lib: utils/serial: Skip baudrate config if input frequency is zero

We should skip baudrate config for UART8250 and SiFive UART when
input frequency is zero.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/lib/utils/serial/sifive-uart.c b/lib/utils/serial/sifive-uart.c
index b82a1b3..72c8a62 100644 (file)
--- a/lib/utils/serial/sifive-uart.c
+++ b/lib/utils/serial/sifive-uart.c
@@ -89,7 +89,8 @@ int sifive_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
        uart_baudrate = baudrate;
 
        /* Configure baudrate */
-       set_reg(UART_REG_DIV, uart_min_clk_divisor(in_freq, 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 */

diff --git a/lib/utils/serial/uart8250.c b/lib/utils/serial/uart8250.c
index 42f1881..9635ba8 100644 (file)
--- a/lib/utils/serial/uart8250.c
+++ b/lib/utils/serial/uart8250.c
@@ -100,10 +100,14 @@ int uart8250_init(unsigned long base, u32 in_freq, u32 baudrate, u32 reg_shift,
        set_reg(UART_IER_OFFSET, 0x00);
        /* Enable DLAB */
        set_reg(UART_LCR_OFFSET, 0x80);
-       /* Set divisor low byte */
-       set_reg(UART_DLL_OFFSET, bdiv & 0xff);
-       /* Set divisor high byte */
-       set_reg(UART_DLM_OFFSET, (bdiv >> 8) & 0xff);
+
+       if (bdiv) {
+               /* Set divisor low byte */
+               set_reg(UART_DLL_OFFSET, bdiv & 0xff);
+               /* Set divisor high byte */
+               set_reg(UART_DLM_OFFSET, (bdiv >> 8) & 0xff);
+       }
+
        /* 8 bits, no parity, one stop bit */
        set_reg(UART_LCR_OFFSET, 0x03);
        /* Enable FIFO */