src/cpu,soc/amd/common/block/cpu: Add preload_microcode

This will enable preloading the microcode. By preloading the
file, into cbfs_cache we reduce boot time. 

BUG=b:179699789
TEST=Boot guybrush with CL chain and see microcode preloading and a
reduction of 1 ms.
| 112 - started reading uCode                         | 1.041     | 1.204     Δ(  0.16,    0.01%) |
| 113 - finished reading uCode                        | 1.365     | 0.011     Δ( -1.35,   -0.10%) |

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: If0c634c692c97769e71acd1175fc464dc592c356
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58963
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>

src/cpu/Makefile.inc

@@ -56,7 +56,12 @@ $(obj)/cpu_microcode_blob.bin: $$(wildcard $$(cpu_microcode_bins))
 
 cpu_microcode_blob.bin-file ?= $(obj)/cpu_microcode_blob.bin
 cpu_microcode_blob.bin-type := microcode
+# The AMD LPC SPI DMA controller requires source files to be 64 byte aligned.
+ifeq ($(CONFIG_SOC_AMD_COMMON_BLOCK_LPC_SPI_DMA),y)
+cpu_microcode_blob.bin-align := 64
+else
 cpu_microcode_blob.bin-align := 16
+endif
 
 ifneq ($(CONFIG_CPU_MICROCODE_CBFS_LOC),)
 cpu_microcode_blob.bin-COREBOOT-position := $(CONFIG_CPU_MICROCODE_CBFS_LOC)

src/include/cpu/amd/microcode.h

@@ -2,5 +2,6 @@
 #define CPU_AMD_MICROCODE_H
 
 void amd_update_microcode_from_cbfs(void);
+void preload_microcode(void);
 
 #endif /* CPU_AMD_MICROCODE_H */

src/soc/amd/common/block/cpu/update_microcode.c

@@ -10,6 +10,8 @@
 #include <cbfs.h>
 #include <timestamp.h>
 
+#define CPU_MICROCODE_BLOB_NAME "cpu_microcode_blob.bin"
+
 _Static_assert(CONFIG_SOC_AMD_COMMON_BLOCK_UCODE_SIZE > 0,
 	       "SOC_AMD_COMMON_BLOCK_UCODE_SIZE is not set");
 
@@ -97,9 +99,10 @@ void amd_update_microcode_from_cbfs(void)
 	/* Cache the buffer so each CPU doesn't need to read the uCode from flash */
 	if (!cache_valid) {
 		timestamp_add_now(TS_READ_UCODE_START);
-		ucode_list = cbfs_map("cpu_microcode_blob.bin", &ucode_len);
+		ucode_list = cbfs_map(CPU_MICROCODE_BLOB_NAME, &ucode_len);
 		if (!ucode_list) {
-			printk(BIOS_WARNING, "cpu_microcode_blob.bin not found. Skipping updates.\n");
+			printk(BIOS_WARNING,
+			       CPU_MICROCODE_BLOB_NAME " not found. Skipping updates.\n");
 			return;
 		}
 
@@ -120,3 +123,12 @@ void amd_update_microcode_from_cbfs(void)
 
 	apply_microcode_patch(&ucode_cache);
 }
+
+void preload_microcode(void)
+{
+	if (!CONFIG(CBFS_PRELOAD))
+		return;
+
+	printk(BIOS_DEBUG, "Preloading microcode %s\n", CPU_MICROCODE_BLOB_NAME);
+	cbfs_preload(CPU_MICROCODE_BLOB_NAME);
+}