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watchdog: ixp4xx: Rewrite driver to use core

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This rewrites the IXP4xx watchdog driver as follows:

- Spawn the watchdog driver as a platform device from the timer
  driver. It's one device in the hardware, and the fact that
  Linux splits the handling into two different devices is
  a Linux pecularity, and thus it becomes a Linux pecularity
  to spawn a separate watchdog driver.

- Spawn the watchdog driver from the timer driver at probe().
  This is well after the timer driver as actually registered and
  started and we know the register base is available.

- Instead of looping back callbacks to the timer drivers for all
  watchdog calls, pass the register base to the watchdog driver
  and manage the registers there. The two drivers aren't even
  interested in the same register so the spinlock is totally
  surplus, delete it.

- Replace pretty much all of the content in the watchdog driver
  with a simple, modern watchdog driver utilizing the watchdog
  core instead of registering its own misc device and ioctl()
  handling.

- Drop module parameters as the same already exist in the
  watchdog core.

What remains is a slim elegant (IMO) watchdog driver using the
watchdog core, spawning from device tree or boardfile alike.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210726121214.2572836-1-linus.walleij@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
Linus Walleij 2021-07-26 14:12:14 +02:00 committed by Wim Van Sebroeck
parent dbe80cf471
commit 580b8e2899
3 changed files with 171 additions and 193 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/clocksource/timer-ixp4xx.c
View File

@ -18,6 +18,7 @@
#include <linux/delay.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
/* Goes away with OF conversion */
#include <linux/platform_data/timer-ixp4xx.h>
@ -29,9 +30,6 @@
#define IXP4XX_OSRT1_OFFSET 0x08 /* Timer 1 Reload */
#define IXP4XX_OST2_OFFSET 0x0C /* Timer 2 Timestamp */
#define IXP4XX_OSRT2_OFFSET 0x10 /* Timer 2 Reload */
#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */
#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */
#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */
#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */
/*
@ -45,17 +43,10 @@
#define IXP4XX_OSST_TIMER_1_PEND 0x00000001
#define IXP4XX_OSST_TIMER_2_PEND 0x00000002
#define IXP4XX_OSST_TIMER_TS_PEND 0x00000004
#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008
#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010
#define IXP4XX_WDT_KEY 0x0000482E
#define IXP4XX_WDT_RESET_ENABLE 0x00000001
#define IXP4XX_WDT_IRQ_ENABLE 0x00000002
#define IXP4XX_WDT_COUNT_ENABLE 0x00000004
/* Remaining registers are for the watchdog and defined in the watchdog driver */
struct ixp4xx_timer {
void __iomem *base;
unsigned int tick_rate;
u32 latch;
struct clock_event_device clkevt;
#ifdef CONFIG_ARM
@ -181,7 +172,6 @@ static __init int ixp4xx_timer_register(void __iomem *base,
if (!tmr)
return -ENOMEM;
tmr->base = base;
tmr->tick_rate = timer_freq;
/*
* The timer register doesn't allow to specify the two least
@ -239,6 +229,40 @@ static __init int ixp4xx_timer_register(void __iomem *base,
return 0;
}
static struct platform_device ixp4xx_watchdog_device = {
.name = "ixp4xx-watchdog",
.id = -1,
};
/*
* This probe gets called after the timer is already up and running. The main
* function on this platform is to spawn the watchdog device as a child.
*/
static int ixp4xx_timer_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
/* Pass the base address as platform data and nothing else */
ixp4xx_watchdog_device.dev.platform_data = local_ixp4xx_timer->base;
ixp4xx_watchdog_device.dev.parent = dev;
return platform_device_register(&ixp4xx_watchdog_device);
}
static const struct of_device_id ixp4xx_timer_dt_id[] = {
{ .compatible = "intel,ixp4xx-timer", },
{ /* sentinel */ },
};
static struct platform_driver ixp4xx_timer_driver = {
.probe = ixp4xx_timer_probe,
.driver = {
.name = "ixp4xx-timer",
.of_match_table = ixp4xx_timer_dt_id,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(ixp4xx_timer_driver);
/**
* ixp4xx_timer_setup() - Timer setup function to be called from boardfiles
* @timerbase: physical base of timer block

1
drivers/watchdog/Kconfig
View File

@ -475,6 +475,7 @@ config FTWDT010_WATCHDOG
config IXP4XX_WATCHDOG
tristate "IXP4xx Watchdog"
depends on ARCH_IXP4XX
select WATCHDOG_CORE
help
Say Y here if to include support for the watchdog timer
in the Intel IXP4xx network processors. This driver can

