d70f67cd60
This patch adds a driver for the 8254 Programmable Interrupt Timer (PIT). The driver introduced by this patch programs the PIT to generate interrupt periodically. The interrupt frequency can be configured by the user. On each PIT interrupt, a callback configured by the user is called. As expected, that callback is executed in interrupt context so the user should be aware of what it is not supposed to do (e.g. to call blocking functions). Issues marked as FIXME are all related to missing APIs on the PIC driver so they will be addressed by a future commit.
46 lines
1.9 KiB
C
46 lines
1.9 KiB
C
/*
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* Copyright (C) 2015, Intel Corporation. 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
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* 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
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef PIT_H
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#define PIT_H
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#include <stdint.h>
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typedef void (*pit_int_callback)(void);
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/**
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* Initializes the 8254 Programmable Interrupt Timer chip (Counter 0 only).
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* The PIT Interrupt callback is implemented by the driver's users. It is
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* called from interrupt context, so it has to return as soon as possible.
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*/
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void pit_init(uint32_t ticks_rate, pit_int_callback c);
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#endif /* PIT_H */
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