pcm052: add 'm4go' command

Add the 'm4go' command to pcm052-based targets.
It loads scatter file images.

Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud@3adev.fr>

board/phytec/pcm052/pcm052.c

@@ -513,3 +513,41 @@ int checkboard(void)
 
 	return 0;
 }
+
+static int do_m4go(cmd_tbl_t *cmdtp, int flag, int argc,
+		       char * const argv[])
+{
+	ulong addr;
+
+	/* Consume 'm4go' */
+	argc--; argv++;
+
+	/*
+	 * Parse provided address - default to load_addr in case not provided.
+	 */
+
+	if (argc)
+		addr = simple_strtoul(argv[0], NULL, 16);
+	else
+		addr = load_addr;
+
+	/*
+	 * Write boot address in PERSISTENT_ENTRY1[31:0] aka SRC_GPR2[31:0]
+	 */
+	writel(addr + 0x401, 0x4006E028);
+
+	/*
+	 * Start secondary processor by enabling its clock
+	 */
+	writel(0x15a5a, 0x4006B08C);
+
+	return 1;
+}
+
+U_BOOT_CMD(
+	m4go, 2 /* one arg max */, 1 /* repeatable */, do_m4go,
+	"start the secondary Cortex-M4 from scatter file image",
+	"[<addr>]\n"
+	"    - start secondary Cortex-M4 core using a scatter file image\n"
+	"The argument needs to be a scatter file\n"
+);