mmc: au1xmmc: handle highmem pages

Use kmap_atomic to map the scatterlist entry before using it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/au1xmmc.c

@@ -40,6 +40,7 @@
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
+#include <linux/highmem.h>
 #include <linux/leds.h>
 #include <linux/mmc/host.h>
 #include <linux/slab.h>
@@ -405,7 +406,7 @@ static void au1xmmc_send_pio(struct au1xmmc_host *host)
 
 	/* This is the pointer to the data buffer */
 	sg = &data->sg[host->pio.index];
-	sg_ptr = sg_virt(sg) + host->pio.offset;
+	sg_ptr = kmap_atomic(sg_page(sg)) + sg->offset + host->pio.offset;
 
 	/* This is the space left inside the buffer */
 	sg_len = data->sg[host->pio.index].length - host->pio.offset;
@@ -421,11 +422,12 @@ static void au1xmmc_send_pio(struct au1xmmc_host *host)
 		if (!(status & SD_STATUS_TH))
 			break;
 
-		val = *sg_ptr++;
+		val = sg_ptr[count];
 
 		__raw_writel((unsigned long)val, HOST_TXPORT(host));
 		wmb(); /* drain writebuffer */
 	}
+	kunmap_atomic(sg_ptr);
 
 	host->pio.len -= count;
 	host->pio.offset += count;
@@ -462,7 +464,7 @@ static void au1xmmc_receive_pio(struct au1xmmc_host *host)
 
 	if (host->pio.index < host->dma.len) {
 		sg = &data->sg[host->pio.index];
-		sg_ptr = sg_virt(sg) + host->pio.offset;
+		sg_ptr = kmap_atomic(sg_page(sg)) + sg->offset + host->pio.offset;
 
 		/* This is the space left inside the buffer */
 		sg_len = sg_dma_len(&data->sg[host->pio.index]) - host->pio.offset;
@@ -501,8 +503,10 @@ static void au1xmmc_receive_pio(struct au1xmmc_host *host)
 		val = __raw_readl(HOST_RXPORT(host));
 
 		if (sg_ptr)
-			*sg_ptr++ = (unsigned char)(val & 0xFF);
+			sg_ptr[count] = (unsigned char)(val & 0xFF);
 	}
+	if (sg_ptr)
+		kunmap_atomic(sg_ptr);
 
 	host->pio.len -= count;
 	host->pio.offset += count;