[OE-core] [RFC 3/3] linux-firmware: MACHINEOVERRIDES for BCM43430 NVRAM

[Ryan Harkin]

On 23 August 2018 at 08:06, Andre McCurdy <armccurdy at gmail.com> wrote:
>
> On Wed, Aug 22, 2018 at 11:12 PM, Ryan Harkin <ryan.harkin at linaro.org>
wrote:
> > On 22 August 2018 at 23:55, Andre McCurdy <armccurdy at gmail.com> wrote:
> >> On Wed, Aug 22, 2018 at 2:56 PM, Ryan Harkin <ryan.harkin at linaro.org>
> >> wrote:
> >> > On Wed, 22 Aug 2018, 21:42 Andre McCurdy, <armccurdy at gmail.com>
wrote:
> >> >> On Wed, Aug 22, 2018 at 1:10 PM, Ryan Harkin <ryan.harkin at linaro.org
>
> >> >> wrote:
> >> >> > On Wed, 22 Aug 2018, 20:02 Martin Jansa, <martin.jansa at gmail.com>
> >> >> > wrote:
> >> >> >>
> >> >> >> Your 1st parameter is wrong, compare again with the example I
gave
> >> >> >> you
> >> >> >> (don't include "brcm/" path in 1st param, because you want the
> >> >> >> symlink
> >> >> >> to
> >> >> >> point to just brcmfmac43430-sdio.AP6212.txt like you did in the
> >> >> >> version
> >> >> >> after cd).
> >> >> >
> >> >> > That doesn't work either. I tried it with the same result, but
didn't
> >> >> > send a
> >> >> > log of it. That works for you?
> >> >>
> >> >> Martin's example is correct so maybe check your tests again for
typos.
> >> >> It it still doesn't work then please do send a log.
> >> >>
> >> >> The link will point to whatever you define via the first parameter,
so
> >> >> if you changed the first parameter it shouldn't be possible to get
> >> >> "the same result".
> >> >>
> >> >>   $ mkdir foo
> >> >>   $ ln -sf test_target foo/test1
> >> >>   $ ln -sf brcm/test_target foo/test2
> >> >>   $ ls -l foo
> >> >>
> >> >>   lrwxrwxrwx 1 andre andre 11 Aug 22 13:35 test1 -> test_target
> >> >>   lrwxrwxrwx 1 andre andre 16 Aug 22 13:35 test2 -> brcm/test_target
> >> >
> >> > Yes, that's essentially the same as what I'm getting.
> >> >
> >> > Now try "cat foo/test1" and what happens?
> >> >
> >> > There is no file called test_target in the foo directory. And
neither is
> >> > there a file called brcm/test_target in the foo directory.
> >>
> >> Correct. The above was just an example to show that you can * create
> >> symlinks * in the foo directory without cd'ing into the foo directory
> >> first.
> >>
> >> If you'd like the symlinks in the example to point to valid targets
> >> then you need to create the targets too, e.g.
> >>
> >>   $ mkdir -p foo/brcm
> >>   $ echo hello > foo/test_target
> >>   $ echo hello2 > foo/brcm/test_target
> >>
> >> But note that the process of creating a symlink is always the same,
> >> regardless of whether the symlink points to a valid target or not (so
> >> you can run these extra commands to create the targets before or after
> >> you create the symlinks).
> >
> > So that doesn't work for me how I expect it to work. I must be missing
> > something fundamental here.
> >
> > The recipe is trying to create a soft link from a file in the current
> > directory to a file in the sub-directory. On my system, your example
creates
> > links from a file in the sub-directory to the another file in the
> > sub-directory.
> >
> > So, to copy your example, but creating the file "test_target" from the
> > start:
> >
> > $ mkdir -p /tmp/test
> > $ cd /tmp/test
> > $ mkdir foo
> > $ echo 1 > test_target
>
> Here you are creating "test_target" in the directory which contains
> foo, not inside foo. So a symlink inside foo pointing to "test_target"
> isn't going to work.

Exactly my point! Martin asked me to do this:

> ln -sf brcmfmac43430-sdio.AP6212.txt
${D}${nonarch_base_libdir}/firmware/brcm/brcmfmac43430-sdio.txt

Which is in essence what I'm doing above. It won't work. The file
"brcmfmac43430-sdio.AP6212.txt" doesn't exist in the current directory.
That's why there's a "cd" command in there.

