Rockbox Development > New Ports
SanDisk Sansa c200v2, m200v4, clipv1, clipv2, clip+, and fuzev2
FlynDice:
Funman: Thanks for the caching article, sorry to drop & run on you like that but I had kids getting up and had to run off to fly across the country...
I don't know if I'm misunderstanding your comment on irc about looking in the OF for mrc/mcr whether you didn't find them or just what you found wasn't real interesting. I found them in the e280 by _not_ forcing thumb in the objdump/disassembly.
The clipv2(the new one) had roughly the same mmu startup routines as the e200. http://pastie.org/435466
Still researching dma and cache but nothing really new so far.
funman:
No problem ^^
The mrc/mcr instructions are not interesting, there's nothing that we aren't doing already.
And indeed they are ARM instructions which don't exist in thumb mode.
I have played with your patch and updated FS#10048, still no success with caching, but at least the MMU works fine!
I also opened FS#10092 which cleans up a bit system_init() : it would be nice to test on e200v2 & m200v4 (domonoky?)
By the way, has progress on c200v2 stopped?
If someone is willing to write code and test it on target, I can help by disassembly for LCD & buttons.
sko:
@funman:
I have tested your MMU patch (e250v2):
* playback (ogg) stops after 2-3 seconds (worked before)
* if I enable i/dcache bootloader looks fine, but main build start screen (the one before the menu) is mirrored and RB hangs there, one time it showed a prefetch error message (mirrored too), unfortunately i didn't notice the address (and wasn't able to reproduce until now), but I think it was FFFFFFFC.
I also tested your cleanup-patch and I couldn't find any problems, so I think it works.
FlynDice:
I"ve been looking at he gigabeat fx the past few days seeking clues and noticed that they don't seem to use the IRAM, at least not in the way that we use it for the as3525. I thought the main difference between the 922 and 920 is the smaller I/Dcaches on the 922. In their app.lds they have no IRAM and in boot.lds theyhave an IRAMSIZE of 4K but it isn't used for anything it seems. Do they use it differently? And if so is there a good reason?
Edit:Ach nevermind, been submerged in this a little too long and everything's starting to run together on me, I was thinking our IRAM was part of the 922 instead of part of the as3525....
saratoga:
--- Quote from: FlynDice on April 04, 2009, 04:52:21 PM --- In their app.lds they have no IRAM and in boot.lds theyhave an IRAMSIZE of 4K but it isn't used for anything it seems. Do they use it differently? And if so is there a good reason?
--- End quote ---
The Gigabeat F doesn't use IRAM because theres so little of it. 4KB isn't enough for codecs (which are currently designed for at least 48KB). We could use it for core stuff, but so far no obvious use for such a small amount has been found.
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