x86: Add some notes for MRC cache with Intel FSP

MRC cache relies on Intel FSP to produce a special GUID that
contains the MRC cache data. Add such information in the
CONFIG_ENABLE_MRC_CACHE help entry.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2ba36b790cd1fd97fdf5a0f3a2fd1dfae0ab0b54..65cbb9cc660da3a4c4b763a610beb8ddc7c3aa1f 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -274,6 +274,13 @@ config ENABLE_MRC_CACHE
          to be used for speeding up boot time on future reboots and/or
          power cycles.
 
+         For platforms that use Intel FSP for the memory initialization,
+         please check FSP output HOB via U-Boot command 'fsp hob' to see
+         if there is FSP_NON_VOLATILE_STORAGE_HOB_GUID (asm/fsp/fsp_hob.h).
+         If such GUID does not exist, MRC cache is not avaiable on such
+         platform (eg: Intel Queensbay), which means selecting this option
+         here does not make any difference.
+
 config HAVE_MRC
        bool "Add a System Agent binary"
        depends on !HAVE_FSP