Date:   Wed, 20 Jan 2021 11:03:55 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Arnd Bergmann <arnd@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-watchdog@...r.kernel.org,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Arnd Bergmann <arnd@...db.de>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH 5/5] watchdog: remove coh901 driver

On Wed, Jan 20, 2021 at 05:27:45PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> The ST-Ericsson U300 platform is getting removed, so this driver is no
> longer needed.
> 
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

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

> ---
>  .../watchdog/stericsson-coh901327.txt         |  19 -
>  drivers/watchdog/Kconfig                      |  11 -
>  drivers/watchdog/Makefile                     |   1 -
>  drivers/watchdog/coh901327_wdt.c              | 408 ------------------
>  4 files changed, 439 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/watchdog/stericsson-coh901327.txt
>  delete mode 100644 drivers/watchdog/coh901327_wdt.c
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/stericsson-coh901327.txt b/Documentation/devicetree/bindings/watchdog/stericsson-coh901327.txt
> deleted file mode 100644
> index 8ffb88e39e76..000000000000
> --- a/Documentation/devicetree/bindings/watchdog/stericsson-coh901327.txt
> +++ /dev/null
> @@ -1,19 +0,0 @@
> -ST-Ericsson COH 901 327 Watchdog timer
> -
> -Required properties:
> -- compatible: must be "stericsson,coh901327".
> -- reg: physical base address of the controller and length of memory mapped
> -  region.
> -- interrupts: the interrupt used for the watchdog timeout warning.
> -
> -Optional properties:
> -- timeout-sec: contains the watchdog timeout in seconds.
> -
> -Example:
> -
> -watchdog: watchdog@...12000 {
> -	compatible = "stericsson,coh901327";
> -	reg = <0xc0012000 0x1000>;
> -	interrupts = <3>;
> -	timeout-sec = <60>;
> -};
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 10efbb351f14..3b73735b0c8b 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -619,17 +619,6 @@ config SUNXI_WATCHDOG
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called sunxi_wdt.
>  
> -config COH901327_WATCHDOG
> -	bool "ST-Ericsson COH 901 327 watchdog"
> -	depends on ARCH_U300 || (ARM && COMMON_CLK && COMPILE_TEST)
> -	default y if MACH_U300
> -	select WATCHDOG_CORE
> -	help
> -	  Say Y here to include Watchdog timer support for the
> -	  watchdog embedded into the ST-Ericsson U300 series platforms.
> -	  This watchdog is used to reset the system and thus cannot be
> -	  compiled as a module.
> -
>  config NPCM7XX_WATCHDOG
>  	tristate "Nuvoton NPCM750 watchdog"
>  	depends on ARCH_NPCM || COMPILE_TEST
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 1ff40d6a027f..1685dbc70a15 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -61,7 +61,6 @@ obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
>  obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>  obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>  obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
> -obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
>  obj-$(CONFIG_NPCM7XX_WATCHDOG) += npcm_wdt.o
>  obj-$(CONFIG_STMP3XXX_RTC_WATCHDOG) += stmp3xxx_rtc_wdt.o
>  obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o
> diff --git a/drivers/watchdog/coh901327_wdt.c b/drivers/watchdog/coh901327_wdt.c
> deleted file mode 100644
> index 260c50b08483..000000000000
> --- a/drivers/watchdog/coh901327_wdt.c
> +++ /dev/null
> @@ -1,408 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * coh901327_wdt.c
> - *
> - * Copyright (C) 2008-2009 ST-Ericsson AB
> - * Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
> - * Author: Linus Walleij <linus.walleij@...ricsson.com>
> - */
> -#include <linux/moduleparam.h>
> -#include <linux/mod_devicetable.h>
> -#include <linux/types.h>
