static void *simuart_thread(void *arg)
{
unsigned char ch;
ssize_t nread;
int next;
int prev;
/* Now loop, collecting a buffering data from stdin forever */
for (;;)
{
/* Read one character from stdin */
nread = read(0, &ch, 1);
/* Check for failures (but don't do anything) */
if (nread == 1)
{
#ifdef CONFIG_SIM_UART_DATAPOST
sched_lock();
#endif
/* Get the index to the next slot in the UART buffer */
prev = g_uarthead;
next = prev + 1;
if (next >= SIMUART_BUFSIZE)
{
next = 0;
}
/* Would adding this character cause an overflow? */
if (next != g_uarttail)
{
/* No.. Add the character to the UART buffer */
g_uartbuffer[prev] = ch;
/* Update the head index (BEFORE posting) */
g_uarthead = next;
/* Was the buffer previously empty? */
if (prev == g_uarttail)
{
/* Yes.. signal any (NuttX) threads waiting for serial
* input.
*/
#ifdef CONFIG_SIM_UART_DATAPOST
simuart_post();
#else
g_uart_data_available = 1;
#endif
}
}
#ifdef CONFIG_SIM_UART_DATAPOST
/* REVISIT: This is very weird and scary here. When sched_unlock()
* is called, we may do a lonjmp() style context switch meaning
* that the logic will be run running on this thread! (but with a
* different stack). So we do not get back here until the task
* sleeps again. I can't help but believe that that is going to
* be a problem someday.
*/
sched_unlock();
#endif
}
}
return NULL;
}
void up_idle(void)
{
#ifdef CONFIG_SMP
/* In the SMP configuration, only one CPU should do these operations. It
* should not matter which, however.
*/
static volatile spinlock_t lock;
/* The one that gets the lock is the one that executes the IDLE operations */
if (up_testset(&lock) != SP_UNLOCKED)
{
/* We didn't get it... Give other pthreads/CPUs a shot and try again
* later.
*/
pthread_yield();
return;
}
#endif
#ifdef CONFIG_SCHED_TICKLESS
/* Driver the simulated interval timer */
up_timer_update();
#else
/* If the system is idle, then process "fake" timer interrupts.
* Hopefully, something will wake up.
*/
sched_process_timer();
#endif
#if defined(CONFIG_DEV_CONSOLE) && !defined(CONFIG_SIM_UART_DATAPOST)
/* Handle UART data availability */
if (g_uart_data_available)
{
g_uart_data_available = 0;
simuart_post();
}
#endif
#ifdef CONFIG_NET_ETHERNET
/* Run the network if enabled */
netdriver_loop();
#endif
#ifdef CONFIG_PM
/* Fake some power management stuff for testing purposes */
{
static enum pm_state_e state = PM_NORMAL;
enum pm_state_e newstate;
newstate = pm_checkstate();
if (newstate != state)
{
if (pm_changestate(newstate) == OK)
{
state = newstate;
}
}
}
#endif
#if defined(CONFIG_SIM_WALLTIME) || defined(CONFIG_SIM_X11FB)
/* Wait a bit so that the sched_process_timer() is called close to the
* correct rate.
*/
(void)up_hostusleep(1000000 / CLK_TCK);
/* Handle X11-related events */
#ifdef CONFIG_SIM_X11FB
if (g_x11initialized)
{
#if defined(CONFIG_SIM_TOUCHSCREEN) || defined(CONFIG_SIM_AJOYSTICK)
/* Drive the X11 event loop */
if (g_eventloop)
{
up_x11events();
}
#endif
/* Update the display periodically */
g_x11refresh += 1000000 / CLK_TCK;
if (g_x11refresh > 500000)
{
up_x11update();
}
}
#endif
#endif
#ifdef CONFIG_SMP
/* Release the spinlock */
lock = SP_UNLOCKED;
/* Give other pthreads/CPUs a shot */
pthread_yield();
#endif
}
