diff options
| author | Hauke Mehrtens <hauke.mehrtens@intel.com> | 2019-07-22 15:03:57 +0200 |
|---|---|---|
| committer | Hauke Mehrtens <hauke.mehrtens@intel.com> | 2019-07-24 13:57:09 +0200 |
| commit | 90df0f3e241dc233c3121dfc5e1be937c6c987bc (patch) | |
| tree | 69d9333e6aa0610f600989b7a239130396ae53d9 /utils/io | |
| parent | e7faabcf119a8543e0633e47e2da7300d0116a43 (diff) | |
io: Open /dev/mem with O_SYNC for uncached access
Only when /dev/mem is opened with O_SYNC the write and *read* is done
uncached. We saw wrong values read out from the hardware without setting
O_SYNC, the busybox devmem tool showed different values, when O_SYNC is
also set for the io tool, it reads out the same values as devmem.
When looking at the drivers/char/mem.c file in the kernel it is behaving
differently based on the O_DSYNC flag.
Signed-off-by: Hauke Mehrtens <hauke.mehrtens@intel.com>
Diffstat (limited to 'utils/io')
| -rw-r--r-- | utils/io/Makefile | 2 | ||||
| -rw-r--r-- | utils/io/src/io.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/utils/io/Makefile b/utils/io/Makefile index a861e7477..fe3f779b2 100644 --- a/utils/io/Makefile +++ b/utils/io/Makefile @@ -6,7 +6,7 @@ include $(TOPDIR)/rules.mk PKG_NAME:=io -PKG_RELEASE:=1 +PKG_RELEASE:=2 include $(INCLUDE_DIR)/package.mk diff --git a/utils/io/src/io.c b/utils/io/src/io.c index 257205404..519291213 100644 --- a/utils/io/src/io.c +++ b/utils/io/src/io.c @@ -343,7 +343,7 @@ main (int argc, char **argv) printf("Attempting to map 0x%lx bytes at address 0x%08lx\n", real_len, real_addr); - mfd = open("/dev/mem", (memfunc == MEM_READ) ? O_RDONLY : O_RDWR); + mfd = open("/dev/mem", (memfunc == MEM_READ) ? (O_RDONLY | O_SYNC) : (O_RDWR | O_SYNC)); if (mfd == -1) { perror("open /dev/mem"); fprintf(stderr, "Is CONFIG_DEVMEM activated?\n"); |