Qualcomm's proprietary Android boot-loaders capture boot time stats, like the time when the bootloader started execution and at what point the bootloader handed over control to the kernel etc. in the IMEM region. This information is captured in a specific format by this driver by mapping a structure to the IMEM memory region and then accessing the members of the structure to log the information in a debugfs file. This information is useful in verifying if existing boot KPIs have regressed or not. A sample log in SM8450(waipio) device is as follows:- /sys/kernel/debug/146aa6b0.boot_stats # cat abl_time 17898 ms /sys/kernel/debug/146aa6b0.boot_stats # cat pre_abl_time 2879 ms The Module Power Manager(MPM) sleep counter starts ticking at the PBL stage and the timestamp generated by the sleep counter is logged by the Qualcomm proprietary bootloader(ABL) at two points-> First when it starts execution which is logged here as "pre_abl_time" and the second when it is about to load the kernel logged as "abl_time". Both these values are read up by the driver from IMEM region and printed as above. Changes in V4 *Implemented the comments on V3 of the patch series Souradeep Chowdhury (3): dt-bindings: sram: qcom,imem: Add Boot Stat region within IMEM soc: qcom: boot_stat: Add Driver Support for Boot Stats MAINTAINERS: Add the entry for boot_stats driver support Documentation/ABI/testing/debugfs-driver-bootstat | 17 ++++ .../devicetree/bindings/sram/qcom,imem.yaml | 22 +++++ MAINTAINERS | 7 ++ drivers/soc/qcom/Kconfig | 9 ++ drivers/soc/qcom/Makefile | 1 + drivers/soc/qcom/boot_stats.c | 101 +++++++++++++++++++++ 6 files changed, 157 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-driver-bootstat create mode 100644 drivers/soc/qcom/boot_stats.c -- 2.7.4