> -#include <linux/watchdog.h>
> -#include <linux/interrupt.h>
> -#include <linux/pm.h>
> -#include <linux/platform_device.h>
> -#include <linux/io.h>
> -#include <linux/bitops.h>
> -#include <linux/clk.h>
> -#include <linux/delay.h>
> -#include <linux/err.h>
> -
> -#define DRV_NAME "WDOG COH 901 327"
> -
> -/*
> - * COH 901 327 register definitions
> - */
> -
> -/* WDOG_FEED Register 32bit (-/W) */
> -#define U300_WDOG_FR							0x00
> -#define U300_WDOG_FR_FEED_RESTART_TIMER					0xFEEDU
> -/* WDOG_TIMEOUT Register 32bit (R/W) */
> -#define U300_WDOG_TR							0x04
> -#define U300_WDOG_TR_TIMEOUT_MASK					0x7FFFU
> -/* WDOG_DISABLE1 Register 32bit (-/W) */
> -#define U300_WDOG_D1R							0x08
> -#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER				0x2BADU
> -/* WDOG_DISABLE2 Register 32bit (R/W) */
> -#define U300_WDOG_D2R							0x0C
> -#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER				0xCAFEU
> -#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED				0xDABEU
> -#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED				0x0000U
> -/* WDOG_STATUS Register 32bit (R/W) */
> -#define U300_WDOG_SR							0x10
> -#define U300_WDOG_SR_STATUS_TIMED_OUT					0xCFE8U
> -#define U300_WDOG_SR_STATUS_NORMAL					0x0000U
> -#define U300_WDOG_SR_RESET_STATUS_RESET					0xE8B4U
> -/* WDOG_COUNT Register 32bit (R/-) */
> -#define U300_WDOG_CR							0x14
> -#define U300_WDOG_CR_VALID_IND						0x8000U
> -#define U300_WDOG_CR_VALID_STABLE					0x0000U
> -#define U300_WDOG_CR_COUNT_VALUE_MASK					0x7FFFU
> -/* WDOG_JTAGOVR Register 32bit (R/W) */
> -#define U300_WDOG_JOR							0x18
> -#define U300_WDOG_JOR_JTAG_MODE_IND					0x0002U
> -#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE				0x0001U
> -/* WDOG_RESTART Register 32bit (-/W) */
> -#define U300_WDOG_RR							0x1C
> -#define U300_WDOG_RR_RESTART_VALUE_RESUME				0xACEDU
> -/* WDOG_IRQ_EVENT Register 32bit (R/W) */
> -#define U300_WDOG_IER							0x20
> -#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND				0x0001U
> -#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE				0x0001U
> -/* WDOG_IRQ_MASK Register 32bit (R/W) */
> -#define U300_WDOG_IMR							0x24
> -#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE				0x0001U
> -/* WDOG_IRQ_FORCE Register 32bit (R/W) */
> -#define U300_WDOG_IFR							0x28
> -#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE			0x0001U
> -
> -/* Default timeout in seconds = 1 minute */
> -#define U300_WDOG_DEFAULT_TIMEOUT					60
> -
> -static unsigned int margin;
> -static int irq;
> -static void __iomem *virtbase;
> -static struct device *parent;
> -
> -static struct clk *clk;
> -
> -/*
> - * Enabling and disabling functions.
> - */
> -static void coh901327_enable(u16 timeout)
> -{
> -	u16 val;
> -	unsigned long freq;
> -	unsigned long delay_ns;
> -
> -	/* Restart timer if it is disabled */
> -	val = readw(virtbase + U300_WDOG_D2R);
> -	if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
> -		writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
> -		       virtbase + U300_WDOG_RR);
> -	/* Acknowledge any pending interrupt so it doesn't just fire off */
> -	writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
> -	       virtbase + U300_WDOG_IER);
> -	/*
> -	 * The interrupt is cleared in the 32 kHz clock domain.
> -	 * Wait 3 32 kHz cycles for it to take effect
> -	 */
> -	freq = clk_get_rate(clk);
> -	delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
> -	delay_ns = 3 * delay_ns; /* Wait 3 cycles */
> -	ndelay(delay_ns);
> -	/* Enable the watchdog interrupt */
> -	writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
> -	/* Activate the watchdog timer */
> -	writew(timeout, virtbase + U300_WDOG_TR);
> -	/* Start the watchdog timer */
> -	writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
> -	/*
> -	 * Extra read so that this change propagate in the watchdog.
