potential GSOC project: Improve the Raspberry Pi BSP

Gedare Bloom gedare at rtems.org
Thu Mar 20 18:48:27 UTC 2014 

On Thu, Mar 20, 2014 at 2:13 PM, Andre Marques
<andre.lousa.marques at gmail.com> wrote:
> On 03/20/14 13:58, Gedare Bloom wrote:
>>
>> Andre and Alan,
>> I would be interested in seeing something like...
>> rtems_spi_initialize(&spi_handle)
>> rtems_spi_write(&spi_handle, data)
>> rtems_spi_read(&spi_handle, &data)
>> rtems_spi_ioctl(&spi_handle, &spi_control)
>> or something similar, where spi can be replaced with i2c,  gpio, 1-wire,
>> etc.
>>
>> Something more generic might even work, like
>> rtems_bus_initialize(BUS_TYPE_SPI, &bus_handle, ...)
>> rtems_bus_write(&bus_handle, data)
>> etc.
>>
>> This interface should "cover" the cpukit/libi2c,
>
>
> cpukit/libi2c already provides those methods as rtems_libi2c_*, and the type
> of bus (i2c or spi) can be specified. The libi2c API separates the low level
> driver (board dependent) of the high level driver (device dependent). In
> this way every BSP only need to provide the low level driver, as the device
> drivers using the i2c or spi buses can be reused.
>
> Not sure about what you meant with covering the libi2c.
>
OK good it sounds like libi2c has much of the "generic" part taken care of.

> GPIO seems to lack a generic interface in rtems, so I will think of one.
>
Good.
-Gedare

>
>>   and be implemented in
>> RPi as an example. then, any BSP that implements this interface can
>> support the applications that use it.
>> -Gedare
>>
>> On Thu, Mar 20, 2014 at 5:36 AM, Andre Marques
>> <andre.lousa.marques at gmail.com> wrote:
>>>
>>> On 03/20/14 02:21, Alan Cudmore wrote:
>>>
>>> Interesting idea.
>>> Part of this may be done:
>>> GPIO : Can start with Pierre's implementation
>>> i2c: Isn't there a libi2c already?
>>> SPI: ?
>>>
>>>
>>> cpukit/libi2c also deals with SPI.
>>>
>>> It is also implemented on the FreeBSD port to RPi
>>>
>>>
>>> https://github.com/freebsd/freebsd/blob/master/sys/arm/broadcom/bcm2835/bcm2835_spi.c
>>>
>>> and more info can be found at
>>>
>>> http://elinux.org/RPi_SPI
>>>
>>>
>>> SD card: ? There should be at least one example to follow in the ARM
>>> tree.
>>>
>>> Framebuffer: I think this is well defined.
>>>
>>>
>>> Alan
>>>
>>>
>>>
>>> On Wed, Mar 19, 2014 at 7:59 PM, Gedare Bloom <gedare at rtems.org> wrote:
>>>>
>>>> On Wed, Mar 19, 2014 at 7:04 PM, Joel Sherrill
>>>> <joel.sherrill at oarcorp.com> wrote:
>>>>>
>>>>> On 3/19/2014 4:18 PM, Pierre Ficheux wrote:
>>>>>>
>>>>>> Hi Alan,
>>>>>>
>>>>>> ----- Mail original -----
>>>>>>>
>>>>>>> De: "Alan Cudmore" <alan.cudmore at gmail.com>
>>>>>>> À: "Pierre Ficheux" <pierre.ficheux at openwide.fr>
>>>>>>> Cc: "Andre Marques" <andre.lousa.marques at gmail.com>,
>>>>>>> rtems-users at rtems.org
>>>>>>> Envoyé: Mercredi 19 Mars 2014 22:10:50
>>>>>>> Objet: Re: potential GSOC project: Improve the Raspberry Pi BSP
>>>>>>>
>>>>>>>
>>>>>>> Hi Pierre,
>>>>>>> We hope to use your GPIO implementation for this project. Any
>>>>>>> problems with incorporating it into the BSP?
>>>>>>
>>>>>> No problem at all.
>>>>>>
>>>>>>> For the USB and MMC support, the u-boot code would be nice, but it is
>>>>>>> GPL and not compatible with the RTEMS libraries. But it could serve
>>>>>>> as a reference.
>>>>>>
>>>>>> I'm not aware of RTEMS licensing issue :) I know it's GPL with linking
>>>>>> exception but what's the problem with "libraries" ?
>>>>>
>>>>> Ultimately, everything is statically linked together. So the license of
>>>>> a library
>>>>> could virally impact the license of all users.
>>>>>
>>>>> Ideally this support would be part of the BSP.
>>>>>
>>>>> There is a proposed API and simple driver model for analogs and
>>>>> discrete
>>>>> IO
>>>>> in RTEMS git in another git module. It includes some shell commands to
>>>>> assist
>>>>> in debugging and playing with IO settings.
