[U-Boot-Users] [PATCH] Support for "sleep" mode for mips

[Rodolfo Giometti <giometti@linux.it>]

Here a patch against u-boot 1.1.4 to support "sleep" mode for mips
processors. I tested this feature on Au1100 based board.

The patch add a new define CFG_WAKEUP_MODE and a new per-board
function lowlevel_wakeup().

The define is used to mask the new function if you don't need "sleep"
support and the lowlevel_wakeup() is needed since the wake up sequence
may be different from the boot one.

Regards,

Rodolfo


 cpu/mips/start.S |   59 +++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 53 insertions(+), 6 deletions(-)

Rodolfo Giometti:
      Support for "sleep" mode added.

diff-tree eb1d649... (from 05d8dce...)
Author: Rodolfo Giometti <giometti@enneenne.com>
Date:   Fri Mar 31 18:33:38 2006 +0200

    Support for "sleep" mode added.

diff-tree eb1d6496e7428e5e6e20887bfb5edd6989d2169f (from 05d8dce9d07cf4073ea15fbc448c1ce22b6baf0f)
Author: Rodolfo Giometti <giometti@zaigor.enneenne.com>
Date:   Fri Mar 31 18:33:38 2006 +0200

    Support for "sleep" mode added.

diff --git a/cpu/mips/start.S b/cpu/mips/start.S
index e91e213..72f17ee 100644
--- a/cpu/mips/start.S
+++ b/cpu/mips/start.S
@@ -26,6 +26,7 @@
 #include <config.h>
 #include <version.h>
 #include <asm/regdef.h>
+#include <asm/au1x00.h>
 #include <asm/mipsregs.h>
 
 
@@ -252,12 +253,6 @@ reset:
 	nop
 #endif
 
-	/* Initialize any external memory.
-	 */
-	la      t9, lowlevel_init
-	jalr    t9
-	nop
-
 	/* Initialize caches...
 	 */
 	la      t9, mips_cache_reset
@@ -269,6 +264,58 @@ reset:
 	li	t0, CONF_CM_CACHABLE_NONCOHERENT
 	mtc0	t0, CP0_CONFIG
 
+#ifdef CFG_WAKEUP_MODE
+	/* Now check the wakeup cause
+	 */
+	li      t0, SYS_WAKESRC
+	lw      t1, 0(t0)
+	andi    t1, t1, 0x00000002	/* check the SW bit */
+	beq     zero, t1, 1f
+	nop
+
+#if 0
+        /* Infinite loop to allow JTAG attach after sleep mode (debug only)
+	 */
+2:	li      t1, 0
+        beq	t1, zero, 2b
+	nop
+#endif
+
+	/* Wakeup any external memory.
+	 */
+	la	t9, lowlevel_wakeup
+	jalr	t9
+	nop
+
+	/* Jump into the Linux code
+	 */
+	li	t0, SYS_SCRATCH0
+	lw      t1, 0(t0)
+	move	sp, t1
+	li	t0, SYS_SCRATCH1
+	lw      t1, 0(t0)
+	j	t1 			/* this cause a jump into already
+	nop				   frozen Linux (brr! :) */	
+
+	/* If we reach this point we come from a normal system power up,
+           so just clear the wakeup cause registers and call the
+	   lowlevel_init function as normal
+	 */
+#endif
+
+1:	li      t0, SYS_WAKEMSK
+	li      t1, 0x00000000
+	sw      t1, 0(t0)
+
+	li      t0, SYS_WAKESRC
+	li      t1, 0x00000000
+	sw      t1, 0(t0)
+
+	/* Initialize any external memory.
+	 */
+	la	t9, lowlevel_init
+	jalr	t9
+	nop
 
 	/* Set up temporary stack.
 	 */


-- 

GNU/Linux Solutions                  e-mail:    giometti at enneenne.com
Linux Device Driver                             giometti at gnudd.com
Embedded Systems                     		giometti at linux.it
UNIX programming                     phone:     +39 349 2432127