Initial commit of library code, moved from leaftest repo

git-svn-id: https://leaflabs.googlecode.com/svn/trunk/library@69 749a229e-a60e-11de-b98f-4500b42dc123

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;
+}