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Sharing the GPMC Bus with other devices. e.g. FPGA

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Sharing the GPMC Bus with other devices. e.g. FPGA

JamesAng
Hi all,

I know there are past discussions on the use of GPMC with FPGA but the Nabble's search-engine is getting erratic results.

Does anyone have a simple tutorial or documented guide on the use of a simple GPMC driver & user-land application to communicate (read/write) to FPGA using Overo? i.e. assuming the FPGA is another memory-storage like the NAND.

I want to know if the GPMC resource can be shared for both Ethernet/LAN and other devices.

Thanks a lot in adv.

James.
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Re: Sharing the GPMC Bus with other devices. e.g. FPGA

Philip Balister


On 09/28/2011 03:14 AM, JamesAng wrote:

>
> Hi all,
>
> I know there are past discussions on the use of GPMC with FPGA but the
> Nabble's search-engine is getting erratic results.
>
> Does anyone have a simple tutorial or documented guide on the use of a
> simple GPMC driver&  user-land application to communicate (read/write) to
> FPGA using Overo? i.e. assuming the FPGA is another memory-storage like the
> NAND.
>
> I want to know if the GPMC resource can be shared for both Ethernet/LAN and
> other devices.

Yes, it shares fine.

This is probably more complex than you want :)

https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2

Philip

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Re: Sharing the GPMC Bus with other devices. e.g. FPGA

JamesAng
Hi Philip,

Philip Balister wrote
On 09/28/2011 03:14 AM, JamesAng wrote:
>
> Hi all,
>
> I know there are past discussions on the use of GPMC with FPGA but the
> Nabble's search-engine is getting erratic results.
>
> Does anyone have a simple tutorial or documented guide on the use of a
> simple GPMC driver&  user-land application to communicate (read/write) to
> FPGA using Overo? i.e. assuming the FPGA is another memory-storage like the
> NAND.
>
> I want to know if the GPMC resource can be shared for both Ethernet/LAN and
> other devices.

Yes, it shares fine.

This is probably more complex than you want :)

https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2

Philip
Thanks in adv for pointing me to your share on the topic.

Do you have some guides/wiki/documentations for newbies like me to start reading from on using the GPMC with simple read/write to FPGA?

In that git repo, where should I start looking at to understand the relevant parts of the code used?

James
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Re: Sharing the GPMC Bus with other devices. e.g. FPGA

Philip Balister
On 10/02/2011 10:16 PM, JamesAng wrote:

>
> Hi Philip,
>
>
> Philip Balister wrote:
>>
>> On 09/28/2011 03:14 AM, JamesAng wrote:
>>>
>>> Hi all,
>>>
>>> I know there are past discussions on the use of GPMC with FPGA but the
>>> Nabble's search-engine is getting erratic results.
>>>
>>> Does anyone have a simple tutorial or documented guide on the use of a
>>> simple GPMC driver&   user-land application to communicate (read/write) to
>>> FPGA using Overo? i.e. assuming the FPGA is another memory-storage like
>>> the
>>> NAND.
>>>
>>> I want to know if the GPMC resource can be shared for both Ethernet/LAN
>>> and
>>> other devices.
>>
>> Yes, it shares fine.
>>
>> This is probably more complex than you want :)
>>
>> https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2
>>
>> Philip
>>
>
> Thanks in adv for pointing me to your share on the topic.
>
> Do you have some guides/wiki/documentations for newbies like me to start
> reading from on using the GPMC with simple read/write to FPGA?
>

No :)

> In that git repo, where should I start looking at to understand the relevant
> parts of the code used?


arch/arm/mach-omap2/board-overo.c has the gpmc configuration code.
drivers/misc/usrp_e.c has the actual driver code.

Philip

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definitive record of customers, application performance, security
threats, fraudulent activity and more. Splunk takes this data and makes
sense of it. Business sense. IT sense. Common sense.
http://p.sf.net/sfu/splunk-d2dcopy1
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Re: Sharing the GPMC Bus with other devices. e.g. FPGA

JamesAng
Hi Philip,

Philip Balister wrote
On 10/02/2011 10:16 PM, JamesAng wrote:
>
> Hi Philip,
>
> Philip Balister wrote:
>>
>> On 09/28/2011 03:14 AM, JamesAng wrote:
>>>

> Do you have some guides/wiki/documentations for newbies like me to start
> reading from on using the GPMC with simple read/write to FPGA?
>

No :)

> In that git repo, where should I start looking at to understand the relevant
> parts of the code used?


arch/arm/mach-omap2/board-overo.c has the gpmc configuration code.
drivers/misc/usrp_e.c has the actual driver code.
Noted.. I'll look from there and try to understand what it suppose to do..
(^^,)"
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Re: Sharing the GPMC Bus with other devices. e.g. FPGA

