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3804197383
Based on SP805 Programmer's model (ARM DDI 0270B). This driver
provides three public APIs:
void sp805_start(uintptr_t base, unsigned long ticks);
void sp805_stop(uintptr_t base);
void sp805_refresh(uintptr_t base, unsigned long ticks);
Upon start, the watchdog starts counting down from the number of
ticks specified. When the count reaches 0 an interrupt is triggered.
The watchdog restarts counting down from the number of ticks
specified. If the count reaches 0 again, the system is reset. A
mechanism to handle the interrupt has not been implemented. Instead,
the API to refresh the watchdog should be used instead to prevent a
system reset.
Change-Id: I799d53f8d1213b10b341a4a67fde6486e89a3dab
75 lines
2.5 KiB
C
75 lines
2.5 KiB
C
/*
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* Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of ARM nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <mmio.h>
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#include <sp805.h>
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#include <stdint.h>
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/* Inline register access functions */
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static inline void sp805_write_wdog_load(uintptr_t base, unsigned long value)
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{
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mmio_write_32(base + SP805_WDOG_LOAD_OFF, value);
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}
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static inline void sp805_write_wdog_ctrl(uintptr_t base, unsigned long value)
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{
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mmio_write_32(base + SP805_WDOG_CTR_OFF, value);
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}
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static inline void sp805_write_wdog_lock(uintptr_t base, unsigned long value)
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{
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mmio_write_32(base + SP805_WDOG_LOCK_OFF, value);
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}
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/* Public API implementation */
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void sp805_start(uintptr_t base, unsigned long ticks)
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{
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sp805_write_wdog_load(base, ticks);
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sp805_write_wdog_ctrl(base, SP805_CTR_RESEN | SP805_CTR_INTEN);
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/* Lock registers access */
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sp805_write_wdog_lock(base, 0);
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}
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void sp805_stop(uintptr_t base)
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{
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sp805_write_wdog_lock(base, WDOG_UNLOCK_KEY);
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sp805_write_wdog_ctrl(base, 0);
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}
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void sp805_refresh(uintptr_t base, unsigned long ticks)
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{
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sp805_write_wdog_lock(base, WDOG_UNLOCK_KEY);
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sp805_write_wdog_load(base, ticks);
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sp805_write_wdog_lock(base, 0);
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}
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