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 <[email protected]> schrieb am 04.08.2017 23:23:19: > Von: Laurent Pinchart <[email protected]> > An: [email protected] > Kopie: Hannes Schmelzer <[email protected]>, Simon Glass > <[email protected]> > 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 <[email protected]> > > > > --- > > > > 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); > > + else > > + newp++; > > + > > > > data += 4; > > *len += 4; > -- > Regards, > > Laurent Pinchart > _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
