drivers/watchdog/omap_wdt.c - u-boot - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * omap_wdt.c
  *
  * (C) Copyright 2013
  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
  *
  * Based on:
  *
  * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
  *
  * commit 2d991a164a61858012651e13c59521975504e260
  * Author: Bill Pemberton <wfp5p@virginia.edu>
  * Date:   Mon Nov 19 13:21:41 2012 -0500
  *
  * watchdog: remove use of __devinit
  *
  * CONFIG_HOTPLUG is going away as an option so __devinit is no longer
  * needed.
  *
  * Author: MontaVista Software, Inc.
  *	 <gdavis@mvista.com> or <source@mvista.com>
  *
  * History:
  *
  * 20030527: George G. Davis <gdavis@mvista.com>
  *	Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
  *	(c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  *	Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
  *
  * Copyright (c) 2004 Texas Instruments.
  *	1. Modified to support OMAP1610 32-KHz watchdog timer
  *	2. Ported to 2.6 kernel
  *
  * Copyright (c) 2005 David Brownell
  *	Use the driver model and standard identifiers; handle bigger timeouts.
  */

 #include <common.h>
 #include <log.h>
 #include <watchdog.h>
 #include <asm/ti-common/omap_wdt.h>
 #include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/arch/cpu.h>
 #include <wdt.h>
 #include <dm.h>
 #include <errno.h>

 /* Hardware timeout in seconds */
 #define WDT_HW_TIMEOUT 60

 #if !CONFIG_IS_ENABLED(WDT)
 static unsigned int wdt_trgr_pattern = 0x1234;

 void hw_watchdog_reset(void)
 {
 	struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;

 	/*
 	 * Somebody just triggered watchdog reset and write to WTGR register
 	 * is in progress. It is resetting right now, no need to trigger it
 	 * again
 	 */
 	if ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
 		return;

 	wdt_trgr_pattern = ~wdt_trgr_pattern;
 	writel(wdt_trgr_pattern, &wdt->wdtwtgr);

 	/*
 	 * Don't wait for posted write to complete, i.e. don't check
 	 * WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
 	 * WTGR register outside of this func, and if entering it
 	 * we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
 	 * was just triggered. This prevents us from wasting time in busy
 	 * polling of WDT_WWPS_PEND_WTGR bit.
 	 */
 }

 static int omap_wdt_set_timeout(unsigned int timeout)
 {
 	struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
 	u32 pre_margin = GET_WLDR_VAL(timeout);

 	/* just count up at 32 KHz */
 	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
 		;

 	writel(pre_margin, &wdt->wdtwldr);
 	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
 		;

 	return 0;
 }

 void hw_watchdog_disable(void)
 {
 	struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;

 	/*
 	 * Disable watchdog
 	 */
 	writel(0xAAAA, &wdt->wdtwspr);
 	while (readl(&wdt->wdtwwps) != 0x0)
 		;
 	writel(0x5555, &wdt->wdtwspr);
 	while (readl(&wdt->wdtwwps) != 0x0)
 		;
 }

 void hw_watchdog_init(void)
 {
 	struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;

 	/*
 	 * Make sure the watchdog is disabled. This is unfortunately required
 	 * because writing to various registers with the watchdog running has no
 	 * effect.
 	 */
 	hw_watchdog_disable();

 	/* initialize prescaler */
 	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
 		;

 	writel(WDT_WCLR_PRE | (PTV << WDT_WCLR_PTV_OFF), &wdt->wdtwclr);
 	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
 		;

 	omap_wdt_set_timeout(WDT_HW_TIMEOUT);

 	/* Sequence to enable the watchdog */
 	writel(0xBBBB, &wdt->wdtwspr);
 	while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
 		;

 	writel(0x4444, &wdt->wdtwspr);
 	while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
 		;
 }

 void watchdog_reset(void)
 {
 	hw_watchdog_reset();
 }

 #else

 static int omap3_wdt_reset(struct udevice *dev)
 {
 	struct omap3_wdt_priv *priv = dev_get_priv(dev);

 	/*
 	 * Somebody just triggered watchdog reset and write to WTGR register
 	 * is in progress. It is resetting right now, no need to trigger it
 	 * again
 	 */
 	if ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
 		return 0;

 	priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
 	writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);
 	/*
 	 * Don't wait for posted write to complete, i.e. don't check
 	 * WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
 	 * WTGR register outside of this func, and if entering it
 	 * we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
 	 * was just triggered. This prevents us from wasting time in busy
 	 * polling of WDT_WWPS_PEND_WTGR bit.
 	 */
 	return 0;
 }

 static int omap3_wdt_stop(struct udevice *dev)
 {
 	struct omap3_wdt_priv *priv = dev_get_priv(dev);