JamesAng
In reply to this post by Philip Balister
Hi Philip,

Philip Balister wrote
On 10/02/2011 10:16 PM, JamesAng wrote:
>
> Hi Philip,
>
>
> Philip Balister wrote:
>>
>> On 09/28/2011 03:14 AM, JamesAng wrote:
>>>
>>> Hi all,
>>>
>>> I know there are past discussions on the use of GPMC with FPGA but the
>>> Nabble's search-engine is getting erratic results.
>>>
>>> Does anyone have a simple tutorial or documented guide on the use of a
>>> simple GPMC driver&   user-land application to communicate (read/write) to
>>> FPGA using Overo? i.e. assuming the FPGA is another memory-storage like
>>> the
>>> NAND.
>>>
>>> I want to know if the GPMC resource can be shared for both Ethernet/LAN
>>> and
>>> other devices.
>>
>> Yes, it shares fine.
>>
>> This is probably more complex than you want :)
>>
>> https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2
>>
>> Philip
>>
>
> Thanks in adv for pointing me to your share on the topic.
>
> Do you have some guides/wiki/documentations for newbies like me to start
> reading from on using the GPMC with simple read/write to FPGA?
>

No :)

> In that git repo, where should I start looking at to understand the relevant
> parts of the code used?


arch/arm/mach-omap2/board-overo.c has the gpmc configuration code.
drivers/misc/usrp_e.c has the actual driver code.
I'm reading the files and would if you have some documentation such as the timing diagram, the data-flow, diagrams etc that I can use to x-reference to the codes to understand it in detail?

Is there a user-land test application that is using the driver?

Many thanks in adv.

James.
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Fwd: Sharing the GPMC Bus with other devices. e.g. FPGA

JamesAng
In reply to this post by Philip Balister
Hi Philip,

I wonder if you have missing the below earlier message.

Would you be able to share more lights to this mysterious part of
communicating by GPMC on OMAP to/from FPGA?

Many thanks in adv.

James.

---------- Forwarded message ----------
From: JamesAng <[hidden email]>
Date: Mon, Oct 24, 2011 at 12:15 PM
Subject: Re: [Gumstix-users] Sharing the GPMC Bus with other devices. e.g. FPGA
To: [hidden email]



Hi Philip,


Philip Balister wrote:

>
> On 10/02/2011 10:16 PM, JamesAng wrote:
>>
>> Hi Philip,
>>
>>
>> Philip Balister wrote:
>>>
>>> On 09/28/2011 03:14 AM, JamesAng wrote:
>>>>
>>>> Hi all,
>>>>
>>>> I know there are past discussions on the use of GPMC with FPGA but the
>>>> Nabble's search-engine is getting erratic results.
>>>>
>>>> Does anyone have a simple tutorial or documented guide on the use of a
>>>> simple GPMC driver&   user-land application to communicate (read/write)
>>>> to
>>>> FPGA using Overo? i.e. assuming the FPGA is another memory-storage like
>>>> the
>>>> NAND.
>>>>
>>>> I want to know if the GPMC resource can be shared for both Ethernet/LAN
>>>> and
>>>> other devices.
>>>
>>> Yes, it shares fine.
>>>
>>> This is probably more complex than you want :)
>>>
>>> https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2
>>>
>>> Philip
>>>
>>
>> Thanks in adv for pointing me to your share on the topic.
>>
>> Do you have some guides/wiki/documentations for newbies like me to start
>> reading from on using the GPMC with simple read/write to FPGA?
>>
>
> No :)
>
>> In that git repo, where should I start looking at to understand the
>> relevant
>> parts of the code used?
>
>
> arch/arm/mach-omap2/board-overo.c has the gpmc configuration code.
> drivers/misc/usrp_e.c has the actual driver code.
>

I'm reading the files and would if you have some documentation such as the
timing diagram, the data-flow, diagrams etc that I can use to x-reference to
the codes to understand it in detail?

Is there a user-land test application that is using the driver?

Many thanks in adv.

James.

--
Regards,
James

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Re: Sharing the GPMC Bus with other devices. e.g. FPGA

nilesh
In reply to this post by JamesAng
HI,
I have download and build the "https://github.com/balister/linux-omap-philip/commits/e100-2.6.38-2" Linux kernel and Test it on overo Gumstix board.

Initally i have unable to understand the working of the driver uxactly so i have bypass the DMA and the gpio144 and gpio146 and test the GPMC only. But this gives very slow speed of transfering data around few hundred KBPS because of the time consumed by the write initialiazaton of user application. it is around 8ms for wach write call.

How can i reduce the time , i mean to say i want to acess the memory pointer directly from user application without calling the driver write operation. (dont know the exact method but something like memory mapping).

also i am unable to test the data transfer with DMA. it give" dma missaligned err with device 0"

Will you please share me the details u have observed. also how much speed u got.

Thanks in advance
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