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https://github.com/AsahiLinux/u-boot
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268 lines
6.7 KiB
C
268 lines
6.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* omap_wdt.c
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*
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* (C) Copyright 2013
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* Heiko Schocher, DENX Software Engineering, hs@denx.de.
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*
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* Based on:
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*
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* Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
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*
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* commit 2d991a164a61858012651e13c59521975504e260
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* Author: Bill Pemberton <wfp5p@virginia.edu>
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* Date: Mon Nov 19 13:21:41 2012 -0500
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*
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* watchdog: remove use of __devinit
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*
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* CONFIG_HOTPLUG is going away as an option so __devinit is no longer
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* needed.
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*
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* Author: MontaVista Software, Inc.
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* <gdavis@mvista.com> or <source@mvista.com>
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*
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* History:
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*
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* 20030527: George G. Davis <gdavis@mvista.com>
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* Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
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* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
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* Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
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*
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* Copyright (c) 2004 Texas Instruments.
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* 1. Modified to support OMAP1610 32-KHz watchdog timer
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* 2. Ported to 2.6 kernel
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*
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* Copyright (c) 2005 David Brownell
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* Use the driver model and standard identifiers; handle bigger timeouts.
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*/
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#include <common.h>
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#include <log.h>
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#include <watchdog.h>
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#include <asm/arch/hardware.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/arch/cpu.h>
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#include <wdt.h>
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#include <dm.h>
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#include <errno.h>
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/* Hardware timeout in seconds */
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#define WDT_HW_TIMEOUT 60
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#if !CONFIG_IS_ENABLED(WDT)
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static unsigned int wdt_trgr_pattern = 0x1234;
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void hw_watchdog_reset(void)
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{
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struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
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/*
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* Somebody just triggered watchdog reset and write to WTGR register
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* is in progress. It is resetting right now, no need to trigger it
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* again
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*/
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if ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
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return;
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wdt_trgr_pattern = ~wdt_trgr_pattern;
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writel(wdt_trgr_pattern, &wdt->wdtwtgr);
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/*
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* Don't wait for posted write to complete, i.e. don't check
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* WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
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* WTGR register outside of this func, and if entering it
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* we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
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* was just triggered. This prevents us from wasting time in busy
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* polling of WDT_WWPS_PEND_WTGR bit.
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*/
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}
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static int omap_wdt_set_timeout(unsigned int timeout)
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{
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struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
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u32 pre_margin = GET_WLDR_VAL(timeout);
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/* just count up at 32 KHz */
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while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
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;
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writel(pre_margin, &wdt->wdtwldr);
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while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
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;
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return 0;
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}
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void hw_watchdog_disable(void)
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{
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struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
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/*
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* Disable watchdog
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*/
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writel(0xAAAA, &wdt->wdtwspr);
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while (readl(&wdt->wdtwwps) != 0x0)
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;
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writel(0x5555, &wdt->wdtwspr);
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while (readl(&wdt->wdtwwps) != 0x0)
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;
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}
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void hw_watchdog_init(void)
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{
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struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
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/*
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* Make sure the watchdog is disabled. This is unfortunately required
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* because writing to various registers with the watchdog running has no
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* effect.
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*/
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hw_watchdog_disable();
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/* initialize prescaler */
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while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
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;
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writel(WDT_WCLR_PRE | (PTV << WDT_WCLR_PTV_OFF), &wdt->wdtwclr);
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while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
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;
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omap_wdt_set_timeout(WDT_HW_TIMEOUT);
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/* Sequence to enable the watchdog */
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writel(0xBBBB, &wdt->wdtwspr);
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while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
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;
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writel(0x4444, &wdt->wdtwspr);
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while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
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;
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}
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void watchdog_reset(void)
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{
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hw_watchdog_reset();
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}
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#else
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static int omap3_wdt_reset(struct udevice *dev)
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{
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struct omap3_wdt_priv *priv = dev_get_priv(dev);
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/*
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* Somebody just triggered watchdog reset and write to WTGR register
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* is in progress. It is resetting right now, no need to trigger it
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* again
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*/
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if ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
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return 0;
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priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
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writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);
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/*
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* Don't wait for posted write to complete, i.e. don't check
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* WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
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* WTGR register outside of this func, and if entering it
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* we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
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* was just triggered. This prevents us from wasting time in busy
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* polling of WDT_WWPS_PEND_WTGR bit.
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*/
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return 0;
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}
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static int omap3_wdt_stop(struct udevice *dev)
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{
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struct omap3_wdt_priv *priv = dev_get_priv(dev);
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/* disable watchdog */
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writel(0xAAAA, &priv->regs->wdtwspr);
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while (readl(&priv->regs->wdtwwps) != 0x0)
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;
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writel(0x5555, &priv->regs->wdtwspr);
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while (readl(&priv->regs->wdtwwps) != 0x0)
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;
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return 0;
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}
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static int omap3_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
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{
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struct omap3_wdt_priv *priv = dev_get_priv(dev);
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u32 pre_margin = GET_WLDR_VAL(timeout_ms / 1000);
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/*
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* Make sure the watchdog is disabled. This is unfortunately required
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* because writing to various registers with the watchdog running has
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* no effect.
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*/
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omap3_wdt_stop(dev);
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/* initialize prescaler */
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while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
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;
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writel(WDT_WCLR_PRE | (PTV << WDT_WCLR_PTV_OFF), &priv->regs->wdtwclr);
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while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
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;
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/* just count up at 32 KHz */
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while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
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;
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writel(pre_margin, &priv->regs->wdtwldr);
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while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
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;
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/* Sequence to enable the watchdog */
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writel(0xBBBB, &priv->regs->wdtwspr);
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while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
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;
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writel(0x4444, &priv->regs->wdtwspr);
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while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
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;
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/* Trigger the watchdog to actually reload the counter. */
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while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
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;
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priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
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writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);
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while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
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;
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return 0;
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}
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static int omap3_wdt_probe(struct udevice *dev)
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{
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struct omap3_wdt_priv *priv = dev_get_priv(dev);
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priv->regs = (struct wd_timer *)devfdt_get_addr(dev);
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if (!priv->regs)
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return -EINVAL;
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priv->wdt_trgr_pattern = 0x1234;
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debug("%s: Probing wdt%u\n", __func__, dev->seq);
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return 0;
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}
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static const struct wdt_ops omap3_wdt_ops = {
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.start = omap3_wdt_start,
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.stop = omap3_wdt_stop,
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.reset = omap3_wdt_reset,
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};
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static const struct udevice_id omap3_wdt_ids[] = {
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{ .compatible = "ti,omap3-wdt" },
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{ }
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};
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U_BOOT_DRIVER(omap3_wdt) = {
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.name = "omap3_wdt",
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.id = UCLASS_WDT,
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.of_match = omap3_wdt_ids,
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.ops = &omap3_wdt_ops,
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.probe = omap3_wdt_probe,
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.priv_auto_alloc_size = sizeof(struct omap3_wdt_priv),
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};
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#endif /* !CONFIG_IS_ENABLED(WDT) */
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