esp8266/machine_uart: Add rxbuf keyword arg to UART constructor/init.

As per the machine.UART documentation, this is used to set the length of
the UART RX buffer.

ports/esp8266/machine_uart.c

@@ -57,20 +57,21 @@ STATIC const char *_parity_name[] = {"None", "1", "0"};
 
 STATIC void pyb_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, timeout=%u, timeout_char=%u)",
+    mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, rxbuf=%u, timeout=%u, timeout_char=%u)",
         self->uart_id, self->baudrate, self->bits, _parity_name[self->parity],
-        self->stop, self->timeout, self->timeout_char);
+        self->stop, uart0_get_rxbuf_len() - 1, self->timeout, self->timeout_char);
 }
 
 STATIC void pyb_uart_init_helper(pyb_uart_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_timeout, ARG_timeout_char };
+    enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_rxbuf, ARG_timeout, ARG_timeout_char };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_bits, MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_parity, MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
         { MP_QSTR_stop, MP_ARG_INT, {.u_int = 0} },
         //{ MP_QSTR_tx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
         //{ MP_QSTR_rx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_rxbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
     };
@@ -144,6 +145,20 @@ STATIC void pyb_uart_init_helper(pyb_uart_obj_t *self, size_t n_args, const mp_o
             break;
     }
 
+    // set rx ring buffer
+    if (args[ARG_rxbuf].u_int > 0) {
+        uint16_t len = args[ARG_rxbuf].u_int + 1; // account for usable items in ringbuf
+        byte *buf;
+        if (len <= UART0_STATIC_RXBUF_LEN) {
+            buf = uart_ringbuf_array;
+            MP_STATE_PORT(uart0_rxbuf) = NULL; // clear any old pointer
+        } else {
+            buf = m_new(byte, len);
+            MP_STATE_PORT(uart0_rxbuf) = buf; // retain root pointer
+        }
+        uart0_set_rxbuf(buf, len);
+    }
+
     // set timeout
     self->timeout = args[ARG_timeout].u_int;
 

ports/esp8266/mpconfigport.h

@@ -201,6 +201,7 @@ extern const struct _mp_obj_module_t mp_module_onewire;
 #define MICROPY_PORT_ROOT_POINTERS \
     const char *readline_hist[8]; \
     mp_obj_t pin_irq_handler[16]; \
+    byte *uart0_rxbuf; \
 
 // We need to provide a declaration/definition of alloca()
 #include <alloca.h>

ports/esp8266/uart.c

@@ -36,7 +36,7 @@ static os_event_t uart_evt_queue[16];
 
 // A small, static ring buffer for incoming chars
 // This will only be populated if the UART is not attached to dupterm
-static byte uart_ringbuf_array[16];
+uint8 uart_ringbuf_array[UART0_STATIC_RXBUF_LEN];
 static ringbuf_t uart_ringbuf = {uart_ringbuf_array, sizeof(uart_ringbuf_array), 0, 0};
 
 static void uart0_rx_intr_handler(void *para);
@@ -269,6 +269,19 @@ void ICACHE_FLASH_ATTR uart_setup(uint8 uart) {
     ETS_UART_INTR_ENABLE();
 }
 
+int ICACHE_FLASH_ATTR uart0_get_rxbuf_len(void) {
+    return uart_ringbuf.size;
+}
+
+void ICACHE_FLASH_ATTR uart0_set_rxbuf(uint8 *buf, int len) {
+    ETS_UART_INTR_DISABLE();
+    uart_ringbuf.buf = buf;
+    uart_ringbuf.size = len;
+    uart_ringbuf.iget = 0;
+    uart_ringbuf.iput = 0;
+    ETS_UART_INTR_ENABLE();
+}
+
 // Task-based UART interface
 
 #include "py/obj.h"

ports/esp8266/uart.h

@@ -6,6 +6,8 @@
 #define UART0 (0)
 #define UART1 (1)
 
+#define UART0_STATIC_RXBUF_LEN (16)
+
 typedef enum {
     UART_FIVE_BITS = 0x0,
     UART_SIX_BITS = 0x1,
@@ -91,6 +93,8 @@ typedef struct {
     int               buff_uart_no;  //indicate which uart use tx/rx buffer
 } UartDevice;
 
+extern uint8 uart_ringbuf_array[UART0_STATIC_RXBUF_LEN];
+
 void uart_init(UartBautRate uart0_br, UartBautRate uart1_br);
 int uart0_rx(void);
 bool uart_rx_wait(uint32_t timeout_us);
@@ -99,6 +103,8 @@ void uart_tx_one_char(uint8 uart, uint8 TxChar);
 void uart_flush(uint8 uart);
 void uart_os_config(int uart);
 void uart_setup(uint8 uart);
+int uart0_get_rxbuf_len(void);
+void uart0_set_rxbuf(uint8 *buf, int len);
 // check status of rx/tx
 int uart_rx_any(uint8 uart);
 int uart_tx_any_room(uint8 uart);