> -	 */
> -	(void) readw(virtbase + U300_WDOG_CR);
> -	val = readw(virtbase + U300_WDOG_D2R);
> -	if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
> -		dev_err(parent,
> -			"%s(): watchdog not enabled! D2R value %04x\n",
> -			__func__, val);
> -}
> -
> -static void coh901327_disable(void)
> -{
> -	u16 val;
> -
> -	/* Disable the watchdog interrupt if it is active */
> -	writew(0x0000U, virtbase + U300_WDOG_IMR);
> -	/* If the watchdog is currently enabled, attempt to disable it */
> -	val = readw(virtbase + U300_WDOG_D2R);
> -	if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
> -		writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
> -		       virtbase + U300_WDOG_D1R);
> -		writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
> -		       virtbase + U300_WDOG_D2R);
> -		/* Write this twice (else problems occur) */
> -		writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
> -		       virtbase + U300_WDOG_D2R);
> -	}
> -	val = readw(virtbase + U300_WDOG_D2R);
> -	if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
> -		dev_err(parent,
> -			"%s(): watchdog not disabled! D2R value %04x\n",
> -			__func__, val);
> -}
> -
> -static int coh901327_start(struct watchdog_device *wdt_dev)
> -{
> -	coh901327_enable(wdt_dev->timeout * 100);
> -	return 0;
> -}
> -
> -static int coh901327_stop(struct watchdog_device *wdt_dev)
> -{
> -	coh901327_disable();
> -	return 0;
> -}
> -
> -static int coh901327_ping(struct watchdog_device *wdd)
> -{
> -	/* Feed the watchdog */
> -	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
> -	       virtbase + U300_WDOG_FR);
> -	return 0;
> -}
> -
> -static int coh901327_settimeout(struct watchdog_device *wdt_dev,
> -				unsigned int time)
> -{
> -	wdt_dev->timeout = time;
> -	/* Set new timeout value */
> -	writew(time * 100, virtbase + U300_WDOG_TR);
> -	/* Feed the dog */
> -	writew(U300_WDOG_FR_FEED_RESTART_TIMER,
> -	       virtbase + U300_WDOG_FR);
> -	return 0;
> -}
> -
> -static unsigned int coh901327_gettimeleft(struct watchdog_device *wdt_dev)
> -{
> -	u16 val;
> -
> -	/* Read repeatedly until the value is stable! */
> -	val = readw(virtbase + U300_WDOG_CR);
> -	while (val & U300_WDOG_CR_VALID_IND)
> -		val = readw(virtbase + U300_WDOG_CR);
> -	val &= U300_WDOG_CR_COUNT_VALUE_MASK;
> -	if (val != 0)
> -		val /= 100;
> -
> -	return val;
> -}
> -
> -/*
> - * This interrupt occurs 10 ms before the watchdog WILL bark.
> - */
> -static irqreturn_t coh901327_interrupt(int irq, void *data)
> -{
> -	u16 val;
> -
> -	/*
> -	 * Ack IRQ? If this occurs we're FUBAR anyway, so
> -	 * just acknowledge, disable the interrupt and await the imminent end.
> -	 * If you at some point need a host of callbacks to be called
> -	 * when the system is about to watchdog-reset, add them here!
> -	 *
> -	 * NOTE: on future versions of this IP-block, it will be possible
> -	 * to prevent a watchdog reset by feeding the watchdog at this
> -	 * point.
> -	 */
> -	val = readw(virtbase + U300_WDOG_IER);
> -	if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
> -		writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
> -		       virtbase + U300_WDOG_IER);
> -	writew(0x0000U, virtbase + U300_WDOG_IMR);
> -	dev_crit(parent, "watchdog is barking!\n");
> -	return IRQ_HANDLED;
> -}
> -
> -static const struct watchdog_info coh901327_ident = {
> -	.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
> -	.identity = DRV_NAME,
> -};
> -
> -static const struct watchdog_ops coh901327_ops = {
> -	.owner = THIS_MODULE,
> -	.start = coh901327_start,
> -	.stop = coh901327_stop,
> -	.ping = coh901327_ping,
> -	.set_timeout = coh901327_settimeout,
> -	.get_timeleft = coh901327_gettimeleft,
> -};
> -
> -static struct watchdog_device coh901327_wdt = {
> -	.info = &coh901327_ident,
> -	.ops = &coh901327_ops,
> -	/*
> -	 * Max timeout is 327 since the 10ms
> -	 * timeout register is max
> -	 * 0x7FFF = 327670ms ~= 327s.