>>>>
>>>> Would adding "generic" RTEMS interfaces for GPIO, i2c, SPI, and SD
>>>> card with example implementations in Raspberry Pi be feasible and
>>>> interesting?
>>>>
>>>> -Gedare
>>>>
>>>>>>> Also, I am not sure how to approach the USB and network
>>>>>>> implementation. For example, we could probably get the Ethernet to
>>>>>>> work, and the USB code would just be "a bunch of files" in the
>>>>>>> ethernet driver directory. But I think the right way would be to use
>>>>>>> the FreeBSD library support of the USB and Ethernet devices. I just
>>>>>>> don't know how to do that :)
>>>>>>
>>>>>> I do agree. I talked about U-Boot for MMC support though it includes
>>>>>> USB support too.
>>>>>
>>>>> If this were in the new BSD USB/TCP/IP code, it should be
>>>>> straightforward to
>>>>> support both USB and TCP/IP.
>>>>>>
>>>>>> regards
>>>>>>>
>>>>>>> Alan
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Mar 19, 2014 at 4:33 PM, Pierre Ficheux <
>>>>>>> pierre.ficheux at openwide.fr > wrote:
>>>>>>>
>>>>>>>
>>>>>>> USB should be interesting too on RPi because of Ethernet support ;)
>>>>>>>
>>>>>>> Regarding SD card you should take a look at U-Boot for RPi which
>>>>>>> includes MMC support in drivers/mmc. U-Boot includes USB support for
>>>>>>> RPi too in drivers/usb.
>>>>>>>
>>>>>>> https://github.com/gonzoua/u-boot-pi
>>>>>>>
>>>>>>> regards
>>>>>>>
>>>>>>> ----- Mail original -----
>>>>>>>>
>>>>>>>> De: "Andre Marques" < andre.lousa.marques at gmail.com >
>>>>>>>> À: "Alan Cudmore" < alan.cudmore at gmail.com >
>>>>>>>> Cc: rtems-users at rtems.org
>>>>>>>> Envoyé: Mercredi 19 Mars 2014 20:59:56
>>>>>>>> Objet: Re: potential GSOC project: Improve the Raspberry Pi BSP
>>>>>>>>
>>>>>>>> Hello Alan,
>>>>>>>>
>>>>>>>> I have decided to go with the framebuffer instead of the USB
>>>>>>>> support.
>>>>>>>> Will update the proposal with this.
>>>>>>>>
>>>>>>>> Before GSOC I am considering to look at the SD card access through
>>>>>>>> the onboard card reader. What do you think?
>>>>>>>>
>>>>>>>> --André Marques.
>>>>>>>>
>>>>>>>> On 03/19/14 00:56, Alan Cudmore wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hi André ,
>>>>>>>> I agree about the USB stack. I am not even sure about how to
>>>>>>>> integrate a driver that depends on the FreeBSD USB stack.
>>>>>>>>
>>>>>>>>
>>>>>>>> The GPIO driver from Pierre is the one I was referring to. I don't
>>>>>>>> think anyone ever made a decision on how to integrate the GPIO
>>>>>>>> driver. If we have macros in the BSP header files then the GPIO can
>>>>>>>> be programmed with the simple macros or the driver that Pierre
>>>>>>>> wrote. If the project decides to use the GPIO device model for
>>>>>>>> other
>>>>>>>> BSPs, then the generic driver code can be moved to a shared
>>>>>>>> directory at a later date.
>>>>>>>>
>>>>>>>>
>>>>>>>> Thanks for the update,
>>>>>>>>
>>>>>>>>
>>>>>>>> Alan
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Tue, Mar 18, 2014 at 11:04 AM, Andre Marques <
>>>>>>>> andre.lousa.marques at gmail.com > wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> about the USB driver port from FreeBSD I am finding it difficult to
>>>>>>>> gauge how much work it would involve, so I will follow your
>>>>>>>> suggestion and look at something else.
>>>>>>>>
>>>>>>>> As for GPIO I belive the work that has been done is this:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> https://github.com/pficheux/raspberry_pi/tree/master/RTEMS/gpio_driver
>>>>>>>>
>>>>>>>> Am I right?
>>>>>>>>
>>>>>>>> I also found a discussion on the best way of implementing the
>>>>>>>> driver
>>>>>>>>
>>>>>>>> http://www.rtems.org/pipermail/rtems-users/2013-October/012059.html
>>>>>>>>
>>>>>>>> but i am not sure if that came to a decision.
>>>>>>>>
>>>>>>>> Meanwhile I will update the proposal with some basic info on the
>>>>>>>> drivers.
