Re: patch: power off

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

> Current x68k kernel supports software power-off (by sysmon(4)),
> but in fact, the kernel does not turn off the power.  Power off
> is happened in IPLROM after software reset.
> 
> So, I wrote a patch that the kernel does power off itself.
> Any comments?

Basically looks good, but I have some dumb comments. (see below)

> I have tested only on XM6i because my X68030 has failed.  I'm
> happy if someone could test it on the real machine.

Powerdown after turning the power switch off just works on my X68030.

> +ENTRY_NOPROFILE(dopoweroff)
> +     movql   #1,%d1                  | shutdown
> +     bra     Ldoboot_main
> +
>  ENTRY_NOPROFILE(doboot)
> +     movql   #0,%d1                  | reboot
> +
> +Ldoboot_main:

It would be better to make doboot() take "howto" arg rather than
having different entry points. (patch attached)

> +#else /* without pxhtc patch, delay is local label */
> +     bsr     _delay

_ASM_LABEL(_delay) is more explicit for a function call.

> -     if (((howto & RB_POWERDOWN) == RB_POWERDOWN) && power_switch_is_off)
> -             doboot();
> -     else if (/*((howto & RB_POWERDOWN) == RB_POWERDOWN) ||*/
> -              ((howto & RB_HALT) == RB_HALT)) {
> +     if (((howto & RB_POWERDOWN) == RB_POWERDOWN) && power_switch_is_off) {
> +             dopoweroff();
> +     } else if ((howto & RB_HALT) == RB_HALT) {
>               printf("System halted.  Hit any key to reboot.\n\n");
>               (void)cngetc();
>       }

I wonder if the system port for powerdown can be accessed even before
the MMU is turned off.

If so, we can prepare a "poweroff" function and call it in cpu_reboot()
before calling doboot() like macppc does:
http://nxr.netbsd.org/xref/src/sys/arch/macppc/macppc/machdep.c?r=1.164#202

---
Index: x68k/locore.s
===================================================================
RCS file: /cvsroot/src/sys/arch/x68k/x68k/locore.s,v
retrieving revision 1.117
diff -u -p -d -r1.117 locore.s
--- x68k/locore.s       22 Mar 2014 21:49:18 -0000      1.117
+++ x68k/locore.s       23 Mar 2014 15:20:45 -0000
@@ -899,6 +899,7 @@ L_delay:
  * memory this way.
  */
 ENTRY_NOPROFILE(doboot)
+       movl    %sp@(4),%d1             | save "howto" arg
        movw    #PSL_HIGHIPL,%sr        | cut off any interrupts
        subal   %a1,%a1                 | a1 = 0
 
@@ -915,18 +916,44 @@ Ldoboot0:
        movc    %d0,%cacr               | disable on-chip cache(s)
 
        | ok, turn off MMU..
-Ldoreboot:
 #if defined(M68040) || defined(M68060)
        tstl    %d2                     | 68040?
        jne     LmotommuF               | no, skip
        movc    %a1,%cacr               | caches off
        .long   0x4e7b9003              | movc a1(=0),tc ; disable MMU
-       jra     Ldoreboot1
+       jra     Ldoboot1
 LmotommuF:
 #endif
        clrl    %sp@
        pmove   %sp@,%tc                | disable MMU
-Ldoreboot1:
+
+Ldoboot1:
+       /* Reset the stack pointer after MMU disabled */
+       subal   %a5,%a5                 | XXX firstpa=0 because PA==VA
+       ASRELOC(tmpstk, %a0)
+       movl    %a0,%sp
+
+       andl    #0x800,%d1
+       tstl    %d1                     | if ((howto & RB_POWERDOWN) == 0)
+       beq     Ldoreboot               |  then reboot
+
+       leal    0xe8e00f,%a0            | write a power-off sequence
+       movb    #0x00,%a0@              |  to system port
+       movb    #0x0f,%a0@
+       movb    #0x0f,%a0@
+
+       movl    #1000000,%sp@-          | wait a bit
+#define WITH_PXHTC 0
+#if WITH_PXHTC /* with pxhtc patch, delay is a pointer to function */
+       RELOC(delay, %a0)
+       moval   %a0@,%a0
+       jsr     %a0@
+#else /* without pxhtc patch, delay is local label */
+       bsr     _ASM_LABEL(_delay)
+#endif
+       /* PASSTHROUGH */               | passthrough even if came back
+
+Ldoreboot:
        moveml  0x00ff0000,#0x0101      | get RESET vectors in ROM
                                        |       (d0: ssp, a0: pc)
        moveml  #0x0101,%a1@            | put them at 0x0000 (for Xellent30)
Index: x68k/machdep.c
===================================================================
RCS file: /cvsroot/src/sys/arch/x68k/x68k/machdep.c,v
retrieving revision 1.188
diff -u -p -d -r1.188 machdep.c
--- x68k/machdep.c      22 Mar 2014 21:49:18 -0000      1.188
+++ x68k/machdep.c      23 Mar 2014 15:20:45 -0000
@@ -107,7 +107,7 @@ __KERNEL_RCSID(0, "$NetBSD: machdep.c,v 
 #include <machine/autoconf.h>
 #include <arch/x68k/dev/intiovar.h>
 
-extern void doboot(void) __attribute__((__noreturn__));
+extern void doboot(int) __attribute__((__noreturn__));
 
 /* the following is used externally (sysctl_hw) */
 char   machine[] = MACHINE;    /* from <machine/param.h> */
@@ -517,23 +517,22 @@ cpu_reboot(int howto, char *bootstr)
         *      Power cannot be removed; simply halt the system (b)
         *      Power switch state is checked in shutdown hook
         *  a2: the power switch is off
-        *      Remove the power; the simplest way is go back to ROM eg. reboot
+        *      Remove power by power-off sequence via system port in doboot()
         * b) RB_HALT
         *      call cngetc
         * c) otherwise
         *      Reboot
         */
-       if (((howto & RB_POWERDOWN) == RB_POWERDOWN) && power_switch_is_off)
-               doboot();
-       else if (/*((howto & RB_POWERDOWN) == RB_POWERDOWN) ||*/
-                ((howto & RB_HALT) == RB_HALT)) {
+       if (((howto & RB_POWERDOWN) == RB_POWERDOWN) && power_switch_is_off) {
+               doboot(RB_POWERDOWN);
+       } else if ((howto & RB_HALT) == RB_HALT) {
                printf("System halted.  Hit any key to reboot.\n\n");
                (void)cngetc();
        }
 
        printf("rebooting...\n");
        DELAY(1000000);
-       doboot();
+       doboot(RB_AUTOBOOT);
        /* NOTREACHED */
 }
 

---
Izumi Tsutsui