mmc: bounce requests for simple hosts
Some hosts cannot do scatter/gather in hardware. Since not doing sg
is such a big performance hit, we (optionally) bounce the requests
to a simple linear buffer that we hand over to the driver.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h
index 1590b3f..64e66e0 100644
--- a/drivers/mmc/card/queue.h
+++ b/drivers/mmc/card/queue.h
@@ -14,6 +14,9 @@
void *data;
struct request_queue *queue;
struct scatterlist *sg;
+ char *bounce_buf;
+ struct scatterlist *bounce_sg;
+ unsigned int bounce_sg_len;
};
extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *, spinlock_t *);
@@ -21,4 +24,8 @@
extern void mmc_queue_suspend(struct mmc_queue *);
extern void mmc_queue_resume(struct mmc_queue *);
+extern unsigned int mmc_queue_map_sg(struct mmc_queue *);
+extern void mmc_queue_bounce_pre(struct mmc_queue *);
+extern void mmc_queue_bounce_post(struct mmc_queue *);
+
#endif