From 5e2479bd0e0dc41f2b9f6b4345bc5d4557837056 Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 25 May 2012 11:32:45 +0100 Subject: [PATCH] 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 Tested-by: Linus Walleij Signed-off-by: Russell King --- drivers/dma/amba-pl08x.c | 18 +++++++++++++----- 1 file 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; + } } }