[PATCH v2 0/4] Add minimal boot support for Raspberry Pi 5

[Andrea della Porta]

Hi,

This patchset adds minimal support for the Broadcom BCM2712 SoC and for
the on-board SDHCI controller on Broadcom BCM2712 in order to make it
possible to boot (particularly) a Raspberry Pi 5 from SD card and get a
console through uart.
Changes to arm64/defconfig are not needed since the actual options work
as they are.
This work is heavily based on downstream contributions.

Tested on Tumbleweed substituting the stock kernel with upstream one,
either chainloading uboot+grub+kernel or directly booting the kernel
from 1st stage bootloader. Steps to reproduce:
- prepare an SD card from a Raspberry enabled raw image, mount the first
  FAT partition.
- make sure the FAT partition is big enough to contain the kernel,
  anything bigger than 64Mb is usually enough, depending on your kernel
  config options.
- build the kernel and dtbs making sure that the support for your root
  fs type is compiled as builtin.
- copy the kernel image in your FAT partition overwriting the older one
  (e.g. kernel*.img for Raspberry Pi OS or u-boot.bin for Tumbleweed).
- copy arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dtb on FAT partition.
- make sure you have a cmdline.txt file in FAT partition with the
  following content:
  # cat /boot/efi/cmdline.txt
  root=/dev/mmcblk0p3 rootwait rw console=tty ignore_loglevel earlycon 
  console=ttyAMA10,115200
- if you experience random SD issues during boot, try to set
  initial_turbo=0 in config.txt.

Changes in V2:

- the patchshet has been considerably simplified, both in terms of dts and
  driver code. Notably, the pinctrl/pinmux driver (and associated binding)
  was not strictly needed to use the SD card so it has been dropped.
- dropped the optional SD express support patch
- the patches order has been revisited
- pass all checks (binding, dtb, checkpatch)

Many thanks,
Andrea

References:
- Link to V1: https://lore.kernel.org/all/cover.1713036964.git.andrea.porta@suse.com/

Andrea della Porta (4):
  dt-bindings: arm: bcm: Add BCM2712 SoC support
  dt-bindings: mmc: Add support for BCM2712 SD host controller
  mmc: sdhci-brcmstb: Add BCM2712 support
  arm64: dts: broadcom: Add support for BCM2712

 .../devicetree/bindings/arm/bcm/bcm2835.yaml  |   6 +
 .../bindings/mmc/brcm,sdhci-brcmstb.yaml      |  23 ++
 arch/arm64/boot/dts/broadcom/Makefile         |   1 +
 .../boot/dts/broadcom/bcm2712-rpi-5-b.dts     |  62 ++++
 arch/arm64/boot/dts/broadcom/bcm2712.dtsi     | 302 ++++++++++++++++++
 drivers/mmc/host/sdhci-brcmstb.c              |  81 +++++
 6 files changed, 475 insertions(+)
 create mode 100644 arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
 create mode 100644 arch/arm64/boot/dts/broadcom/bcm2712.dtsi

-- 
2.35.3