14074Swollman// SPDX-License-Identifier: GPL-2.0-or-later 24074Swollman/* 34074Swollman * OMAP2+ MPU WD_TIMER-specific code 44074Swollman * 54074Swollman * Copyright (C) 2012 Texas Instruments, Inc. 64074Swollman */ 75792Swollman 84074Swollman#include <linux/kernel.h> 94074Swollman#include <linux/io.h> 104074Swollman#include <linux/err.h> 114074Swollman 124074Swollman#include <linux/platform_data/omap-wd-timer.h> 134074Swollman 144074Swollman#include "omap_hwmod.h" 154074Swollman#include "omap_device.h" 164074Swollman#include "wd_timer.h" 174074Swollman#include "common.h" 184074Swollman#include "prm.h" 194074Swollman#include "soc.h" 204074Swollman 214074Swollman/* 224074Swollman * In order to avoid any assumptions from bootloader regarding WDT 234074Swollman * settings, WDT module is reset during init. This enables the watchdog 244074Swollman * timer. Hence it is required to disable the watchdog after the WDT reset 254074Swollman * during init. Otherwise the system would reboot as per the default 264074Swollman * watchdog timer registers settings. 274074Swollman */ 284074Swollman#define OMAP_WDT_WPS 0x34 294074Swollman#define OMAP_WDT_SPR 0x48 304893Swollman 314074Swollmanint omap2_wd_timer_disable(struct omap_hwmod *oh) 324074Swollman{ 334074Swollman void __iomem *base; 344074Swollman 354074Swollman if (!oh) { 364074Swollman pr_err("%s: Could not look up wdtimer_hwmod\n", __func__); 374074Swollman return -EINVAL; 385101Swollman } 394074Swollman 404074Swollman base = omap_hwmod_get_mpu_rt_va(oh); 414074Swollman if (!base) { 424074Swollman pr_err("%s: Could not get the base address for %s\n", 434074Swollman oh->name, __func__); 444074Swollman return -EINVAL; 454074Swollman } 464074Swollman 474074Swollman /* sequence required to disable watchdog */ 484074Swollman writel_relaxed(0xAAAA, base + OMAP_WDT_SPR); 494074Swollman while (readl_relaxed(base + OMAP_WDT_WPS) & 0x10) 505792Swollman cpu_relax(); 514074Swollman 525792Swollman writel_relaxed(0x5555, base + OMAP_WDT_SPR); 535792Swollman while (readl_relaxed(base + OMAP_WDT_WPS) & 0x10) 545792Swollman cpu_relax(); 555792Swollman 565792Swollman return 0; 575792Swollman} 584074Swollman 594105Swollman/** 604074Swollman * omap2_wd_timer_reset - reset and disable the WDTIMER IP block 614074Swollman * @oh: struct omap_hwmod * 624074Swollman * 634105Swollman * After the WDTIMER IP blocks are reset on OMAP2/3, we must also take 644105Swollman * care to execute the special watchdog disable sequence. This is 654105Swollman * because the watchdog is re-armed upon OCP softreset. (On OMAP4, 664074Swollman * this behavior was apparently changed and the watchdog is no longer 674074Swollman * re-armed after an OCP soft-reset.) Returns -ETIMEDOUT if the reset 684074Swollman * did not complete, or 0 upon success. 694074Swollman * 704074Swollman * XXX Most of this code should be moved to the omap_hwmod.c layer 714074Swollman * during a normal merge window. omap_hwmod_softreset() should be 724074Swollman * renamed to omap_hwmod_set_ocp_softreset(), and omap_hwmod_softreset() 734074Swollman * should call the hwmod _ocp_softreset() code. 745101Swollman * 755101Swollman * Returns: %0 on success or -errno value on error. 764105Swollman */ 774074Swollmanint omap2_wd_timer_reset(struct omap_hwmod *oh) 784074Swollman{ 794074Swollman int c = 0; 804074Swollman 814074Swollman /* Write to the SOFTRESET bit */ 825792Swollman omap_hwmod_softreset(oh); 834893Swollman 844105Swollman /* Poll on RESETDONE bit */ 854074Swollman omap_test_timeout((omap_hwmod_read(oh, 865792Swollman oh->class->sysc->syss_offs) 874074Swollman & SYSS_RESETDONE_MASK), 884074Swollman MAX_MODULE_SOFTRESET_WAIT, c); 894074Swollman 904074Swollman if (oh->class->sysc->srst_udelay) 914074Swollman udelay(oh->class->sysc->srst_udelay); 924074Swollman 934074Swollman if (c == MAX_MODULE_SOFTRESET_WAIT) 945792Swollman pr_warn("%s: %s: softreset failed (waited %d usec)\n", 955792Swollman __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 965792Swollman else 974105Swollman pr_debug("%s: %s: softreset in %d usec\n", __func__, 984074Swollman oh->name, c); 994074Swollman 1005101Swollman return (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT : 1015101Swollman omap2_wd_timer_disable(oh); 1024105Swollman} 1034074Swollman