> -	 */
> -	.min_timeout = 1,
> -	.max_timeout = 327,
> -	.timeout = U300_WDOG_DEFAULT_TIMEOUT,
> -};
> -
> -static int __init coh901327_probe(struct platform_device *pdev)
> -{
> -	struct device *dev = &pdev->dev;
> -	int ret;
> -	u16 val;
> -
> -	parent = dev;
> -
> -	virtbase = devm_platform_ioremap_resource(pdev, 0);
> -	if (IS_ERR(virtbase))
> -		return PTR_ERR(virtbase);
> -
> -	clk = clk_get(dev, NULL);
> -	if (IS_ERR(clk)) {
> -		ret = PTR_ERR(clk);
> -		dev_err(dev, "could not get clock\n");
> -		return ret;
> -	}
> -	ret = clk_prepare_enable(clk);
> -	if (ret) {
> -		dev_err(dev, "could not prepare and enable clock\n");
> -		goto out_no_clk_enable;
> -	}
> -
> -	val = readw(virtbase + U300_WDOG_SR);
> -	switch (val) {
> -	case U300_WDOG_SR_STATUS_TIMED_OUT:
> -		dev_info(dev, "watchdog timed out since last chip reset!\n");
> -		coh901327_wdt.bootstatus |= WDIOF_CARDRESET;
> -		/* Status will be cleared below */
> -		break;
> -	case U300_WDOG_SR_STATUS_NORMAL:
> -		dev_info(dev, "in normal status, no timeouts have occurred.\n");
> -		break;
> -	default:
> -		dev_info(dev, "contains an illegal status code (%08x)\n", val);
> -		break;
> -	}
> -
> -	val = readw(virtbase + U300_WDOG_D2R);
> -	switch (val) {
> -	case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
> -		dev_info(dev, "currently disabled.\n");
> -		break;
> -	case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
> -		dev_info(dev, "currently enabled! (disabling it now)\n");
> -		coh901327_disable();
> -		break;
> -	default:
> -		dev_err(dev, "contains an illegal enable/disable code (%08x)\n",
> -			val);
> -		break;
> -	}
> -
> -	/* Reset the watchdog */
> -	writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
> -
> -	irq = platform_get_irq(pdev, 0);
> -	if (request_irq(irq, coh901327_interrupt, 0,
> -			DRV_NAME " Bark", pdev)) {
> -		ret = -EIO;
> -		goto out_no_irq;
> -	}
> -
> -	watchdog_init_timeout(&coh901327_wdt, margin, dev);
> -
> -	coh901327_wdt.parent = dev;
> -	ret = watchdog_register_device(&coh901327_wdt);
> -	if (ret)
> -		goto out_no_wdog;
> -
> -	dev_info(dev, "initialized. (timeout=%d sec)\n",
> -			coh901327_wdt.timeout);
> -	return 0;
> -
> -out_no_wdog:
> -	free_irq(irq, pdev);
> -out_no_irq:
> -	clk_disable_unprepare(clk);
> -out_no_clk_enable:
> -	clk_put(clk);
> -	return ret;
> -}
> -
> -#ifdef CONFIG_PM
> -
> -static u16 wdogenablestore;
> -static u16 irqmaskstore;
> -
> -static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
> -{
> -	irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
> -	wdogenablestore = readw(virtbase + U300_WDOG_D2R);
> -	/* If watchdog is on, disable it here and now */
> -	if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
> -		coh901327_disable();
> -	return 0;
> -}
> -
> -static int coh901327_resume(struct platform_device *pdev)
> -{
> -	/* Restore the watchdog interrupt */
> -	writew(irqmaskstore, virtbase + U300_WDOG_IMR);
> -	if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
> -		/* Restart the watchdog timer */
> -		writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
> -		       virtbase + U300_WDOG_RR);
> -		writew(U300_WDOG_FR_FEED_RESTART_TIMER,
> -		       virtbase + U300_WDOG_FR);
> -	}
> -	return 0;
> -}
> -#else
> -#define coh901327_suspend NULL
> -#define coh901327_resume  NULL
> -#endif
> -
> -/*
> - * Mistreating the watchdog is the only way to perform a software reset of the
> - * system on EMP platforms. So we implement this and export a symbol for it.
> - */
> -void coh901327_watchdog_reset(void)
> -{
> -	/* Enable even if on JTAG too */
> -	writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
> -	       virtbase + U300_WDOG_JOR);
> -	/*
> -	 * Timeout = 5s, we have to wait for the watchdog reset to
> -	 * actually take place: the watchdog will be reloaded with the
> -	 * default value immediately, so we HAVE to reboot and get back
> -	 * into the kernel in 30s, or the device will reboot again!
> -	 * The boot loader will typically deactivate the watchdog, so we
> -	 * need time enough for the boot loader to get to the point of
> -	 * deactivating the watchdog before it is shut down by it.
> -	 *
> -	 * NOTE: on future versions of the watchdog, this restriction is
> -	 * gone: the watchdog will be reloaded with a default value (1 min)
> -	 * instead of last value, and you can conveniently set the watchdog
> -	 * timeout to 10ms (value = 1) without any problems.
> -	 */
> -	coh901327_enable(500);
> -	/* Return and await doom */
> -}
> -
> -static const struct of_device_id coh901327_dt_match[] = {
> -	{ .compatible = "stericsson,coh901327" },
> -	{},
> -};
> -
> -static struct platform_driver coh901327_driver = {
> -	.driver = {
> -		.name	= "coh901327_wdog",
> -		.of_match_table = coh901327_dt_match,
> -		.suppress_bind_attrs = true,
> -	},
> -	.suspend	= coh901327_suspend,
> -	.resume		= coh901327_resume,
> -};
> -builtin_platform_driver_probe(coh901327_driver, coh901327_probe);
> -
> -/* not really modular, but ... */
> -module_param(margin, uint, 0);
> -MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
> -- 
> 2.29.2
> 

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