rtems-libbsd build error
Christian Mauderer
christian.mauderer at embedded-brains.de
Tue Apr 16 10:54:09 UTC 2019
Am 16.04.19 um 11:28 schrieb Vijay Kumar Banerjee:
>
>
>
> On Fri, Apr 12, 2019 at 9:16 PM Christian Mauderer <list at c-mauderer.de
> <mailto:list at c-mauderer.de>> wrote:
>
> Am 12.04.19 um 16:26 schrieb Vijay Kumar Banerjee:
> >
> >
> > On Wed, Apr 10, 2019 at 12:50 PM Christian Mauderer
> > <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>> wrote:
> >
> > Am 09.04.19 um 18:12 schrieb Vijay Kumar Banerjee:
> > > Hi,
> > >
> > > I have imported and ported the the drivers in 2 pairs(import
> and port)
> > > of commits
> > > for each one. Please have a look at this branch
> > > https://github.com/thelunatic/rtems-libbsd/commits/tda19988
> >
> > One detail: You have a commit named "tda19988.c: import from
> FreeBSD".
> > Please remove the ".c".
> >
> > Noted.
> >
> > Maybe it would be a good idea to split of the I2C part and put
> it in
> > front of the other two parts. You can develop and test that
> independent
> > with a test that just accesses some of the I2C devices on the
> board via
> > the FreeBSD API and the translation driver discussed below.
> >
> > This is a good idea, I'll import iicbus separately and add the other
> > two on top of it.
> >
> > >
> > > I have also tried running the media01.exe and have seen it
> running
> > fine
> > > without
> > > throwing any exceptions.
> > >
> > > I have used the fb.c and iicbus.c codes from the
> freebsd source. From
> > > what I
> > > understand, I think the next big steps would be to write an
> RTEMS
> > > implementation layer for these portions of the code? And then a
> > test in the
> > > libbsd, like media01, to write to the /dev/fb0
> > >
> > > Can you please help me chalk out a rough outline of the next
> set of
> > > actions? :)
> >
> > As far as I can tell, there are two possible I2C buses here:
> >
> > 1. The one between the AM335x and the TDA19988.
> >
> > 2. The one directly on the HDMI connector (called HDMI_DSCL and
> > HDMI_DSDA). I assume that's an I2C bus too.
> >
> > For 1. the RTEMS driver should be used. You'll need some code that
> > translates the FreeBSD API to the one used in RTEMS. Basically
> that will
> > just be a FreeBSD-I2C-driver.
> >
> > For 2: If that even is an independent I2C bus, you can use the
> driver
> > provided by FreeBSD. I don't think that it is necessary to
> translate to
> > the RTEMS API here.
> >
> > I had a look at the iic and iicbus codes in freebsd and the bbb-i2c.c
> > This looks very confusing to me. Are we looking for something like a
> > rtems-iicbus.c in the rtemsbsd that works like a wrapper to the
> bbb-i2c
> > code, and uses the freebsd api of DEVMETHODs?
>
> Yes correct. Basically it would be necessary to have a I2C device driver
> for FreeBSD that translates to the RTEMS API.
>
> >
> > I've not been able to figure out at one look, how to relate them and
> > get a wrapper like that. Any suggestions on how to approach this?
>
> I haven't had a look at the FreeBSD drivers yet. The first part that I
> would have a look at is the description of the user facing FreeBSD API:
>
> https://www.freebsd.org/cgi/man.cgi?query=iic&apropos=0&sektion=0&manpath=FreeBSD+12.0-RELEASE+and+Ports&arch=default&format=html
>
> Nice thing: They use a struct iic_msg that is compatible with Linux's
> struct i2c_msg (according to the man page). We are Linux compatible too.
> Can be a big advantage.
>
> Then take a look at the simplest i2c driver that you can find in FreeBSD
> that uses the transfer API.
> freebsd-org/sys/dev/drm2/radeon/atombios_i2c.c looks good to me.
> Basically you have to implement the following functions (replace
> radeon_atom... by a useful prefix):
>
> static device_method_t radeon_atom_hw_i2c_methods[] = {
> DEVMETHOD(device_probe, radeon_atom_hw_i2c_probe),
> DEVMETHOD(device_attach, radeon_atom_hw_i2c_attach),
> DEVMETHOD(device_detach, radeon_atom_hw_i2c_detach),
> DEVMETHOD(iicbus_reset, radeon_atom_hw_i2c_reset),
> DEVMETHOD(iicbus_transfer, radeon_atom_hw_i2c_xfer),
> DEVMETHOD_END
> };
>
> The iicbus_transfer function seems to get a struct iic_msg as a
> parameter. Now that's really lucky.
>
> With that you should be able to open the i2c device in RTEMS and just
> pass the structure via the correct ioctl call to the RTEMS driver.
>
> Basically you just have to pass the bus to use as a parameter to the
> driver. Take a look at some of the other drivers in nexus-devices.h that
> have for example an address as a parameter to see how you can do that.
>
> This gave a good idea of the objective. :)
>
> I had a look at the bbb-i2c.c code and how it's registering
> and setting up the i2c_bus struct with the transfer, set and destroy
> fucntions.
> I have a question from the fundamentals, the only function
> of bbb-i2c.c
> <https://git.rtems.org/rtems/tree/bsps/arm/beagle/i2c/bbb-i2c.c#n414>
> that is 'accessible' with the header file is am335x_i2c_bus_register
> which basically sets the i2c_bus struct
> and calls the i2c_bus_register function from the dev/i2c.c .
