Re: [PATCH v3 6/6] hw/char: cadence_uart: Log a guest error when device is unclocked or in reset

[Alistair Francis <alistair23@gmail.com>]

On Wed, Sep 1, 2021 at 10:52 PM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> We've got SW that expects FSBL (Bootlooader) to setup clocks and
> resets. It's quite common that users run that SW on QEMU without
> FSBL (FSBL typically requires the Xilinx tools installed). That's
> fine, since users can stil use -device loader to enable clocks etc.
>
> To help folks understand what's going, a log (guest-error) message
> would be helpful here. In particular with the serial port since
> things will go very quiet if they get things wrong.
>
> Suggested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

>
> ---
>
> Changes in v3:
> - new patch: hw/char: cadence_uart: Log a guest error when unclocked or in reset
>
>  hw/char/cadence_uart.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
> index 5f5a4645ac..c069a30842 100644
> --- a/hw/char/cadence_uart.c
> +++ b/hw/char/cadence_uart.c
> @@ -240,6 +240,8 @@ static int uart_can_receive(void *opaque)
>
>      /* ignore characters when unclocked or in reset */
>      if (!clock_is_enabled(s->refclk) || device_is_in_reset(DEVICE(s))) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: uart is unclocked or in reset\n",
> +                      __func__);
>          return 0;
>      }
>
> @@ -376,6 +378,8 @@ static void uart_event(void *opaque, QEMUChrEvent event)
>
>      /* ignore characters when unclocked or in reset */
>      if (!clock_is_enabled(s->refclk) || device_is_in_reset(DEVICE(s))) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: uart is unclocked or in reset\n",
> +                      __func__);
>          return;
>      }
>
> @@ -413,6 +417,8 @@ static MemTxResult uart_write(void *opaque, hwaddr offset,
>
>      /* ignore access when unclocked or in reset */
>      if (!clock_is_enabled(s->refclk) || device_is_in_reset(DEVICE(s))) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: uart is unclocked or in reset\n",
> +                      __func__);
>          return MEMTX_ERROR;
>      }
>
> @@ -478,6 +484,8 @@ static MemTxResult uart_read(void *opaque, hwaddr offset,
>
>      /* ignore access when unclocked or in reset */
>      if (!clock_is_enabled(s->refclk) || device_is_in_reset(DEVICE(s))) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: uart is unclocked or in reset\n",
> +                      __func__);
>          return MEMTX_ERROR;
>      }
>
> --
> 2.25.1
>
>