 	/* disable watchdog */
 	writel(0xAAAA, &priv->regs->wdtwspr);
 	while (readl(&priv->regs->wdtwwps) != 0x0)
 		;
 	writel(0x5555, &priv->regs->wdtwspr);
 	while (readl(&priv->regs->wdtwwps) != 0x0)
 		;
 	return 0;
 }

 static int omap3_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
 {
 	struct omap3_wdt_priv *priv = dev_get_priv(dev);
 	u32 pre_margin = GET_WLDR_VAL(timeout_ms / 1000);
 	/*
 	 * Make sure the watchdog is disabled. This is unfortunately required
 	 * because writing to various registers with the watchdog running has
 	 * no effect.
 	 */
 	omap3_wdt_stop(dev);

 	/* initialize prescaler */
 	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
 		;

 	writel(WDT_WCLR_PRE | (PTV << WDT_WCLR_PTV_OFF), &priv->regs->wdtwclr);
 	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
 		;
 	/* just count up at 32 KHz */
 	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
 		;

 	writel(pre_margin, &priv->regs->wdtwldr);
 	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
 		;
 	/* Sequence to enable the watchdog */
 	writel(0xBBBB, &priv->regs->wdtwspr);
 	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
 		;

 	writel(0x4444, &priv->regs->wdtwspr);
 	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
 		;

 	/* Trigger the watchdog to actually reload the counter. */
 	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
 		;

 	priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
 	writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);

 	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
 		;

 	return 0;
 }

 static int omap3_wdt_probe(struct udevice *dev)
 {
 	struct omap3_wdt_priv *priv = dev_get_priv(dev);

 	priv->regs = dev_read_addr_ptr(dev);
 	if (!priv->regs)
 		return -EINVAL;

 	priv->wdt_trgr_pattern = 0x1234;
 	debug("%s: Probing wdt%u\n", __func__, dev_seq(dev));
 	return 0;
 }

 static const struct wdt_ops omap3_wdt_ops = {
 	.start = omap3_wdt_start,
 	.stop = omap3_wdt_stop,
 	.reset = omap3_wdt_reset,
 };

 static const struct udevice_id omap3_wdt_ids[] = {
 	{ .compatible = "ti,omap3-wdt" },
 	{ }
 };

 U_BOOT_DRIVER(omap3_wdt) = {
 	.name = "omap3_wdt",
 	.id = UCLASS_WDT,
 	.of_match = omap3_wdt_ids,
 	.ops = &omap3_wdt_ops,
 	.probe = omap3_wdt_probe,
 	.priv_auto	= sizeof(struct omap3_wdt_priv),
 };
 #endif /* !CONFIG_IS_ENABLED(WDT) */
	// SPDX-License-Identifier: GPL-2.0
	/*
	* omap_wdt.c
	*
	* (C) Copyright 2013
	* Heiko Schocher, DENX Software Engineering, hs@denx.de.
	*
	* Based on:
	*
	* Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
	*
	* commit 2d991a164a61858012651e13c59521975504e260
	* Author: Bill Pemberton <wfp5p@virginia.edu>
	* Date: Mon Nov 19 13:21:41 2012 -0500
	*
	* watchdog: remove use of __devinit
	*
	* CONFIG_HOTPLUG is going away as an option so __devinit is no longer
	* needed.
	*
	* Author: MontaVista Software, Inc.
	* <gdavis@mvista.com> or <source@mvista.com>
	*
	* History:
	*
	* 20030527: George G. Davis <gdavis@mvista.com>
	* Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
	* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
	* Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
	*
	* Copyright (c) 2004 Texas Instruments.
	* 1. Modified to support OMAP1610 32-KHz watchdog timer
	* 2. Ported to 2.6 kernel
	*
	* Copyright (c) 2005 David Brownell
	* Use the driver model and standard identifiers; handle bigger timeouts.
	*/

	#include <common.h>
	#include <log.h>
	#include <watchdog.h>
	#include <asm/ti-common/omap_wdt.h>
	#include <asm/io.h>
	#include <asm/processor.h>
	#include <asm/arch/cpu.h>
	#include <wdt.h>
	#include <dm.h>
	#include <errno.h>

	/* Hardware timeout in seconds */
	#define WDT_HW_TIMEOUT 60

	#if !CONFIG_IS_ENABLED(WDT)
	static unsigned int wdt_trgr_pattern = 0x1234;

	void hw_watchdog_reset(void)
	{
	struct wd_timer wdt = (struct wd_timer )WDT_BASE;

	/*
	* Somebody just triggered watchdog reset and write to WTGR register
	* is in progress. It is resetting right now, no need to trigger it
	* again
	*/
	if ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
	return;

	wdt_trgr_pattern = ~wdt_trgr_pattern;
	writel(wdt_trgr_pattern, &wdt->wdtwtgr);

	/*
	* Don't wait for posted write to complete, i.e. don't check
	* WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
	* WTGR register outside of this func, and if entering it
	* we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
	* was just triggered. This prevents us from wasting time in busy
	* polling of WDT_WWPS_PEND_WTGR bit.
	*/
	}

	static int omap_wdt_set_timeout(unsigned int timeout)
	{
	struct wd_timer wdt = (struct wd_timer )WDT_BASE;
	u32 pre_margin = GET_WLDR_VAL(timeout);

