I'm just trying to support the save_and_sleep() support into u-boot
for an au1100 based board.
Into u-boot I added the following code:
Index: cpu/mips/start.S
===================================================================
RCS file: /home/develop/cvs_private/uboot-mips-exadron/cpu/mips/start.S,v
retrieving revision 1.2
diff -u -r1.2 start.S
--- cpu/mips/start.S 12 Oct 2005 12:55:54 -0000 1.2
+++ cpu/mips/start.S 16 Dec 2005 15:29:22 -0000
@@ -26,6 +26,7 @@
#include <config.h>
#include <version.h>
#include <asm/regdef.h>
+#include <asm/au1x00.h>
#include <asm/mipsregs.h>
@@ -273,6 +274,33 @@
li t0, CONF_CM_CACHABLE_NONCOHERENT
mtc0 t0, CP0_CONFIG
+ /* 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
+
+ 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
+ */
+
+1: li t0, SYS_WAKEMSK
+ li t1, 0x00000000
+ sw t1, 0(t0)
+
+ li t0, SYS_WAKESRC
+ li t1, 0x00000000
+ sw t1, 0(t0)
/* Set up temporary stack.
*/
in order to restore the scratch registers contents as descibed into
file "linux/arch/mips/au1000/common/sleeper.S":
/* Now set up the scratch registers so the boot rom will
* return to this point upon wakeup.
*/
la k0, 1f
lui k1, 0xb190
ori k1, 0x18
sw sp, 0(k1)
ori k1, 0x1c
sw k0, 0(k1)
However it seems something is wrong since the system at the end of
save_and_sleep() does not correctly continue its execution...
Unlikely my JTAG do not allow me to follow the code after the
save_and_sleep()'s return (I definitely have to buy a better one),
however I noticed that when the system tryes to resume the register 29
(the sp) doing:
lw $29, PT_R29(sp)
something goes wrong!
Suggestions? :)
Thanks in advance,
Rodolfo
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