Add boot menu support

This patch adds boot menu support to SLOF. When boot menu is enabled from qemu
commandline with '-boot menu=on', on pressing F12 key it displays the list of
devices to boot from and waits for user's input. This is in line with x86 qemu
bios feature.

Signed-off-by: Avik Sil <aviksil@linux.vnet.ibm.com>
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>

board-qemu/slof/OF.fs

@@ -119,6 +119,18 @@ d# 512000000 VALUE tb-frequency   \ default value - needed for "ms" to work
 
 370 cp
 
+: check-boot-menu
+   s" qemu,boot-menu" get-chosen IF
+      decode-int 1 = IF
+         ." Press F12 for boot menu." cr cr
+      THEN
+      2drop
+   THEN
+;
+check-boot-menu
+
+380 cp
+
 \ Grab rtas from qemu
 #include "rtas.fs"
 

slof/fs/start-up.fs

@@ -44,7 +44,7 @@
       key CASE
 	  4f  OF (function-key) ENDOF
 	  5b  OF
-	     key key drop (function-key) ENDOF
+	     key key (function-key) ENDOF
 	  dup OF 0 ENDOF
        ENDCASE
    THEN
@@ -68,18 +68,97 @@
 \ Watchdog will be rearmed during load if use-load-watchdog variable is TRUE
 TRUE VALUE use-load-watchdog?
 
+1 value my-boot-dev
+1 value digit-val
+0 value boot-dev-no
+
+: boot-selected
+   1 to my-boot-dev
+   BEGIN parse-word dup WHILE
+      boot-dev-no my-boot-dev = IF
+         s" boot " 2swap $cat
+         ['] evaluate catch ?dup IF     \ and execute it
+            ." boot attempt returned: "
+            abort"-str @ count type cr
+            throw
+         THEN
+         0 0 load-list 2!
+         UNLOOP EXIT
+      ELSE
+         2drop
+      THEN
+      my-boot-dev 1 + to my-boot-dev
+   REPEAT 2drop 0 0 load-list 2!
+
+   (boot)
+;
+
+: boot-start
+   \ Remove multiple F12 key presses if any
+   BEGIN key? WHILE
+      key drop
+   REPEAT
+
+   decimal
+   BEGIN parse-word dup WHILE
+      my-boot-dev (u.) s" . " $cat type 2dup type ." : " de-alias type cr
+      my-boot-dev 1 + to my-boot-dev
+   REPEAT 2drop 0 0 load-list 2!
+
+   cr BEGIN KEY dup emit
+      dup isdigit IF
+         dup 30 - to digit-val
+         boot-dev-no a * digit-val + to boot-dev-no
+      THEN
+   d = UNTIL
+
+   boot-dev-no my-boot-dev < IF
+      s" boot-selected " s" $bootdev" evaluate $cat strdup evaluate
+   ELSE
+      ." Invalid choice!" cr
+   THEN
+   hex
+;
+
+: boot-menu-start
+   ." Select boot device:" cr cr
+   s" boot-start " s" $bootdev" evaluate $cat strdup evaluate
+;
+
+: boot-menu-enabled? ( -- true|false )
+   s" qemu,boot-menu" get-chosen IF
+      decode-int 1 = IF
+         2drop TRUE EXIT
+      THEN
+      2drop
+   THEN
+   FALSE
+;
+
+: f12-pressed?
+   34 = >r 32 = r> and IF
+      TRUE
+   ELSE
+      FALSE
+   THEN
+;
 
 : start-it ( -- )
    key? IF
       key CASE
 	 [char] s  OF (s-pressed) ENDOF
 	 1b        OF
-
-	    (esc-sequence) CASE
-	       1   OF console-clean-fifo sms-start (boot) ENDOF
-	       dup OF (boot?) ENDOF
-	    ENDCASE
-
+	     (esc-sequence) CASE
+		 1   OF
+                        console-clean-fifo
+                        f12-pressed? boot-menu-enabled? and IF
+		           boot-menu-start
+                        ELSE
+                           (boot?)
+                        THEN
+                     ENDOF
+		 dup OF (boot?) ENDOF
+	     ENDCASE
 	 ENDOF
 	 dup OF (boot?) ENDOF
       ENDCASE