diff options
| -rw-r--r-- | lib/utils/serial/sifive-uart.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/lib/utils/serial/sifive-uart.c b/lib/utils/serial/sifive-uart.c index 9478a77f..7078611a 100644 --- a/lib/utils/serial/sifive-uart.c +++ b/lib/utils/serial/sifive-uart.c @@ -48,12 +48,12 @@ static inline unsigned int uart_min_clk_divisor(uint64_t in_freq, uint64_t max_target_hz) { uint64_t quotient = (in_freq + max_target_hz - 1) / (max_target_hz); + /* Avoid underflow */ - if (quotient == 0) { + if (quotient == 0) return 0; - } else { + else return quotient - 1; - } } static u32 get_reg(u32 num) @@ -77,8 +77,10 @@ static void sifive_uart_putc(char ch) static int sifive_uart_getc(void) { u32 ret = get_reg(UART_REG_RXFIFO); + if (!(ret & UART_RXFIFO_EMPTY)) return ret & UART_RXFIFO_DATA; + return -1; } @@ -97,10 +99,13 @@ int sifive_uart_init(unsigned long base, u32 in_freq, u32 baudrate) /* Configure baudrate */ if (in_freq) set_reg(UART_REG_DIV, uart_min_clk_divisor(in_freq, baudrate)); + /* Disable interrupts */ set_reg(UART_REG_IE, 0); + /* Enable TX */ set_reg(UART_REG_TXCTRL, UART_TXCTRL_TXEN); + /* Enable Rx */ set_reg(UART_REG_RXCTRL, UART_RXCTRL_RXEN); |