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/arm64/boot.c

@@ -25,15 +25,16 @@
 #include <arch/transition.h>
 #include <console/console.h>
 #include <program_loading.h>
+#include <rules.h>
 #include <string.h>
 
-void arch_payload_run(const struct payload *payload)
+static void run_payload(struct prog *prog)
 {
 	void (*doit)(void *);
 	void *arg;
 
-	doit = prog_entry(&payload->prog);
-	arg = prog_entry_arg(&payload->prog);
+	doit = prog_entry(prog);
+	arg = prog_entry_arg(prog);
 
 	uint8_t current_el = get_current_el();
 
@@ -61,3 +62,23 @@ void arch_payload_run(const struct payload *payload)
 	cache_sync_instructions();
 	transition_with_entry(doit, arg, &exc_state);
 }
+
+void arch_prog_run(struct prog *prog)
+{
+	void (*doit)(void *);
+	void *arg;
+
+	if (ENV_RAMSTAGE && prog->type == PROG_PAYLOAD)
+		run_payload(prog);
+		return;
+
+	doit = prog_entry(prog);
+	arg = prog_entry_arg(prog);
+
+	doit(prog_entry_arg(prog));
+}
+
+void arch_payload_run(struct payload *payload)
+{
+	arch_prog_run(&payload->prog);
+}