Clean up various C source and headers to appease -Wstrict-prototypes

In C, func() is a function taking an unspecified number of arguments,
vs func(void) a function taking no arguments. In C++ both forms indicate
"no arguments."

Update these headers to use the (void) form, which is correct in both
languages and avoids complaints when -Wstrict-prototypes is specified.

src/rp2_common/pico_multicore/include/pico/multicore.h

@@ -36,7 +36,7 @@ extern "C" {
  *  \ingroup pico_multicore
  *
  */
-void multicore_reset_core1();
+void multicore_reset_core1(void);
 
 /*! \brief  Run code on core 1
  *  \ingroup pico_multicore
@@ -58,7 +58,7 @@ void multicore_launch_core1_with_stack(void (*entry)(void), uint32_t *stack_bott
  *  \ingroup pico_multicore
  *
  */
-void multicore_sleep_core1();
+void multicore_sleep_core1(void);
 
 /*! \brief  Launch code on core 1 with no stack protection
  *  \ingroup pico_multicore
@@ -85,7 +85,7 @@ void multicore_launch_core1_raw(void (*entry)(void), uint32_t *sp, uint32_t vect
  *
  * \return true if the FIFO has data in it, false otherwise
  */
-static inline bool multicore_fifo_rvalid() {
+static inline bool multicore_fifo_rvalid(void) {
     return !!(sio_hw->fifo_st & SIO_FIFO_ST_VLD_BITS);
 }
 
@@ -94,7 +94,7 @@ static inline bool multicore_fifo_rvalid() {
  *
  *  @return true if the FIFO is full, false otherwise
  */
-static inline bool multicore_fifo_wready() {
+static inline bool multicore_fifo_wready(void) {
     return !!(sio_hw->fifo_st & SIO_FIFO_ST_RDY_BITS);
 }
 
@@ -120,7 +120,7 @@ bool multicore_fifo_push_timeout_us(uint32_t data, uint64_t timeout_us);
  *
  * \return 32 bit unsigned data from the FIFO.
  */
-uint32_t multicore_fifo_pop_blocking();
+uint32_t multicore_fifo_pop_blocking(void);
 
 bool multicore_fifo_pop_timeout_us(uint64_t timeout_us, uint32_t *out);
 
@@ -128,7 +128,7 @@ bool multicore_fifo_pop_timeout_us(uint64_t timeout_us, uint32_t *out);
  *  \ingroup multicore_fifo
  *
  */
-static inline void multicore_fifo_drain() {
+static inline void multicore_fifo_drain(void) {
     while (multicore_fifo_rvalid())
         (void) sio_hw->fifo_rd;
 }
@@ -136,7 +136,7 @@ static inline void multicore_fifo_drain() {
 /*! \brief Clear FIFO interrupt
  *  \ingroup multicore_fifo
 */
-static inline void multicore_fifo_clear_irq() {
+static inline void multicore_fifo_clear_irq(void) {
     // Write any value to clear any interrupts
     sio_hw->fifo_st = 0xff;
 }
@@ -153,19 +153,19 @@ static inline void multicore_fifo_clear_irq() {
  * 1 | Value is 1 if this core’s TX FIFO is not full (i.e. if FIFO_WR is ready for more data)
  * 0 | Value is 1 if this core’s RX FIFO is not empty (i.e. if FIFO_RD is valid)
 */
-static inline int32_t multicore_fifo_get_status() {
+static inline int32_t multicore_fifo_get_status(void) {
     return sio_hw->fifo_st;
 }
 
 // call this from the lockout victim thread
-void multicore_lockout_victim_init();
+void multicore_lockout_victim_init(void);
 
 // start locking out the other core (it will be
 bool multicore_lockout_start_timeout_us(uint64_t timeout_us);
-void multicore_lockout_start_blocking();
+void multicore_lockout_start_blocking(void);
 
 bool multicore_lockout_end_timeout_us(uint64_t timeout_us);
-void multicore_lockout_end_blocking();
+void multicore_lockout_end_blocking(void);
 
 #ifdef __cplusplus
 }

src/rp2_common/pico_multicore/multicore.c

@@ -46,7 +46,7 @@ bool multicore_fifo_push_timeout_us(uint32_t data, uint64_t timeout_us) {
     return true;
 }
 
-static inline uint32_t multicore_fifo_pop_blocking_inline() {
+static inline uint32_t multicore_fifo_pop_blocking_inline(void) {
     // If nothing there yet, we wait for an event first,
     // to try and avoid too much busy waiting
     while (!multicore_fifo_rvalid())
@@ -75,7 +75,7 @@ bool multicore_fifo_pop_timeout_us(uint64_t timeout_us, uint32_t *out) {
 // Default stack for core1 ... if multicore_launch_core1 is not included then .stack1 section will be garbage collected
 static uint32_t __attribute__((section(".stack1"))) core1_stack[PICO_CORE1_STACK_SIZE / sizeof(uint32_t)];
 
-static void __attribute__ ((naked)) core1_trampoline() {
+static void __attribute__ ((naked)) core1_trampoline(void) {
     __asm("pop {r0, r1, pc}");
 }
 
@@ -110,7 +110,7 @@ void multicore_sleep_core1() {
     // note we give core1 an invalid stack pointer, as it should not be used
     // note also if we ge simply passed a function that returned immediately, we'd end up in core1_hang anyway
     //  however that would waste 2 bytes for that function (the horror!)
-    extern void core1_hang(); // in crt0.S
+    extern void core1_hang(void); // in crt0.S
     multicore_launch_core1_raw(core1_hang, (uint32_t *) -1, scb_hw->vtor);
 }
 
@@ -161,7 +161,7 @@ static bool lockout_in_progress;
 
 // note this method is in RAM because lockout is used when writing to flash
 // it only makes inline calls
-static void __isr __not_in_flash_func(multicore_lockout_handler)() {
+static void __isr __not_in_flash_func(multicore_lockout_handler)(void) {
     multicore_fifo_clear_irq();
     while (multicore_fifo_rvalid()) {
         if (sio_hw->fifo_rd == LOCKOUT_MAGIC_START) {
@@ -176,7 +176,7 @@ static void __isr __not_in_flash_func(multicore_lockout_handler)() {
     }
 }
 
-static void check_lockout_mutex_init() {
+static void check_lockout_mutex_init(void) {
     // use known available lock - we only need it briefly
     uint32_t save = hw_claim_lock();
     if (!mutex_is_initialzed(&lockout_mutex)) {
@@ -259,4 +259,4 @@ bool multicore_lockout_end_timeout_us(uint64_t timeout_us) {
 
 void multicore_lockout_end_blocking() {
     multicore_lockout_end_block_until(at_the_end_of_time);
-}
+}