Message-ID: <20180118200832.GA29961@roeck-us.net>
Date:   Thu, 18 Jan 2018 12:08:32 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Corentin Labbe <clabbe.montjoie@...il.com>
Cc:     wim@...ux-watchdog.org, egtvedt@...fundet.no,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org
Subject: Re: [PATCH] watchdog: remove at32ap700x_wdt

On Thu, Jan 18, 2018 at 08:52:56PM +0100, Corentin Labbe wrote:
> Since AVR32 is gone, this driver is useless.
> 

Quite true.

> Signed-off-by: Corentin Labbe <clabbe.montjoie@...il.com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/watchdog/Kconfig          |   9 -
>  drivers/watchdog/Makefile         |   3 -
>  drivers/watchdog/at32ap700x_wdt.c | 433 --------------------------------------
>  3 files changed, 445 deletions(-)
>  delete mode 100644 drivers/watchdog/at32ap700x_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 34d1c6851fa7..aff773bcebdb 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -814,15 +814,6 @@ config SPRD_WATCHDOG
>  	  Say Y here to include watchdog timer supported
>  	  by Spreadtrum system.
>  
> -# AVR32 Architecture
> -
> -config AT32AP700X_WDT
> -	tristate "AT32AP700x watchdog"
> -	depends on CPU_AT32AP700X || COMPILE_TEST
> -	help
> -	  Watchdog timer embedded into AT32AP700x devices. This will reboot
> -	  your system when the timeout is reached.
> -
>  # BLACKFIN Architecture
>  
>  config BFIN_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index b43bab87ff62..0474d38aa854 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -91,9 +91,6 @@ obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
>  obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o
>  obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o
>  
> -# AVR32 Architecture
> -obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> -
>  # BLACKFIN Architecture
>  obj-$(CONFIG_BFIN_WDT) += bfin_wdt.o
>  
> diff --git a/drivers/watchdog/at32ap700x_wdt.c b/drivers/watchdog/at32ap700x_wdt.c
> deleted file mode 100644
> index 81ba8920f127..000000000000
> --- a/drivers/watchdog/at32ap700x_wdt.c
> +++ /dev/null
> @@ -1,433 +0,0 @@
> -/*
> - * Watchdog driver for Atmel AT32AP700X devices
> - *
> - * Copyright (C) 2005-2006 Atmel Corporation
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License version 2 as
> - * published by the Free Software Foundation.
> - *
> - *
> - * Errata: WDT Clear is blocked after WDT Reset
> - *
> - * A watchdog timer event will, after reset, block writes to the WDT_CLEAR
> - * register, preventing the program to clear the next Watchdog Timer Reset.
> - *
> - * If you still want to use the WDT after a WDT reset a small code can be
> - * insterted at the startup checking the AVR32_PM.rcause register for WDT reset
> - * and use a GPIO pin to reset the system. This method requires that one of the
> - * GPIO pins are available and connected externally to the RESET_N pin. After
> - * the GPIO pin has pulled down the reset line the GPIO will be reset and leave
> - * the pin tristated with pullup.
