| Message ID | 20240607182342.117143-1-gsomlo@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | lib: serial: fix RX path in litex-uart | expand |
On Fri, Jun 7, 2024 at 11:54 PM Gabriel Somlo <gsomlo@gmail.com> wrote: > > 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 <charles.papon.90@gmail.com> > Signed-off-by: Gabriel Somlo <gsomlo@gmail.com> LGTM. Reviewed-by: Anup Patel <anup@brainfault.org> Applied this patch to the riscv/opensbi repo. Thanks, Anup > --- > 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 = { > -- > 2.45.1 > > > -- > opensbi mailing list > opensbi@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/opensbi
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 = {
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 <charles.papon.90@gmail.com> Signed-off-by: Gabriel Somlo <gsomlo@gmail.com> --- lib/utils/serial/litex-uart.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)