afd9b5b0b7
This commit implements pic_eoi(int irq) and a helper macro PIC_INT(irq). This first checks which PICs should be 'acked' given an IRQ number, while the macro returns the actual system interrupt number for the IRQ according to the offset used on the PIC initialization.
91 lines
3.2 KiB
C
91 lines
3.2 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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#include "drivers/rtc.h"
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#include "drivers/pic.h"
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#include "helpers.h"
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#include "interrupt.h"
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#define RTC_INDEX_REGISTER 0x70
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#define RTC_TARGET_REGISTER 0x71
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#define RTC_IRQ 8
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#define RTC_INT PIC_INT(RTC_IRQ)
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static void (*user_callback)(void);
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static void
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rtc_handler()
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{
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user_callback();
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/* Clear Register C otherwise interrupts will not happen again.
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* Register C is automatically cleared when it is read so we do
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* a dummy read to clear it.
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*/
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outb(RTC_INDEX_REGISTER, 0x0C);
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inb(RTC_TARGET_REGISTER);
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/* Issue the End of Interrupt to PIC */
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pic_eoi(RTC_IRQ);
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}
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/*---------------------------------------------------------------------------*/
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/* Initialize the Real Time Clock.
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* @frequency: RTC has very specific values for frequency. They are: 2, 4, 8,
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* 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, and 8192 Hz.
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* value otherwise it will not work properly.
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* @callback: This callback is called every time the RTC IRQ is raised.
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* It is executed in interrupt context.
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*/
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void
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rtc_init(rtc_frequency_t frequency, void (*callback)(void))
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{
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uint8_t reg_a, reg_b;
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user_callback = callback;
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SET_INTERRUPT_HANDLER(RTC_INT, 0, rtc_handler);
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/* Select interrupt period to 7.8125 ms */
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outb(RTC_INDEX_REGISTER, 0x0A);
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reg_a = inb(RTC_TARGET_REGISTER);
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reg_a &= 0xF0;
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reg_a |= frequency;
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outb(RTC_INDEX_REGISTER, 0x0A);
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outb(RTC_TARGET_REGISTER, reg_a);
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/* Enable periodic interrupt */
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outb(RTC_INDEX_REGISTER, 0x0B);
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reg_b = inb(RTC_TARGET_REGISTER);
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outb(RTC_INDEX_REGISTER, 0x0B);
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outb(RTC_TARGET_REGISTER, reg_b | BIT(6));
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pic_unmask_irq(RTC_IRQ);
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}
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