[Skiboot] [PATCH 3/3] ibm-fsp: Use finalise_dt() for DT fixups

Stewart Smith stewart at linux.ibm.com
Tue Jul 16 14:42:28 AEST 2019

"Oliver O'Halloran" <oohall at gmail.com> writes:
> From Gautham's patch to fix pstates_init() that this was based on:
>> On FSP based systems (particularly POWER8), we perform
>> occ_pstates_init() late in the boot to allow OCC to be loaded. Hence
>> this was being performed in platform.exit(). occ_pstates_init() would
>> add pstate information into the device-tree.
>> A recent commit 9fc0c1287ada ("Move FSP specific op-panel calls to
>> platform.exit()") moved the invocation of platform.exit() after the
>> creation of device-tree blob. As a result, on FSP based systems, we
>> don't have the pstate information in the device-tree, and thus the
>> Kernel is unable to perform frequency scaling.
>> Fix this by moving occ_pstates_init() out of ibm_fsp_exit() and call
>> it before the creation of the device-tree blob.
> The same patch also broke fast-reboot on ZZ. Without this patch applied
> we get the following assert() fail when fast rebooting:
> [ 1153.398889405,5] CUPD: Waiting read marker LID and in flight parsm completion...
> [ 1153.398892228,3] Duplicate property "mi-version" in node /ibm,opal/firmware
> [ 1153.398894036,0] Aborting!
> CPU 0054 Backtrace:
>  S: 0000000031ea39b0 R: 0000000030013828   .backtrace+0x34
>  S: 0000000031ea3a70 R: 000000003001b268   ._abort+0x4c
>  S: 0000000031ea3af0 R: 0000000030027788   .new_property+0x80
>  S: 0000000031ea3b80 R: 00000000300278d0   .dt_add_property+0xa8
>  S: 0000000031ea3c10 R: 0000000030081a98   .fsp_code_update_wait_vpd+0x19c
>  S: 0000000031ea3d10 R: 000000003008ff98   .ibm_fsp_exit+0x1c
>  S: 0000000031ea3d80 R: 0000000030014864   .load_and_boot_kernel+0xb14
>  S: 0000000031ea3e60 R: 000000003002685c   .fast_reboot_entry+0x38c
>  S: 0000000031ea3f00 R: 0000000030002988   reset_fast_reboot_wakeup+0x40
> This happens because fsp_code_update_wait_vpd(true) adds some properties
> to the DT so moving it to finalise_dt fixes that crash too.
> Cc: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
> Cc: Gautham R. Shenoy <ego at linux.vnet.ibm.com>
> Cc: Vaidyanathan Srinivasan <svaidy at linux.ibm.com>
> Fixes: 9fc0c1287ada ("Move FSP specific op-panel calls to platform.exit()")
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>

Thanks (and sorry for breaking things). Series merged to master as of 4c929bb54629fc60d8178383b4e5f854a8d1909c
Stewart Smith
OPAL Architect, IBM.

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