stmhal: Fix uart off by 1 circular buffer size.

Ryan Shaw · dpgeorge · commit c03dd3b2f943 · 2015-12-04T22:20:47.000Z
diff --git a/stmhal/uart.c b/stmhal/uart.c
@@ -429,7 +429,8 @@ STATIC void pyb_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_k
         }
         mp_printf(print, ", stop=%u, timeout=%u, timeout_char=%u, read_buf_len=%u)",
             self->uart.Init.StopBits == UART_STOPBITS_1 ? 1 : 2,
-            self->timeout, self->timeout_char, self->read_buf_len);
+            self->timeout, self->timeout_char,
+            self->read_buf_len == 0 ? 0 : self->read_buf_len - 1); // -1 to adjust for usable length of buffer
     }
 }
 
@@ -538,8 +539,8 @@ STATIC mp_obj_t pyb_uart_init_helper(pyb_uart_obj_t *self, mp_uint_t n_args, con
         __HAL_UART_DISABLE_IT(&self->uart, UART_IT_RXNE);
     } else {
         // read buffer using interrupts
-        self->read_buf_len = args[7].u_int;
-        self->read_buf = m_new(byte, args[7].u_int << self->char_width);
+        self->read_buf_len = args[7].u_int + 1; // +1 to adjust for usable length of buffer
+        self->read_buf = m_new(byte, self->read_buf_len << self->char_width);
         __HAL_UART_ENABLE_IT(&self->uart, UART_IT_RXNE);
         HAL_NVIC_SetPriority(self->irqn, IRQ_PRI_UART, IRQ_SUBPRI_UART); 
         HAL_NVIC_EnableIRQ(self->irqn);

Original file line number	Diff line number	Diff line change
`@@ -429,7 +429,8 @@ STATIC void pyb_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_k`
`429`	`429`	`}`
`430`	`430`	`mp_printf(print, ", stop=%u, timeout=%u, timeout_char=%u, read_buf_len=%u)",`
`431`	`431`	`self->uart.Init.StopBits == UART_STOPBITS_1 ? 1 : 2,`
`432`		`- self->timeout, self->timeout_char, self->read_buf_len);`
	`432`	`+ self->timeout, self->timeout_char,`
	`433`	`+ self->read_buf_len == 0 ? 0 : self->read_buf_len - 1); // -1 to adjust for usable length of buffer`
`433`	`434`	`}`
`434`	`435`	`}`
`435`	`436`
`@@ -538,8 +539,8 @@ STATIC mp_obj_t pyb_uart_init_helper(pyb_uart_obj_t *self, mp_uint_t n_args, con`
`538`	`539`	`__HAL_UART_DISABLE_IT(&self->uart, UART_IT_RXNE);`
`539`	`540`	`} else {`
`540`	`541`	`// read buffer using interrupts`
`541`		`- self->read_buf_len = args[7].u_int;`
`542`		`- self->read_buf = m_new(byte, args[7].u_int << self->char_width);`
	`542`	`+ self->read_buf_len = args[7].u_int + 1; // +1 to adjust for usable length of buffer`
	`543`	`+ self->read_buf = m_new(byte, self->read_buf_len << self->char_width);`
`543`	`544`	`__HAL_UART_ENABLE_IT(&self->uart, UART_IT_RXNE);`
`544`	`545`	`HAL_NVIC_SetPriority(self->irqn, IRQ_PRI_UART, IRQ_SUBPRI_UART);`
`545`	`546`	`HAL_NVIC_EnableIRQ(self->irqn);`