Re: [PATCH v2 9/9] hw/char/sh_serial: Return correct number of empty RX FIFO elements

[Richard Henderson <richard.henderson@linaro.org>]

On 2/20/25 01:29, Philippe Mathieu-Daudé wrote:
> In the IOCanReadHandler sh_serial_can_receive(), if the Serial
> Control Register 'Receive Enable' bit is set (bit 4), then we
> return a size of (1 << 4) which happens to be equal to 16, so
> effectively SH_RX_FIFO_LENGTH.
> 
> The IOReadHandler, sh_serial_receive1() takes care to receive
> multiple chars, but if the FIFO is partly filled, we only process
> the number of free slots in the FIFO, discarding the other chars!
> 
> Fix by returning how many elements the FIFO can queue in the
> IOCanReadHandler, so we don't have to process more than that in
> the IOReadHandler, thus not discarding anything.
> 
> Remove the now unnecessary check on 's->rx_cnt < SH_RX_FIFO_LENGTH'
> in IOReadHandler, reducing the block indentation.
> 
> Fixes: 63242a007a1 ("SH4: Serial controller improvement")
> Signed-off-by: Philippe Mathieu-Daudé<philmd@linaro.org>
> Reviewed-by: Luc Michel<luc.michel@amd.com>
> ---
>   hw/char/sh_serial.c | 30 ++++++++++++++----------------
>   1 file changed, 14 insertions(+), 16 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~