> To use the DEVMETHOD api, we need to be able to call the
> transfer, destroy etc. functions of the bbb-i2c.c from the translation
> layer in rtemsbsd. How do I #include the bbb-i2c.c in the new
> translation driver that I'll write?
>
> Hope my question is stated clearly, please correct me if I'm getting
> some fundamentals wrong.
You are not fundamentally wrong but slightly off:
Regarding the question how you access transfer, destroy, ... of the
driver directly: Don't.
You basically don't need to have a look at the bbb-i2c.c file of RTEMS
for that driver. Where you should have a look is the Linux I2C API
(which has been the model for the RTEMS API).
Basically your drivers transfer function will do about the following:
- Open "/dev/i2c0" (or some other path - that will be a parameter to the
driver and has to be stored by probe or attach in some device structure).
- Translate the "struct iic_msg" you get as an input to a "struct
i2c_msg". Most likely that's just a cast.
- Pass that via an ioctl call to the opened bus.
- Check return value and translate to the matching return of FreeBSD.
- Close "/dev/i2c0"
Some of the open / close might could move to attach / detach. But that
would be an optimization.
That driver will work on any BSP that implements the current i2c API. So
it's a generic translation layer.
Best regards
Christian
>
> >
> > Can we not totally use the iicbus in the freebsd source?
>
> We already have a I2C driver for that BSP in RTEMS. If you would use the
> FreeBSD code, they would fight for the hardware. Of course it would be
> possible to replace the RTEMS driver by a FreeBSD one. But that would
> potentially break some applications. Besides that I think that a lot of
> RTEMS BSPs already have an I2C driver so a generic wrapper could be
> helpful for other BSPs too.
>
> >
> > >
> > > Thanks
> > >
> > > On Tue, Apr 9, 2019 at 5:28 AM Chris Johns <chrisj at rtems.org
> <mailto:chrisj at rtems.org>
> > <mailto:chrisj at rtems.org <mailto:chrisj at rtems.org>>
> > > <mailto:chrisj at rtems.org <mailto:chrisj at rtems.org>
> <mailto:chrisj at rtems.org <mailto:chrisj at rtems.org>>>> wrote:
> > >
> > > On 8/4/19 12:30 am, Vijay Kumar Banerjee wrote:
> > > > On Sun, Apr 7, 2019 at 6:24 PM Christian Mauderer
> > > <list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>> wrote:
> > > > Am 07.04.19 um 14:50 schrieb Vijay Kumar Banerjee:
> > > > > On Sun, Apr 7, 2019 at 6:08 PM Christian Mauderer
> > > <list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > > <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de> <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>
> > > > > <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de> <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>>> wrote:
> > > > > Am 07.04.19 um 14:35 schrieb Vijay Kumar
> Banerjee:
> > > > > > On Sun, Apr 7, 2019 at 5:37 PM Christian
> Mauderer
> > > > > <list at c-mauderer.de
> <mailto:list at c-mauderer.de> <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>
> > > > <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de> <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>>
> > > > > > <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>
> > > > <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de> <mailto:list at c-mauderer.de
> <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>
> > > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>
> > <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>
> <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>>>>>> wrote:
> > > > > > Am 07.04.19 um 13:08 schrieb Vijay Kumar
> > Banerjee:
> > > >
> > > > I don't think that there are a lot of docs for how
> to test.
> > > Although I'm
> > > > sure that there are some scripts to run a number
> of libbsd
> > > tests, I'm
> > > > not sure where. Maybe in the RTEMS tester but I think
> > that is
> > > mainly for
> > > > the core tests?
> > >
> > > The documentation for testing can be found here ...
> > >
> > >
> https://docs.rtems.org/branches/master/user/testing/index.html
> > >
> > > > so far I know, RTEMS Tester is only for core tests.
> > >
> > > The `rtems-test` command checks the for test start and end
> > banners.
> > > I am not
> > > sure if libbsd supports the test banners. Maybe it could
> now with
> > > Sebastian's
> > > movement of the test support code into libtest.
> > >
> > > > I'll ask in the devel if there's some way to run
> libbsd test
> > with
> > > the tester.
> > >
> > > There is the `rtems-run` command which has similar args to
> > > `rtems-test`. It does
> > > suffer from a limitation I have not fixed which is stdin
> is not
> > > passed through
> > > to the console of the target. I also think the command has a
> > timeout
> > > running,
> > > but I am not sure about this one.
> > >
> > > Chris
> > >
> >
> > --
> > --------------------------------------------
> > embedded brains GmbH
> > Herr Christian Mauderer
> > Dornierstr. 4
> > D-82178 Puchheim
> > Germany
> > email: christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>
> > Phone: +49-89-18 94 741 - 18
> > Fax: +49-89-18 94 741 - 08
> > PGP: Public key available on request.
> >
> > Diese Nachricht ist keine geschäftliche Mitteilung im Sinne
> des EHUG.
> >
>
--
--------------------------------------------
embedded brains GmbH
Herr Christian Mauderer
Dornierstr. 4
D-82178 Puchheim
Germany
email: christian.mauderer at embedded-brains.de
Phone: +49-89-18 94 741 - 18
Fax: +49-89-18 94 741 - 08
PGP: Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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