Re: [PATCH] Fix STM32F2XX USART data register readout

[Alistair Francis <alistair23@gmail.com>]

On Mon, Nov 29, 2021 at 12:46 AM Olivier Hériveaux
<olivier.heriveaux@ledger.fr> wrote:
>
> Fix issue where the data register may be overwritten by next character
> reception before being read and returned.
>
> Signed-off-by: Olivier Hériveaux <olivier.heriveaux@ledger.fr>

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

Alistair

> ---
>  hw/char/stm32f2xx_usart.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/char/stm32f2xx_usart.c b/hw/char/stm32f2xx_usart.c
> index 8df0832424..fde67f4f03 100644
> --- a/hw/char/stm32f2xx_usart.c
> +++ b/hw/char/stm32f2xx_usart.c
> @@ -103,10 +103,11 @@ static uint64_t stm32f2xx_usart_read(void *opaque, hwaddr addr,
>          return retvalue;
>      case USART_DR:
>          DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
> +        retvalue = s->usart_dr & 0x3FF;
>          s->usart_sr &= ~USART_SR_RXNE;
>          qemu_chr_fe_accept_input(&s->chr);
>          qemu_set_irq(s->irq, 0);
> -        return s->usart_dr & 0x3FF;
> +        return retvalue;
>      case USART_BRR:
>          return s->usart_brr;
>      case USART_CR1:
> --
> 2.17.1
>
>
> --
>
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