[RFC PATCH 0/1] Add driver to read secondary bootloader (XBL) log

[Ninad Naik]

Boot time logs for Qualcomm secondary boot-loader or XBL can help to
identify different set of information regarding firmware configuration,
SoC boot KPIs. A dedicated region is carved out in the memory map in order
to store this log in the memory.

The objective of this driver is to read the XBL boot log stored in
this memory region post boot-up, and provide an entry in debugfs, which
can be used to read back the logs and print them on to the console.

Further, this log can be parsed to extract different set of information
as required.

For example, one use case can be parsing boot time KPIs to calculate,
 - PBL End time
 - SBL End time
 - UEFI Start/Stop time

Corresponding log contents as captured in /sys/kernel/debug/xbl_log entry
which prints the above counters,

        S -     59378 - PBL, End
        B -     68198 - SBL1, Start
        B -   1308877 - SBL1, End
        UEFI Start     [ 3370]
         - 0x0AF001000 [ 3375] Sec.efi
        UEFI Total : 466 m
        POST Time      [ 3836] OS Loader
         - 0x0ABE10000 [ 3838] LinuxLoader.efi
        Exit EBS        [ 4878] UEFI End

        /* Note - these are few excerpts picked from the complete XBL log
         *        as tested on SA8775p
         */

Ninad Naik (1):
  soc: qcom: Add driver to read secondary bootloader (XBL) log

 drivers/soc/qcom/Kconfig        |  13 +++
 drivers/soc/qcom/Makefile       |   1 +
 drivers/soc/qcom/dump_xbl_log.c | 139 ++++++++++++++++++++++++++++++++
 3 files changed, 153 insertions(+)
 create mode 100644 drivers/soc/qcom/dump_xbl_log.c

-- 
2.41.0