At present we assume that CAR (Cache-as-RAM) is used if HOBs (Hand-off
bLocks) are not, since HOBs typically indicate that an FSP is in use, and
FSPs handle the CAR init.
However this is a bit indirect, and for FSP2 machines which use their own
CAR implementation (such as apollolake) but use the FSP for other
functions, the logic is wrong.
To fix this, add a dedicated Kconfig option to indicate when CAR is used.
Signed-off-by: Simon Glass <s...@chromium.org>
---
Changes in v2: None
arch/x86/Kconfig | 8 ++++++++
arch/x86/cpu/start.S | 4 ++--
configs/slimbootloader_defconfig | 1 +
3 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 314f8def7a4..47bf28c434f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -364,6 +364,14 @@ config HAVE_FSP
Note: Without this binary U-Boot will not be able to set up its
SDRAM so will not boot.
+config USE_CAR
+ bool "Use Cache-As-RAM (CAR) to get temporary RAM at start-up"
+ default y if !HAVE_FSP
+ help
+ Select this option if your board uses CAR init code, typically in a
+ car.S file, to get some initial memory for code execution. This is
+ common with Intel CPUs which don't use FSP.
+
choice
prompt "FSP version"
depends on HAVE_FSP
diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
index 3c9bdf2a9d6..9b763942743 100644
--- a/arch/x86/cpu/start.S
+++ b/arch/x86/cpu/start.S
@@ -90,7 +90,7 @@ early_board_init_ret:
jmp car_init
.globl car_init_ret
car_init_ret:
-#ifndef CONFIG_USE_HOB
+#ifdef CONFIG_USE_CAR
/*
* We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
* or fully initialised SDRAM - we really don't care which)
@@ -130,7 +130,7 @@ car_init_ret:
/* Get address of global_data */
mov %fs:0, %edx
-#ifdef CONFIG_USE_HOB
+#if defined(CONFIG_USE_HOB) && !defined(CONFIG_USE_CAR)
/* Store the HOB list if we have one */
test %esi, %esi
jz skip_hob
diff --git a/configs/slimbootloader_defconfig b/configs/slimbootloader_defconfig
index f9fecff45ea..3cbb83c7a47 100644
--- a/configs/slimbootloader_defconfig
+++ b/configs/slimbootloader_defconfig
@@ -18,3 +18,4 @@ CONFIG_REGMAP=y
CONFIG_SYSCON=y
# CONFIG_PCI_PNP is not set
CONFIG_CONSOLE_SCROLL_LINES=5
+# CONFIG_USE_CAR is not set
--
2.23.0.444.g18eeb5a265-goog
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