Hi Shimoda-san,
On Wed, Aug 28, 2019 at 1:15 PM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> This patch adds dma-channel-mask property support not to reserve
> some DMA channels for some reasons. (for example: a heterogeneous
> CPU uses it.)
Thanks for your patch!
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
One suggestion below.
> --- a/drivers/dma/sh/rcar-dmac.c
> +++ b/drivers/dma/sh/rcar-dmac.c
> @@ -1806,7 +1806,17 @@ static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
> return -EINVAL;
> }
>
> - dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
> + /*
> + * If the driver is unable to read dma-channel-mask property,
> + * the driver assumes that it can use all channels.
> + */
> + ret = of_property_read_u32(np, "dma-channel-mask",
> + &dmac->channels_mask);
> + if (ret < 0)
> + dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
You could keep the preinitialization, and just ignore the return value:
dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
of_property_read_u32(np, "dma-channel-mask", &dmac->channels_mask);
>
> +
> + /* If the property has out-of-channel mask, this driver clears it */
> + dmac->channels_mask &= GENMASK(dmac->n_channels - 1, 0);
>
> return 0;
> }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