> - */
> -
> -#include <linux/init.h>
> -#include <linux/kernel.h>
> -#include <linux/module.h>
> -#include <linux/moduleparam.h>
> -#include <linux/miscdevice.h>
> -#include <linux/fs.h>
> -#include <linux/platform_device.h>
> -#include <linux/watchdog.h>
> -#include <linux/uaccess.h>
> -#include <linux/io.h>
> -#include <linux/spinlock.h>
> -#include <linux/slab.h>
> -
> -#define TIMEOUT_MIN		1
> -#define TIMEOUT_MAX		2
> -#define TIMEOUT_DEFAULT		TIMEOUT_MAX
> -
> -/* module parameters */
> -static int timeout =  TIMEOUT_DEFAULT;
> -module_param(timeout, int, 0);
> -MODULE_PARM_DESC(timeout,
> -		"Timeout value. Limited to be 1 or 2 seconds. (default="
> -		__MODULE_STRING(TIMEOUT_DEFAULT) ")");
> -
> -static bool nowayout = WATCHDOG_NOWAYOUT;
> -module_param(nowayout, bool, 0);
> -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> -		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> -
> -/* Watchdog registers and write/read macro */
> -#define WDT_CTRL		0x00
> -#define WDT_CTRL_EN		   0
> -#define WDT_CTRL_PSEL		   8
> -#define WDT_CTRL_KEY		  24
> -
> -#define WDT_CLR			0x04
> -
> -#define WDT_RCAUSE		0x10
> -#define WDT_RCAUSE_POR		   0
> -#define WDT_RCAUSE_EXT		   2
> -#define WDT_RCAUSE_WDT		   3
> -#define WDT_RCAUSE_JTAG		   4
> -#define WDT_RCAUSE_SERP		   5
> -
> -#define WDT_BIT(name)		(1 << WDT_##name)
> -#define WDT_BF(name, value)	((value) << WDT_##name)
> -
> -#define wdt_readl(dev, reg)				\
> -	__raw_readl((dev)->regs + WDT_##reg)
> -#define wdt_writel(dev, reg, value)			\
> -	__raw_writel((value), (dev)->regs + WDT_##reg)
> -
> -struct wdt_at32ap700x {
> -	void __iomem		*regs;
> -	spinlock_t		io_lock;
> -	int			timeout;
> -	int			boot_status;
> -	unsigned long		users;
> -	struct miscdevice	miscdev;
> -};
> -
> -static struct wdt_at32ap700x *wdt;
> -static char expect_release;
> -
> -/*
> - * Disable the watchdog.
> - */
> -static inline void at32_wdt_stop(void)
> -{
> -	unsigned long psel;
> -
> -	spin_lock(&wdt->io_lock);
> -	psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
> -	wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
> -	wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
> -	spin_unlock(&wdt->io_lock);
> -}
> -
> -/*
> - * Enable and reset the watchdog.
> - */
> -static inline void at32_wdt_start(void)
> -{
> -	/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
> -	unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
> -
> -	spin_lock(&wdt->io_lock);
> -	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
> -			| WDT_BF(CTRL_PSEL, psel)
> -			| WDT_BF(CTRL_KEY, 0x55));
> -	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
> -			| WDT_BF(CTRL_PSEL, psel)
> -			| WDT_BF(CTRL_KEY, 0xaa));
> -	spin_unlock(&wdt->io_lock);
> -}
> -
> -/*
> - * Pat the watchdog timer.
> - */
> -static inline void at32_wdt_pat(void)
> -{
> -	spin_lock(&wdt->io_lock);
> -	wdt_writel(wdt, CLR, 0x42);
> -	spin_unlock(&wdt->io_lock);
> -}
> -
> -/*
> - * Watchdog device is opened, and watchdog starts running.
> - */
> -static int at32_wdt_open(struct inode *inode, struct file *file)
> -{
> -	if (test_and_set_bit(1, &wdt->users))
> -		return -EBUSY;
> -
> -	at32_wdt_start();
> -	return nonseekable_open(inode, file);
> -}
> -
> -/*
> - * Close the watchdog device.
> - */
> -static int at32_wdt_close(struct inode *inode, struct file *file)
> -{
> -	if (expect_release == 42) {
> -		at32_wdt_stop();
> -	} else {
> -		dev_dbg(wdt->miscdev.parent,
> -			"unexpected close, not stopping watchdog!\n");
> -		at32_wdt_pat();
> -	}
> -	clear_bit(1, &wdt->users);
> -	expect_release = 0;
> -	return 0;
> -}
> -
> -/*
> - * Change the watchdog time interval.
> - */
> -static int at32_wdt_settimeout(int time)
> -{
> -	/*
> -	 * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
> -	 * 2 ^ 16 allowing up to 2 seconds timeout.
> -	 */
> -	if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
> -		return -EINVAL;
> -
> -	/*
> -	 * Set new watchdog time. It will be used when at32_wdt_start() is
> -	 * called.
> -	 */
> -	wdt->timeout = time;
> -	return 0;
> -}
> -
> -/*
> - * Get the watchdog status.
