1 /*
2 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include "pico/stdio/driver.h"
8 #include "pico/stdio_uart.h"
9 #include "pico/binary_info.h"
10 #include "hardware/gpio.h"
11
12 static uart_inst_t *uart_instance;
13
14 #if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
15 static void (*chars_available_callback)(void*);
16 static void *chars_available_param;
17 #endif
18
19 #if PICO_NO_BI_STDIO_UART
20 #define stdio_bi_decl_if_func_used(x)
21 #else
22 #define stdio_bi_decl_if_func_used bi_decl_if_func_used
23 #endif
24
stdio_uart_init()25 void stdio_uart_init() {
26 #ifdef uart_default
27 int tx_pin = -1;
28 int rx_pin = -1;
29 #ifdef PICO_DEFAULT_UART_TX_PIN
30 tx_pin = PICO_DEFAULT_UART_TX_PIN;
31 #ifdef PICO_DEFAULT_UART_RX_PIN
32 rx_pin = PICO_DEFAULT_UART_RX_PIN;
33 stdio_bi_decl_if_func_used(bi_program_feature("UART stdin / stdout"));
34 bi_decl_if_func_used(bi_2pins_with_func(PICO_DEFAULT_UART_RX_PIN, PICO_DEFAULT_UART_TX_PIN, GPIO_FUNC_UART));
35 #else
36 stdio_bi_decl_if_func_used(bi_program_feature("UART stdout"));
37 bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_TX_PIN, GPIO_FUNC_UART));
38 #endif
39 #elif defined(PICO_DEFAULT_UART_RX_PIN)
40 rx_pin = PICO_DEFAULT_UART_RX_PIN;
41 stdio_bi_decl_if_func_used(bi_program_feature("UART stdin"));
42 bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_RX_PIN, GPIO_FUNC_UART));
43 #endif
44 #if !defined(PICO_DEFAULT_UART_BAUD_RATE)
45 panic("UART baud rate undefined");
46 #else
47 stdio_uart_init_full(uart_default, PICO_DEFAULT_UART_BAUD_RATE, tx_pin, rx_pin);
48 #endif
49 #endif
50 }
51
stdout_uart_init()52 void stdout_uart_init() {
53 #if defined(uart_default) && defined(PICO_DEFAULT_UART_TX_PIN)
54 bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_TX_PIN, GPIO_FUNC_UART));
55 #if !defined(PICO_DEFAULT_UART_BAUD_RATE)
56 panic("UART baud rate undefined");
57 #else
58 stdio_bi_decl_if_func_used(bi_program_feature("UART stdout"));
59 stdio_uart_init_full(uart_default, PICO_DEFAULT_UART_BAUD_RATE, PICO_DEFAULT_UART_TX_PIN, -1);
60 #endif
61 #endif
62 }
63
stdin_uart_init()64 void stdin_uart_init() {
65 #if defined(uart_default) && defined(PICO_DEFAULT_UART_RX_PIN)
66 bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_RX_PIN, GPIO_FUNC_UART));
67 #if !defined(PICO_DEFAULT_UART_BAUD_RATE)
68 panic("UART baud rate undefined");
69 #else
70 stdio_bi_decl_if_func_used(bi_program_feature("UART stdin"));
71 stdio_uart_init_full(uart_default, PICO_DEFAULT_UART_BAUD_RATE, -1, PICO_DEFAULT_UART_RX_PIN);
72 #endif
73 #endif
74 }
75
stdio_uart_init_full(struct uart_inst * uart,uint baud_rate,int tx_pin,int rx_pin)76 void stdio_uart_init_full(struct uart_inst *uart, uint baud_rate, int tx_pin, int rx_pin) {
77 uart_instance = uart;
78 if (tx_pin >= 0) gpio_set_function((uint)tx_pin, GPIO_FUNC_UART);
79 if (rx_pin >= 0) gpio_set_function((uint)rx_pin, GPIO_FUNC_UART);
80 uart_init(uart_instance, baud_rate);
81 stdio_set_driver_enabled(&stdio_uart, true);
82 }
83
stdio_uart_out_chars(const char * buf,int length)84 static void stdio_uart_out_chars(const char *buf, int length) {
85 for (int i = 0; i <length; i++) {
86 uart_putc(uart_instance, buf[i]);
87 }
88 }
89
stdio_uart_in_chars(char * buf,int length)90 int stdio_uart_in_chars(char *buf, int length) {
91 int i=0;
92 while (i<length && uart_is_readable(uart_instance)) {
93 buf[i++] = uart_getc(uart_instance);
94 }
95 #if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
96 if (chars_available_callback) {
97 // Re-enable interrupts after reading a character
98 uart_set_irq_enables(uart_instance, true, false);
99 }
100 #endif
101 return i ? i : PICO_ERROR_NO_DATA;
102 }
103
104 #if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
on_uart_rx(void)105 static void on_uart_rx(void) {
106 if (chars_available_callback) {
107 // Interrupts will go off until the uart is read, so disable them
108 uart_set_irq_enables(uart_instance, false, false);
109 chars_available_callback(chars_available_param);
110 }
111 }
112
stdio_uart_set_chars_available_callback(void (* fn)(void *),void * param)113 static void stdio_uart_set_chars_available_callback(void (*fn)(void*), void *param) {
114 static_assert(UART1_IRQ == UART0_IRQ + 1, "");
115 const uint UART_IRQ = UART0_IRQ + uart_get_index(uart_instance);
116 if (fn && !chars_available_callback) {
117 irq_set_exclusive_handler(UART_IRQ, on_uart_rx);
118 irq_set_enabled(UART_IRQ, true);
119 uart_set_irq_enables(uart_instance, true, false);
120 } else if (!fn && chars_available_callback) {
121 uart_set_irq_enables(uart_instance, false, false);
122 irq_set_enabled(UART_IRQ, false);
123 irq_remove_handler(UART_IRQ, on_uart_rx);
124 }
125 chars_available_callback = fn;
126 chars_available_param = param;
127 }
128 #endif
129
130 stdio_driver_t stdio_uart = {
131 .out_chars = stdio_uart_out_chars,
132 .in_chars = stdio_uart_in_chars,
133 #if PICO_STDIO_UART_SUPPORT_CHARS_AVAILABLE_CALLBACK
134 .set_chars_available_callback = stdio_uart_set_chars_available_callback,
135 #endif
136 #if PICO_STDIO_ENABLE_CRLF_SUPPORT
137 .crlf_enabled = PICO_STDIO_UART_DEFAULT_CRLF
138 #endif
139 };
140