pxe: try bootz if bootm fails to find a valid image

Standard pxelinux servers will typically use a zImage rather than u-boot
image format, so fallback to bootz if bootm fails.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>

common/cmd_pxe.c

@@ -579,6 +579,7 @@ static int label_localboot(struct pxe_label *label)
 static int label_boot(struct pxe_label *label)
 {
 	char *bootm_argv[] = { "bootm", NULL, NULL, NULL, NULL };
+	char initrd_str[22];
 	int bootm_argc = 3;
 
 	label_print(label);
@@ -604,7 +605,10 @@ static int label_boot(struct pxe_label *label)
 			return 1;
 		}
 
-		bootm_argv[2] = getenv("ramdisk_addr_r");
+		bootm_argv[2] = initrd_str;
+		strcpy(bootm_argv[2], getenv("ramdisk_addr_r"));
+		strcat(bootm_argv[2], ":");
+		strcat(bootm_argv[2], getenv("filesize"));
 	} else {
 		bootm_argv[2] = "-";
 	}
@@ -649,6 +653,11 @@ static int label_boot(struct pxe_label *label)
 		bootm_argc = 4;
 
 	do_bootm(NULL, 0, bootm_argc, bootm_argv);
+
+#ifdef CONFIG_CMD_BOOTZ
+	/* Try booting a zImage if do_bootm returns */
+	do_bootz(NULL, 0, bootm_argc, bootm_argv);
+#endif
 	return 1;
 }