	/* just count up at 32 KHz */
	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
	;

	writel(pre_margin, &wdt->wdtwldr);
	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
	;

	return 0;
	}

	void hw_watchdog_disable(void)
	{
	struct wd_timer wdt = (struct wd_timer )WDT_BASE;

	/*
	* Disable watchdog
	*/
	writel(0xAAAA, &wdt->wdtwspr);
	while (readl(&wdt->wdtwwps) != 0x0)
	;
	writel(0x5555, &wdt->wdtwspr);
	while (readl(&wdt->wdtwwps) != 0x0)
	;
	}

	void hw_watchdog_init(void)
	{
	struct wd_timer wdt = (struct wd_timer )WDT_BASE;

	/*
	* Make sure the watchdog is disabled. This is unfortunately required
	* because writing to various registers with the watchdog running has no
	* effect.
	*/
	hw_watchdog_disable();

	/* initialize prescaler */
	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
	;

	writel(WDT_WCLR_PRE \| (PTV << WDT_WCLR_PTV_OFF), &wdt->wdtwclr);
	while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
	;

	omap_wdt_set_timeout(WDT_HW_TIMEOUT);

	/* Sequence to enable the watchdog */
	writel(0xBBBB, &wdt->wdtwspr);
	while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
	;

	writel(0x4444, &wdt->wdtwspr);
	while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
	;
	}

	void watchdog_reset(void)
	{
	hw_watchdog_reset();
	}

	#else

	static int omap3_wdt_reset(struct udevice *dev)
	{
	struct omap3_wdt_priv *priv = dev_get_priv(dev);

	/*
	* Somebody just triggered watchdog reset and write to WTGR register
	* is in progress. It is resetting right now, no need to trigger it
	* again
	*/
	if ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
	return 0;

	priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
	writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);
	/*
	* Don't wait for posted write to complete, i.e. don't check
	* WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
	* WTGR register outside of this func, and if entering it
	* we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
	* was just triggered. This prevents us from wasting time in busy
	* polling of WDT_WWPS_PEND_WTGR bit.
	*/
	return 0;
	}

	static int omap3_wdt_stop(struct udevice *dev)
	{
	struct omap3_wdt_priv *priv = dev_get_priv(dev);

	/* disable watchdog */
	writel(0xAAAA, &priv->regs->wdtwspr);
	while (readl(&priv->regs->wdtwwps) != 0x0)
	;
	writel(0x5555, &priv->regs->wdtwspr);
	while (readl(&priv->regs->wdtwwps) != 0x0)
	;
	return 0;
	}

	static int omap3_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
	{
	struct omap3_wdt_priv *priv = dev_get_priv(dev);
	u32 pre_margin = GET_WLDR_VAL(timeout_ms / 1000);
	/*
	* Make sure the watchdog is disabled. This is unfortunately required
	* because writing to various registers with the watchdog running has
	* no effect.
	*/
	omap3_wdt_stop(dev);

	/* initialize prescaler */
	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
	;

	writel(WDT_WCLR_PRE \| (PTV << WDT_WCLR_PTV_OFF), &priv->regs->wdtwclr);
	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
	;
	/* just count up at 32 KHz */
	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
	;

	writel(pre_margin, &priv->regs->wdtwldr);
	while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
	;
	/* Sequence to enable the watchdog */
	writel(0xBBBB, &priv->regs->wdtwspr);
	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
	;

	writel(0x4444, &priv->regs->wdtwspr);
	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
	;

	/* Trigger the watchdog to actually reload the counter. */
	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
	;

	priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
	writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);

	while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
	;

	return 0;
	}

	static int omap3_wdt_probe(struct udevice *dev)
	{
	struct omap3_wdt_priv *priv = dev_get_priv(dev);

	priv->regs = dev_read_addr_ptr(dev);
	if (!priv->regs)
	return -EINVAL;

	priv->wdt_trgr_pattern = 0x1234;
	debug("%s: Probing wdt%u\n", __func__, dev_seq(dev));
	return 0;
	}

	static const struct wdt_ops omap3_wdt_ops = {
	.start = omap3_wdt_start,
	.stop = omap3_wdt_stop,
	.reset = omap3_wdt_reset,
	};

	static const struct udevice_id omap3_wdt_ids[] = {
	{ .compatible = "ti,omap3-wdt" },
	{ }
	};

	U_BOOT_DRIVER(omap3_wdt) = {
	.name = "omap3_wdt",
	.id = UCLASS_WDT,
	.of_match = omap3_wdt_ids,
	.ops = &omap3_wdt_ops,
	.probe = omap3_wdt_probe,
	.priv_auto = sizeof(struct omap3_wdt_priv),
	};
	#endif /* !CONFIG_IS_ENABLED(WDT) */