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// 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);
if (IS_ERR_OR_NULL(dir))
return;
if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
&bcm_kona_fops))
wdt->debugfs = dir;
else
debugfs_remove_recursive(dir);
}
static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
{
struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
if (wdt && wdt->debugfs) {
debugfs_remove_recursive(wdt->debugfs);
wdt->debugfs = NULL;
}
}
#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 -ENODEV;
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) {
dev_err(dev, "Failed to register watchdog device");
return ret;
}
bcm_kona_wdt_debug_init(pdev);
dev_dbg(dev, "Broadcom Kona Watchdog Timer");
return 0;
}
static int bcm_kona_wdt_remove(struct platform_device *pdev)
{
bcm_kona_wdt_debug_exit(pdev);
dev_dbg(&pdev->dev, "Watchdog driver disabled");
return 0;
}
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 = 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");
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