On 9/27/21 09:21, Bin Meng wrote:
> At present the codes detect whether the DMA channel is claimed by:
>
> claimed = !!s->chan[ch].control & CONTROL_CLAIM;
>
> As ! has higher precedence over & (bitwise and), this is essentially
>
> claimed = (!!s->chan[ch].control) & CONTROL_CLAIM;
>
> which is wrong, as any non-zero bit set in the control register will
> produce a result of a claimed channel.
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
Maybe worth adding:
Reported using GCC 9.3.0 on Ubuntu 20.04:
suggest parentheses around operand of ‘!’ or change ‘&’ to ‘&&’ or ‘!’
to ‘~’ [-Werror=parentheses]
> Fixes: de7c7988d25d ("hw/dma: sifive_pdma: reset Next* registers when
> Control.claim is set")
> Signed-off-by: Bin Meng <bmeng...@gmail.com>
>
> ---
>
> Changes in v2:
> - reword the commit message
>
> hw/dma/sifive_pdma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/dma/sifive_pdma.c b/hw/dma/sifive_pdma.c
> index b4fd40573a..b8ec7621f3 100644
> --- a/hw/dma/sifive_pdma.c
> +++ b/hw/dma/sifive_pdma.c
> @@ -243,7 +243,7 @@ static void sifive_pdma_write(void *opaque, hwaddr offset,
> offset &= 0xfff;
> switch (offset) {
> case DMA_CONTROL:
> - claimed = !!s->chan[ch].control & CONTROL_CLAIM;
> + claimed = !!(s->chan[ch].control & CONTROL_CLAIM);
>
> if (!claimed && (value & CONTROL_CLAIM)) {
> /* reset Next* registers */
>
