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Commit 5e2479bd authored by Russell King's avatar Russell King
Browse files

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: default avatarLinus Walleij <linus.walleij@linaro.org>
Tested-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ad0de2ac

drivers/dma/amba-pl08x.c

+13 −5
Original line number Diff line number Diff line
@@ -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;

	}
@@ -324,11 +328,15 @@ 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) {

	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;

		}

	}

}



/*

 * Physical channel handling