In my haste I forgot the most important part of this patch, I'm sorry Arnd.
Suggested-by: Arnd Bergmann <[email protected]> On 2016-05-11 15:15:11 +0200, Niklas Söderlund wrote: > Currently the following DT description would result in dmac0 always > being tried first and dmac1 second if dmac0 was unavailable. This > results in heavier use of dmac0 then of dmac1. This patch adds an > approximate average distribution over the two nodes lessening the load > of anyone of them. > > i2c6: i2c@e60b0000 { > ... > dmas = <&dmac0 0x77>, <&dmac0 0x78>, > <&dmac1 0x77>, <&dmac1 0x78>; > dma-names = "tx", "rx", "tx", "rx"; > ... > }; > > Signed-off-by: Arnd Bergmann <[email protected]> > Signed-off-by: Niklas Söderlund <[email protected]> > --- > drivers/dma/of-dma.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c > index 1e1f298..faae0bf 100644 > --- a/drivers/dma/of-dma.c > +++ b/drivers/dma/of-dma.c > @@ -240,8 +240,9 @@ struct dma_chan *of_dma_request_slave_channel(struct > device_node *np, > struct of_phandle_args dma_spec; > struct of_dma *ofdma; > struct dma_chan *chan; > - int count, i; > + int count, i, start; > int ret_no_channel = -ENODEV; > + static atomic_t last_index; > > if (!np || !name) { > pr_err("%s: not enough information provided\n", __func__); > @@ -259,8 +260,15 @@ struct dma_chan *of_dma_request_slave_channel(struct > device_node *np, > return ERR_PTR(-ENODEV); > } > > + /* > + * approximate an average distribution across multiple > + * entries with the same name > + */ > + start = atomic_inc_return(&last_index); > for (i = 0; i < count; i++) { > - if (of_dma_match_channel(np, name, i, &dma_spec)) > + if (of_dma_match_channel(np, name, > + (i + start) % count, > + &dma_spec)) > continue; > > mutex_lock(&of_dma_lock); > -- > 2.8.2 > -- Regards, Niklas Söderlund
