Registers can be write-once but ioctl does not necessarily return with
an error. Thus it is a good idea to allow verifying the data written.
Signed-off-by: Enrico Jorns <ejo@xxxxxxxxxxxxxx>
---
mmc.c | 7 ++++---
mmc_cmds.c | 28 ++++++++++++++++++++++++++--
2 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/mmc.c b/mmc.c
index 795b4e3..3f813b4 100644
--- a/mmc.c
+++ b/mmc.c
@@ -56,9 +56,10 @@ static struct Command commands[] = {
"Print extcsd data from <device>.",
NULL
},
- { do_write_extcsd, 3,
- "extcsd write", "<offset> <value> <device>\n"
- "Write <value> at offset <offset> to <device>'s extcsd.",
+ { do_write_extcsd, -3,
+ "extcsd write", "<offset> <value> <device> [--verify]\n"
+ "Write <value> at offset <offset> to <device>'s extcsd.\n"
+ " --verify Verify data written",
NULL
},
{ do_writeprotect_boot_get, -1,
diff --git a/mmc_cmds.c b/mmc_cmds.c
index df66986..154020e 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -1986,9 +1986,10 @@ int do_write_extcsd(int nargs, char **argv)
int fd, ret;
int offset, value;
char *device;
+ int verify = 0;
- if (nargs != 4) {
- fprintf(stderr, "Usage: mmc extcsd write <offset> <value> </path/to/mmcblkX>\n");
+ if (nargs != 4 && nargs != 5) {
+ fprintf(stderr, "Usage: mmc extcsd write <offset> <value> </path/to/mmcblkX> [--verify]\n");
exit(1);
}
@@ -1996,6 +1997,14 @@ int do_write_extcsd(int nargs, char **argv)
value = strtol(argv[2], NULL, 0);
device = argv[3];
+ if (nargs == 5) {
+ if (strcmp(argv[4], "--verify") == 0) {
+ verify = 1;
+ } else {
+ fprintf(stderr, "Unknown argument: '%s'\n", argv[4]);
+ }
+ }
+
fd = open(device, O_RDWR);
if (fd < 0) {
perror("open");
@@ -2010,6 +2019,21 @@ int do_write_extcsd(int nargs, char **argv)
exit(1);
}
+ if (verify) {
+ __u8 ext_csd[512];
+
+ ret = read_extcsd(fd, ext_csd);
+ if (ret) {
+ fprintf(stderr, "Could not read EXT_CSD from %s\n", device);
+ exit(1);
+ }
+
+ if (ext_csd[offset] != value) {
+ fprintf(stderr, "Verification failed: expected 0x%x, got 0x%x\n", value, ext_csd[offset]);
+ exit(1);
+ }
+ }
+
return ret;
}
--
2.39.2
