[PATCH] lib: utils/serial: Modify uart_getc to a blocking function

[Xiang W]

在 2021-11-13星期六的 15:06 +0800，Xiang W写道：
> If uart_getc is non-blocking, if the sending end is faster than the
> receiving end, the data received by some functions(sbi_gets) is
> incomplete
> 
Revoke this patch

Regards,
Xiang W
> Signed-off-by: Xiang W <wxjstz at 126.com>
> ---
>  lib/utils/serial/gaisler-uart.c |  5 ++---
>  lib/utils/serial/shakti-uart.c  |  7 +++----
>  lib/utils/serial/sifive-uart.c  |  9 +++++----
>  lib/utils/serial/uart8250.c     |  6 +++---
>  lib/utils/sys/htif.c            | 11 +++++------
>  5 files changed, 18 insertions(+), 20 deletions(-)
> 
> diff --git a/lib/utils/serial/gaisler-uart.c
> b/lib/utils/serial/gaisler-uart.c
> index 49298e9..1dc5ae0 100644
> --- a/lib/utils/serial/gaisler-uart.c
> +++ b/lib/utils/serial/gaisler-uart.c
> @@ -51,9 +51,8 @@ static void gaisler_uart_putc(char ch)
>  
>  static int gaisler_uart_getc(void)
>  {
> -       u32 ret = get_reg(UART_REG_STATUS);
> -       if (!(ret & UART_STATUS_DATAREADY))
> -               return -1;
> +       while (!(get_reg(UART_REG_STATUS) & UART_STATUS_DATAREADY))
> +               ;
>         return get_reg(UART_REG_DATA) & UART_DATA_DATA;
>  }
>  
> diff --git a/lib/utils/serial/shakti-uart.c
> b/lib/utils/serial/shakti-uart.c
> index e77a985..a5b72aa 100644
> --- a/lib/utils/serial/shakti-uart.c
> +++ b/lib/utils/serial/shakti-uart.c
> @@ -32,10 +32,9 @@ static void shakti_uart_putc(char ch)
>  
>  static int shakti_uart_getc(void)
>  {
> -       u16 status = readw(uart_base + REG_STATUS);
> -       if (status & UART_RX_FULL)
> -               return readb(uart_base + REG_RX);
> -       return -1;
> +       while (!(readw(uart_base + REG_STATUS) & UART_RX_FULL))
> +               ;
> +       return readb(uart_base + REG_RX);
>  }
>  
>  static struct sbi_console_device shakti_console = {
> diff --git a/lib/utils/serial/sifive-uart.c
> b/lib/utils/serial/sifive-uart.c
> index 57d80fa..68a9ca7 100644
> --- a/lib/utils/serial/sifive-uart.c
> +++ b/lib/utils/serial/sifive-uart.c
> @@ -76,10 +76,11 @@ 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;
> +       u32 ret;
> +       do
> +               ret = get_reg(UART_REG_RXFIFO);
> +       while (ret & UART_RXFIFO_EMPTY);
> +       return ret & UART_RXFIFO_DATA;
>  }
>  
>  static struct sbi_console_device sifive_console = {
> diff --git a/lib/utils/serial/uart8250.c
> b/lib/utils/serial/uart8250.c
> index 1cf6624..bab8111 100644
> --- a/lib/utils/serial/uart8250.c
> +++ b/lib/utils/serial/uart8250.c
> @@ -79,9 +79,9 @@ static void uart8250_putc(char ch)
>  
>  static int uart8250_getc(void)
>  {
> -       if (get_reg(UART_LSR_OFFSET) & UART_LSR_DR)
> -               return get_reg(UART_RBR_OFFSET);
> -       return -1;
> +       while (!(get_reg(UART_LSR_OFFSET) & UART_LSR_DR))
> +               ;
> +       return get_reg(UART_RBR_OFFSET);
>  }
>  
>  static struct sbi_console_device uart8250_console = {
> diff --git a/lib/utils/sys/htif.c b/lib/utils/sys/htif.c
> index 7c69c7f..dfda30a 100644
> --- a/lib/utils/sys/htif.c
> +++ b/lib/utils/sys/htif.c
> @@ -47,7 +47,7 @@
>  
>  volatile uint64_t tohost __attribute__((section(".htif")));
>  volatile uint64_t fromhost __attribute__((section(".htif")));
> -static int htif_console_buf;
> +static int htif_console_buf = -1;
>  static spinlock_t htif_lock = SPIN_LOCK_INITIALIZER;
>  
>  static void __check_fromhost()
> @@ -130,12 +130,11 @@ static int htif_getc(void)
>  
>         spin_lock(&htif_lock);
>  
> -       __check_fromhost();
> +       while (htif_console_buf < 0)
> +               __check_fromhost();
>         ch = htif_console_buf;
> -       if (ch >= 0) {
> -               htif_console_buf = -1;
> -               __set_tohost(HTIF_DEV_CONSOLE, HTIF_CONSOLE_CMD_GETC,
> 0);
> -       }
> +       htif_console_buf = -1;
> +       __set_tohost(HTIF_DEV_CONSOLE, HTIF_CONSOLE_CMD_GETC, 0);
>  
>         spin_unlock(&htif_lock);
>