: ACPI: duplicate ACPI sleep "alarm" attribute in sysfs

Index: linux-2.6.20-rc2-mm1/drivers/acpi/sleep/proc.c
===================================================================
@@ -15,6 +15,290 @@
 
 #define _COMPONENT		ACPI_SYSTEM_COMPONENT
 ACPI_MODULE_NAME("sleep")
+
+static int get_date_field(char **p, u32 * value)
+{
+	char *next = NULL;
+	char *string_end = NULL;
+	int result = -EINVAL;
+
+	/*
+	 * Try to find delimeter, only to insert null.  The end of the
+	 * string won't have one, but is still valid.
+	 */
+	next = strpbrk(*p, "- :");
+	if (next)
+		*next++ = '\0';
+
+	*value = simple_strtoul(*p, &string_end, 10);
+
+	/* Signal success if we got a good digit */
+	if (string_end != *p)
+		result = 0;
+
+	if (next)
+		*p = next;
+
+	return result;
+}
+
+/* --------------------------------------------------------------------------
+                              FS Interface (/sys)
+   -------------------------------------------------------------------------- */
+
+static ssize_t alarm_show(struct subsystem *subsys, char *buf){
+	u32 sec, min, hr;
+	u32 day, mo, yr;
+	unsigned char rtc_control = 0;
+	unsigned long flags;
+	ssize_t result = 0;
+
+	spin_lock_irqsave(&rtc_lock, flags);
+
+	sec = CMOS_READ(RTC_SECONDS_ALARM);
+	min = CMOS_READ(RTC_MINUTES_ALARM);
+	hr = CMOS_READ(RTC_HOURS_ALARM);
+	rtc_control = CMOS_READ(RTC_CONTROL);
+
+	/* If we ever get an FACP with proper values... */
+	if (acpi_gbl_FADT->day_alrm)
+		/* ACPI spec: only low 6 its should be cared */
+		day = CMOS_READ(acpi_gbl_FADT->day_alrm) & 0x3F;
+	else
+		day = CMOS_READ(RTC_DAY_OF_MONTH);
+	if (acpi_gbl_FADT->mon_alrm)
+		mo = CMOS_READ(acpi_gbl_FADT->mon_alrm);
+	else
+		mo = CMOS_READ(RTC_MONTH);
+	if (acpi_gbl_FADT->century)
+		yr = CMOS_READ(acpi_gbl_FADT->century) * 100 +
+		    CMOS_READ(RTC_YEAR);
+	else
+		yr = CMOS_READ(RTC_YEAR);
+
+	spin_unlock_irqrestore(&rtc_lock, flags);
+
+	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BCD_TO_BIN(sec);
+		BCD_TO_BIN(min);
+		BCD_TO_BIN(hr);
+		BCD_TO_BIN(day);
+		BCD_TO_BIN(mo);
+		BCD_TO_BIN(yr);
+	}
+
+	/* we're trusting the FADT (see above) */
+	if (!acpi_gbl_FADT->century)
+		/* If we're not trusting the FADT, we should at least make it
+		 * right for _this_ century... ehm, what is _this_ century?
+		 *
+		 * TBD:
+		 *  ASAP: find piece of code in the kernel, e.g. star tracker driver,
+		 *        which we can trust to determine the century correctly. Atom
+		 *        watch driver would be nice, too...
+		 *
+		 *  if that has not happened, change for first release in 2050:
+		 *        if (yr<50)
+		 *                yr += 2100;
+		 *        else
+		 *                yr += 2000;   // current line of code
+		 *
+		 *  if that has not happened either, please do on 2099/12/31:23:59:59
+		 *        s/2000/2100
+		 *
+		 */
+		yr += 2000;
+
+	result = sprintf(buf+result, "%4.4u-", yr);
+	if (mo > 12)
+		result += sprintf(buf+result, "**-");
+	else
+		result +=  sprintf(buf+result, "%2.2u-", mo);
+	if(day > 31)
+		result += sprintf(buf+result, "** ");
+	else
+		result +=  sprintf(buf+result, "%2.2u ", day);
+	if(hr > 23)
+		result += sprintf(buf+result, "**:");
+	else
+		result +=  sprintf(buf+result, "%2.2u:", hr);
+	if(min > 59)
+		result += sprintf(buf+result, "**:");
+	else
+		result +=  sprintf(buf+result, "%2.2u:", min);
+	if(sec > 59)
+		result += sprintf(buf+result, "**\n");
+	else
+		result +=  sprintf(buf+result, "%2.2u\n", sec);
+
+	return result;
+}
+
+static ssize_t alarm_store(struct subsystem *subsys, const char *buf, size_t count){
+	int result = 0;
+	char *p = (char*)buf;
