Re: [PATCH 06/22] watchdog: remove the shwdt driver

Guenter Roeck
2023-01-13T14:04:00Z

On 1/12/23 22:23, Christoph Hellwig wrote:
> Now that arch/sh is removed this driver is dead code.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Guenter Roeck <linux@roeck-us.net>

> ---
> .../watchdog/watchdog-parameters.rst | 12 -
> drivers/watchdog/Kconfig | 20 -
> drivers/watchdog/Makefile | 3 -
> drivers/watchdog/shwdt.c | 344 ------------------
> 4 files changed, 379 deletions(-)
> delete mode 100644 drivers/watchdog/shwdt.c
>
> diff --git a/Documentation/watchdog/watchdog-parameters.rst b/Documentation/watchdog/watchdog-parameters.rst
> index 29153eed668900..553ac2f8ae23f7 100644
> --- a/Documentation/watchdog/watchdog-parameters.rst
> +++ b/Documentation/watchdog/watchdog-parameters.rst
> @@ -579,18 +579,6 @@ scx200_wdt:
>
> -------------------------------------------------
>
> -shwdt:
> - clock_division_ratio:
> - Clock division ratio. Valid ranges are from 0x5 (1.31ms)
> - to 0x7 (5.25ms). (default=7)
> - heartbeat:
> - Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=30
> - nowayout:
> - Watchdog cannot be stopped once started
> - (default=kernel config parameter)
> -
> --------------------------------------------------
> -
> smsc37b787_wdt:
> timeout:
> range is 1-255 units, default is 60
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 0bc40b763b0652..7db0a5e636cf65 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -2015,26 +2015,6 @@ config DIAG288_WATCHDOG
> To compile this driver as a module, choose M here. The module
> will be called diag288_wdt.
>
> -# SUPERH (sh + sh64) Architecture
> -
> -config SH_WDT
> - tristate "SuperH Watchdog"
> - depends on SUPERH && (CPU_SH3 || CPU_SH4 || COMPILE_TEST)
> - select WATCHDOG_CORE
> - help
> - This driver adds watchdog support for the integrated watchdog in the
> - SuperH processors. If you have one of these processors and wish
> - to have watchdog support enabled, say Y, otherwise say N.
> -
> - As a side note, saying Y here will automatically boost HZ to 1000
> - so that the timer has a chance to clear the overflow counter. On
> - slower systems (such as the SH-2 and SH-3) this will likely yield
> - some performance issues. As such, the WDT should be avoided here
> - unless it is absolutely necessary.
> -
> - To compile this driver as a module, choose M here: the
> - module will be called shwdt.
> -
> # SPARC Architecture
>
> # SPARC64 Architecture
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 9cbf6580f16c9f..a852ab4d7176ac 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -195,9 +195,6 @@ obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o
> # S390 Architecture
> obj-$(CONFIG_DIAG288_WATCHDOG) += diag288_wdt.o
>
> -# SUPERH (sh + sh64) Architecture
> -obj-$(CONFIG_SH_WDT) += shwdt.o
> -
> # SPARC Architecture
>
> # SPARC64 Architecture
> diff --git a/drivers/watchdog/shwdt.c b/drivers/watchdog/shwdt.c
> deleted file mode 100644
> index f55533e0e0454e..00000000000000
> --- a/drivers/watchdog/shwdt.c
> +++ /dev/null
> @@ -1,344 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-or-later
> -/*
> - * drivers/watchdog/shwdt.c
> - *
> - * Watchdog driver for integrated watchdog in the SuperH processors.
> - *
> - * Copyright (C) 2001 - 2012 Paul Mundt <lethal@linux-sh.org>
> - *
> - * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
> - * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
> - *
> - * 19-Apr-2002 Rob Radez <rob@osinvestor.com>
> - * Added expect close support, made emulated timeout runtime changeable
> - * general cleanups, add some ioctls
> - */
> -
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> -
> -#include <linux/module.h>
> -#include <linux/moduleparam.h>
> -#include <linux/platform_device.h>
> -#include <linux/init.h>
> -#include <linux/types.h>
> -#include <linux/spinlock.h>
> -#include <linux/watchdog.h>
> -#include <linux/pm_runtime.h>
> -#include <linux/fs.h>
> -#include <linux/mm.h>
> -#include <linux/slab.h>
> -#include <linux/io.h>
> -#include <linux/clk.h>
> -#include <linux/err.h>
> -#include <asm/watchdog.h>
> -
> -#define DRV_NAME "sh-wdt"
> -
> -/*
> - * Default clock division ratio is 5.25 msecs. For an additional table of
> - * values, consult the asm-sh/watchdog.h. Overload this at module load
> - * time.
> - *
> - * In order for this to work reliably we need to have HZ set to 1000 or
> - * something quite higher than 100 (or we need a proper high-res timer
> - * implementation that will deal with this properly), otherwise the 10ms
> - * resolution of a jiffy is enough to trigger the overflow. For things like
> - * the SH-4 and SH-5, this isn't necessarily that big of a problem, though
> - * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
> - * necssary.
