Change in coreboot[master]: lib/cbfs: Add cbfs_preload()

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Furquan Shaikh, Marshall Dawson, Julius Werner, Karthik Ramasubramanian, Felix Held.
Hello build bot (Jenkins), Jason Glenesk, Furquan Shaikh, Marshall Dawson, Julius Werner, Karthik Ramasubramanian, Felix Held,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/56491

to look at the new patch set (#12).

Change subject: lib/cbfs: Add cbfs_preload()
......................................................................

lib/cbfs: Add cbfs_preload()

This API will hide all the complexity of preloading a CBFS file. It
makes it so the callers simply specify the file to preload and CBFS
takes care of the rest. It will start a new thread to read the file into
the cbfs_cache. When the file is actually required (i.e., cbfs_load,
etc) it will wait for the preload thread to complete (if it hasn't
already) and perform verification/decompression using the preloaded
buffer. This design allows decompression/verification to happen in the
main BSP thread so that timestamps are correctly reflected.

BUG=b:179699789
TEST=Test with whole CL chain, verify VGA bios was preloaded and boot
time was reduced by 12ms.

Logs:
Preloading VGA ROM
CBFS DEBUG: _cbfs_preload(name='pci1002,1638.rom', force_ro=false)
CBFS: Found 'pci1002,1638.rom' @0x20ac40 size 0xd800 in mcache @0xcb7dd0f0
spi_dma_readat_dma: start: dest: 0x021c0000, source: 0x51cc80, size: 55296
took 0 us to acquire mutex
start_spi_dma_transaction: dest: 0x021c0000, source: 0x51cc80, remaining: 55296
...
spi_dma_readat_dma: end: dest: 0x021c0000, source: 0x51cc80, remaining: 0
...
CBFS DEBUG: _cbfs_alloc(name='pci1002,1638.rom', alloc=0x00000000(0x00000000), force_ro=false, type=-1)
CBFS: Found 'pci1002,1638.rom' @0x20ac40 size 0xd800 in mcache @0xcb7dd0f0
waiting for thread
took 0 us
CBFS DEBUG: get_preload_rdev(name='pci1002,1638.rom', force_ro=false) preload successful
In CBFS, ROM address for PCI: 03:00.0 = 0x021c0000
PCI expansion ROM, signature 0xaa55, INIT size 0xd800, data ptr 0x01b0
PCI ROM image, vendor ID 1002, device ID 1638,
PCI ROM image, Class Code 030000, Code Type 00
Copying VGA ROM Image from 0x021c0000 to 0xc0000, 0xd800 bytes

$ cbmem
  ...
  40:device configuration                              5,399,404 (8,575)
  65:Option ROM initialization                         5,403,474 (4,070)
  66:Option ROM copy done                              5,403,488 (14)
  ...

Signed-off-by: Raul E Rangel 
Change-Id: I879fc1316f97417a4b82483d353abdbd02b98a31
---
M src/include/cbfs.h
M src/lib/Kconfig
M src/lib/cbfs.c
3 files changed, 190 insertions(+), 6 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/91/56491/12