+	u32 sec, min, hr, day, mo, yr;
+	int adjust = 0;
+	unsigned char rtc_control = 0;
+
+	if (buf[0] == '+') {
+			p++;
+			adjust = 1;
+		}
+
+	if ((result = get_date_field(&p, &yr)))
+		goto end;
+	if ((result = get_date_field(&p, &mo)))
+		goto end;
+	if ((result = get_date_field(&p, &day)))
+		goto end;
+	if ((result = get_date_field(&p, &hr)))
+		goto end;
+	if ((result = get_date_field(&p, &min)))
+		goto end;
+	if ((result = get_date_field(&p, &sec)))
+		goto end;
+
+	if (sec > 59) {
+		min += 1;
+		sec -= 60;
+	}
+	if (min > 59) {
+		hr += 1;
+		min -= 60;
+	}
+	if (hr > 23) {
+		day += 1;
+		hr -= 24;
+	}
+	if (day > 31) {
+		mo += 1;
+		day -= 31;
+	}
+	if (mo > 12) {
+		yr += 1;
+		mo -= 12;
+	}
+	spin_lock_irq(&rtc_lock);
+
+	rtc_control = CMOS_READ(RTC_CONTROL);
+	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BIN_TO_BCD(yr);
+		BIN_TO_BCD(mo);
+		BIN_TO_BCD(day);
+		BIN_TO_BCD(hr);
+		BIN_TO_BCD(min);
+		BIN_TO_BCD(sec);
+	}
+
+	if (adjust) {
+		yr += CMOS_READ(RTC_YEAR);
+		mo += CMOS_READ(RTC_MONTH);
+		day += CMOS_READ(RTC_DAY_OF_MONTH);
+		hr += CMOS_READ(RTC_HOURS);
+		min += CMOS_READ(RTC_MINUTES);
+		sec += CMOS_READ(RTC_SECONDS);
+	}
+
+	spin_unlock_irq(&rtc_lock);
+
+	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BCD_TO_BIN(yr);
+		BCD_TO_BIN(mo);
+		BCD_TO_BIN(day);
+		BCD_TO_BIN(hr);
+		BCD_TO_BIN(min);
+		BCD_TO_BIN(sec);
+	}
+
+	if (sec > 59) {
+		min++;
+		sec -= 60;
+	}
+	if (min > 59) {
+		hr++;
+		min -= 60;
+	}
+	if (hr > 23) {
+		day++;
+		hr -= 24;
+	}
+	if (day > 31) {
+		mo++;
+		day -= 31;
+	}
+	if (mo > 12) {
+		yr++;
+		mo -= 12;
+	}
+	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BIN_TO_BCD(yr);
+		BIN_TO_BCD(mo);
+		BIN_TO_BCD(day);
+		BIN_TO_BCD(hr);
+		BIN_TO_BCD(min);
+		BIN_TO_BCD(sec);
+	}
+
+	spin_lock_irq(&rtc_lock);
+	/*
+	 * Disable alarm interrupt before setting alarm timer or else
+	 * when ACPI_EVENT_RTC is enabled, a spurious ACPI interrupt occurs
+	 */
+	rtc_control &= ~RTC_AIE;
+	CMOS_WRITE(rtc_control, RTC_CONTROL);
+	CMOS_READ(RTC_INTR_FLAGS);
+
+	/* write the fields the rtc knows about */
+	CMOS_WRITE(hr, RTC_HOURS_ALARM);
+	CMOS_WRITE(min, RTC_MINUTES_ALARM);
+	CMOS_WRITE(sec, RTC_SECONDS_ALARM);
+
+	/*
+	 * If the system supports an enhanced alarm it will have non-zero
+	 * offsets into the CMOS RAM here -- which for some reason are pointing
+	 * to the RTC area of memory.
+	 */
+	if (acpi_gbl_FADT->day_alrm)
+		CMOS_WRITE(day, acpi_gbl_FADT->day_alrm);
+	if (acpi_gbl_FADT->mon_alrm)
+		CMOS_WRITE(mo, acpi_gbl_FADT->mon_alrm);
+	if (acpi_gbl_FADT->century)
+		CMOS_WRITE(yr / 100, acpi_gbl_FADT->century);
+	/* enable the rtc alarm interrupt */
+	rtc_control |= RTC_AIE;
+	CMOS_WRITE(rtc_control, RTC_CONTROL);
+	CMOS_READ(RTC_INTR_FLAGS);
+
+	spin_unlock_irq(&rtc_lock);
+
+	acpi_clear_event(ACPI_EVENT_RTC);
+	acpi_enable_event(ACPI_EVENT_RTC, 0);
+
+	result = count;
+
+      end:
+	return result;
+}
+
+static struct subsys_attribute alarm_attr = {
+	.attr	= {
+		.name = __stringify(alarm),
+		.mode = 0644,
+	},
+	.show	= alarm_show,
+	.store	= alarm_store,
+};
+
+extern struct subsystem power_subsys;
+static int alarm_add_sysfs(void)
+{
+	return sysfs_create_file(&power_subsys.kset.kobj, &alarm_attr.attr);
+}
+
+/* --------------------------------------------------------------------------
+                              FS Interface (/proc)
+   -------------------------------------------------------------------------- */
 #ifdef	CONFIG_ACPI_SLEEP_PROC_SLEEP
 static int acpi_system_sleep_seq_show(struct seq_file *seq, void *offset)
 {

