| Message ID | 1462972511-20927-1-git-send-email-niklas.soderlund+renesas@ragnatech.se (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
In my haste I forgot the most important part of this patch, I'm sorry Arnd. Suggested-by: Arnd Bergmann <arnd@arndb.de> 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 <arnd@arndb.de> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> > --- > 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 >
On Wed, May 11, 2016 at 03:15:11PM +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"; > ... > }; Applied, thanks
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);
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 <arnd@arndb.de> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> --- drivers/dma/of-dma.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)