From 7830e987856eb1319c82664702892b6d50a93e7a Mon Sep 17 00:00:00 2001 From: Gabriel Somlo Date: Fri, 7 Jun 2024 14:23:42 -0400 Subject: lib: serial: fix RX path in litex-uart When used to read characters from the terminal (e.g., when the SBI console is used via ecall from linux with `console=hvc0`), we must acknowledge receipt of each character to "pop" it off the LiteUART hardware queue, and allow the next character to be made available. Fixes: 52af6e4b ("lib: utils: Add LiteX UART support") Suggested-by: Dolu1990 Signed-off-by: Gabriel Somlo Reviewed-by: Anup Patel --- lib/utils/serial/litex-uart.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/lib/utils/serial/litex-uart.c b/lib/utils/serial/litex-uart.c index f843bf3..caf8699 100644 --- a/lib/utils/serial/litex-uart.c +++ b/lib/utils/serial/litex-uart.c @@ -20,6 +20,8 @@ #define UART_REG_EV_PENDING 4 #define UART_REG_EV_ENABLE 5 +#define UART_EV_RX 0x2 + /* clang-format on */ static volatile u32 *uart_base; @@ -42,10 +44,14 @@ static void litex_uart_putc(char ch) static int litex_uart_getc(void) { + int ret; + if (get_reg(UART_REG_RXEMPTY)) return -1; - else - return get_reg(UART_REG_RXTX); + + ret = get_reg(UART_REG_RXTX); + set_reg(UART_REG_EV_PENDING, UART_EV_RX); /* ack. char read */ + return ret; } static struct sbi_console_device litex_console = { -- cgit v1.1