>>>>>>>>
>>>>>>>> --André Marques.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 03/14/14 13:16, Andre Marques wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> On 03/14/14 02:33, Alan Cudmore wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Andre,
>>>>>>>> I think your project proposal looks good, but I wonder if including
>>>>>>>> USB support is too much. There are low level "bare metal" USB
>>>>>>>> examples out there for the Raspberry Pi, and that may serve as a
>>>>>>>> starting point, but I think a real USB implementation will use the
>>>>>>>> BSD library that has been ported to RTEMS. It may be possible,
>>>>>>>> since
>>>>>>>> there is a FreeBSD port to the Raspberry Pi. Maybe others can help
>>>>>>>> here.
>>>>>>>>
>>>>>>>>
>>>>>>>> I will take a look into this.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> If you think that GPIO, SPI, and I2C are not enough, then you could
>>>>>>>> always look at the framebuffer or SD card access.
>>>>>>>>
>>>>>>>>
>>>>>>>> Yes, right now I am trying to clarify everything the best I can so
>>>>>>>> I
>>>>>>>> don't end up with a lot more (or less) work than I can handle.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Finally, it may be necessary to have an Raspberry Pi and a few
>>>>>>>> peripherals. For example, I have an inexpensive I2C compass module
>>>>>>>> that I use with linux, and I have a breadboard wired up with LEDs
>>>>>>>> to
>>>>>>>> test GPIO.
>>>>>>>>
>>>>>>>>
>>>>>>>> Right now I have access to a Raspberry Pi at the university, not
>>>>>>>> sure
>>>>>>>> about the peripherals though. Anyway, if this projects really goes
>>>>>>>> forward I will get myself a raspberry and peripherals (I have
>>>>>>>> already some other components, like a breadboard, leds, wire, etc).
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Alan
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Mar 13, 2014 at 8:32 PM, Alan Cudmore <
>>>>>>>> alan.cudmore at gmail.com > wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> I'm glad there is interest in this project. Andre, I will read your
>>>>>>>> proposal and provide feedback.
>>>>>>>> Joel, I was on the melange site and the system recognizes my
>>>>>>>> account.
>>>>>>>> Do I need to do anything to be a mentor for RTEMS?
>>>>>>>> Alan
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Mar 13, 2014 at 7:31 PM, Andre Marques <
>>>>>>>> andre.lousa.marques at gmail.com > wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> It is now on melange too.
>>>>>>>>
>>>>>>>> --André Marques.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 03/13/14 23:21, Hesham Moustafa wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hi Andre,
>>>>>>>>
>>>>>>>>
>>>>>>>> I quote from RTEMS SoC page :
>>>>>>>>
>>>>>>>> "GSOC STUDENTS! PLEASE FILL IN THE APPLICATION AT
>>>>>>>> http://www.google-melange.com ! YOU CAN EDIT UNTIL THE DEADLINE!
>>>>>>>> BUT
>>>>>>>> YOU WILL NOT GET A SLOT IF YOU DO NOT APPLY THROUGH Google!!!"
>>>>>>>>
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Hesham
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Fri, Mar 14, 2014 at 1:16 AM, Andre Marques <
>>>>>>>> andre.lousa.marques at gmail.com > wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> I just posted the first proposal draft for "Raspberry Pi BSP
>>>>>>>> Peripherals " in the RTEMS Wiki
>>>>>>>>
>>>>>>>> http://wiki.rtems.org/wiki/index.php/RTEMSSummerOfCode
>>>>>>>>
>>>>>>>> Any feedback is more than welcome. Should I post it already in
>>>>>>>> melange too?
>>>>>>>>
>>>>>>>> --André Marques.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 03/13/14 15:26, Joel Sherrill wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 3/13/2014 9:46 AM, Andre Marques wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> I would be very interested in working in this project because I'm
>>>>>>>> currently trying to work with Raspberry Pi and RTEMS for my
>>>>>>>> undergraduate thesis, so this could be a great followup to that for
>>>>>>>> the summer.
>>>>>>>>
>>>>>>>> I will need to do some reseach on it before making a proposal (the
>>>>>>>> time is also gettting shorter), but will post a proposal draft very
>>>>>>>> soon.
>>>>>>>>
>>>>>>>> This would be a great area to work. As Alan says, the list is
>>>>>>>> likely
>>>>>>>> too much for
>>>>>>>> one student, so it seems likely that the work could be divided for
>>>>>>>> two students
>>>>>>>> working on different parts.
>>>>>>>>
>>>>>>>> For the Pi Master list, I would like to add the Geert board. That
>>>>>>>> looks like something
>>>>>>>> of interest to RTEMS folks.
>>>>>>>>
>>>>>>>> --joel
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --André Marques.
