1 /* 2 * OMAP2+ MPU WD_TIMER-specific code 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/io.h> 12 #include <linux/err.h> 13 14 #include <plat/omap_hwmod.h> 15 16 #include "wd_timer.h" 17 18 /* 19 * In order to avoid any assumptions from bootloader regarding WDT 20 * settings, WDT module is reset during init. This enables the watchdog 21 * timer. Hence it is required to disable the watchdog after the WDT reset 22 * during init. Otherwise the system would reboot as per the default 23 * watchdog timer registers settings. 24 */ 25 #define OMAP_WDT_WPS 0x34 26 #define OMAP_WDT_SPR 0x48 27 28 29 int omap2_wd_timer_disable(struct omap_hwmod *oh) 30 { 31 void __iomem *base; 32 33 if (!oh) { 34 pr_err("%s: Could not look up wdtimer_hwmod\n", __func__); 35 return -EINVAL; 36 } 37 38 base = omap_hwmod_get_mpu_rt_va(oh); 39 if (!base) { 40 pr_err("%s: Could not get the base address for %s\n", 41 oh->name, __func__); 42 return -EINVAL; 43 } 44 45 /* sequence required to disable watchdog */ 46 __raw_writel(0xAAAA, base + OMAP_WDT_SPR); 47 while (__raw_readl(base + OMAP_WDT_WPS) & 0x10) 48 cpu_relax(); 49 50 __raw_writel(0x5555, base + OMAP_WDT_SPR); 51 while (__raw_readl(base + OMAP_WDT_WPS) & 0x10) 52 cpu_relax(); 53 54 return 0; 55 } 56 57