diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-05-25 11:32:45 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-07-01 14:15:50 +0100 |
| commit | 5e2479bd0e0dc41f2b9f6b4345bc5d4557837056 (patch) | |
| tree | 4822ee508024f5470cebfda8a1312e82ee05415b /drivers/dma | |
| parent | ad0de2ac3218d372149d89d9d5c5058aca6aa29b (diff) | |
| download | linux-5e2479bd0e0dc41f2b9f6b4345bc5d4557837056.tar.bz2 | |
dmaengine: PL08x: track mux usage on a per-channel basis.
Keep track of the number of descriptors currently using a MUX setting
on a per-channel basis. This allows us to know when we have descriptors
queued somewhere which have been assigned a DMA request signal.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/amba-pl08x.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index c203d2f22bca..ac9fdccb2c19 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -227,6 +227,7 @@ enum pl08x_dma_chan_state { * @waiting: a TX descriptor on this channel which is waiting for a physical * channel to become available * @signal: the physical DMA request signal which this channel is using + * @mux_use: count of descriptors using this DMA request signal setting */ struct pl08x_dma_chan { struct dma_chan chan; @@ -244,6 +245,7 @@ struct pl08x_dma_chan { bool slave; struct pl08x_txd *waiting; int signal; + unsigned mux_use; }; /** @@ -310,10 +312,12 @@ static int pl08x_request_mux(struct pl08x_dma_chan *plchan) const struct pl08x_platform_data *pd = plchan->host->pd; int ret; - if (pd->get_signal) { + if (plchan->mux_use++ == 0 && pd->get_signal) { ret = pd->get_signal(plchan->cd); - if (ret < 0) + if (ret < 0) { + plchan->mux_use = 0; return ret; + } plchan->signal = ret; } @@ -324,9 +328,13 @@ static void pl08x_release_mux(struct pl08x_dma_chan *plchan) { const struct pl08x_platform_data *pd = plchan->host->pd; - if (plchan->signal >= 0 && pd->put_signal) { - pd->put_signal(plchan->cd, plchan->signal); - plchan->signal = -1; + if (plchan->signal >= 0) { + WARN_ON(plchan->mux_use == 0); + + if (--plchan->mux_use == 0 && pd->put_signal) { + pd->put_signal(plchan->cd, plchan->signal); + plchan->signal = -1; + } } } |