sh: SuperH Mobile suspend support

This patch contains CONFIG_SUSPEND support to the SuperH
architecture. If enabled, SuperH Mobile processors will
register their suspend callbacks during boot.

To suspend, use "echo mem > /sys/power/state". To allow
wakeup, make sure "/sys/device/platform/../power/wakeup"
contains "enabled". Additional per-device driver patches
are most likely needed.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

5 files changed, 231 insertions, 0 deletions

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index adffbf4048b1..a0c879d17fd6 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -181,6 +181,7 @@ config CPU_SHX3
 
 config ARCH_SHMOBILE
         bool
+        select ARCH_SUSPEND_POSSIBLE
 
 choice
         prompt "Processor sub-type selection"
diff --git a/arch/sh/include/asm/suspend.h b/arch/sh/include/asm/suspend.h
index 5d6d8aba5682..b1b995370e79 100644
--- a/arch/sh/include/asm/suspend.h
+++ b/arch/sh/include/asm/suspend.h
@@ -1,6 +1,7 @@
 #ifndef _ASM_SH_SUSPEND_H
 #define _ASM_SH_SUSPEND_H
 
+#ifndef __ASSEMBLY__
 static inline int arch_prepare_suspend(void) { return 0; }
 
 #include <asm/ptrace.h>
@@ -9,5 +10,13 @@ struct swsusp_arch_regs {
         struct pt_regs user_regs;
         unsigned long bank1_regs[8];
 };
+#endif
+
+/* flags passed to assembly suspend code */
+#define SUSP_SH_SLEEP           (1 << 0) /* Regular sleep mode */
+#define SUSP_SH_STANDBY         (1 << 1) /* SH-Mobile Software standby mode */
+#define SUSP_SH_RSTANDBY        (1 << 2) /* SH-Mobile R-standby mode */
+#define SUSP_SH_USTANDBY        (1 << 3) /* SH-Mobile U-standby mode */
+#define SUSP_SH_SF              (1 << 4) /* Enable self-refresh */
 
 #endif /* _ASM_SH_SUSPEND_H */
diff --git a/arch/sh/kernel/cpu/sh4a/Makefile b/arch/sh/kernel/cpu/sh4a/Makefile
index 1a92361feeb9..09967dc0065a 100644
--- a/arch/sh/kernel/cpu/sh4a/Makefile
+++ b/arch/sh/kernel/cpu/sh4a/Makefile
@@ -35,6 +35,10 @@ pinmux-$(CONFIG_CPU_SUBTYPE_SH7723)	:= pinmux-sh7723.o
 pinmux-$(CONFIG_CPU_SUBTYPE_SH7785)     := pinmux-sh7785.o
 pinmux-$(CONFIG_CPU_SUBTYPE_SH7786)     := pinmux-sh7786.o
 
