[ECOS] EB40A: Running one Function from RAM,rest in FLASH

[ECOS] EB40A: Running one Function from RAM,rest in FLASH

[Vinay.S]

hi!
	Can somebody help me out?
	I have a variant of ATMEL EB40A board,running ECOS.I have a code in which
some functions need to run from RAM( due to timing constraints)and rest of
code runs from flash.

regards,
Vinay



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Re: [ECOS] EB40A: Running one Function from RAM,rest in FLASH

[Gary Thomas]

On Tue, 2003-12-09 at 13:04, Vinay.S wrote:
> hi!
> 	Can somebody help me out?
> 	I have a variant of ATMEL EB40A board,running ECOS.I have a code in which
> some functions need to run from RAM( due to timing constraints)and rest of
> code runs from flash.

Look at how we run the FLASH drivers (look in devs/flash/...)  The low
level drivers live in RAM even if the main code lives in FLASH

-- 
Gary Thomas <gary@mlbassoc.com>
MLB Associates


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[ECOS] EB40A: Running one Function from RAM,rest in FLASH

[Vinay.S]

hi!
	Can somebody help me out?
	I have a variant of ATMEL EB40A board,running ECOS.I have a code in which
some functions need to run from RAM( due to timing constraints)and rest of
code runs from flash.

regards,
Vinay



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Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss

RE: [ECOS] EB40A: Running one Function from RAM,rest in FLASH

[Michael Anburaj]

Hi Vinay,

You have two options here.

1. You build & link the RAM resident code for the RAM address space & locate 
it in Flash (can be done using the linker script). And at run time you 
should move this code from Flash to RAM. ItÂ’s very simple in GCC & the same 
is possible under ADS/SDT tool-chains too, using the scatter map (which is a 
linker script).

2. Build the RAM resident modules as position independent code (PIC) – 
possible with GCC & ADS/SDT tool-chains. Malloc space in RAM region & copy 
the code from flash to RAM & use function pointers to access these function.

Email me if you need more clarity on this.

Cheers,
-Mike.

>From: "Vinay.S" <vinay@hunolabs.com>
>Reply-To: <vinay@hunolabs.com>
>To: "Ecos-Discuss" <ecos-discuss@sources.redhat.com>
>Subject: [ECOS] EB40A: Running one Function from RAM,rest in FLASH
>Date: Wed, 10 Dec 2003 00:57:29 +0530
>
>hi!
>	Can somebody help me out?
>	I have a variant of ATMEL EB40A board,running ECOS.I have a code in which
>some functions need to run from RAM( due to timing constraints)and rest of
>code runs from flash.
>
>regards,
>Vinay
>
>
>
>--
>Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
>and search the list archive: http://sources.redhat.com/ml/ecos-discuss
>

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RE: [ECOS] EB40A: Running one Function from RAM,rest in FLASH

[Gary Thomas]

Please copy the mailing list to your replies - that way everyone
benefits :-)

On Wed, 2003-12-10 at 13:33, Vinay.S wrote:
> hi gary,
> Thanks man.
> 	Actually just using the following
> __attribute__(SECTION("2ram.dummy")) worked for me.
> 	Can u please tell me what the above statement does? or atleast direct me to
> proper resources regarding the same.

Look at the linker file .../hal/arm/arch/current/src/arm.ld
The attribute tells the linker that the code for this particular
function goes in the "2ram.dummy" section, rather than .text.XXX
In turn, the linker will arrange that this code is then placed in
initialized data (RAM) at runtime.

> regards,
> Vinay
> 
> -----Original Message-----
> From: ecos-discuss-owner@sources.redhat.com
> [mailto:ecos-discuss-owner@sources.redhat.com]On Behalf Of Gary Thomas
> Sent: Wednesday, December 10, 2003 1:37 AM
> To: vinay@hunolabs.com
> Cc: Ecos-Discuss
> Subject: Re: [ECOS] EB40A: Running one Function from RAM,rest in FLASH
> 
> 
> On Tue, 2003-12-09 at 13:04, Vinay.S wrote:
> > hi!
> > 	Can somebody help me out?
> > 	I have a variant of ATMEL EB40A board,running ECOS.I have a code in which
> > some functions need to run from RAM( due to timing constraints)and rest of
> > code runs from flash.
> 
> Look at how we run the FLASH drivers (look in devs/flash/...)  The low
> level drivers live in RAM even if the main code lives in FLASH
> 

-- 
Gary Thomas <gary@mlbassoc.com>
MLB Associates


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Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss