On Fri, Feb 18, 2011 at 7:55 PM, Harald Welte laforge@gnumonks.org wrote:
On Fri, Feb 18, 2011 at 07:27:59AM -0700, Marius Cirsta wrote:
From what I understand MT6235 has just one ARM926EJS processor and a DSP. This probably means that the it runs both the application and the GSM stack on a single CPU , right ?
It's actually 2 DSP cores. But yes, your last statement is correct.
Didn't read the datasheet that well it seems.
I read in an article about Symbian that it's able to do this because it's a realtime OS but to my knowledge Linux is not ( hence the GSM stack runs on a second processor in Android phones ). Now I also know there's a realtime Linux kernel but the question is would it be possible to run both the application and GSM stack together on the MT6235 under Linux.
Don't believe marketing crap by any company (or the Symbian foundation) ;)
I usually don't but since I have only basic knowledge in telecom I thought what they said was true and it did acutally make sense.
Layer 2 and Layer 3 of GSM have no realtime requirements, it's only the L1 that has. Running L1 inside the kernel in IRQ priority should solve all those problems. If not, we can still use the FIQ to pre-empt all the other IRQs in the kernel.
Layer2 + Layer3 then run as regular userspace programs on top of the kernel.
The entire' "realtime vs. non-realtime" debate often seems nothing but a religious and/or marketing war.
Thanks for these clarifications , it answers my question. I do have another one though , out of curiosity. Why do most if not all Android phone have a separate core for running the GSM stack ? Even MT6516 has a dedicated ARM 7 core. I cand think of the advantages being isolation of the GSM stack and keeping it hidden and proprietary but until now I thought it was a must.
Regards, Harald --
- Harald Welte laforge@gnumonks.org http://laforge.gnumonks.org/
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