@@ -150,32 +434,6 @@ static int acpi_system_alarm_open_fs(str
 	return single_open(file, acpi_system_alarm_seq_show, PDE(inode)->data);
 }
 
-static int get_date_field(char **p, u32 * value)
-{
-	char *next = NULL;
-	char *string_end = NULL;
-	int result = -EINVAL;
-
-	/*
-	 * Try to find delimeter, only to insert null.  The end of the
-	 * string won't have one, but is still valid.
-	 */
-	next = strpbrk(*p, "- :");
-	if (next)
-		*next++ = '\0';
-
-	*value = simple_strtoul(*p, &string_end, 10);
-
-	/* Signal success if we got a good digit */
-	if (string_end != *p)
-		result = 0;
-
-	if (next)
-		*p = next;
-
-	return result;
-}
-
 static ssize_t
 acpi_system_write_alarm(struct file *file,
 			const char __user * buffer, size_t count, loff_t * ppos)

@@ -498,6 +756,9 @@ static int acpi_sleep_proc_init(void)
 	if (entry)
 		entry->proc_fops = &acpi_system_wakeup_device_fops;
 
+	if(alarm_add_sysfs())
+		return -EINVAL;
+
 	acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, NULL);
 	return 0;
 }

Index: g26/drivers/rtc/rtc-sysfs.c
===================================================================
@@ -78,6 +78,92 @@ static struct attribute_group rtc_attr_g
 	.attrs = rtc_attrs,
 };
 
