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  • /*
     * omap_wdt.c
     *
     * (C) Copyright 2013
     * Heiko Schocher, DENX Software Engineering, hs@denx.de.
     *
     * SPDX-License-Identifier:	GPL-2.0
     *
     * 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 <watchdog.h>
    #include <asm/arch/hardware.h>
    #include <asm/io.h>
    #include <asm/processor.h>
    #include <asm/arch/cpu.h>
    
    /* Hardware timeout in seconds */
    #define WDT_HW_TIMEOUT 60
    
    static unsigned int wdt_trgr_pattern = 0x1234;
    
    void hw_watchdog_reset(void)
    {
    	struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
    
    	/* wait for posted write to complete */
    	while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
    		;
    
    	wdt_trgr_pattern = ~wdt_trgr_pattern;
    	writel(wdt_trgr_pattern, &wdt->wdtwtgr);
    
    	/* wait for posted write to complete */
    	while ((readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WTGR))
    		;
    }
    
    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_init(void)
    {
    	struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
    
    	/* 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 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)
    		;
    }