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/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*****************************************************************************/
/**
* @file exti.c
*
* @brief External interrupt control routines
*/
#include "libmaple.h"
#include "exti.h"
#include "nvic.h"
typedef struct ExtIChannel {
void (*handler)(void);
uint32 irq_line;
} ExtIChannel;
static ExtIChannel exti_channels[] = {
{ .handler = NULL, .irq_line = NVIC_EXTI0 }, // EXTI0
{ .handler = NULL, .irq_line = NVIC_EXTI1 }, // EXTI1
{ .handler = NULL, .irq_line = NVIC_EXTI2 }, // EXTI2
{ .handler = NULL, .irq_line = NVIC_EXTI3 }, // EXTI3
{ .handler = NULL, .irq_line = NVIC_EXTI4 }, // EXTI4
{ .handler = NULL, .irq_line = NVIC_EXTI9_5 }, // EXTI5
{ .handler = NULL, .irq_line = NVIC_EXTI9_5 }, // EXTI6
{ .handler = NULL, .irq_line = NVIC_EXTI9_5 }, // EXTI7
{ .handler = NULL, .irq_line = NVIC_EXTI9_5 }, // EXTI8
{ .handler = NULL, .irq_line = NVIC_EXTI9_5 }, // EXTI9
{ .handler = NULL, .irq_line = NVIC_EXTI15_10 }, // EXTI10
{ .handler = NULL, .irq_line = NVIC_EXTI15_10 }, // EXTI11
{ .handler = NULL, .irq_line = NVIC_EXTI15_10 }, // EXTI12
{ .handler = NULL, .irq_line = NVIC_EXTI15_10 }, // EXTI13
{ .handler = NULL, .irq_line = NVIC_EXTI15_10 }, // EXTI14
{ .handler = NULL, .irq_line = NVIC_EXTI15_10 }, // EXTI15
};
static inline void clear_pending(int bit) {
__set_bits(EXTI_PR, BIT(bit));
/* If the pending bit is cleared as the last instruction in an ISR,
* it won't actually be cleared in time and the ISR will fire again.
* Insert a 2-cycle buffer to allow it to take effect. */
asm volatile("nop");
asm volatile("nop");
}
static inline void dispatch_handler(uint32 channel) {
ASSERT(exti_channels[channel].handler);
if (exti_channels[channel].handler) {
(exti_channels[channel].handler)();
}
}
/* For EXTI0 through EXTI4, only one handler
* is associated with each channel, so we
* don't have to keep track of which channel
* we came from */
void EXTI0_IRQHandler(void) {
dispatch_handler(EXTI0);
clear_pending(EXTI0);
}
void EXTI1_IRQHandler(void) {
dispatch_handler(EXTI1);
clear_pending(EXTI1);
}
void EXTI2_IRQHandler(void) {
dispatch_handler(EXTI2);
clear_pending(EXTI2);
}
void EXTI3_IRQHandler(void) {
dispatch_handler(EXTI3);
clear_pending(EXTI3);
}
void EXTI4_IRQHandler(void) {
dispatch_handler(EXTI4);
clear_pending(EXTI4);
}
void EXTI9_5_IRQHandler(void) {
/* Figure out which channel it came from */
uint32 pending;
uint32 i;
pending = REG_GET(EXTI_PR);
pending = GET_BITS(pending, 5, 9);
/* Dispatch every handler if the pending bit is set */
for (i = 0; i < 5; i++) {
if (pending & 0x1) {
dispatch_handler(EXTI5 + i);
clear_pending(EXTI5 + i);
}
pending >>= 1;
}
}
void EXTI15_10_IRQHandler(void) {
/* Figure out which channel it came from */
uint32 pending;
uint32 i;
pending = REG_GET(EXTI_PR);
pending = GET_BITS(pending, 10, 15);
/* Dispatch every handler if the pending bit is set */
for (i = 0; i < 6; i++) {
if (pending & 0x1) {
dispatch_handler(EXTI10 + i);
clear_pending(EXTI10 + i);
}
pending >>= 1;
}
}
/**
* @brief Register a handler to run upon external interrupt
* @param port source port of pin (eg EXTI_CONFIG_PORTA)
* @param pin pin number on the source port
* @param handler function handler to execute
* @param mode type of transition to trigger on
*/
void exti_attach_interrupt(uint32 port,
uint32 pin,
voidFuncPtr handler,
uint32 mode) {
static uint32 afio_regs[] = {
AFIO_EXTICR1, // EXT0-3
AFIO_EXTICR2, // EXT4-7
AFIO_EXTICR3, // EXT8-11
AFIO_EXTICR4, // EXT12-15
};
/* Note: All of the following code assumes that EXTI0 = 0 */
ASSERT(EXTI0 == 0);
ASSERT(handler);
uint32 channel = pin;
/* map port to channel */
__write(afio_regs[pin/4], (port << ((pin % 4) * 4)));
/* Unmask appropriate interrupt line */
__set_bits(EXTI_IMR, BIT(channel));
/* Set trigger mode */
switch (mode) {
case EXTI_RISING:
__set_bits(EXTI_RTSR, BIT(channel));
break;
case EXTI_FALLING:
__set_bits(EXTI_FTSR, BIT(channel));
break;
case EXTI_RISING_FALLING:
__set_bits(EXTI_RTSR, BIT(channel));
__set_bits(EXTI_FTSR, BIT(channel));
break;
}
/* Configure the enable interrupt bits for the NVIC */
nvic_irq_enable(exti_channels[channel].irq_line);
/* Register the handler */
exti_channels[channel].handler = handler;
}
/**
* @brief Unregister an external interrupt handler
* @param channel channel to disable (eg EXTI0)
*/
void exti_detach_interrupt(uint32 channel) {
ASSERT(channel < NR_EXTI_CHANNELS);
ASSERT(EXTI0 == 0);
__clear_bits(EXTI_IMR, BIT(channel));
__clear_bits(EXTI_FTSR, BIT(channel));
__clear_bits(EXTI_RTSR, BIT(channel));
nvic_irq_disable(exti_channels[channel].irq_line);
exti_channels[channel].handler = NULL;
}
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