at_hdmac: bugfix for enabling channel irq

commit 46389470 deleted redundant
chan_id and chancnt initialization in dma drivers as this is done
in dma_async_device_register().

However, atc_enable_irq() relied on chan_id set before registering
the device, what left only channel 0 functional for this driver.

This patch introduces atc_enable/disable_chan_irq() as a variant
of atc_enable/disable_irq() with the channel as explicit argument.
Signed-off-by: Nikolaus Voss <n.voss@weinmann.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

drivers/dma/at_hdmac.c

@@ -1343,7 +1343,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
 
 		tasklet_init(&atchan->tasklet, atc_tasklet,
 				(unsigned long)atchan);
-		atc_enable_irq(atchan);
+		atc_enable_chan_irq(atdma, i);
 	}
 
 	/* set base routines */
@@ -1410,7 +1410,7 @@ static int __exit at_dma_remove(struct platform_device *pdev)
 		struct at_dma_chan	*atchan = to_at_dma_chan(chan);
 
 		/* Disable interrupts */
-		atc_disable_irq(atchan);
+		atc_disable_chan_irq(atdma, chan->chan_id);
 		tasklet_disable(&atchan->tasklet);
 
 		tasklet_kill(&atchan->tasklet);

drivers/dma/at_hdmac_regs.h

@@ -327,28 +327,27 @@ static void atc_dump_lli(struct at_dma_chan *atchan, struct at_lli *lli)
 }
 
 
-static void atc_setup_irq(struct at_dma_chan *atchan, int on)
+static void atc_setup_irq(struct at_dma *atdma, int chan_id, int on)
 {
-	struct at_dma	*atdma = to_at_dma(atchan->chan_common.device);
-	u32		ebci;
+	u32 ebci;
 
 	/* enable interrupts on buffer transfer completion & error */
-	ebci =    AT_DMA_BTC(atchan->chan_common.chan_id)
-		| AT_DMA_ERR(atchan->chan_common.chan_id);
+	ebci =    AT_DMA_BTC(chan_id)
+		| AT_DMA_ERR(chan_id);
 	if (on)
 		dma_writel(atdma, EBCIER, ebci);
 	else
 		dma_writel(atdma, EBCIDR, ebci);
 }
 
-static inline void atc_enable_irq(struct at_dma_chan *atchan)
+static void atc_enable_chan_irq(struct at_dma *atdma, int chan_id)
 {
-	atc_setup_irq(atchan, 1);
+	atc_setup_irq(atdma, chan_id, 1);
 }
 
-static inline void atc_disable_irq(struct at_dma_chan *atchan)
+static void atc_disable_chan_irq(struct at_dma *atdma, int chan_id)
 {
-	atc_setup_irq(atchan, 0);
+	atc_setup_irq(atdma, chan_id, 0);
 }