stm32/machine_uart: Allow re-init'ing a static UART object.

Just disallow changing the rxbuf which will be some static RAM (can't free
it and soft-reset would lose any dynamically allocated buffer).

1 files changed, 21 insertions, 18 deletions

diff --git a/ports/stm32/machine_uart.c b/ports/stm32/machine_uart.c
index 1cf5817e0..39a45a2a1 100644
--- a/ports/stm32/machine_uart.c
+++ b/ports/stm32/machine_uart.c
@@ -237,11 +237,6 @@ STATIC mp_obj_t pyb_uart_init_helper(pyb_uart_obj_t *self, size_t n_args, const
     mp_arg_parse_all(n_args, pos_args, kw_args,
         MP_ARRAY_SIZE(allowed_args), allowed_args, (mp_arg_val_t *)&args);
 
-    // static UARTs are used for internal purposes and shouldn't be reconfigured
-    if (self->is_static) {
-        mp_raise_ValueError(MP_ERROR_TEXT("UART is static and can't be init'd"));
-    }
-
     // baudrate
     uint32_t baudrate = args.baudrate.u_int;
 
@@ -306,20 +301,28 @@ STATIC mp_obj_t pyb_uart_init_helper(pyb_uart_obj_t *self, size_t n_args, const
         self->timeout_char = min_timeout_char;
     }
 
-    // setup the read buffer
-    m_del(byte, self->read_buf, self->read_buf_len << self->char_width);
-    if (args.rxbuf.u_int >= 0) {
-        // rxbuf overrides legacy read_buf_len
-        args.read_buf_len.u_int = args.rxbuf.u_int;
-    }
-    if (args.read_buf_len.u_int <= 0) {
-        // no read buffer
-        uart_set_rxbuf(self, 0, NULL);
+    if (self->is_static) {
+        // Static UARTs have fixed memory for the rxbuf and can't be reconfigured.
+        if (args.rxbuf.u_int >= 0) {
+            mp_raise_ValueError(MP_ERROR_TEXT("UART is static and rxbuf can't be changed"));
+        }
+        uart_set_rxbuf(self, self->read_buf_len, self->read_buf);
     } else {
-        // read buffer using interrupts
-        size_t len = args.read_buf_len.u_int + 1; // +1 to adjust for usable length of buffer
-        uint8_t *buf = m_new(byte, len << self->char_width);
-        uart_set_rxbuf(self, len, buf);
+        // setup the read buffer
+        m_del(byte, self->read_buf, self->read_buf_len << self->char_width);
+        if (args.rxbuf.u_int >= 0) {
+            // rxbuf overrides legacy read_buf_len
+            args.read_buf_len.u_int = args.rxbuf.u_int;
+        }
+        if (args.read_buf_len.u_int <= 0) {
+            // no read buffer
+            uart_set_rxbuf(self, 0, NULL);
+        } else {
+            // read buffer using interrupts
+            size_t len = args.read_buf_len.u_int + 1; // +1 to adjust for usable length of buffer
+            uint8_t *buf = m_new(byte, len << self->char_width);
+            uart_set_rxbuf(self, len, buf);
+        }
     }
 
     // compute actual baudrate that was configured