> - */
> -static int at32_wdt_get_status(void)
> -{
> -	int rcause;
> -	int status = 0;
> -
> -	rcause = wdt_readl(wdt, RCAUSE);
> -
> -	switch (rcause) {
> -	case WDT_BIT(RCAUSE_EXT):
> -		status = WDIOF_EXTERN1;
> -		break;
> -	case WDT_BIT(RCAUSE_WDT):
> -		status = WDIOF_CARDRESET;
> -		break;
> -	case WDT_BIT(RCAUSE_POR):  /* fall through */
> -	case WDT_BIT(RCAUSE_JTAG): /* fall through */
> -	case WDT_BIT(RCAUSE_SERP): /* fall through */
> -	default:
> -		break;
> -	}
> -
> -	return status;
> -}
> -
> -static const struct watchdog_info at32_wdt_info = {
> -	.identity	= "at32ap700x watchdog",
> -	.options	= WDIOF_SETTIMEOUT |
> -			  WDIOF_KEEPALIVEPING |
> -			  WDIOF_MAGICCLOSE,
> -};
> -
> -/*
> - * Handle commands from user-space.
> - */
> -static long at32_wdt_ioctl(struct file *file,
> -				unsigned int cmd, unsigned long arg)
> -{
> -	int ret = -ENOTTY;
> -	int time;
> -	void __user *argp = (void __user *)arg;
> -	int __user *p = argp;
> -
> -	switch (cmd) {
> -	case WDIOC_GETSUPPORT:
> -		ret = copy_to_user(argp, &at32_wdt_info,
> -				sizeof(at32_wdt_info)) ? -EFAULT : 0;
> -		break;
> -	case WDIOC_GETSTATUS:
> -		ret = put_user(0, p);
> -		break;
> -	case WDIOC_GETBOOTSTATUS:
> -		ret = put_user(wdt->boot_status, p);
> -		break;
> -	case WDIOC_SETOPTIONS:
> -		ret = get_user(time, p);
> -		if (ret)
> -			break;
> -		if (time & WDIOS_DISABLECARD)
> -			at32_wdt_stop();
> -		if (time & WDIOS_ENABLECARD)
> -			at32_wdt_start();
> -		ret = 0;
> -		break;
> -	case WDIOC_KEEPALIVE:
> -		at32_wdt_pat();
> -		ret = 0;
> -		break;
> -	case WDIOC_SETTIMEOUT:
> -		ret = get_user(time, p);
> -		if (ret)
> -			break;
> -		ret = at32_wdt_settimeout(time);
> -		if (ret)
> -			break;
> -		/* Enable new time value */
> -		at32_wdt_start();
> -		/* fall through */
> -	case WDIOC_GETTIMEOUT:
> -		ret = put_user(wdt->timeout, p);
> -		break;
> -	}
> -
> -	return ret;
> -}
> -
> -static ssize_t at32_wdt_write(struct file *file, const char __user *data,
> -				size_t len, loff_t *ppos)
> -{
> -	/* See if we got the magic character 'V' and reload the timer */
> -	if (len) {
> -		if (!nowayout) {
> -			size_t i;
> -
> -			/*
> -			 * note: just in case someone wrote the magic
> -			 * character five months ago...
