[PATCH v2 0/4] Better smartphone support (Qualcomm)

[Caleb Connolly]

Improve support for running U-Boot on [Qualcomm] smartphones, with:

* A boot menu which can be entered by holding power during boot
* Hang on panic (so errors can be read on the display)
* Serial gadget which can be enabled by holding volume down or via
  boot menu

In its current form, U-Boot's boot menu is perfectly adequate, however
once an option is picked U-Boot will just drop to the CLI again.

On a phone (with no keyboard), dropping to the CLI effectively makes the
device unusable until manually rebooted, since there is no way to run
any commands...

To rectify this, let's revive CONFIG_BOOT_RETRY for the
hush parser and make it run the contents of "bootcmd", as well as
re-reading the value of the bootretry environment variable. In tandem,
this provides for a flexible menu system which we can enter and exit.
See qcom-phone.env in patch 1 for more details.

Finally, provide some rough-ish documentation to describe how Qualcomm
phone support works and outline some debugging steps for when UART and
the framebuffer are unavailable.

This series depends on CONFIG_REMAP_PHONE_KEYS [1] to enable navigating the
boot menu when using upstream DT.

[1]: https://lore.kernel.org/u-boot/20240714194948.1271135-1-caleb.connolly@linaro.org/

---
Changes in v2:
- Fix CONFIG_BUTTON_REMAP_PHONE_KEYS name in qcom-phone.config
- Add Tom and Simon to CC
- Link to v1: https://lore.kernel.org/r/20240831-qcom-phones-v1-0-08614edd8e35@linaro.org

---
Caleb Connolly (4):
      board/qualcomm: introduce phone config
      cli_hush: run bootmenu on retry
      bootretry: check for bootretry variable changes
      doc: board/qualcomm: describe phone support and bringup

 board/qualcomm/qcom-phone.config |  12 ++++
 board/qualcomm/qcom-phone.env    |  49 ++++++++++++++++
 boot/bootretry.c                 |   2 +
 common/cli_hush.c                |   2 +-
 common/cli_hush_upstream.c       |   2 +-
 doc/board/qualcomm/board.rst     |   5 ++
 doc/board/qualcomm/index.rst     |   1 +
 doc/board/qualcomm/phones.rst    | 122 +++++++++++++++++++++++++++++++++++++++
 8 files changed, 193 insertions(+), 2 deletions(-)
---
change-id: 20240831-qcom-phones-c789d14de657
base-commit: 00292c6b39b3f7dcb34e8c3ae6ef276ac862a146

// Caleb (they/them)