+# Power Mangement & Sleep mode
+pm-$(CONFIG_ARCH_SHMOBILE)              := pm-sh_mobile.o sleep-sh_mobile.o
+
 obj-y                   += $(clock-y)
 obj-$(CONFIG_SMP)       += $(smp-y)
 obj-$(CONFIG_GENERIC_GPIO)      += $(pinmux-y)
+obj-$(CONFIG_PM)        += $(pm-y)
diff --git a/arch/sh/kernel/cpu/sh4a/pm-sh_mobile.c b/arch/sh/kernel/cpu/sh4a/pm-sh_mobile.c
new file mode 100644
index 000000000000..8c067adf6830
--- /dev/null
+++ b/arch/sh/kernel/cpu/sh4a/pm-sh_mobile.c
@@ -0,0 +1,92 @@
+/*
+ * arch/sh/kernel/cpu/sh4a/pm-sh_mobile.c
+ *
+ * Power management support code for SuperH Mobile
+ *
+ *  Copyright (C) 2009 Magnus Damm
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/suspend.h>
+#include <asm/suspend.h>
+#include <asm/uaccess.h>
+
+/*
+ * Sleep modes available on SuperH Mobile:
+ *
+ * Sleep mode is just plain "sleep" instruction
+ * Sleep Self-Refresh mode is above plus RAM put in Self-Refresh
+ * Standby Self-Refresh mode is above plus stopped clocks
+ */
+#define SUSP_MODE_SLEEP         (SUSP_SH_SLEEP)
+#define SUSP_MODE_SLEEP_SF      (SUSP_SH_SLEEP | SUSP_SH_SF)
+#define SUSP_MODE_STANDBY_SF    (SUSP_SH_STANDBY | SUSP_SH_SF)
+
+/*
+ * The following modes are not there yet:
+ *
+ * R-standby mode is unsupported, but will be added in the future
+ * U-standby mode is low priority since it needs bootloader hacks
+ *
+ * All modes should be tied in with cpuidle. But before that can
+ * happen we need to keep track of enabled hardware blocks so we
+ * can avoid entering sleep modes that stop clocks to hardware
+ * blocks that are in use even though the cpu core is idle.
+ */
+
+extern const unsigned char sh_mobile_standby[];
+extern const unsigned int sh_mobile_standby_size;
+
+static void sh_mobile_call_standby(unsigned long mode)
+{
+        extern void *vbr_base;
+        void *onchip_mem = (void *)0xe5200000; /* ILRAM */
+        void (*standby_onchip_mem)(unsigned long) = onchip_mem;
+
+        /* Note: Wake up from sleep may generate exceptions!
+         * Setup VBR to point to on-chip ram if self-refresh is
+         * going to be used.
+         */
+        if (mode & SUSP_SH_SF)
+                asm volatile("ldc %0, vbr" : : "r" (onchip_mem) : "memory");
+
+        /* Copy the assembly snippet to the otherwise ununsed ILRAM */
+        memcpy(onchip_mem, sh_mobile_standby, sh_mobile_standby_size);
+        wmb();
+        ctrl_barrier();
+
+        /* Let assembly snippet in on-chip memory handle the rest */
+        standby_onchip_mem(mode);
+
+        /* Put VBR back in System RAM again */
+        if (mode & SUSP_SH_SF)
+                asm volatile("ldc %0, vbr" : : "r" (&vbr_base) : "memory");
+}
+
+static int sh_pm_enter(suspend_state_t state)
+{
+        local_irq_disable();
+        set_bl_bit();
+        sh_mobile_call_standby(SUSP_MODE_STANDBY_SF);
+        local_irq_disable();
+        clear_bl_bit();
+        return 0;
+}
+
+static struct platform_suspend_ops sh_pm_ops = {
+        .enter          = sh_pm_enter,
+        .valid          = suspend_valid_only_mem,
+};
+
+static int __init sh_pm_init(void)
+{
+        suspend_set_ops(&sh_pm_ops);
+        return 0;
+}
+
+late_initcall(sh_pm_init);
diff --git a/arch/sh/kernel/cpu/sh4a/sleep-sh_mobile.S b/arch/sh/kernel/cpu/sh4a/sleep-sh_mobile.S
new file mode 100644
index 000000000000..5d888ef53d82
--- /dev/null
+++ b/arch/sh/kernel/cpu/sh4a/sleep-sh_mobile.S
@@ -0,0 +1,125 @@
+/*
+ * arch/sh/kernel/cpu/sh4a/sleep-sh_mobile.S
+ *
+ * Sleep mode and Standby modes support for SuperH Mobile
+ *
+ *  Copyright (C) 2009 Magnus Damm
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/sys.h>
+#include <linux/errno.h>
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/suspend.h>
+
+/* manage self-refresh and enter standby mode.
+ * this code will be copied to on-chip memory and executed from there.
+ */
+
+        .balign         4096,0,4096
+ENTRY(sh_mobile_standby)
+        mov     r4, r0
+
+        tst     #SUSP_SH_SF, r0
+        bt      skip_set_sf
+
+        /* SDRAM: disable power down and put in self-refresh mode */
+        mov.l   1f, r4
+        mov.l   2f, r1
+        mov.l   @r4, r2
+        or      r1, r2
+        mov.l   3f, r3
+        and     r3, r2
+        mov.l   r2, @r4
+
+skip_set_sf:
+        tst     #SUSP_SH_SLEEP, r0
+        bt      test_standby
+
+        /* set mode to "sleep mode" */
+        bra     do_sleep
+         mov    #0x00, r1
+
+test_standby:
+        tst     #SUSP_SH_STANDBY, r0
+        bt      test_rstandby
+
+        /* set mode to "software standby mode" */
+        bra     do_sleep
+         mov    #0x80, r1
+
+test_rstandby:
+        tst     #SUSP_SH_RSTANDBY, r0
+        bt      test_ustandby
+
+        /* set mode to "r-standby mode" */
+        bra     do_sleep
+         mov    #0x20, r1
+
+test_ustandby:
+        tst     #SUSP_SH_USTANDBY, r0
+        bt      done_sleep
+
+        /* set mode to "u-standby mode" */
+        mov     #0x10, r1
+
+        /* fall-through */
+
+do_sleep:
+        /* setup and enter selected standby mode */
+        mov.l   5f, r4
+        mov.l   r1, @r4
+        sleep
+
+done_sleep:
+        /* reset standby mode to sleep mode */
+        mov.l   5f, r4
+        mov     #0x00, r1
+        mov.l   r1, @r4
+
+        tst     #SUSP_SH_SF, r0
+        bt      skip_restore_sf
+
+        /* SDRAM: set auto-refresh mode */
+        mov.l   1f, r4
+        mov.l   @r4, r2
+        mov.l   4f, r3
+        and     r3, r2
+        mov.l   r2, @r4
+        mov.l   6f, r4
+        mov.l   7f, r1
+        mov.l   8f, r2
+        mov.l   @r4, r3
+        mov     #-1, r4
+        add     r4, r3
+        or      r2, r3
+        mov.l   r3, @r1
+skip_restore_sf:
+        rts
+         nop
+
+        .balign 4
+1:      .long   0xfe400008 /* SDCR0 */
+2:      .long   0x00000400
+3:      .long   0xffff7fff
+4:      .long   0xfffffbff
+5:      .long   0xa4150020 /* STBCR */
+6:      .long   0xfe40001c /* RTCOR */
+7:      .long   0xfe400018 /* RTCNT */
+8:      .long   0xa55a0000
+
+/* interrupt vector @ 0x600 */
+        .balign         0x400,0,0x400
+        .long   0xdeadbeef
+        .balign         0x200,0,0x200
+        /* sh7722 will end up here in sleep mode */
+        rte
+         nop
+sh_mobile_standby_end:
+
+ENTRY(sh_mobile_standby_size)
+        .long sh_mobile_standby_end - sh_mobile_standby