit(pdev);
dev_dbg(&pdev->dev, "Watchdog driver disabled");
}
static const struct of_device_id bcm_kona_wdt_of_match[] = {
{ .compatible = "brcm,kona-wdt", },
{},
};
MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
static struct platform_driver bcm_kona_wdt_driver = {
.driver = {
.name = BCM_KONA_WDT_NAME,
.of_match_table = bcm_kona_wdt_of_match,
},
.probe = bcm_kona_wdt_probe,
.remove_new = bcm_kona_wdt_remove,
};
module_platform_driver(bcm_kona_wdt_driver);
MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
MODULE_LICENSE("GPL v2");