Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 48 insertions, 0 deletions

diff --git a/Documentation/admin-guide/init.rst b/Documentation/admin-guide/init.rst
new file mode 100644
index 000000000..41f06a091
--- /dev/null
+++ b/Documentation/admin-guide/init.rst
@@ -0,0 +1,48 @@
+Explaining the "No working init found." boot hang message
+=========================================================
+:Authors: Andreas Mohr <andi at lisas period de>
+          Cristian Souza <cristianmsbr at gmail period com>
+
+This document provides some high-level reasons for failure
+(listed roughly in order of execution) to load the init binary.
+
+1) **Unable to mount root FS**: Set "debug" kernel parameter (in bootloader
+   config file or CONFIG_CMDLINE) to get more detailed kernel messages.
+
+2) **init binary doesn't exist on rootfs**: Make sure you have the correct
+   root FS type (and ``root=`` kernel parameter points to the correct
+   partition), required drivers such as storage hardware (such as SCSI or
+   USB!) and filesystem (ext3, jffs2, etc.) are builtin (alternatively as
+   modules, to be pre-loaded by an initrd).
+
+3) **Broken console device**: Possibly a conflict in ``console= setup``
+   --> initial console unavailable. E.g. some serial consoles are unreliable
+   due to serial IRQ issues (e.g. missing interrupt-based configuration).
+   Try using a different ``console= device`` or e.g. ``netconsole=``.
+
+4) **Binary exists but dependencies not available**: E.g. required library
+   dependencies of the init binary such as ``/lib/ld-linux.so.2`` missing or
+   broken. Use ``readelf -d <INIT>|grep NEEDED`` to find out which libraries
+   are required.
+
+5) **Binary cannot be loaded**: Make sure the binary's architecture matches
+   your hardware. E.g. i386 vs. x86_64 mismatch, or trying to load x86 on ARM
+   hardware. In case you tried loading a non-binary file here (shell script?),
+   you should make sure that the script specifies an interpreter in its
+   shebang header line (``#!/...``) that is fully working (including its
+   library dependencies). And before tackling scripts, better first test a
+   simple non-script binary such as ``/bin/sh`` and confirm its successful
+   execution. To find out more, add code ``to init/main.c`` to display
+   kernel_execve()s return values.
+
+Please extend this explanation whenever you find new failure causes
+(after all loading the init binary is a CRITICAL and hard transition step
+which needs to be made as painless as possible), then submit a patch to LKML.
+Further TODOs:
+
+- Implement the various ``run_init_process()`` invocations via a struct array
+  which can then store the ``kernel_execve()`` result value and on failure
+  log it all by iterating over **all** results (very important usability fix).
+- Try to make the implementation itself more helpful in general, e.g. by
+  providing additional error messages at affected places.
+