diff options
Diffstat (limited to 'src/lib/exti.c')
-rw-r--r-- | src/lib/exti.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/src/lib/exti.c b/src/lib/exti.c new file mode 100644 index 0000000..8e46bb1 --- /dev/null +++ b/src/lib/exti.c @@ -0,0 +1,250 @@ +#include "exti.h" +#include "util.h" + +volatile static voidFuncPtr exti_handlers[NR_EXTI_CHANNELS]; + +static inline void clear_pending(int bit) { + REG_SET(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"); +} + +/* 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) { + ASSERT(exti_handlers[EXTI0]); + if (exti_handlers[EXTI0]) { + exti_handlers[EXTI0](); + } + + /* Clear pending bit*/ + clear_pending(EXTI0); +} + +void EXTI1_IRQHandler(void) { + ASSERT(exti_handlers[EXTI1]); + /* Call registered handler */ + if (exti_handlers[EXTI1]) { + exti_handlers[EXTI1](); + } + + /* Clear pending bit*/ + clear_pending(EXTI1); +} + +void EXTI2_IRQHandler(void) { + ASSERT(exti_handlers[EXTI2]); + /* Call registered handler */ + if (exti_handlers[EXTI2]) { + exti_handlers[EXTI2](); + } + + /* Clear pending bit*/ + clear_pending(EXTI2); +} + +void EXTI3_IRQHandler(void) { + ASSERT(exti_handlers[EXTI3]); + /* Call registered handler */ + if (exti_handlers[EXTI3]) { + exti_handlers[EXTI3](); + } + + /* Clear pending bit*/ + clear_pending(EXTI3); +} + +void EXTI4_IRQHandler(void) { + ASSERT(exti_handlers[EXTI4]); + /* Call registered handler */ + if (exti_handlers[EXTI4]) { + exti_handlers[EXTI4](); + } + + /* Clear pending bit*/ + clear_pending(EXTI4); +} + +void EXTI9_5_IRQHandler(void) { + /* Figure out which channel it came from */ + uint32_t pending; + uint32_t 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) { + exti_handlers[EXTI5 + i](); + clear_pending(EXTI5 + i); + } + pending >>= 1; + } +} + +void EXTI15_10_IRQHandler(void) { + /* Figure out which channel it came from */ + uint32_t pending; + uint32_t 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) { + exti_handlers[EXTI10 + i](); + clear_pending(EXTI10 + i); + } + pending >>= 1; + } +} + + +void exti_attach_interrupt(uint8_t channel, uint8_t port, voidFuncPtr handler, uint8_t mode) { + ASSERT(channel < NR_EXTI_CHANNELS); + ASSERT(port < NR_EXTI_PORTS); + ASSERT(mode < NR_EXTI_MODES); + ASSERT(EXTI0 == 0); + + /* Note: All of the following code assumes that EXTI0 = 0 */ + + /* Map port to the correct EXTI channel */ + switch (channel) { + case EXTI0: + case EXTI1: + case EXTI2: + case EXTI3: + REG_SET_MASK(AFIO_EXTICR1, BIT_MASK_SHIFT(port, channel*4)); + break; + + case EXTI4: + case EXTI5: + case EXTI6: + case EXTI7: + REG_SET_MASK(AFIO_EXTICR2, BIT_MASK_SHIFT(port, (channel-4)*4)); + break; + + case EXTI8: + case EXTI9: + case EXTI10: + case EXTI11: + REG_SET_MASK(AFIO_EXTICR3, BIT_MASK_SHIFT(port, (channel-8)*4)); + break; + + case EXTI12: + case EXTI13: + case EXTI14: + case EXTI15: + REG_SET_MASK(AFIO_EXTICR4, BIT_MASK_SHIFT(port, (channel-12)*4)); + break; + } + + /* Unmask appropriate interrupt line */ + REG_SET_BIT(EXTI_IMR, channel); + + /* Set trigger mode */ + switch (mode) { + case EXTI_RISING: + REG_SET_BIT(EXTI_RTSR, channel); + break; + + case EXTI_FALLING: + REG_SET_BIT(EXTI_FTSR, channel); + break; + + case EXTI_RISING_FALLING: + REG_SET_BIT(EXTI_RTSR, channel); + REG_SET_BIT(EXTI_FTSR, channel); + break; + } + + /* Configure the enable interrupt bits for the NVIC */ + switch (channel) { + case EXTI0: + case EXTI1: + case EXTI2: + case EXTI3: + case EXTI4: + REG_SET(NVIC_ISER0, BIT(channel + 6)); + break; + + /* EXTI5-9 map to the same isr */ + case EXTI5: + case EXTI6: + case EXTI7: + case EXTI8: + case EXTI9: + REG_SET(NVIC_ISER0, BIT(23)); + break; + + /* EXTI10-15 map to the same isr */ + case EXTI10: + case EXTI11: + case EXTI12: + case EXTI13: + case EXTI14: + case EXTI15: + REG_SET(NVIC_ISER1, BIT(8)); + break; + } + + /* Register the handler */ + exti_handlers[channel] = handler; +} + + +void exti_detach_interrupt(uint8_t channel) { + ASSERT(channel < NR_EXTI_CHANNELS); + ASSERT(EXTI0 == 0); + /* Is this interrupt actually on? */ + ASSERT((REG_GET(EXTI_IMR) >> channel) & 0x01); + + /* Clear EXTI_IMR line */ + REG_CLEAR_BIT(EXTI_IMR, channel); + + /* Clear triggers */ + REG_CLEAR_BIT(EXTI_FTSR, channel); + REG_CLEAR_BIT(EXTI_RTSR, channel); + + /* Turn off the associated interrupt */ + switch (channel) { + case EXTI0: + case EXTI1: + case EXTI2: + case EXTI3: + case EXTI4: + REG_SET(NVIC_ICER0, BIT(channel + 6)); + break; + case EXTI5: + case EXTI6: + case EXTI7: + case EXTI8: + case EXTI9: + /* Are there any other channels enabled? + * If so, don't disable the interrupt handler */ + if (GET_BITS(REG_GET(EXTI_IMR), 5, 9) == 0) { + REG_SET(NVIC_ICER0, BIT(23)); + } + break; + case EXTI10: + case EXTI11: + case EXTI12: + case EXTI13: + case EXTI14: + case EXTI15: + /* Are there any other channels enabled? + * If so, don't disable the interrupt handler */ + if (GET_BITS(REG_GET(EXTI_IMR), 10, 15) == 0) { + REG_SET(NVIC_ICER1, BIT(8)); + } + break; + } + + /* Clear handler function pointer */ + exti_handlers[channel] = 0; +} |