program loading: add prog_run() function

The prog_run() function abstracts away what is required
for running a given program. Within it, there are 2
calls: 1. platform_prog_run() and 2. arch_prog_run().
The platform_prog_run() allows for a chipset to intercept
a program that will be run. This allows for CPU switching
as currently needed in t124 and t132.

Change-Id: I22a5dd5bfb1018e7e46475e47ac993a0941e2a8c
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8846
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/arch/riscv/Makefile.inc

@@ -31,6 +31,7 @@ ifeq ($(CONFIG_ARCH_BOOTBLOCK_RISCV),y)
 bootblock_lds = $(src)/arch/riscv/bootblock.ld
 
 bootblock-y = bootblock.S stages.c
+bootblock-y += boot.c
 bootblock-y += rom_media.c
 bootblock-y += \
 	$(top)/src/lib/memchr.c \
@@ -52,6 +53,7 @@ endif
 ################################################################################
 ifeq ($(CONFIG_ARCH_ROMSTAGE_RISCV),y)
 
+romstage-y += boot.c
 romstage-y += stages.c
 romstage-y += rom_media.c
 romstage-y += \

src/arch/riscv/boot.c

@@ -17,11 +17,17 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include <arch/stages.h>
 #include <program_loading.h>
 
-void arch_payload_run(const struct payload *payload)
+void arch_prog_run(struct prog *prog)
 {
-//	uart_rx_byte(0);
-	stage_exit(prog_entry(&payload->prog));
+	void (*doit)(void *);
+
+	doit = prog_entry(prog);
+	doit(prog_entry_arg(prog));
+}
+
+void arch_payload_run(struct payload *payload)
+{
+	arch_prog_run(&payload->prog);
 }