mmc: atmel-mci: fix burst/chunk size modification

The use of DMA slave config operation requires that the burst size
(aka chunk size) is specified through this interface.
Modify atmel-mci slave driver to use this specification on its side.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 456c077..f2c115e 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -910,6 +910,7 @@
 	enum dma_data_direction		direction;
 	enum dma_transfer_direction	slave_dirn;
 	unsigned int			sglen;
+	u32				maxburst;
 	u32 iflags;
 
 	data->error = -EINPROGRESS;
@@ -943,17 +944,18 @@
 	if (!chan)
 		return -ENODEV;
 
-	if (host->caps.has_dma)
-		atmci_writel(host, ATMCI_DMA, ATMCI_DMA_CHKSIZE(3) | ATMCI_DMAEN);
-
 	if (data->flags & MMC_DATA_READ) {
 		direction = DMA_FROM_DEVICE;
 		host->dma_conf.direction = slave_dirn = DMA_DEV_TO_MEM;
+		maxburst = atmci_convert_chksize(host->dma_conf.src_maxburst);
 	} else {
 		direction = DMA_TO_DEVICE;
 		host->dma_conf.direction = slave_dirn = DMA_MEM_TO_DEV;
+		maxburst = atmci_convert_chksize(host->dma_conf.dst_maxburst);
 	}
 
+	atmci_writel(host, ATMCI_DMA, ATMCI_DMA_CHKSIZE(maxburst) | ATMCI_DMAEN);
+
 	sglen = dma_map_sg(chan->device->dev, data->sg,
 			data->sg_len, direction);