[Skiboot] [PATCH] core/flash: Retry requests as necessary in flash_load_resource()

[Stewart Smith]

Andrew Jeffery <andrew at aj.id.au> writes:
> We would like to successfully boot if we have a dependency on the BMC
> for flash even if the BMC is not current ready to service flash
> requests. On the assumption that it will become ready, retry for several
> minutes to cover a BMC reboot cycle and *eventually* rather than
> *immediately* crash out with:
>
>     [  269.549748] reboot: Restarting system
>     [  390.297462587,5] OPAL: Reboot request...
>     [  390.297737995,5] RESET: Initiating fast reboot 1...
>     [  391.074707590,5] Clearing unused memory:
>     [  391.075198880,5] PCI: Clearing all devices...
>     [  391.075201618,7] Clearing region 201ffe000000-201fff800000
>     [  391.086235699,5] PCI: Resetting PHBs and training links...
>     [  391.254089525,3] FFS: Error 17 reading flash header
>     [  391.254159668,3] FLASH: Can't open ffs handle: 17
>     [  392.307245135,5] PCI: Probing slots...
>     [  392.363723191,5] PCI Summary:
>     ...
>     [  393.423255262,5] OCC: All Chip Rdy after 0 ms
>     [  393.453092828,5] INIT: Starting kernel at 0x20000000, fdt at
>     0x30800a88 390645 bytes
>     [  393.453202605,0] FATAL: Kernel is zeros, can't execute!
>     [  393.453247064,0] Assert fail: core/init.c:593:0
>     [  393.453289682,0] Aborting!
>     CPU 0040 Backtrace:
>      S: 0000000031e03ca0 R: 000000003001af60   ._abort+0x4c
>      S: 0000000031e03d20 R: 000000003001afdc   .assert_fail+0x34
>      S: 0000000031e03da0 R: 00000000300146d8   .load_and_boot_kernel+0xb30
>      S: 0000000031e03e70 R: 0000000030026cf0   .fast_reboot_entry+0x39c
>      S: 0000000031e03f00 R: 0000000030002a4c   fast_reset_entry+0x2c
>      --- OPAL boot ---
>
> The OPAL flash API hooks directly into the blocklevel layer, so there's
> no delay for e.g. the host kernel, just for asynchronously loaded
> resources during boot.

Merged to master as of cccf5d79de07844cf095b8f45146b92944d15c2e.

No doubt at some point somebody is going to go "huh" when running some
crazy simulator or broken machine, but I think I'm okay with that :)
-- 
Stewart Smith
OPAL Architect, IBM.