[Fsuk-manchester] Raspberry Pi source code and register documentation from Broadcom

[Bob Ham]

Hi all,

Yesterday Broadcom dropped a load of source code and register
documentation for the graphics stack of the BCM21553 mobile SoC.  This
has the same VideoCore IV graphics core as the BCM2835 chip used on the
Raspberry Pi:

https://blog.broadcom.com/chip-design/android-for-all-broadcom-gives-developers-keys-to-the-videocore-kingdom/

The Raspberry Pi's chip requires a firmware blob to be loaded by the
graphics core before it will boot an operating system on the CPU.  (As I
understand it, this is due to the chip's design history where it was
originally a video processor chip before someone thought to use up space
on the die with an ARM CPU core.)  At present, the firmware blob is
proprietary.  This is the biggest problem with the Raspberry Pi.

There is some debate over whether the information released by Broadcom
will enable a free firmware to be produced.  However, there are some
good initial indications that it will:

  "Under brcm_usrlib/dag/vmcsx/vcfw/ I found what seems to be the
  complete vcos (VideoCore OS) firmware. So by my inexpert assessment,
  this appears to be everything needed to boot a VideoCore SoC!"
  -- https://lwn.net/Articles/588931/
  
Time will tell.  Even so, it's not all roses as there are still parts of
the chip stuck in proprietary land:

  "This isn’t the end of the road for us: there are still significant
  parts of the multimedia hardware on BCM2835 which are only accessible
  via the blob."
  -- http://www.raspberrypi.org/archives/6299


So, a step forward and possibly the removal of a big stumbling block for
freedom :-)

Bob

-- 
Bob Ham <address@hidden>

for (;;) { ++pancakes; }

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