> - *
> - * As a result of this timing problem, the only modes that are particularly
> - * feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
> - * overflow periods respectively.
> - *
> - * Also, since we can't really expect userspace to be responsive enough
> - * before the overflow happens, we maintain two separate timers .. One in
> - * the kernel for clearing out WOVF every 2ms or so (again, this depends on
> - * HZ == 1000), and another for monitoring userspace writes to the WDT device.
> - *
> - * As such, we currently use a configurable heartbeat interval which defaults
> - * to 30s. In this case, the userspace daemon is only responsible for periodic
> - * writes to the device before the next heartbeat is scheduled. If the daemon
> - * misses its deadline, the kernel timer will allow the WDT to overflow.
> - */
> -static int clock_division_ratio = WTCSR_CKS_4096;
> -#define next_ping_period(cks) (jiffies + msecs_to_jiffies(cks - 4))
> -
> -#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */
> -static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
> -static bool nowayout = WATCHDOG_NOWAYOUT;
> -static unsigned long next_heartbeat;
> -
> -struct sh_wdt {
> - void __iomem *base;
> - struct device *dev;
> - struct clk *clk;
> - spinlock_t lock;
> -
> - struct timer_list timer;
> -};
> -
> -static int sh_wdt_start(struct watchdog_device *wdt_dev)
> -{
> - struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> - unsigned long flags;
> - u8 csr;
> -
> - pm_runtime_get_sync(wdt->dev);
> - clk_enable(wdt->clk);
> -
> - spin_lock_irqsave(&wdt->lock, flags);
> -
> - next_heartbeat = jiffies + (heartbeat * HZ);
> - mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
> -
> - csr = sh_wdt_read_csr();
> - csr |= WTCSR_WT | clock_division_ratio;
> - sh_wdt_write_csr(csr);
> -
> - sh_wdt_write_cnt(0);
> -
> - /*
> - * These processors have a bit of an inconsistent initialization
> - * process.. starting with SH-3, RSTS was moved to WTCSR, and the
> - * RSTCSR register was removed.
> - *
> - * On the SH-2 however, in addition with bits being in different
> - * locations, we must deal with RSTCSR outright..
> - */
> - csr = sh_wdt_read_csr();
> - csr |= WTCSR_TME;
> - csr &= ~WTCSR_RSTS;
> - sh_wdt_write_csr(csr);
> -
> -#ifdef CONFIG_CPU_SH2
> - csr = sh_wdt_read_rstcsr();
> - csr &= ~RSTCSR_RSTS;
> - sh_wdt_write_rstcsr(csr);
> -#endif
> - spin_unlock_irqrestore(&wdt->lock, flags);
> -
> - return 0;
> -}
> -
> -static int sh_wdt_stop(struct watchdog_device *wdt_dev)
> -{
> - struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> - unsigned long flags;
> - u8 csr;
> -
> - spin_lock_irqsave(&wdt->lock, flags);
> -
> - del_timer(&wdt->timer);
> -
> - csr = sh_wdt_read_csr();
> - csr &= ~WTCSR_TME;
> - sh_wdt_write_csr(csr);
> -
> - spin_unlock_irqrestore(&wdt->lock, flags);
> -
> - clk_disable(wdt->clk);
> - pm_runtime_put_sync(wdt->dev);
> -
> - return 0;
> -}
> -
> -static int sh_wdt_keepalive(struct watchdog_device *wdt_dev)
> -{
> - struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> - unsigned long flags;
> -
> - spin_lock_irqsave(&wdt->lock, flags);
> - next_heartbeat = jiffies + (heartbeat * HZ);
> - spin_unlock_irqrestore(&wdt->lock, flags);
> -
> - return 0;
> -}
> -
> -static int sh_wdt_set_heartbeat(struct watchdog_device *wdt_dev, unsigned t)
> -{
> - struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> - unsigned long flags;
> -
> - if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */
> - return -EINVAL;
> -
> - spin_lock_irqsave(&wdt->lock, flags);
> - heartbeat = t;
> - wdt_dev->timeout = t;
> - spin_unlock_irqrestore(&wdt->lock, flags);
> -
> - return 0;
> -}
> -
> -static void sh_wdt_ping(struct timer_list *t)
> -{
> - struct sh_wdt *wdt = from_timer(wdt, t, timer);
> - unsigned long flags;
> -
> - spin_lock_irqsave(&wdt->lock, flags);
> - if (time_before(jiffies, next_heartbeat)) {
> - u8 csr;
> -
> - csr = sh_wdt_read_csr();
> - csr &= ~WTCSR_IOVF;
> - sh_wdt_write_csr(csr);
> -
> - sh_wdt_write_cnt(0);
> -
> - mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
> - } else
> - dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
> - "the watchdog\n");
> - spin_unlock_irqrestore(&wdt->lock, flags);
> -}
> -
> -static const struct watchdog_info sh_wdt_info = {
> - .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
> - WDIOF_MAGICCLOSE,
> - .firmware_version = 1,
> - .identity = "SH WDT",
> -};
> -
> -static const struct watchdog_ops sh_wdt_ops = {
> - .owner = THIS_MODULE,
> - .start = sh_wdt_start,
> - .stop = sh_wdt_stop,
> - .ping = sh_wdt_keepalive,
> - .set_timeout = sh_wdt_set_heartbeat,
> -};
> -
> -static struct watchdog_device sh_wdt_dev = {
> - .info = &sh_wdt_info,
> - .ops = &sh_wdt_ops,
> -};
> -
> -static int sh_wdt_probe(struct platform_device *pdev)
> -{
> - struct sh_wdt *wdt;
> - int rc;
> -
> - /*
> - * As this driver only covers the global watchdog case, reject
> - * any attempts to register per-CPU watchdogs.
