x86: Add multi-processor init

Most modern x86 CPUs include more than one CPU core. The OS normally requires
that these 'Application Processors' (APs) be brought up by the boot loader.
Add the required support to U-Boot to init additional APs.

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

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 467fe251d8..8e734fdfb4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -361,6 +361,36 @@ config FSP_TEMP_RAM_ADDR
 	  Stack top address which is used in FspInit after DRAM is ready and
 	  CAR is disabled.
 
+config MAX_CPUS
+        int "Maximum number of CPUs permitted"
+        default 4
+        help
+          When using multi-CPU chips it is possible for U-Boot to start up
+          more than one CPU. The stack memory used by all of these CPUs is
+          pre-allocated so at present U-Boot wants to know the maximum
+          number of CPUs that may be present. Set this to at least as high
+          as the number of CPUs in your system (it uses about 4KB of RAM for
+          each CPU).
+
+config SMP
+	bool "Enable Symmetric Multiprocessing"
+	default n
+	help
+	  Enable use of more than one CPU in U-Boot and the Operating System
+	  when loaded. Each CPU will be started up and information can be
+	  obtained using the 'cpu' command. If this option is disabled, then
+	  only one CPU will be enabled regardless of the number of CPUs
+	  available.
+
+config AP_STACK_SIZE
+	hex
+	default 0x1000
+	help
+	  Each additional CPU started by U-Boot requires its own stack. This
+	  option sets the stack size used by each CPU and directly affects
+	  the memory used by this initialisation process. Typically 4KB is
+	  enough space.
+
 config TSC_CALIBRATION_BYPASS
 	bool "Bypass Time-Stamp Counter (TSC) calibration"
 	default n