Hi Stefan,
Stefan Roese <s...@denx.de> wrote on Sat, 1 Sep 2018 10:50:54 +0200:
> On 31.08.2018 16:57, Miquel Raynal wrote:
> > All U-Boot users must define the mtdparts environment variable with:
> > setenv mtdparts mtdparts=...
> > > While this may ease the partition declaration job to be passed to
> > Linux, this is a pure software limitation and forcing this prefix is a
> > complete non-sense. Let the user to declare manually the mtdparts
> > variable without the prefix.
> > > Signed-off-by: Miquel Raynal <miquel.ray...@bootlin.com>
> > Acked-by: Jagan Teki <ja...@openedev.com>
> > ---
> > cmd/mtdparts.c | 17 ++++++-----------
> > 1 file changed, 6 insertions(+), 11 deletions(-)
> > > diff --git a/cmd/mtdparts.c b/cmd/mtdparts.c
> > index 2e547894c6..f7ed1a0779 100644
> > --- a/cmd/mtdparts.c
> > +++ b/cmd/mtdparts.c
> > @@ -44,7 +44,7 @@
> > *
> > * 'mtdparts' - partition list
> > *
> > - * mtdparts=mtdparts=<mtd-def>[;<mtd-def>...]
> > + * mtdparts=[mtdparts=]<mtd-def>[;<mtd-def>...]
> > *
> > * <mtd-def> := <mtd-id>:<part-def>[,<part-def>...]
> > * <mtd-id> := unique device tag used by linux kernel to find mtd
> > device (mtd->name)
> > @@ -62,11 +62,11 @@
> > *
> > * 1 NOR Flash, with 1 single writable partition:
> > * mtdids=nor0=edb7312-nor
> > - * mtdparts=mtdparts=edb7312-nor:-
> > + * mtdparts=[mtdparts=]edb7312-nor:-
> > *
> > * 1 NOR Flash with 2 partitions, 1 NAND with one
> > * mtdids=nor0=edb7312-nor,nand0=edb7312-nand
> > - *
> > mtdparts=mtdparts=edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
> > + *
> > mtdparts=[mtdparts=]edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
> > *
> > */
> > > @@ -1099,9 +1099,6 @@ static int generate_mtdparts(char *buf, u32
> > buflen)
> > return 0;
> > }
> > > - strcpy(p, "mtdparts=");
> > - p += 9;
> > -
> > list_for_each(dentry, &devices) {
> > dev = list_entry(dentry, struct mtd_device, link);
> > > @@ -1572,11 +1569,9 @@ static int parse_mtdparts(const char *const
> > mtdparts)
> > if (!p)
> > p = mtdparts;
> > > - if (strncmp(p, "mtdparts=", 9) != 0) {
> > - printf("mtdparts variable doesn't start with 'mtdparts='\n");
> > - return err;
> > - }
> > - p += 9;
> > + /* Skip the useless prefix, if any */
> > + if (strncmp(p, "mtdparts=", 9) == 0)
> > + p += 9;
> > > while (*p != '\0') {
> > err = 1;
> >
> I always wondered about this double mtdparts thing but was never brave
> enough to touch it. ;)
If I understand correctly, this double mtdparts thing comes from lazy
people who decided to build the bootargs this way:
setenv mtdparts "mtdparts=mtddev0:-(all)"
setenv bootargs "console=/dev/tty0 [...] ${mtdparts}"
instead of this way:
setenv mtdparts "mtddev0:-(all)"
setenv bootargs "console=/dev/tty0 [...] mtdparts=${mtdparts}"
Which, personally, I find much clearer.
I'm still puzzled by the real use of mtdids, I will check this week if
I didn't broke anything in the way U-Boot and Linux share the
MTD devices and their partitions.
Thanks,
Miquèl
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