dmaengine: PL08x: clean up get_signal/put_signal

Try to avoid dereferencing the DMA engine's channel struct in these
platform helpers; instead, pass a pointer to the channel data into
get_signal(), and the returned signal number to put_signal().

Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/dma/amba-pl08x.c

@@ -874,7 +874,7 @@ static int prep_phy_channel(struct pl08x_dma_chan *plchan,
 	 * Can the platform allow us to use this channel?
 	 */
 	if (plchan->slave && pl08x->pd->get_signal) {
-		ret = pl08x->pd->get_signal(plchan);
+		ret = pl08x->pd->get_signal(plchan->cd);
 		if (ret < 0) {
 			dev_dbg(&pl08x->adev->dev,
 				"unable to use physical channel %d for transfer on %s due to platform restrictions\n",
@@ -909,7 +909,7 @@ static void release_phy_channel(struct pl08x_dma_chan *plchan)
 	struct pl08x_driver_data *pl08x = plchan->host;
 
 	if ((plchan->phychan->signal >= 0) && pl08x->pd->put_signal) {
-		pl08x->pd->put_signal(plchan);
+		pl08x->pd->put_signal(plchan->cd, plchan->phychan->signal);
 		plchan->phychan->signal = -1;
 	}
 	pl08x_put_phy_channel(pl08x, plchan->phychan);

include/linux/amba/pl08x.h

@@ -225,8 +225,8 @@ struct pl08x_platform_data {
 	const struct pl08x_channel_data *slave_channels;
 	unsigned int num_slave_channels;
 	struct pl08x_channel_data memcpy_channel;
-	int (*get_signal)(struct pl08x_dma_chan *);
-	void (*put_signal)(struct pl08x_dma_chan *);
+	int (*get_signal)(const struct pl08x_channel_data *);
+	void (*put_signal)(const struct pl08x_channel_data *, int);
 	u8 lli_buses;
 	u8 mem_buses;
 };