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Detail:
  * Compute module support consists of eMMC support in the SDHCI driver. The
    eMMC chip on the Compute module only works reliably if under-clocked to
    25 MHz.
  * Pi 1 vs Pi 2 differences are selected at runtime by checking the CPU ID,
    so a single ROM image will work with both boards.
  * Added ARMv7 cache maintenance routine for use on Pi 2.
  * The physical address of the peripherals has moved in Pi 2 to make space
    for the 1 GB of RAM.
  * The ARM physical address space is mapped differently onto the GPU
    address space in Pi 2 because the ARM now uses the L2 cache that comes
    with the Cortex-A7 instead of the GPU's L2 cache.
  * Still waiting for confirmation on the board revision ID that will be
    used for Pi 2, so may require further tweaks for production releases.


Version 0.40. Tagged as 'BCM2835-0_40'

Version 0.39. Tagged as 'BCM2835-0_39'

Detail:
  The activity GPIO pin has been reassigned and its sense is inverted,
  compared to earlier boards. More importantly, the SD card detect pin has
  been removed entirely, so we need to signal to the SD stack to use its
  new timeout-based state machine (rather than polling for card presence).
Admin:
  Already in use in RC12a.

Version 0.35. Tagged as 'BCM2835-0_35'

Detail:
  * Engage the GPIO controller's pull-up resistors on SDCLK, CMD and DAT0-DAT3.
    In tests, this seems to address the worst of the unreliability we have
    seen previously.
  * Remove the entry to change the bus between push-pull and open-drain modes.
    The BCM2835 simply doesn't seem to be able to do this. Fortunately, all
    the cards I have tested seem to be OK with the GPIO controller's pull-up
    on the CMD line (however strong that is - it's undocumented) engaged at
    all times.
  * Time a dummy command in order to calculate the speed of the input clock
    to the SD controller block (there doesn't appear to be any way to read
    its speed directly!) This is necessary because recent versions of the
    firmware have not only changed the default clock speed, but even made it
    a user-configurable option in config.txt. It's very important that we
    know how fast it is - if we set the dividers so SDCLK is too slow, then
    the workaround for the register write bug won't work, too fast and we
    overclock the cards, potentially damaging them.
  * Re-enable high speed mode. As long as we don't use the High Speed Enable
    bit in Host Control 1 (see change in SDIODriver 0.03) this seems to work
    for me.
Admin:
  Tested against my collection of test cards on a Raspberry Pi with the
  firmware from the 2012-06-22 commit on github, and with
  init_emmc_clock=100000000 in config.txt (though other values, or the
  absence of that line, or the entire file, should also work). The only
  issues I had appeared to be due to mechanical problems with the SD socket,
  and went away after the card was reseated one or more times.

Version 0.10. Tagged as 'BCM2835-0_10'

Detail:
  * Bugfix to HAL_FIQDisableAll - it wasn't clearing the FIQ register (would
    only have caused trouble in practice if the same device was subsequently
    enabled as an IRQ).
  * Added a load of memory barriers to s.Interrupts and s.Timers to conform
    to the requirement stated in 1.3 of the datasheet.
  * Added a HAL device for the Arasan SDHCI controller. Note that this does
    not currently work reliably, and results vary from card to card. High
    speed support is currently disabled until we are able to verify that it
    works reliably.
  * Added a sprinkling of "GET Hdr:ListOpts" because the space reserved for
    the SDHCI HAL device in hdr.StaticWS is determined by including
    Hdr:HALDevice and Hdr:SDHCIDevice, which need it.
  * When support for saving "CMOS" to the SD card is added, the ROM image
    file (kernel.img) is the only one we can count on the bootloader
    installing in memory, so I think we're going to have to work using the
    table in s.CMOS. Broadcom seems to like messing around with the space
    just after the processor vector table, so rather than adding a pointer
    to the table there, I've opted to mark it using a magic word.
Admin:
  Tested on a Raspberry Pi - as noted above, there are reliability issues.

Version 0.09. Tagged as 'BCM2835-0_09'