dmaengine: shdma: restore partial transfer calculation

The recent shdma driver split has mistakenly removed support for partial
DMA transfer size calculation on forced termination. This patch restores
it.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/dma/sh/shdma.c b/drivers/dma/sh/shdma.c
index 027c9be..f41bcc5 100644
--- a/drivers/dma/sh/shdma.c
+++ b/drivers/dma/sh/shdma.c
@@ -381,6 +381,17 @@
 	return true;
 }
 
+static size_t sh_dmae_get_partial(struct shdma_chan *schan,
+				  struct shdma_desc *sdesc)
+{
+	struct sh_dmae_chan *sh_chan = container_of(schan, struct sh_dmae_chan,
+						    shdma_chan);
+	struct sh_dmae_desc *sh_desc = container_of(sdesc,
+					struct sh_dmae_desc, shdma_desc);
+	return (sh_desc->hw.tcr - sh_dmae_readl(sh_chan, TCR)) <<
+		sh_chan->xmit_shift;
+}
+
 /* Called from error IRQ or NMI */
 static bool sh_dmae_reset(struct sh_dmae_device *shdev)
 {
@@ -632,6 +643,7 @@
 	.start_xfer = sh_dmae_start_xfer,
 	.embedded_desc = sh_dmae_embedded_desc,
 	.chan_irq = sh_dmae_chan_irq,
+	.get_partial = sh_dmae_get_partial,
 };
 
 static int __devinit sh_dmae_probe(struct platform_device *pdev)