Hi Laurent,
thanks for reporting this. I just came back from holiday. I will check / fix this as soon as possible.
cheers, Hannes
Laurent Pinchart laurent.pinchart@ideasonboard.com schrieb am 04.08.2017 23:23:19:
Von: Laurent Pinchart laurent.pinchart@ideasonboard.com An: u-boot@lists.denx.de Kopie: Hannes Schmelzer hannes.schmelzer@br-automation.com, Simon
Glass
sjg@chromium.org Datum: 04.08.2017 23:23 Betreff: Re: cmd/fdt: support single value replacement within an array
Hi Hannes,
(I'm not subscribed to the list, please keep me CC'ed on replies)
On Tuesday 30 May 2017 13:05:00 Hannes Schmelzer wrote:
With this commit we can modify single values within an array of a dts property.
But with this commit U-Boot crashes if you try to create a new property
with
the fdt set command :-/
I've tested v2017.07 with the commit reverted, and fdt set works again
for me.
The issue is that your fdt_getprop() call fails and return NULL with len
set
to -1. You can easily imagine what the memcpy() following it will do.
This is useful if we have for example a pwm-backlight where we want to modifiy the pwm frequency per u-boot script.
The pwm is described in dts like this:
backlight { pwms = <0x0000002b 0x00000000 0x004c4b40>; };
For changing the frequency, here the 3rd parameter, we simply type:
fdt set /backlight pwms <? ? 0x1E8480>;
For doing all this we:
- backup the property content into our 'SCRATCHPAD'
- only modify the array-cell if the new content doesn't start with '?'
Signed-off-by: Hannes Schmelzer hannes.schmelzer@br-automation.com
cmd/fdt.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)
diff --git a/cmd/fdt.c b/cmd/fdt.c index a21415d..e55102a 100644 --- a/cmd/fdt.c +++ b/cmd/fdt.c @@ -257,6 +257,7 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag, int
argc,
char * const argv[])> char *prop; /* property */ int nodeoffset; /* node offset from libfdt */ static char data[SCRATCHPAD]; /* storage for the property */
const void *ptmp; int len; /* new length of the property */ int ret; /* return value */@@ -268,13 +269,6 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag,
int
argc, char * const argv[])> pathp = argv[2]; prop = argv[3];
if (argc == 4) {len = 0;} else {ret = fdt_parse_prop(&argv[4], argc - 4, data, &len);if (ret != 0)return ret;} nodeoffset = fdt_path_offset (working_fdt, pathp); if (nodeoffset < 0) {@@ -286,6 +280,21 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag,
int
argc, char * const argv[]) return 1; }
if (argc == 4) {len = 0;} else {ptmp = fdt_getprop(working_fdt, nodeoffset, prop,&len);
if (len > SCRATCHPAD) {printf("prop (%d) doesn't fit in scratchpad!\n",
len);return 1;}memcpy(data, ptmp, len);ret = fdt_parse_prop(&argv[4], argc - 4, data, &len);if (ret != 0)return ret;}ret = fdt_setprop(working_fdt, nodeoffset, prop, data, len); if (ret < 0) { printf ("libfdt fdt_setprop(): %s\n",fdt_strerror(ret)); @@ -766,7 +775,11 @@ static int fdt_parse_prop(char * const *newval,
int
count, char *data, int *len) cp = newp; tmp = simple_strtoul(cp, &newp, 0);
*(fdt32_t *)data = cpu_to_fdt32(tmp);
if (*cp != '?')*(fdt32_t *)data = cpu_to_fdt32(tmp);elsenewp++;data += 4; *len += 4;-- Regards,
Laurent Pinchart