Re: [Qemu-devel] [Qemu-arm] [PATCH for-2.12] hw/char/cmsdk-apb-uart.c: Correctly clear INTSTATUS bits on writes

[Philippe Mathieu-Daudé]

On 04/10/2018 10:42 AM, Peter Maydell wrote:
> The CMSDK APB UART INTSTATUS register bits are all write-one-to-clear.
> We were getting this correct for the TXO and RXO bits (which need
> special casing because their state lives in the STATE register),
> but had forgotten to handle the normal bits for RX and TX which
> we do store in our s->intstatus field.
> 
> Perform the W1C operation on the bits in s->intstatus too.
> 
> Fixes: https://bugs.launchpad.net/qemu/+bug/1760262
> Cc: address@hidden
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> Not a disaster if this doesn't get into 2.12, I guess. I think
> it's missed the rc3 boat, so if we need an rc4 for some other
> reason we can put it in.
> 
>  hw/char/cmsdk-apb-uart.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/char/cmsdk-apb-uart.c b/hw/char/cmsdk-apb-uart.c
> index 1ad1e14295..9c0929d8a2 100644
> --- a/hw/char/cmsdk-apb-uart.c
> +++ b/hw/char/cmsdk-apb-uart.c
> @@ -274,6 +274,7 @@ static void uart_write(void *opaque, hwaddr offset, 
> uint64_t value,
>           * is then reflected into the intstatus value by the update 
> function).

The comment was correct :)

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

>           */
>          s->state &= ~(value & (R_INTSTATUS_TXO_MASK | R_INTSTATUS_RXO_MASK));
> +        s->intstatus &= ~value;
>          cmsdk_apb_uart_update(s);
>          break;
>      case A_BAUDDIV:
>