> -			 */
> -			expect_release = 0;
> -
> -			/*
> -			 * scan to see whether or not we got the magic
> -			 * character
> -			 */
> -			for (i = 0; i != len; i++) {
> -				char c;
> -				if (get_user(c, data + i))
> -					return -EFAULT;
> -				if (c == 'V')
> -					expect_release = 42;
> -			}
> -		}
> -		/* someone wrote to us, we should pat the watchdog */
> -		at32_wdt_pat();
> -	}
> -	return len;
> -}
> -
> -static const struct file_operations at32_wdt_fops = {
> -	.owner		= THIS_MODULE,
> -	.llseek		= no_llseek,
> -	.unlocked_ioctl	= at32_wdt_ioctl,
> -	.open		= at32_wdt_open,
> -	.release	= at32_wdt_close,
> -	.write		= at32_wdt_write,
> -};
> -
> -static int __init at32_wdt_probe(struct platform_device *pdev)
> -{
> -	struct resource	*regs;
> -	int ret;
> -
> -	if (wdt) {
> -		dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
> -		return -EBUSY;
> -	}
> -
> -	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	if (!regs) {
> -		dev_dbg(&pdev->dev, "missing mmio resource\n");
> -		return -ENXIO;
> -	}
> -
> -	wdt = devm_kzalloc(&pdev->dev, sizeof(struct wdt_at32ap700x),
> -			GFP_KERNEL);
> -	if (!wdt)
> -		return -ENOMEM;
> -
> -	wdt->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
> -	if (!wdt->regs) {
> -		ret = -ENOMEM;
> -		dev_dbg(&pdev->dev, "could not map I/O memory\n");
> -		goto err_free;
> -	}
> -
> -	spin_lock_init(&wdt->io_lock);
> -	wdt->boot_status = at32_wdt_get_status();
> -
> -	/* Work-around for watchdog silicon errata. */
> -	if (wdt->boot_status & WDIOF_CARDRESET) {
> -		dev_info(&pdev->dev, "CPU must be reset with external "
> -				"reset or POR due to silicon errata.\n");
> -		ret = -EIO;
> -		goto err_free;
> -	} else {
> -		wdt->users = 0;
> -	}
> -
> -	wdt->miscdev.minor	= WATCHDOG_MINOR;
> -	wdt->miscdev.name	= "watchdog";
> -	wdt->miscdev.fops	= &at32_wdt_fops;
> -	wdt->miscdev.parent	= &pdev->dev;
> -
> -	platform_set_drvdata(pdev, wdt);
> -
> -	if (at32_wdt_settimeout(timeout)) {
> -		at32_wdt_settimeout(TIMEOUT_DEFAULT);
> -		dev_dbg(&pdev->dev,
> -			"default timeout invalid, set to %d sec.\n",
> -			TIMEOUT_DEFAULT);
> -	}
> -
> -	ret = misc_register(&wdt->miscdev);
> -	if (ret) {
> -		dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
> -		goto err_free;
> -	}
> -
> -	dev_info(&pdev->dev,
> -		"AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
> -		wdt->regs, wdt->timeout, nowayout);
> -
> -	return 0;
> -
> -err_free:
> -	wdt = NULL;
> -	return ret;
> -}
> -
> -static int __exit at32_wdt_remove(struct platform_device *pdev)
> -{
> -	if (wdt && platform_get_drvdata(pdev) == wdt) {
> -		/* Stop the timer before we leave */
> -		if (!nowayout)
> -			at32_wdt_stop();
> -
> -		misc_deregister(&wdt->miscdev);
> -		wdt = NULL;
> -	}
> -	return 0;
> -}
> -
> -static void at32_wdt_shutdown(struct platform_device *pdev)
> -{
> -	at32_wdt_stop();
> -}
> -
> -#ifdef CONFIG_PM
> -static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
> -{
> -	at32_wdt_stop();
> -	return 0;
> -}
> -
> -static int at32_wdt_resume(struct platform_device *pdev)
> -{
> -	if (wdt->users)
> -		at32_wdt_start();
> -	return 0;
> -}
> -#else
> -#define at32_wdt_suspend NULL
> -#define at32_wdt_resume NULL
> -#endif
> -
> -/* work with hotplug and coldplug */
> -MODULE_ALIAS("platform:at32_wdt");
> -
> -static struct platform_driver at32_wdt_driver = {
> -	.remove		= __exit_p(at32_wdt_remove),
> -	.suspend	= at32_wdt_suspend,
> -	.resume		= at32_wdt_resume,
> -	.driver		= {
> -		.name	= "at32_wdt",
> -	},
> -	.shutdown	= at32_wdt_shutdown,
> -};
> -
> -module_platform_driver_probe(at32_wdt_driver, at32_wdt_probe);
> -
> -MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@...fundet.no>");
> -MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
> -MODULE_LICENSE("GPL");
> -- 
> 2.13.6
> 

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