[POWERPC] pasemi: Idle loops

Powersave support on PA6T. Right now it only uses 'doze' mode, and
will default to no savings (spin).

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

5 files changed, 178 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/pasemi/Makefile b/arch/powerpc/platforms/pasemi/Makefile
index 1be1a993c5f5..fe4da46074bb 100644
--- a/arch/powerpc/platforms/pasemi/Makefile
+++ b/arch/powerpc/platforms/pasemi/Makefile
@@ -1 +1,2 @@
-obj-y   += setup.o pci.o time.o
+obj-y   += setup.o pci.o time.o idle.o powersave.o
+
diff --git a/arch/powerpc/platforms/pasemi/idle.c b/arch/powerpc/platforms/pasemi/idle.c
new file mode 100644
index 000000000000..1ca3ff381591
--- /dev/null
+++ b/arch/powerpc/platforms/pasemi/idle.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2006-2007 PA Semi, Inc
+ *
+ * Maintained by: Olof Johansson <olof@lixom.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+#include <asm/machdep.h>
+#include <asm/reg.h>
+
+#include "pasemi.h"
+
+struct sleep_mode {
+        char *name;
+        void (*entry)(void);
+};
+
+static struct sleep_mode modes[] = {
+        { .name = "spin", .entry = &idle_spin },
+        { .name = "doze", .entry = &idle_doze },
+};
+
+static int current_mode = 0;
+
+static int pasemi_system_reset_exception(struct pt_regs *regs)
+{
+        /* If we were woken up from power savings, we need to return
+         * to the calling function, since nip is not saved across
+         * all modes.
+         */
+
+        if (regs->msr & SRR1_WAKEMASK)
+                regs->nip = regs->link;
+
+        switch (regs->msr & SRR1_WAKEMASK) {
+        case SRR1_WAKEEE:
+                do_IRQ(regs);
+                break;
+        case SRR1_WAKEDEC:
+                timer_interrupt(regs);
+                break;
+        default:
+                /* do system reset */
+                return 0;
+        }
+        /* everything handled */
+        regs->msr |= MSR_RI;
+        return 1;
+}
+
+void __init pasemi_idle_init(void)
+{
+        ppc_md.system_reset_exception = pasemi_system_reset_exception;
+        ppc_md.power_save = modes[current_mode].entry;
+        printk(KERN_INFO "Using PA6T idle loop (%s)\n", modes[current_mode].name);
+}
+
+static int __init idle_param(char *p)
+{
+        int i;
+        for (i = 0; i < sizeof(modes)/sizeof(struct sleep_mode); i++) {
+                if (!strcmp(modes[i].name, p)) {
+                        current_mode = i;
+                        break;
+                }
+        }
+        return 0;
+}
+
+early_param("idle", idle_param);
diff --git a/arch/powerpc/platforms/pasemi/pasemi.h b/arch/powerpc/platforms/pasemi/pasemi.h
index 51c2a2397ecf..94fd00cc6a10 100644
--- a/arch/powerpc/platforms/pasemi/pasemi.h
+++ b/arch/powerpc/platforms/pasemi/pasemi.h
@@ -4,4 +4,11 @@
 extern unsigned long pas_get_boot_time(void);
 extern void pas_pci_init(void);
 
+extern void __init pasemi_idle_init(void);
+
+/* Power savings modes, implemented in asm */
+extern void idle_spin(void);
+extern void idle_doze(void);
+
+
 #endif /* _PASEMI_PASEMI_H */
diff --git a/arch/powerpc/platforms/pasemi/powersave.S b/arch/powerpc/platforms/pasemi/powersave.S
new file mode 100644
index 000000000000..6d0fba6aab17
--- /dev/null
+++ b/arch/powerpc/platforms/pasemi/powersave.S
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2006-2007 PA Semi, Inc
+ *
+ * Maintained by: Olof Johansson <olof@lixom.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/ppc_asm.h>
+#include <asm/cputable.h>
+#include <asm/cache.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+
+/* Power savings opcodes since not all binutils have them at this time */
+#define DOZE    .long   0x4c000324
+#define NAP     .long   0x4c000364
+#define SLEEP   .long   0x4c0003a4
+#define RVW     .long   0x4c0003e4
+
+/* Common sequence to do before going to any of the
+ * powersavings modes.
+ */
+
+#define PRE_SLEEP_SEQUENCE      \
+        std     r3,8(r1);       \
+        ptesync ;               \
+        ld      r3,8(r1);       \
+1:      cmpd    r3,r3;          \
+        bne     1b
+
+_doze:
+        PRE_SLEEP_SEQUENCE
+        DOZE
+        b       .
+
+
+_GLOBAL(idle_spin)
+        blr
+
+_GLOBAL(idle_doze)
+        LOAD_REG_ADDR(r3, _doze)
+        b       sleep_common
+
+/* Add more modes here later */
+
+sleep_common:
+        mflr    r0
+        std     r0, 16(r1)
+        stdu    r1,-64(r1)
+
+        LOAD_REG_IMMEDIATE(r6,MSR_DR|MSR_IR|MSR_ME|MSR_EE)
+        mfmsr   r4
+        andc    r5,r4,r6
+        mtmsrd  r5,0
+
+        mtctr   r3
+        bctrl
+
+        mtmsrd  r4,0
+
+        addi    r1,r1,64
+        ld      r0,16(r1)
+        mtlr    r0
+        blr
+
diff --git a/arch/powerpc/platforms/pasemi/setup.c b/arch/powerpc/platforms/pasemi/setup.c
index 4142873a87ef..f69f5e76618f 100644
--- a/arch/powerpc/platforms/pasemi/setup.c
+++ b/arch/powerpc/platforms/pasemi/setup.c
@@ -82,7 +82,7 @@ void __init pas_setup_arch(void)
         conswitchp = &dummy_con;
 #endif
 
-        printk(KERN_DEBUG "Using default idle loop\n");
+        pasemi_idle_init();
 }
 
 /* No legacy IO on our parts */