buildsystem: Make CPU microcode updating more configurable

This patch aims to improve the microcode in CBFS handling that was
brought by the last patches from Stefan and the Chromium team.

Choices in Kconfig
  - 1) Generate microcode from tree (default)
  - 2) Include external microcode file
  - 3) Do not put microcode in CBFS

The idea is to give the user full control over including non-free
blobs in the final ROM image.

MICROCODE_INCLUDE_PATH Kconfig variable is eliminated. Microcode
is handled by a special class, cpu_microcode, as such:

cpu_microcode-y += microcode_file.c

MICROCODE_IN_CBFS should, in the future, be eliminated. Right now it is
needed by intel microcode updating. Once all intel cpus are converted to
cbfs updating, this variable can go away.

These files are then compiled and assembled into a binary CBFS file.
The advantage of doing it this way versus the current method is that
  1) The rule is CPU-agnostic
  2) Gives user more control over if and how to include microcode blobs
  3) The rules for building the microcode binary are kept in
   src/cpu/Makefile.inc, and thus would not clobber the other makefiles,
   which are already overloaded and very difficult to navigate.

Change-Id: I38d0c9851691aa112e93031860e94895857ebb76
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/1245
Tested-by: build bot (Jenkins)
Reviewed-by: Anton Kochkov <anton.kochkov@gmail.com>
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

5 files changed, 13 insertions, 21 deletions

diff --git a/src/cpu/intel/microcode/Makefile.inc b/src/cpu/intel/microcode/Makefile.inc
index f4d01020d1..22655c9532 100644
--- a/src/cpu/intel/microcode/Makefile.inc
+++ b/src/cpu/intel/microcode/Makefile.inc
@@ -1,15 +1,5 @@
-ramstage-y += microcode.c
-
-
-ifeq ($(CONFIG_MICROCODE_IN_CBFS),y)
-
-SRC_PATH = src/cpu/intel/microcode
-FLAGS = -I $(CONFIG_MICROCODE_INCLUDE_PATH) -include $(obj)/config.h
-$(obj)/microcode_blob.o: $(SRC_PATH)/microcode_blob.c
-	$(CC) $(FLAGS) -MMD -c -o $@ $<
-
-$(obj)/microcode_blob.bin: $(obj)/microcode_blob.o
-	objcopy -j .data -O binary $< $@
-
--include $(obj)/microcode_blob.d
-endif
+################################################################################
+## One small file with the awesome super-power of updating the cpu microcode
+## directly from CBFS. You have been WARNED!!!
+################################################################################
+ramstage-y += microcode.c
\ No newline at end of file
diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c
index e84bad9beb..a4471ca042 100644
--- a/src/cpu/intel/microcode/microcode.c
+++ b/src/cpu/intel/microcode/microcode.c
@@ -28,7 +28,7 @@
 #include <cpu/x86/msr.h>
 #include <cpu/intel/microcode.h>
 
-#if CONFIG_MICROCODE_IN_CBFS
+#if CONFIG_CPU_MICROCODE_IN_CBFS
 #ifdef __PRE_RAM__
 #include <arch/cbfs.h>
 #else
@@ -77,7 +77,7 @@ static inline u32 read_microcode_rev(void)
 	return msr.hi;
 }
 
-#if CONFIG_MICROCODE_IN_CBFS
+#if CONFIG_CPU_MICROCODE_IN_CBFS
 static
 #endif
 void intel_update_microcode(const void *microcode_updates)
@@ -144,9 +144,9 @@ void intel_update_microcode(const void *microcode_updates)
 	}
 }
 
-#if CONFIG_MICROCODE_IN_CBFS
+#if CONFIG_CPU_MICROCODE_IN_CBFS
 
-#define MICROCODE_CBFS_FILE "microcode_blob.bin"
+#define MICROCODE_CBFS_FILE "cpu_microcode_blob.bin"
 
 void intel_update_microcode_from_cbfs(void)
 {
diff --git a/src/cpu/intel/model_206ax/Kconfig b/src/cpu/intel/model_206ax/Kconfig
index 6635868453..5c543b88ba 100644
--- a/src/cpu/intel/model_206ax/Kconfig
+++ b/src/cpu/intel/model_206ax/Kconfig
@@ -12,7 +12,7 @@ config CPU_SPECIFIC_OPTIONS
 	select SSE2
 	select UDELAY_LAPIC
 	select SMM_TSEG
-	select MICROCODE_IN_CBFS
+	select CPU_MICROCODE_IN_CBFS
 	#select AP_IN_SIPI_WAIT
 	select TSC_SYNC_MFENCE
 
diff --git a/src/cpu/intel/model_206ax/Makefile.inc b/src/cpu/intel/model_206ax/Makefile.inc
index e9b8e6df8e..6ab4840c48 100644
--- a/src/cpu/intel/model_206ax/Makefile.inc
+++ b/src/cpu/intel/model_206ax/Makefile.inc
@@ -5,4 +5,6 @@ ramstage-$(CONFIG_GENERATE_ACPI_TABLES) += acpi.c
 
 smm-$(CONFIG_HAVE_SMI_HANDLER) += finalize.c
 
+cpu_microcode-$(CONFIG_CPU_MICROCODE_CBFS_GENERATE)  += microcode_blob.c
+
 cpu_incs += $(src)/cpu/intel/model_206ax/cache_as_ram.inc
diff --git a/src/cpu/intel/microcode/microcode_blob.c b/src/cpu/intel/model_206ax/microcode_blob.c
index 69238a9f77..c2538e8ede 100644
--- a/src/cpu/intel/microcode/microcode_blob.c
+++ b/src/cpu/intel/model_206ax/microcode_blob.c
@@ -18,5 +18,5 @@
  */
 
 unsigned microcode[] = {
-#include <microcode_blob.h>
+#include "microcode_blob.h"
 };