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linux/arch/arm/mach-omap2/wd_timer.h

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OMAP2+: wd_timer: separate watchdog disable code from the rest of mach-omap2/devices.c Split the wd_timer disable code out into its own file, mach-omap2/wd_timer.c; it belongs in its own file rather than cluttering up devices.c. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Charulatha Varadarajan <charu@ti.com>
2010-12-22 05:56:17 +03:00
/*
* OMAP2+ MPU WD_TIMER-specific function prototypes
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __ARCH_ARM_MACH_OMAP2_WD_TIMER_H
#define __ARCH_ARM_MACH_OMAP2_WD_TIMER_H
ARM: OMAP: Make plat/omap_hwmod.h local to mach-omap2 Let's make omap_hwmod local to mach-omap2 for ARM common zImage support. Signed-off-by: Tony Lindgren <tony@atomide.com>
2012-10-03 04:41:35 +04:00
#include "omap_hwmod.h"
OMAP2+: wd_timer: separate watchdog disable code from the rest of mach-omap2/devices.c Split the wd_timer disable code out into its own file, mach-omap2/wd_timer.c; it belongs in its own file rather than cluttering up devices.c. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Charulatha Varadarajan <charu@ti.com>
2010-12-22 05:56:17 +03:00
extern int omap2_wd_timer_disable(struct omap_hwmod *oh);
ARM: OMAP2+: WDTIMER integration: fix !PM boot crash, disarm timer after hwmod reset Without runtime PM enabled, hwmod needs to leave all IP blocks in an enabled state by default so any driver access to the HW will succeed. This is accomplished by seting the postsetup_state to enabled for all hwmods during init when runtime PM is disabled. Currently, we have a special case for WDT in that its postsetup_state is always set to disabled. This is done so that the WDT is disabled and the timer is disarmed at boot in case there is no WDT driver. This also means that when runtime PM is disabled, if a WDT driver *is* built in the kernel, the kernel will crash on the first access to the WDT hardware. We can't simply leave the WDT module enabled, because the timer is armed by default after reset. That means that if there is no WDT driver initialzed or loaded before the timer expires, the kernel will reboot. To fix this, a custom reset method is added to the watchdog class of omap_hwmod. This method will *always* disarm the timer after hwmod reset. The WDT timer then will only be rearmed when/if the driver is loaded for the WDT. With the timer disarmed by default, we no longer need a special-case for the postsetup_state of WDT during init, so it is removed. Any platforms wishing to ensure the watchdog remains armed across the entire boot boot can simply disable the reset-on-init feature of the watchdog hwmod using omap_hwmod_no_setup_reset(). Tested on 3530/Overo, 4430/Panda. NOTE: on 4430, the hwmod OCP reset does not seem to rearm the timer as documented in the TRM (and what happens on OMAP3.) I noticed this because testing the HWMOD_INIT_NO_RESET feature with no driver loaded, I expected a reboot part way through the boot, but did not see a reboot. Adding some debug to read the counter, I verified that right after OCP softreset, the counter is not firing. After writing the magic start sequence, the timer starts counting. This means that the timer disarm sequence added here does not seem to be needed for 4430, but is technically the correct way to ensure the timer is disarmed, so it is left in for OMAP4. Special thanks to Paul Walmsley for helping brainstorm ideas to fix this problem. Cc: Paul Walmsley <paul@pwsan.com> Signed-off-by: Kevin Hilman <khilman@ti.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> [paul@pwsan.com: updated the omap2_wd_timer_reset() function in the wake of commit 3c55c1baffa5f719eb2ae9729088bc867f972f53 ("ARM: OMAP2+: hwmod: Revert "ARM: OMAP2+: hwmod: Make omap_hwmod_softreset wait for reset status""); added kerneldoc; rolled in warning fix from Kevin] Signed-off-by: Paul Walmsley <paul@pwsan.com>
2012-05-08 21:34:30 +04:00
extern int omap2_wd_timer_reset(struct omap_hwmod *oh);
OMAP2+: wd_timer: separate watchdog disable code from the rest of mach-omap2/devices.c Split the wd_timer disable code out into its own file, mach-omap2/wd_timer.c; it belongs in its own file rather than cluttering up devices.c. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Charulatha Varadarajan <charu@ti.com>
2010-12-22 05:56:17 +03:00
#endif
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