[RFC PATCH] bootstage: stash boot records to reserved mem before kernel handoff

[vishnu singh]

From: Vishnu Singh <v-singh1 at ti.com>

U-Boot now stashes its bootstage buffer into a reserved memory region
whenever CONFIG_BOOTSTAGE_STASH is enabled, just before exiting to the
kernel. This allows a post boot parser to read a unified timeline
(SPL→U-Boot→Kernel→MCU/DSP) directly from DDR, enabling standardized
and repeatable boot-time profiling across releases and SoCs.

Change summary:
 Call bootstage_stash_default() in announce_and_cleanup()
  when CONFIG_BOOTSTAGE_STASH is set.

Reference boot-time parser utility:
 https://github.com/v-singh1/boot-time-parse

Sample boot time report:
    +--------------------------------------------------------------------+
                     am62xx-evm Boot Time Report
    +--------------------------------------------------------------------+
    Device Power On         : 0 ms
    SPL Time                : 843 ms
    U-Boot Time             : 2173 ms
    Kernel handoff time     : 462 ms
    Kernel Time             : 2522 ms
    Total Boot Time         : 6000 ms
    +--------------------------------------------------------------------+

    +--------------------------------------------------------------------+
                     Bootloader and Kernel Boot Records
    +--------------------------------------------------------------------+
    BOOTSTAGE_AWAKE                =      0 ms (+  0 ms)
    BOOTSTAGE_START_UBOOT_F        =    843 ms (+  0 ms)
    BOOTSTAGE_ACCUM_DM_F           =    843 ms (+  0 ms)
    BOOTSTAGE_START_UBOOT_R        =   1951 ms (+1108 ms)
    BOOTSTAGE_ACCUM_DM_R           =   1951 ms (+  0 ms)
    BOOTSTAGE_NET_ETH_START        =   2032 ms (+ 81 ms)
    BOOTSTAGE_NET_ETH_INIT         =   2053 ms (+ 21 ms)
    BOOTSTAGE_MAIN_LOOP            =   2055 ms (+  2 ms)
    BOOTSTAGE_START_MCU            =   2661 ms (+606 ms)
    BOOTSTAGE_BOOTM_START          =   2959 ms (+298 ms)
    BOOTSTAGE_RUN_OS               =   3016 ms (+ 57 ms)
    BOOTSTAGE_BOOTM_HANDOFF        =   3016 ms (+  0 ms)
    BOOTSTAGE_KERNEL_START         =   3478 ms (+462 ms)
    BOOTSTAGE_KERNEL_END           =   6000 ms (+2522 ms)
    +--------------------------------------------------------------------+

    +--------------------------------------------------------------------+
                     MCU Boot Records
    +--------------------------------------------------------------------+
    MCU_AWAKE                      =   2661 ms (+  0 ms)
    BOARD_PERIPHERALS_INIT         =   2661 ms (+  0 ms)
    MAIN_TASK_CREATE               =   2661 ms (+  0 ms)
    FIRST_TASK                     =   2662 ms (+  1 ms)
    DRIVERS_OPEN                   =   2662 ms (+  0 ms)
    BOARD_DRIVERS_OPEN             =   2662 ms (+  0 ms)
    IPC_SYNC_FOR_LINUX             =   6636 ms (+3974 ms)
    IPC_REGISTER_CLIENT            =   6636 ms (+  0 ms)
    IPC_SUSPEND_TASK               =   6636 ms (+  0 ms)
    IPC_RECEIVE_TASK               =   6636 ms (+  0 ms)
    IPC_SYNC_ALL                   =   6787 ms (+151 ms)
    +--------------------------------------------------------------------+

Signed-off-by: Vishnu Singh <v-singh1 at ti.com>
---
 arch/arm/lib/bootm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index 7eb764e1f4e..b01e763ff28 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -57,6 +57,9 @@ static void announce_and_cleanup(int fake)
 #ifdef CONFIG_BOOTSTAGE_FDT
 	bootstage_fdt_add_report();
 #endif
+	if (IS_ENABLED(CONFIG_BOOTSTAGE_STASH))
+		bootstage_stash_default();
+
 #ifdef CONFIG_BOOTSTAGE_REPORT
 	bootstage_report();
 #endif
-- 
2.50.1