I think, in hind sight, the problem is that there is no path specified for
the original file. Hence, the email I've just sent, suggests I could make
this mod:

-       ( cd ${D}${nonarch_base_libdir}/firmware/brcm/ ; ln -sf
brcmfmac43430-sdio.MUR1DX.txt brcmfmac43430-sdio.txt)
+      ( ln -sf
${D}${nonarch_base_libdir}/firmware/brcm/brcmfmac43430-sdio.MUR1DX.txt
${D}${nonarch_base_libdir}/firmware/brcm/brcmfmac43430-sdio.txt)



>
>
> > $ ln -sf test_target foo/test1
> > $ ln -sf brcm/test_target foo/test2
> > $ ls -l foo
> > total 0
> > lrwxrwxrwx 1 ryan ryan 11 Aug 23 06:54 test1 -> test_target
> > lrwxrwxrwx 1 ryan ryan 16 Aug 23 06:54 test2 -> brcm/test_target
> > $ cat test_target
> > 1
> > $ cat foo/test1
> > cat: foo/test1: No such file or directory
> > $ cat foo/test2
> > cat: foo/test2: No such file or directory
>
> All as expected given that none of the symlink targets exist yet.
>
> > $ echo hello > foo/test_target
> > $ echo hello2 > foo/brcm/test_target
> > bash: foo/brcm/test_target: No such file or directory
>
> You can't create a file within the foo/brcm subdirectory without
> creating that subdirectory first. You've somehow missed that step -
> although it was in my example.

Well, your example said:

>  $ mkdir foo
>  $ ln -sf test_target foo/test1
>  $ ln -sf brcm/test_target foo/test2
>  $ ls -l foo

... and I was trying to show that it doesn't work. Although in fairness,
you did add the "mkdir -p foo/brcm" command in a later email. So I think
we're both arguing the same point and neither of us is making ourselves
very clear.

So I don't think we need to continue down this track. Martin's original
suggestion won't work for the reasons we've both just discussed. If I add
the absolute paths to the source and target, it should be fine.


>
> > $ cat foo/test1
> > hello
> > $ cat foo/test2
> > cat: foo/test2: No such file or directory
> > $ cat test_target
> > 1
> > $ tree
> > .
> > ├── foo
> > │   ├── test1 -> test_target
> > │   ├── test2 -> brcm/test_target
> > │   └── test_target
> > └── test_target
> >
> > 1 directory, 4 files
>
> No real mysteries here. Everything looks as expected given the
> comments above about how you creating the target files.
>
> > So, neither test1 nor test2 are linked to /tmp/test/test_target.
>
> As expected. For a symlink which is in the foo subdirectory, the
> target would have to be "../test_target" to correctly point to your
> /tmp/test/test_target file.
>
> > test1 is
> > linked to /tmp/test/foo/test_target
>
> Not exactly. The test1 symlink in foo just points to "test_target",
> there's no absolute path.
>
> ie if you renamed the foo directory to something else then the test1
> symlink would still point "test_target" and it would still be a valid
> link.
>
> > and test2 is linked to
> > /tmp/test/brcm/test_target, which doesn't exist.
>
> Again, test2 is a relative symlink, not absolute. The test2 symlink
> points to a target which doesn't exist due to a missing "mkdir -p
> foo/brcm" before you tried to create the target file.
>
> > AFAIK, when creating a softlink, you have to give it either an absolute
> > path, or a path relative to the link being created. The path cannot be
> > relative to the original file that you want to link to.
>
> The only real restriction when creating a symlink is that the
> directory which will contain the symlink must exist.
>
> If you want the symlink to point to something then it's up to you to
> arrange that the target exists and the symlink points to it correctly
> - but the symlink can still be created even if the target doesn't
> point to anything valid.
>
> > So, this will work:
> >
> > $cd /tmp/test
> > $ ln -sf ../test_target foo/test3
> > $ cat foo/test3
> > 1
> > $ cat /tmp/test/foo/test3
> > 1
> >
> > But that is a strange way to create the soft link, IMO.
>
> What's strange about it?
>
> > AFAICT, for the recipe, to get rid of the "cd", I'd have to specify an
> > absolute path to the original file:
> >
> > +do_install_append_bcm43430-nvram-mur1dx() {
> > +       ( ln -sf ${PWD}/brcmfmac43430-sdio.MUR1DX.txt
> > ${D}${nonarch_base_libdir}/firmware/brcm/brcmfmac43430-sdio.txt)
> >
> > ... assuming PWD is available to the recipe. There will be a proper
Yocto
> > variable I can use, of course, but I can't think of it right now.
>
> That definitely doesn't look right...
>
> > Either way, Martin's example doesn't work for me. And adding the
absolute
> > path of the original file doesn't seem any neater or clearer than
following
> > the TI example from the do_install a few lines up in the recipe. But I'm
> > happy to do it either way, so long as it works.
>
> Martin's example is basically saying (correctly) that this sequence:
>
>   mkdir foo
>   echo hello > foo/target
>   cd foo
>   ln -sf target link
>   cd ..
>
> is equivalent to this one:
>
>   mkdir foo
>   echo hello > foo/target
>   ln -sf target foo/link
>
> Notice that the first parameter to ln (the thing you want the symlink
> to point to) is the same in both cases. ie it isn't affected by which
> directory you are in when you create the symlink.
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