[PATCH] md: use memmap when possible

[Sascha Hauer]

This adds the missing pieces for:

d8a6e1c ARM/mem: handle data aborts gracefully for md

When possible use memmap and directly and dereference the input pointer
directly in memory_display() so that the data abort occurs where we expect
it and not in the md command. With this d8a6e1c can work as expected.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 commands/md.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/commands/md.c b/commands/md.c
index c1361a6..07a03d5 100644
--- a/commands/md.c
+++ b/commands/md.c
@@ -44,6 +44,7 @@ static int do_mem_md(int argc, char *argv[])
 	char *filename = "/dev/mem";
 	int mode = O_RWSIZE_4;
 	int swab = 0;
+	void *map;
 
 	if (argc < 2)
 		return COMMAND_ERROR_USAGE;
@@ -65,6 +66,13 @@ static int do_mem_md(int argc, char *argv[])
 	if (fd < 0)
 		return 1;
 
+	map = memmap(fd, PROT_READ);
+	if (map != (void *)-1) {
+		ret = memory_display(map + start, start, size,
+				mode >> O_RWSIZE_SHIFT, swab);
+		goto out;
+	}
+
 	do {
 		now = min(size, (loff_t)RW_BUF_SIZE);
 		r = read(fd, mem_rw_buf, now);
-- 
2.1.4