• Robert Sprowson's avatar
    [611][512] Detect CM4 Lite variant using a mailbox tag · 66d0d6ce
    Robert Sprowson authored
    Previously we commandeered GPIO extender IO4 to be told whether eMMC is fitted
    or not, and only if we're certain it is via opt-in (the line being actively
    pulled low) would SDFS treat that as a fixed disc.
    Unfortunately, extender IO4 is used to set 1.8V versus 3.3V signalling on the
    SDIO bus - so some brands of SD card would not work as SD_VDD_override was
    pulled high to 1.8V signalling when 3.3V was needed.
    
    * Change to use the 2 word form of ARM2VC_Tag_GetBoardRevision which returns
      the extended revision word too, b31 of which gives the eMMC fit/no fit state
    * Default to "safe" state of assuming removable media if the firmware is too
      old to support the 8 byte form (pre 29-Feb-2024 commit dc94391)
    * For CM4 (only) ensure the state of the WiFi antenna selector is defined, by
      default choosing the on board PCB antenna and deselecting the UFL socket
    * Use Push/Pull macros for function entry/exit
    
    Version 1.04. Tagged as 'HAL_BCM2835-1_04'
    66d0d6ce