> - */
> - if (pdev->id != -1)
> - return -EINVAL;
> -
> - wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
> - if (unlikely(!wdt))
> - return -ENOMEM;
> -
> - wdt->dev = &pdev->dev;
> -
> - wdt->clk = devm_clk_get(&pdev->dev, NULL);
> - if (IS_ERR(wdt->clk)) {
> - /*
> - * Clock framework support is optional, continue on
> - * anyways if we don't find a matching clock.
> - */
> - wdt->clk = NULL;
> - }
> -
> - wdt->base = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(wdt->base))
> - return PTR_ERR(wdt->base);
> -
> - watchdog_set_nowayout(&sh_wdt_dev, nowayout);
> - watchdog_set_drvdata(&sh_wdt_dev, wdt);
> - sh_wdt_dev.parent = &pdev->dev;
> -
> - spin_lock_init(&wdt->lock);
> -
> - rc = sh_wdt_set_heartbeat(&sh_wdt_dev, heartbeat);
> - if (unlikely(rc)) {
> - /* Default timeout if invalid */
> - sh_wdt_set_heartbeat(&sh_wdt_dev, WATCHDOG_HEARTBEAT);
> -
> - dev_warn(&pdev->dev,
> - "heartbeat value must be 1<=x<=3600, using %d\n",
> - sh_wdt_dev.timeout);
> - }
> -
> - dev_info(&pdev->dev, "configured with heartbeat=%d sec (nowayout=%d)\n",
> - sh_wdt_dev.timeout, nowayout);
> -
> - rc = watchdog_register_device(&sh_wdt_dev);
> - if (unlikely(rc)) {
> - dev_err(&pdev->dev, "Can't register watchdog (err=%d)\n", rc);
> - return rc;
> - }
> -
> - timer_setup(&wdt->timer, sh_wdt_ping, 0);
> - wdt->timer.expires = next_ping_period(clock_division_ratio);
> -
> - dev_info(&pdev->dev, "initialized.\n");
> -
> - pm_runtime_enable(&pdev->dev);
> -
> - return 0;
> -}
> -
> -static int sh_wdt_remove(struct platform_device *pdev)
> -{
> - watchdog_unregister_device(&sh_wdt_dev);
> -
> - pm_runtime_disable(&pdev->dev);
> -
> - return 0;
> -}
> -
> -static void sh_wdt_shutdown(struct platform_device *pdev)
> -{
> - sh_wdt_stop(&sh_wdt_dev);
> -}
> -
> -static struct platform_driver sh_wdt_driver = {
> - .driver = {
> - .name = DRV_NAME,
> - },
> -
> - .probe = sh_wdt_probe,
> - .remove = sh_wdt_remove,
> - .shutdown = sh_wdt_shutdown,
> -};
> -
> -static int __init sh_wdt_init(void)
> -{
> - if (unlikely(clock_division_ratio < 0x5 ||
> - clock_division_ratio > 0x7)) {
> - clock_division_ratio = WTCSR_CKS_4096;
> -
> - pr_info("divisor must be 0x5<=x<=0x7, using %d\n",
> - clock_division_ratio);
> - }
> -
> - return platform_driver_register(&sh_wdt_driver);
> -}
> -
> -static void __exit sh_wdt_exit(void)
> -{
> - platform_driver_unregister(&sh_wdt_driver);
> -}
> -module_init(sh_wdt_init);
> -module_exit(sh_wdt_exit);
> -
> -MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
> -MODULE_DESCRIPTION("SuperH watchdog driver");
> -MODULE_LICENSE("GPL");
> -MODULE_ALIAS("platform:" DRV_NAME);
> -
> -module_param(clock_division_ratio, int, 0);
> -MODULE_PARM_DESC(clock_division_ratio,
> - "Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
> - "to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");
> -
> -module_param(heartbeat, int, 0);
> -MODULE_PARM_DESC(heartbeat,
> - "Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
> - __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
> -
> -module_param(nowayout, bool, 0);
> -MODULE_PARM_DESC(nowayout,
> - "Watchdog cannot be stopped once started (default="
> - __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");