315
drivers/watchdog/ixp4xx_wdt.c
View File

@ -1,220 +1,173 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/char/watchdog/ixp4xx_wdt.c
*
* Watchdog driver for Intel IXP4xx network processors
*
* Author: Deepak Saxena <dsaxena@plexity.net>
* Author: Linus Walleij <linus.walleij@linaro.org>
*
* Copyright 2004 (c) MontaVista, Software, Inc.
* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/of.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>
#include <linux/bits.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/soc/ixp4xx/cpu.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = 60; /* (secs) Default is 1 minute */
static unsigned long wdt_status;
static unsigned long boot_status;
static DEFINE_SPINLOCK(wdt_lock);
#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
static void wdt_enable(void)
{
spin_lock(&wdt_lock);
*IXP4XX_OSWK = IXP4XX_WDT_KEY;
*IXP4XX_OSWE = 0;
*IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
*IXP4XX_OSWK = 0;
spin_unlock(&wdt_lock);
}
static void wdt_disable(void)
{
spin_lock(&wdt_lock);
*IXP4XX_OSWK = IXP4XX_WDT_KEY;
*IXP4XX_OSWE = 0;
*IXP4XX_OSWK = 0;
spin_unlock(&wdt_lock);
}
static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
wdt_enable();
return stream_open(inode, file);
}
static ssize_t
ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
}
wdt_enable();
}
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "IXP4xx Watchdog",
struct ixp4xx_wdt {
struct watchdog_device wdd;
void __iomem *base;
unsigned long rate;
};
/* Fallback if we do not have a clock for this */
#define IXP4XX_TIMER_FREQ 66666000
static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
/* Registers after the timer registers */
#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */
#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */
#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */
#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */
#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008
#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010
#define IXP4XX_WDT_KEY 0x0000482E
#define IXP4XX_WDT_RESET_ENABLE 0x00000001
#define IXP4XX_WDT_IRQ_ENABLE 0x00000002
#define IXP4XX_WDT_COUNT_ENABLE 0x00000004
static inline
struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > 60) {
ret = -EINVAL;
break;
}
heartbeat = time;
wdt_enable();
fallthrough;
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
}
return ret;
return container_of(wdd, struct ixp4xx_wdt, wdd);
}
static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
static int ixp4xx_wdt_start(struct watchdog_device *wdd)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
wdt_disable();
else
pr_crit("Device closed unexpectedly - timer will not stop\n");
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
__raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
__raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);
__raw_writel(wdd->timeout * iwdt->rate,
iwdt->base + IXP4XX_OSWT_OFFSET);
__raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,
iwdt->base + IXP4XX_OSWE_OFFSET);
__raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);
return 0;
}
static const struct file_operations ixp4xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = ixp4xx_wdt_write,
.unlocked_ioctl = ixp4xx_wdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = ixp4xx_wdt_open,
.release = ixp4xx_wdt_release,
};
static struct miscdevice ixp4xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ixp4xx_wdt_fops,
};
static int __init ixp4xx_wdt_init(void)
static int ixp4xx_wdt_stop(struct watchdog_device *wdd)
{
struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
__raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
__raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);
__raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);
return 0;
}
static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
wdd->timeout = timeout;
if (watchdog_active(wdd))
ixp4xx_wdt_start(wdd);
return 0;
}
static const struct watchdog_ops ixp4xx_wdt_ops = {
.start = ixp4xx_wdt_start,
.stop = ixp4xx_wdt_stop,
.set_timeout = ixp4xx_wdt_set_timeout,
.owner = THIS_MODULE,
};
static const struct watchdog_info ixp4xx_wdt_info = {
.options = WDIOF_KEEPALIVEPING
| WDIOF_MAGICCLOSE
| WDIOF_SETTIMEOUT,
.identity = KBUILD_MODNAME,
};
/* Devres-handled clock disablement */
static void ixp4xx_clock_action(void *d)
{
clk_disable_unprepare(d);
}
static int ixp4xx_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct ixp4xx_wdt *iwdt;
struct clk *clk;
int ret;
/*
* FIXME: we bail out on device tree boot but this really needs
* to be fixed in a nicer way: this registers the MDIO bus before
* even matching the driver infrastructure, we should only probe
* detected hardware.
*/
if (of_have_populated_dt())
return -ENODEV;
if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
dev_err(dev, "Rev. A0 IXP42x CPU detected - watchdog disabled\n");
return -ENODEV;
}
boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
WDIOF_CARDRESET : 0;
ret = misc_register(&ixp4xx_wdt_miscdev);
if (ret == 0)
pr_info("timer heartbeat %d sec\n", heartbeat);
return ret;
iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL);
if (!iwdt)
return -ENOMEM;
iwdt->base = dev->platform_data;
/*
* Retrieve rate from a fixed clock from the device tree if
* the parent has that, else use the default clock rate.
*/
clk = devm_clk_get(dev->parent, NULL);
if (!IS_ERR(clk)) {
ret = clk_prepare_enable(clk);
if (ret)
return ret;
ret = devm_add_action_or_reset(dev, ixp4xx_clock_action, clk);
if (ret)
return ret;
iwdt->rate = clk_get_rate(clk);
}
if (!iwdt->rate)
iwdt->rate = IXP4XX_TIMER_FREQ;
iwdt->wdd.info = &ixp4xx_wdt_info;
iwdt->wdd.ops = &ixp4xx_wdt_ops;
iwdt->wdd.min_timeout = 1;
iwdt->wdd.max_timeout = U32_MAX / iwdt->rate;
iwdt->wdd.parent = dev;
/* Default to 60 seconds */
iwdt->wdd.timeout = 60U;
watchdog_init_timeout(&iwdt->wdd, 0, dev);
if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) &
IXP4XX_OSST_TIMER_WARM_RESET)
iwdt->wdd.bootstatus = WDIOF_CARDRESET;
ret = devm_watchdog_register_device(dev, &iwdt->wdd);
if (ret)
return ret;
dev_info(dev, "IXP4xx watchdog available\n");
return 0;
}
static void __exit ixp4xx_wdt_exit(void)
{
misc_deregister(&ixp4xx_wdt_miscdev);
}
module_init(ixp4xx_wdt_init);
module_exit(ixp4xx_wdt_exit);
static struct platform_driver ixp4xx_wdt_driver = {
.probe = ixp4xx_wdt_probe,
.driver = {
.name = "ixp4xx-watchdog",
},
};
module_platform_driver(ixp4xx_wdt_driver);
MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");