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

Thu Aug 23 07:36:43 UTC 2018

On 23 August 2018 at 08:34, Andre McCurdy <armccurdy at gmail.com> wrote:

> On Thu, Aug 23, 2018 at 12:17 AM, Ryan Harkin <ryan.harkin at linaro.org>
> wrote:
> > 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 you're really still quite confused about something here...
>
> You don't need to have any file existing in the current directory (or
> anywhere else) in order to create a symlink. The symlink exists on
> it's own. Creating the file that the symlink points to is an entirely
> separate step.
>
> > 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.
>
> If you make it down as far as the end of the previous email you'll
> find a simplified example of Martin's suggestion. Please try it. It
> does work.
>

I think you're right. As was Martin.

I was starting to respond to your previous email but I'll cut it short and
just say that I apologise for the confusion and distraction and I'll make
the mod Martin suggested and test it works.

> >
> >>
> >> > $ 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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