Add stdio_set_chars_available_callback (#1213)

There's currently no way to be notified in a "stdio" agnostic way
whether there's an incoming character available. You can poll with
getchar_timeout_us, but that's far from ideal.

Add a method that takes a callback to notify that a character might be
available.
This commit is contained in:
Peter Harper 2023-01-31 21:47:36 +00:00 committed by GitHub
parent 0e4e25a343
commit 31780aed2c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 88 additions and 1 deletions

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@ -109,6 +109,14 @@ int putchar_raw(int c);
*/
int puts_raw(const char *s);
/*! \brief get notified when there are input characters available
* \ingroup pico_stdio
*
* \param fn Callback function to be called when characters are available. Pass NULL to cancel any existing callback
* \param param Pointer to pass to the callback
*/
void stdio_set_chars_available_callback(void (*fn)(void*), void *param);
#ifdef __cplusplus
}
#endif

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@ -13,6 +13,7 @@ struct stdio_driver {
void (*out_chars)(const char *buf, int len);
void (*out_flush)(void);
int (*in_chars)(char *buf, int len);
void (*set_chars_available_callback)(void (*fn)(void*), void *param);
stdio_driver_t *next;
#if PICO_STDIO_ENABLE_CRLF_SUPPORT
bool last_ended_with_cr;

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@ -346,3 +346,9 @@ void stdio_set_translate_crlf(stdio_driver_t *driver, bool enabled) {
panic_unsupported();
#endif
}
void stdio_set_chars_available_callback(void (*fn)(void*), void *param) {
for (stdio_driver_t *s = drivers; s; s = s->next) {
if (s->set_chars_available_callback) s->set_chars_available_callback(fn, param);
}
}

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@ -23,6 +23,11 @@
#define PICO_STDIO_UART_DEFAULT_CRLF PICO_STDIO_DEFAULT_CRLF
#endif
// PICO_CONFIG: PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK, Enable UART STDIO support for stdio_set_chars_available_callback. Can be disabled to make use of the uart elsewhere, type=bool default=1, group=pico_stdio_uart
#ifndef PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
#define PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK 1
#endif
#ifdef __cplusplus
extern "C" {
#endif

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@ -11,6 +11,11 @@
static uart_inst_t *uart_instance;
#if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
static void (*chars_available_callback)(void*);
static void *chars_available_param;
#endif
#if PICO_NO_BI_STDIO_UART
#define stdio_bi_decl_if_func_used(x)
#else
@ -87,12 +92,47 @@ int stdio_uart_in_chars(char *buf, int length) {
while (i<length && uart_is_readable(uart_instance)) {
buf[i++] = uart_getc(uart_instance);
}
#if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
if (chars_available_callback) {
// Re-enable interrupts after reading a character
uart_set_irq_enables(uart_instance, true, false);
}
#endif
return i ? i : PICO_ERROR_NO_DATA;
}
#if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
static void on_uart_rx(void) {
if (chars_available_callback) {
// Interrupts will go off until the uart is read, so disable them
uart_set_irq_enables(uart_instance, false, false);
chars_available_callback(chars_available_param);
}
}
static void stdio_uart_set_chars_available_callback(void (*fn)(void*), void *param) {
static_assert(UART1_IRQ == UART0_IRQ + 1, "");
const uint UART_IRQ = UART0_IRQ + uart_get_index(uart_instance);
if (fn && !chars_available_callback) {
irq_set_exclusive_handler(UART_IRQ, on_uart_rx);
irq_set_enabled(UART_IRQ, true);
uart_set_irq_enables(uart_instance, true, false);
} else if (!fn && chars_available_callback) {
uart_set_irq_enables(uart_instance, false, false);
irq_set_enabled(UART_IRQ, false);
irq_remove_handler(UART_IRQ, on_uart_rx);
}
chars_available_callback = fn;
chars_available_param = param;
}
#endif
stdio_driver_t stdio_uart = {
.out_chars = stdio_uart_out_chars,
.in_chars = stdio_uart_in_chars,
#if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
.set_chars_available_callback = stdio_uart_set_chars_available_callback,
#endif
#if PICO_STDIO_ENABLE_CRLF_SUPPORT
.crlf_enabled = PICO_STDIO_UART_DEFAULT_CRLF
#endif

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@ -107,6 +107,11 @@
#define PICO_STDIO_USB_DEVICE_SELF_POWERED 0
#endif
// PICO_CONFIG: PICO_STDIO_USB_SUPPORT_CHARS_AVAILABLE_CALLBACK, Enable USB STDIO support for stdio_set_chars_available_callback. Can be disabled to make use of USB CDC RX callback elsewhere, type=bool default=1, group=pico_stdio_usb
#ifndef PICO_STDIO_USB_SUPPORT_CHARS_AVAILABLE_CALLBACK
#define PICO_STDIO_USB_SUPPORT_CHARS_AVAILABLE_CALLBACK 1
#endif
#ifdef __cplusplus
extern "C" {
#endif

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@ -17,6 +17,7 @@
#include "pico/stdio/driver.h"
#include "pico/mutex.h"
#include "hardware/irq.h"
#include "device/usbd_pvt.h" // for usbd_defer_func
static mutex_t stdio_usb_mutex;
#ifndef NDEBUG
@ -36,6 +37,10 @@ static_assert(PICO_STDIO_USB_LOW_PRIORITY_IRQ >= NUM_IRQS - NUM_USER_IRQS, "");
#else
static uint8_t low_priority_irq_num;
#endif
#if PICO_STDIO_USB_SUPPORT_CHARS_AVAILABLE_CALLBACK
static void (*chars_available_callback)(void*);
static void *chars_available_param;
#endif
static int64_t timer_task(__unused alarm_id_t id, __unused void *user_data) {
int64_t repeat_time;
@ -137,12 +142,29 @@ int stdio_usb_in_chars(char *buf, int length) {
return rc;
}
#if PICO_STDIO_USB_SUPPORT_CHARS_AVAILABLE_CALLBACK
void tud_cdc_rx_cb(__unused uint8_t itf) {
if (chars_available_callback) {
usbd_defer_func(chars_available_callback, chars_available_param, false);
}
}
void stdio_usb_set_chars_available_callback(void (*fn)(void*), void *param) {
chars_available_callback = fn;
chars_available_param = param;
}
#endif
stdio_driver_t stdio_usb = {
.out_chars = stdio_usb_out_chars,
.in_chars = stdio_usb_in_chars,
#if PICO_STDIO_USB_SUPPORT_CHARS_AVAILABLE_CALLBACK
.set_chars_available_callback = stdio_usb_set_chars_available_callback,
#endif
#if PICO_STDIO_ENABLE_CRLF_SUPPORT
.crlf_enabled = PICO_STDIO_USB_DEFAULT_CRLF
#endif
};
bool stdio_usb_init(void) {