Some Mobile GPU Documentation To End The Year

There was a new documentation drop this week that consisted of data-sheets and other programming documentation for the 2D, 3D, and MPEG engines of a mobile GPU.

This isn't related to the forthcoming drop by VIA Technologies that was talked about yesterday, but this news today comes from the OpenMoko camp. The OpenMoko camp published documentation on one of the GPU designs they were using this week with an earlier phone.

The GPU in question is the SMedia Glamo 3362, which was deployed with the Neo FreeRunner phone. The Neo FreeRunner was the successor to the Neo1973 phone and was shipping from the OpenMoko camp back in 2008. Sorry if you were hoping this GPU documentation drop was also about the just-released AMD Radeon HD 7000 series.

Up until recently there's only been an open 2D kernel and X.Org driver for the hardware that was considered open-source software. Data-sheets for the Glamo 3362 GPU were only available under Non-Disclosure Agreements with SMedia.

SMedia has since been acquired by ITE Tech and the OpenMoko crew managed to obtain permission to publicly release the Glamo 3362 graphics processor documentation.

The Glamo 3362 graphics processor features 8MB of SDRAM, a 16-bit interface to the Samsung S3C2410 processor, 3D acceleration with a maximum texture size of 256 x 256, OpenGL ES 1.0/1.1 compliance, and H.263 encode/decode support. The maximum supported frame-buffer size for the Glamo graphics is a mere 512 x 512.

The SMedia Glamo 3362 was used by the OpenMoko Neo FreeRunner, but that seems to be about it... I'm having troubles finding any other mobile device that actually used this graphics chip. However, it may be for the better as even the OpenMoko team was unhappy with this Scheiße-chip. "Note that choosing Glamo has been accepted as a bit of a design mistake, both from performance point of view and openness point of view (3D part). So future Openmoko products will not feature the chip, but the currently (2008) selling Neo FreeRunner (GTA02) does have it and could be usable for 3D acceleration and other accelerations. Known limitations include (?) maximum framebuffer size of 512x512, which effectively excludes FreeRunner's default 480x640 out - so eg. the alternate resolution available, 240x320 (QVGA). is fine."

Back in 2009 there was a developer that did write a GEM and KMS driver for the Glamo 3362 and it worked on this FIC-manufactured phone. That driver, however, never made it into the upstream Linux kernel and is likely not maintained at this point.

The Glamo 3362 documentation for anyone interested can be fetched from this OpenMoko directory. There's eight docs in total with coverage of the command queue, 2D, 3D, and MPEG engine.