>>>>>>>>
>>>>>>>> On 03/13/14 11:23, Alan Cudmore wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> ( I posted this to the rtems-devel list by mistake, my apologies
>>>>>>>> for
>>>>>>>> the duplicate message )
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> f there are still potential GSOC students out there looking for a
>>>>>>>> project, I would like to offer a potential project to work on:
>>>>>>>> Improving the Raspberry Pi BSP. I would be happy to mentor a
>>>>>>>> student
>>>>>>>> for this project. Below is my description for the task.
>>>>>>>>
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Alan
>>>>>>>>
>>>>>>>>
>>>>>>>> One of the RTEMS Open Projects is to contribute a BSP or Board
>>>>>>>> Support Package for readily available boards. The Raspberry Pi is
>>>>>>>> probably the most available board at $25 and $35 USD, and there
>>>>>>>> have
>>>>>>>> been over two million of these boards sold. The RTEMS head (4.11)
>>>>>>>> currently has a basic BSP for the Raspberry Pi, supporting the CPU,
>>>>>>>> a single UART, and timer. It is enough to run some basic RTEMS
>>>>>>>> programs, but expanding the BSP to support peripherals will make it
>>>>>>>> much more useful.
>>>>>>>> For this project, the GSOC student could improve the peripheral
>>>>>>>> support for the Raspberry Pi BSP.
>>>>>>>> The peripherals we need to support (in order of increasing
>>>>>>>> difficulty) include:
>>>>>>>> 1. GPIO (This has been done by one user, but is not integrated)
>>>>>>>> 2. I2C Bus
>>>>>>>> 3. SPI Bus
>>>>>>>> 4. Secure Digital card read and write support (using the SPI bus)
>>>>>>>> 5. Graphics / RTEMS Framebuffer Support (I have a graphics demo
>>>>>>>> working in an RTEMS task)
>>>>>>>> 6. USB Device support
>>>>>>>> 7. HDMI/Graphics console (Requires framebuffer support and USB or
>>>>>>>> GPIO connected keyboard device)
>>>>>>>> 8. Ethernet network support (Requires USB support)
>>>>>>>> The entire list is probably too much for a single student to
>>>>>>>> accomplish, so we can adjust the list of work according to what is
>>>>>>>> possible.
>>>>>>>>
>>>>>>>>
>>>>>>>> It may also be a good idea to add support for both models of the
>>>>>>>> Raspberry Pi (256MB and 512MB) and be able to configure the memory
>>>>>>>> map in the BSP to match the boot time split between the CPU and GPU
>>>>>>>> memory.
>>>>>>>>
>>>>>>>>
>>>>>>>> Finally, in order to do some of this coding, it may be necessary to
>>>>>>>> come up with a more efficient way to load and debug code on the
>>>>>>>> Raspberry Pi. Options include using U-boot or connecting a JTAG
>>>>>>>> debug device to load code.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> rtems-users mailing list rtems-users at rtems.org
>>>>>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>>>>>>
>>>>>>>> --
>>>>>>>> Joel Sherrill, Ph.D. Director of Research & Development
>>>>>>>> joel.sherrill at OARcorp.com On-Line Applications Research
>>>>>>>> Ask me about RTEMS: a free RTOS Huntsville AL 35805
>>>>>>>> Support Available (256) 722-9985
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> rtems-users mailing list
>>>>>>>> rtems-users at rtems.org
>>>>>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> rtems-users mailing list
>>>>>>>> rtems-users at rtems.org
>>>>>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> rtems-users mailing list
>>>>>>>> rtems-users at rtems.org
>>>>>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>>>>>>
>>>>>>> --
>>>>>>> Pierre FICHEUX -/- CTO OW/OWI, France -\- pierre.ficheux at openwide.fr
>>>>>>> http://ingenierie.openwide.fr
>>>>>>> http://www.linuxembedded.fr
>>>>>>> I would love to change the world, but they won't give me the source
>>>>>>> code
>>>>>>>
>>>>>>>
>>>>>> --
>>>>>> Pierre FICHEUX -/- CTO OW/OWI, France -\- pierre.ficheux at openwide.fr
>>>>>>
>>>>>> http://ingenierie.openwide.fr
>>>>>>                                           http://www.linuxembedded.fr
>>>>>> I would love to change the world, but they won't give me the source
>>>>>> code
>>>>>>
>>>>>> _______________________________________________
>>>>>> rtems-users mailing list
>>>>>> rtems-users at rtems.org
>>>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>>>
>>>>> --
>>>>> Joel Sherrill, Ph.D.             Director of Research & Development
>>>>> joel.sherrill at OARcorp.com        On-Line Applications Research
>>>>> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>>>>> Support Available                (256) 722-9985
>>>>>
>>>>> _______________________________________________
>>>>> rtems-users mailing list
>>>>> rtems-users at rtems.org
>>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>
>>>
>>>
>>>
>>> _______________________________________________
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>>> rtems-users at rtems.org
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>>>
>>>
>

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