samd/samd_isr: Change the way a Sercom ISR is registered and called.

Code size diff: +12 Bytes
BSS diff: -12 Bytes
RAM usage: +16 Bytes
Speed increase: a few clock cycles per call
Style improvement: ++

Author: robert-hh

ports/samd/machine_i2c.c

@@ -188,7 +188,7 @@ mp_obj_t machine_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
     i2c->I2CM.BAUD.reg = get_apb_freq() / (2 * self->freq) - 5 - (get_apb_freq() / 1000000) * RISETIME_NS / 2000;
 
     // Enable interrupts
-    sercom_register_irq(self->id, SERCOM_IRQ_TYPE_SPI);
+    sercom_register_irq(self->id, &common_i2c_irq_handler);
     #if defined(MCU_SAMD21)
     NVIC_EnableIRQ(SERCOM0_IRQn + self->id);
     #elif defined(MCU_SAMD51)

ports/samd/machine_spi.c

@@ -218,7 +218,7 @@ STATIC void machine_spi_init(mp_obj_base_t *self_in, size_t n_args, const mp_obj
             #elif defined(MCU_SAMD51)
             NVIC_EnableIRQ(SERCOM0_0_IRQn + 4 * self->id + 2);
             #endif
-            sercom_register_irq(self->id, SERCOM_IRQ_TYPE_SPI);
+            sercom_register_irq(self->id, &common_spi_irq_handler);
         }
 
         sercom_enable(spi, 1);

ports/samd/machine_uart.c

@@ -281,7 +281,7 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
         #elif defined(MCU_SAMD51)
         NVIC_EnableIRQ(SERCOM0_0_IRQn + 4 * self->id + 2);
         #endif
-        sercom_register_irq(self->id, SERCOM_IRQ_TYPE_UART);
+        sercom_register_irq(self->id, &common_uart_irq_handler);
 
         sercom_enable(uart, 1);
     }

ports/samd/samd_isr.c

@@ -108,21 +108,17 @@ void PendSV_Handler(void) {
 }
 
 
-static uint8_t sercom_irq_type[SERCOM_INST_NUM] = {};
+void (*sercom_irq_handler_table[SERCOM_INST_NUM])(int num) = {};
 
-void (*sercom_irq_handler_table[])(int num) = {
-    common_uart_irq_handler,
-    common_spi_irq_handler,
-    common_i2c_irq_handler
-};
-
-void sercom_register_irq(int sercom_id, int mode) {
-    sercom_irq_type[sercom_id] = mode;
+void sercom_register_irq(int sercom_id, void (*sercom_irq_handler)) {
+    if (sercom_id < SERCOM_INST_NUM) {
+        sercom_irq_handler_table[sercom_id] = sercom_irq_handler;
+    }
 }
 
 static inline void common_sercom_irq_handler(int sercom_id) {
-    if (sercom_irq_handler_table[sercom_irq_type[sercom_id]]) {
-        sercom_irq_handler_table[sercom_irq_type[sercom_id]](sercom_id);
+    if (sercom_irq_handler_table[sercom_id]) {
+        sercom_irq_handler_table[sercom_id](sercom_id);
     }
 }
 

ports/samd/samd_soc.h

@@ -39,11 +39,8 @@ void USB_1_Handler_wrapper(void);
 void USB_2_Handler_wrapper(void);
 void USB_3_Handler_wrapper(void);
 
-void common_uart_irq_handler(int uart_nr);
-void common_spi_irq_handler(int spi_nr);
-void common_i2c_irq_handler(int i2c_nr);
 void sercom_enable(Sercom *spi, int state);
-void sercom_register_irq(int sercom_id, int mode);
+void sercom_register_irq(int sercom_id, void (*sercom_irq_handler));
 
 #define SERCOM_IRQ_TYPE_UART  (0)
 #define SERCOM_IRQ_TYPE_SPI   (1)