mmc: wbsd: handle highmem pages

Use sg_copy_{from,to}_buffer to bounce buffer and 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/wbsd.c

@@ -268,43 +268,29 @@ static inline int wbsd_next_sg(struct wbsd_host *host)
 	return host->num_sg;
 }
 
-static inline char *wbsd_sg_to_buffer(struct wbsd_host *host)
+static inline char *wbsd_map_sg(struct wbsd_host *host)
 {
-	return sg_virt(host->cur_sg);
+	return kmap_atomic(sg_page(host->cur_sg)) + host->cur_sg->offset;
 }
 
 static inline void wbsd_sg_to_dma(struct wbsd_host *host, struct mmc_data *data)
 {
-	unsigned int len, i;
-	struct scatterlist *sg;
-	char *dmabuf = host->dma_buffer;
-	char *sgbuf;
-
-	sg = data->sg;
-	len = data->sg_len;
-
-	for (i = 0; i < len; i++) {
-		sgbuf = sg_virt(&sg[i]);
-		memcpy(dmabuf, sgbuf, sg[i].length);
-		dmabuf += sg[i].length;
-	}
+	size_t len = 0;
+	int i;
+
+	for (i = 0; i < data->sg_len; i++)
+		len += data->sg[i].length;
+	sg_copy_to_buffer(data->sg, data->sg_len, host->dma_buffer, len);
 }
 
 static inline void wbsd_dma_to_sg(struct wbsd_host *host, struct mmc_data *data)
 {
-	unsigned int len, i;
-	struct scatterlist *sg;
-	char *dmabuf = host->dma_buffer;
-	char *sgbuf;
-
-	sg = data->sg;
-	len = data->sg_len;
-
-	for (i = 0; i < len; i++) {
-		sgbuf = sg_virt(&sg[i]);
-		memcpy(sgbuf, dmabuf, sg[i].length);
-		dmabuf += sg[i].length;
-	}
+	size_t len = 0;
+	int i;
+
+	for (i = 0; i < data->sg_len; i++)
+		len += data->sg[i].length;
+	sg_copy_from_buffer(data->sg, data->sg_len, host->dma_buffer, len);
 }
 
 /*
@@ -418,7 +404,7 @@ static void wbsd_empty_fifo(struct wbsd_host *host)
 {
 	struct mmc_data *data = host->mrq->cmd->data;
 	char *buffer;
-	int i, fsr, fifo;
+	int i, idx, fsr, fifo;
 
 	/*
 	 * Handle excessive data.
@@ -426,7 +412,8 @@ static void wbsd_empty_fifo(struct wbsd_host *host)
 	if (host->num_sg == 0)
 		return;
 
-	buffer = wbsd_sg_to_buffer(host) + host->offset;
+	buffer = wbsd_map_sg(host) + host->offset;
+	idx = 0;
 
 	/*
 	 * Drain the fifo. This has a tendency to loop longer
@@ -445,8 +432,7 @@ static void wbsd_empty_fifo(struct wbsd_host *host)
 			fifo = 1;
 
 		for (i = 0; i < fifo; i++) {
-			*buffer = inb(host->base + WBSD_DFR);
-			buffer++;
+			buffer[idx++] = inb(host->base + WBSD_DFR);
 			host->offset++;
 			host->remain--;
 
@@ -456,16 +442,19 @@ static void wbsd_empty_fifo(struct wbsd_host *host)
 			 * End of scatter list entry?
 			 */
 			if (host->remain == 0) {
+				kunmap_atomic(buffer);
 				/*
 				 * Get next entry. Check if last.
 				 */
 				if (!wbsd_next_sg(host))
 					return;
 
-				buffer = wbsd_sg_to_buffer(host);
+				buffer = wbsd_map_sg(host);
+				idx = 0;
 			}
 		}
 	}
+	kunmap_atomic(buffer);
 
 	/*
 	 * This is a very dirty hack to solve a
@@ -480,7 +469,7 @@ static void wbsd_fill_fifo(struct wbsd_host *host)
 {
 	struct mmc_data *data = host->mrq->cmd->data;
 	char *buffer;
-	int i, fsr, fifo;
+	int i, idx, fsr, fifo;
 
 	/*
 	 * Check that we aren't being called after the
@@ -489,7 +478,8 @@ static void wbsd_fill_fifo(struct wbsd_host *host)
 	if (host->num_sg == 0)
 		return;
 
-	buffer = wbsd_sg_to_buffer(host) + host->offset;
+	buffer = wbsd_map_sg(host) + host->offset;
+	idx = 0;
 
 	/*
 	 * Fill the fifo. This has a tendency to loop longer
@@ -508,8 +498,7 @@ static void wbsd_fill_fifo(struct wbsd_host *host)
 			fifo = 15;
 
 		for (i = 16; i > fifo; i--) {
-			outb(*buffer, host->base + WBSD_DFR);
-			buffer++;
+			outb(buffer[idx], host->base + WBSD_DFR);
 			host->offset++;
 			host->remain--;
 
@@ -519,16 +508,19 @@ static void wbsd_fill_fifo(struct wbsd_host *host)
 			 * End of scatter list entry?
 			 */
 			if (host->remain == 0) {
+				kunmap_atomic(buffer);
 				/*
 				 * Get next entry. Check if last.
 				 */
 				if (!wbsd_next_sg(host))
 					return;
 
-				buffer = wbsd_sg_to_buffer(host);
+				buffer = wbsd_map_sg(host);
+				idx = 0;
 			}
 		}
 	}
+	kunmap_atomic(buffer);
 
 	/*
 	 * The controller stops sending interrupts for