[E3-hacking] [PATCH v2 1/6] SoC Camera: add driver for OMAP1 camera interface

Janusz Krzysztofik jkrzyszt at tis.icnet.pl
Sat Sep 11 10:32:47 BST 2010

Saturday 11 September 2010 04:06:02 Jasmine Strong wrote:
> On 10 Sep 2010, at 18:21, Janusz Krzysztofik wrote:
> >  Both paths work stable for me, even
> > under heavy load, on my OMAP1510 based Amstrad Delta videophone, that is
> > the oldest, least powerfull OMAP1 implementation.
> You say that, but the ARM925 in OMAP1510 is known not to exhibit the bug 

Then, lucky me ;)

> in  
> OMAP1610, which causes severe slowdown to DRAM writes when the first
> address of an STM instruction is not aligned to a d-cache line boundary. 
> This means that at least last time I looked, the Linux ARM memcpy()
> implementation is often faster on 1510 than 1610.

This sounds like a problem that should be solved at a machine support level 
rather than a camera driver. I don't follow general OMAP development closely 
enough to know if this bug has ever been addressed or is going to be.

Unfortunatelly, I have no access to any OMAP machine other than Amstrad Delta, 
so I'm not able to test the driver, including its performance, on other OMAP1 

Anyways, I think there is always a room for improvement, either in my 
omap1_camera or maybe in the omap24xxcam driver, if someone tries to add 
support for a camera to an OMAP1 board other than 1510, and identifies a more 
optimal, 1610 or higher specific way of handling the OMAP camera interface.

Do you think I should rename the driver to something like "omap1510cam" rather 
than "omap1_camera" then?


> -J.
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