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| author | Jeremy Compostella <jeremy.compostella@intel.com> | 2023-10-12 09:40:12 -0700 |
|---|---|---|
| committer | Matt DeVillier <matt.devillier@amd.corp-partner.google.com> | 2023-10-20 14:33:20 +0000 |
| commit | 226f51c7651d3ece93b2fcc141d791b6ad00fa18 (patch) | |
| tree | b18f6fde0338a5c7c58e6180868d13868b5fd96d /src/arch/x86 | |
| parent | 052fb7c45136263ed194c24fd4d04488a2608fd3 (diff) | |
x86: Add ramstage CBFS cache scratchpad support
Having a CBFS cache scratchpad offers a generic way to decompress CBFS
files through the cbfs_map() function without having to reserve a
per-file specific memory region.
This commit introduces the x86 `RAMSTAGE_CBFS_CACHE_SIZE' Kconfig to
set a ramstage CBFS cache size. A cache size of zero disables the
CBFS cache feature. The default size is 16 KB which seems a
reasonable minimal value large enough to satisfy basic needs such as
the decompression of a small configuration file. This setting can be
adjusted depending on the platform needs and capabilities.
To support S3 suspend/resume use-case, the CBFS cache memory cannot be
released to the operating system. There are two options to meet this
requirement:
1. Define a static CBFS cache buffer (located in the .bss section)
2. Create a new CBMEM entry
Option #2 seems more powerful but considering that:
1. The CBFS cache is actually not a cache but just a scratch pad
designed to be isolated between stages
2. postcar is a very short stage not really needing CBFS cache
3. The static initialization of the `cbfs_cache' global
variable (cf. src/lib/cbfs.c) offers a simple and robust design
=> It is simpler to use a static buffer and limit the support to
ramstage.
Since some AMD SoCs (cf. `SOC_AMD_COMMON_BLOCK_NONCAR' Kconfig) define
a `_cbfs_cache' region, an extra `POSTRAM_CBFS_CACHE_IN_BSS' Kconfig
must be set to enable the use of a static buffer as the CBFS cache
scratchpad.
TEST=Decompression of vbt.bin in ramstage on rex using cbfs_map()
Change-Id: I7fbb1b51cda9f84842992e365b16c5ced1010b89
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77885
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/arch/x86')
| -rw-r--r-- | src/arch/x86/Kconfig | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig index b0e479b1c4..90ece988c0 100644 --- a/src/arch/x86/Kconfig +++ b/src/arch/x86/Kconfig @@ -160,6 +160,23 @@ config PRERAM_CBFS_CACHE_SIZE Define the size of the Pre-RAM stages CBFS cache. A size of zero disables the CBFS cache feature in pre-memory stages. +config POSTRAM_CBFS_CACHE_IN_BSS + bool + default y if !SOC_AMD_COMMON_BLOCK_NONCAR + help + Allocate the post-memory CBFS cache scratchpad in the .bss + section. CBFS cache will rely on a simple static C buffer + while traditionally CBFS cache memory region is reserved in + the device memory layout. + +config RAMSTAGE_CBFS_CACHE_SIZE + hex + default 0x4000 + depends on POSTRAM_CBFS_CACHE_IN_BSS + help + Define the size of the ramstage CBFS cache. A size of zero + disables the CBFS cache feature in ramstage. + config PC80_SYSTEM bool default y if ARCH_X86 |