MIPS: Alchemy: new userspace suspend interface for development boards.

Replace the current sysctl-based suspend interface with a new sysfs-
based one which also uses the Linux-2.6 suspend model.

To configure wakeup sources, a subtree for the demoboards is created
under /sys/power/db1x:

sys/
`-- power
    `-- db1x
        |-- gpio0
        |-- gpio1
        |-- gpio2
        |-- gpio3
        |-- gpio4
        |-- gpio5
        |-- gpio6
        |-- gpio7
        |-- timer
        |-- timer_timeout
        |-- wakemsk
        `-- wakesrc

The nodes 'gpio[0-7]' and 'timer' configure the GPIO0..7 and M2
bits of the SYS_WAKEMSK (wakeup source enable) register.  Writing '1'
enables a wakesource, 0 disables it.

The 'timer_timeout' node holds the timeout in seconds after which the
TOYMATCH2 event should wake the system.

The 'wakesrc' node holds the SYS_WAKESRC register after wakeup (in hex),
the 'wakemsk' node can be used to get/set the wakeup mask directly.

For example, to have the timer wake the system after 10 seconds of sleep,
the following must be done in userspace:

echo 10 > /sys/power/db1x/timer_timeout
echo 1 > /sys/power/db1x/timer
echo mem > /sys/power/sleep

This patch also removes the homebrew CPU frequency switching code.  I don't
understand how it could have ever worked reliably; it does not communicate
the clock changes to peripheral devices other than uarts.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

