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dmaengine: PL08x: track mux usage on a per-channel basis.

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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>
This commit is contained in:
Russell King 2012-05-25 11:32:45 +01:00
parent ad0de2ac32
commit 5e2479bd0e
1 changed files with 13 additions and 5 deletions
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14
drivers/dma/amba-pl08x.c
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@ -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