1. 17 Mar, 2020 2 commits
    • Andre Przywara's avatar
      rpi: Allow using PL011 UART for RPi3/RPi4 · 5e6d821c
      Andre Przywara authored
      
      
      The Broadcom 283x SoCs feature multiple UARTs: the mostly used
      "Mini-UART", which is an 8250 compatible IP, and at least one PL011.
      While the 8250 is usually used for serial console purposes, it suffers
      from a design flaw, where its clock depends on the VPU clock, which can
      change at runtime. This will reliably mess up the baud rate.
      To avoid this problem, people might choose to use the PL011 UART for
      the serial console, which is pin-mux'ed to the very same GPIO pins.
      This can be done by adding "miniuart-bt" to the "dtoverlay=" line in
      config.txt.
      
      To prepare for this situation, use the newly gained freedom of sharing
      one console_t pointer across different UART drivers, to introduce the
      option of choosing the PL011 for the console.
      
      This is for now hard-coded to choose the Mini-UART by default.
      A follow-up patch will introduce automatic detection.
      Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
      Change-Id: I8cf2522151e09ff4ff94a6d396aec6fc4b091a05
      5e6d821c
    • Andre Przywara's avatar
      rpi3: console: Use same "clock-less" setup scheme as RPi4 · 795aefe5
      Andre Przywara authored
      
      
      In the wake of the upcoming unification of the console setup code
      between RPi3 and RPi4, extend the "clock-less" setup scheme to the
      RPi3. This avoid programming any clocks or baud rate registers,
      which makes the port more robust against GPU firmware changes.
      Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
      Change-Id: Ida83a963bb18a878997e9cbd55f8ceac6a2e1c1f
      795aefe5
  2. 13 Sep, 2019 1 commit