 create mode 100644 arch/mips/alchemy/devboards/pm.c

2 files changed, 230 insertions, 0 deletions

diff --git a/arch/mips/alchemy/devboards/Makefile b/arch/mips/alchemy/devboards/Makefile
index c0eb87a66fbd..730f9f2b30e8 100644
--- a/arch/mips/alchemy/devboards/Makefile
+++ b/arch/mips/alchemy/devboards/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-y += prom.o
+obj-$(CONFIG_PM)		+= pm.o
 obj-$(CONFIG_MIPS_PB1000)	+= pb1000/
 obj-$(CONFIG_MIPS_PB1100)	+= pb1100/
 obj-$(CONFIG_MIPS_PB1200)	+= pb1200/
diff --git a/arch/mips/alchemy/devboards/pm.c b/arch/mips/alchemy/devboards/pm.c
new file mode 100644
index 000000000000..d5eb9c325ed0
--- /dev/null
+++ b/arch/mips/alchemy/devboards/pm.c
@@ -0,0 +1,229 @@
+/*
+ * Alchemy Development Board example suspend userspace interface.
+ *
+ * (c) 2008 Manuel Lauss <mano@roarinelk.homelinux.net>
+ */
+
+#include <linux/init.h>
+#include <linux/kobject.h>
+#include <linux/suspend.h>
+#include <linux/sysfs.h>
+#include <asm/mach-au1x00/au1000.h>
+
+/*
+ * Generic suspend userspace interface for Alchemy development boards.
+ * This code exports a few sysfs nodes under /sys/power/db1x/ which
+ * can be used by userspace to en/disable all au1x-provided wakeup
+ * sources and configure the timeout after which the the TOYMATCH2 irq
+ * is to trigger a wakeup.
+ */
+
+
+static unsigned long db1x_pm_sleep_secs;
+static unsigned long db1x_pm_wakemsk;
+static unsigned long db1x_pm_last_wakesrc;
+
+static int db1x_pm_enter(suspend_state_t state)
+{
+	/* enable GPIO based wakeup */
+	au_writel(1, SYS_PININPUTEN);
+
+	/* clear and setup wake cause and source */
+	au_writel(0, SYS_WAKEMSK);
+	au_sync();
+	au_writel(0, SYS_WAKESRC);
+	au_sync();
+
+	au_writel(db1x_pm_wakemsk, SYS_WAKEMSK);
+	au_sync();
+
+	/* setup 1Hz-timer-based wakeup: wait for reg access */
+	while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20)
+		asm volatile ("nop");
+
+	au_writel(au_readl(SYS_TOYREAD) + db1x_pm_sleep_secs, SYS_TOYMATCH2);
+	au_sync();
+
+	/* wait for value to really hit the register */
+	while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20)
+		asm volatile ("nop");
+
+	/* ...and now the sandman can come! */
+	au_sleep();
+
+	return 0;
+}
+
+static int db1x_pm_begin(suspend_state_t state)
+{
+	if (!db1x_pm_wakemsk) {
+		printk(KERN_ERR "db1x: no wakeup source activated!\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void db1x_pm_end(void)
+{
+	/* read and store wakeup source, the clear the register. To
+	 * be able to clear it, WAKEMSK must be cleared first.
+	 */
+	db1x_pm_last_wakesrc = au_readl(SYS_WAKESRC);
+
+	au_writel(0, SYS_WAKEMSK);
+	au_writel(0, SYS_WAKESRC);
+	au_sync();
+
+}
+
+static struct platform_suspend_ops db1x_pm_ops = {
+	.valid		= suspend_valid_only_mem,
+	.begin		= db1x_pm_begin,
+	.enter		= db1x_pm_enter,
+	.end		= db1x_pm_end,
+};
+
+#define ATTRCMP(x) (0 == strcmp(attr->attr.name, #x))
+
+static ssize_t db1x_pmattr_show(struct kobject *kobj,
+				struct kobj_attribute *attr,
+				char *buf)
+{
+	int idx;
+
+	if (ATTRCMP(timer_timeout))
+		return sprintf(buf, "%lu\n", db1x_pm_sleep_secs);
+
+	else if (ATTRCMP(timer))
+		return sprintf(buf, "%u\n",
+				!!(db1x_pm_wakemsk & SYS_WAKEMSK_M2));
+
+	else if (ATTRCMP(wakesrc))
+		return sprintf(buf, "%lu\n", db1x_pm_last_wakesrc);
+
+	else if (ATTRCMP(gpio0) || ATTRCMP(gpio1) || ATTRCMP(gpio2) ||
+		 ATTRCMP(gpio3) || ATTRCMP(gpio4) || ATTRCMP(gpio5) ||
+		 ATTRCMP(gpio6) || ATTRCMP(gpio7)) {
+		idx = (attr->attr.name)[4] - '0';
+		return sprintf(buf, "%d\n",
+			!!(db1x_pm_wakemsk & SYS_WAKEMSK_GPIO(idx)));
+
+	} else if (ATTRCMP(wakemsk)) {
+		return sprintf(buf, "%08lx\n", db1x_pm_wakemsk);
+	}
+
+	return -ENOENT;
+}
+
+static ssize_t db1x_pmattr_store(struct kobject *kobj,
+				 struct kobj_attribute *attr,
+				 const char *instr,
+				 size_t bytes)
+{
+	unsigned long l;
+	int tmp;
+
+	if (ATTRCMP(timer_timeout)) {
+		tmp = strict_strtoul(instr, 0, &l);
+		if (tmp)
+			return tmp;
+
+		db1x_pm_sleep_secs = l;
+
+	} else if (ATTRCMP(timer)) {
+		if (instr[0] != '0')
+			db1x_pm_wakemsk |= SYS_WAKEMSK_M2;
+		else
+			db1x_pm_wakemsk &= ~SYS_WAKEMSK_M2;
+
+	} else if (ATTRCMP(gpio0) || ATTRCMP(gpio1) || ATTRCMP(gpio2) ||
+		   ATTRCMP(gpio3) || ATTRCMP(gpio4) || ATTRCMP(gpio5) ||
+		   ATTRCMP(gpio6) || ATTRCMP(gpio7)) {
+		tmp = (attr->attr.name)[4] - '0';
+		if (instr[0] != '0') {
+			db1x_pm_wakemsk |= SYS_WAKEMSK_GPIO(tmp);
+		} else {
+			db1x_pm_wakemsk &= ~SYS_WAKEMSK_GPIO(tmp);
+		}
+
+	} else if (ATTRCMP(wakemsk)) {
+		tmp = strict_strtoul(instr, 0, &l);
+		if (tmp)
+			return tmp;
+
+		db1x_pm_wakemsk = l & 0x0000003f;
+
+	} else
+		bytes = -ENOENT;
+
+	return bytes;
+}
+
+#define ATTR(x)							\
+	static struct kobj_attribute x##_attribute = 		\
+		__ATTR(x, 0664, db1x_pmattr_show,		\
+				db1x_pmattr_store);
+
+ATTR(gpio0)		/* GPIO-based wakeup enable */
+ATTR(gpio1)
+ATTR(gpio2)
+ATTR(gpio3)
+ATTR(gpio4)
+ATTR(gpio5)
+ATTR(gpio6)
+ATTR(gpio7)
+ATTR(timer)		/* TOYMATCH2-based wakeup enable */
+ATTR(timer_timeout)	/* timer-based wakeup timeout value, in seconds */
+ATTR(wakesrc)		/* contents of SYS_WAKESRC after last wakeup */
+ATTR(wakemsk)		/* direct access to SYS_WAKEMSK */
+
+#define ATTR_LIST(x)	& x ## _attribute.attr
+static struct attribute *db1x_pmattrs[] = {
+	ATTR_LIST(gpio0),
+	ATTR_LIST(gpio1),
+	ATTR_LIST(gpio2),
+	ATTR_LIST(gpio3),
+	ATTR_LIST(gpio4),
+	ATTR_LIST(gpio5),
+	ATTR_LIST(gpio6),
+	ATTR_LIST(gpio7),
+	ATTR_LIST(timer),
+	ATTR_LIST(timer_timeout),
+	ATTR_LIST(wakesrc),
+	ATTR_LIST(wakemsk),
+	NULL,		/* terminator */
+};
+
+static struct attribute_group db1x_pmattr_group = {
+	.name	= "db1x",
+	.attrs	= db1x_pmattrs,
+};
+
+/*
+ * Initialize suspend interface
+ */
+static int __init pm_init(void)
+{
+	/* init TOY to tick at 1Hz if not already done. No need to wait
+	 * for confirmation since there's plenty of time from here to
+	 * the next suspend cycle.
+	 */
+	if (au_readl(SYS_TOYTRIM) != 32767) {
+		au_writel(32767, SYS_TOYTRIM);
+		au_sync();
+	}
+
+	db1x_pm_last_wakesrc = au_readl(SYS_WAKESRC);
+
+	au_writel(0, SYS_WAKESRC);
+	au_sync();
+	au_writel(0, SYS_WAKEMSK);
+	au_sync();
+
+	suspend_set_ops(&db1x_pm_ops);
+
+	return sysfs_create_group(power_kobj, &db1x_pmattr_group);
+}
+
+late_initcall(pm_init);