potential GSOC project: Improve the Raspberry Pi BSP

Joel Sherrill joel.sherrill at OARcorp.com
Thu Mar 20 19:04:42 UTC 2014 

On 3/20/2014 1:48 PM, Gedare Bloom wrote:
> 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.
Please use this as a starting point for the API work.

http://git.rtems.org/multiio/

It includes driver code for two PC-104 multi IO cards, a start at a
driver/library abstraction interface, and shell commands get and
set analogs and discretes.

This code may be far from perfect from a "univeral RTEMS interface
view" but it is fielded. And we have one of the boards here in the
lab.
> -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
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> rtems-users mailing list
>>>> rtems-users at rtems.org
>>>> http://www.rtems.org/mailman/listinfo/rtems-users
>>>>
>>>>
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-- 
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

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