+
+static ssize_t
+rtc_sysfs_show_wakealarm(struct class_device *dev, char *buf)
+{
+	ssize_t retval;
+	unsigned long alarm;
+	struct rtc_wkalrm alm;
+
+	/* Don't show disabled alarms; but the RTC could leave the
+	 * alarm enabled after it's already triggered.  Alarms are
+	 * conceptually one-shot, even though some common hardware
+	 * (PCs) doesn't actually work that way.
+	 *
+	 * REVISIT maybe we should require RTC implementations to
+	 * disable the RTC alarm after it triggers, for uniformity.
+	 */
+	retval = rtc_read_alarm(dev, &alm);
+	if (retval == 0 && alm.enabled) {
+		rtc_tm_to_time(&alm.time, &alarm);
+		retval = sprintf(buf, "%lu\n", alarm);
+	}
+
+	return retval;
+}
+
+static ssize_t
+rtc_sysfs_set_wakealarm(struct class_device *dev, const char *buf, size_t n)
+{
+	ssize_t retval;
+	unsigned long now, alarm;
+	struct rtc_wkalrm alm;
+
+	/* Only request alarms that trigger in the future.  Disable them
+	 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
+	 */
+	retval = rtc_read_time(dev, &alm.time);
+	if (retval < 0)
+		return retval;
+	rtc_tm_to_time(&alm.time, &now);
+
+	alarm = simple_strtoul(buf, NULL, 0);
+	if (alarm > now) {
+		/* Avoid accidentally clobbering active alarms; we can't
+		 * entirely prevent that here, without even the minimal
+		 * locking from the /dev/rtcN api.
+		 */
+		retval = rtc_read_alarm(dev, &alm);
+		if (retval < 0)
+			return retval;
+		if (alm.enabled)
+			return -EBUSY;
+
+		alm.enabled = 1;
+	} else {
+		alm.enabled = 0;
+
+		/* Provide a valid future alarm time.  Linux isn't EFI,
+		 * this time won't be ignored when disabling the alarm.
+		 */
+		alarm = now + 300;
+	}
+	rtc_time_to_tm(alarm, &alm.time);
+
+	retval = rtc_set_alarm(dev, &alm);
+	return (retval < 0) ? retval : n;
+}
+static const CLASS_DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
+		rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
+
+
+/* The reason to trigger an alarm with no process watching it (via sysfs)
+ * is its side effect:  waking from a system state like suspend-to-RAM or
+ * suspend-to-disk.  So: no attribute unless that side effect is possible.
+ * (Userspace may disable that mechanism later.)
+ */
+static inline int rtc_does_wakealarm(struct class_device *class_dev)
+{
+	struct rtc_device *rtc;
+
+	if (!device_can_wakeup(class_dev->dev))
+		return 0;
+	rtc = to_rtc_device(class_dev);
+	return rtc->ops->set_alarm != NULL;
+}
+
+
 static int __devinit rtc_sysfs_add_device(struct class_device *class_dev,
 					struct class_interface *class_intf)
 {

@@ -87,8 +173,18 @@ static int __devinit rtc_sysfs_add_devic
 
 	err = sysfs_create_group(&class_dev->kobj, &rtc_attr_group);
 	if (err)
-		dev_err(class_dev->dev,
-			"failed to create sysfs attributes\n");
+		dev_err(class_dev->dev, "failed to create %s\n",
+				"sysfs attributes");
+	else if (rtc_does_wakealarm(class_dev)) {
+		/* not all RTCs support both alarms and wakeup */
+		err = class_device_create_file(class_dev,
+					&class_device_attr_wakealarm);
+		if (err) {
+			dev_err(class_dev->dev, "failed to create %s\n",
+					"alarm attribute");
+			sysfs_remove_group(&class_dev->kobj, &rtc_attr_group);
+		}
+	}
 
 	return err;
 }

@@ -96,6 +192,9 @@ static int __devinit rtc_sysfs_add_devic
 static void rtc_sysfs_remove_device(struct class_device *class_dev,
 				struct class_interface *class_intf)
 {
+	if (rtc_does_wakealarm(class_dev))
+		class_device_remove_file(class_dev,
+				&class_device_attr_wakealarm);
 	sysfs_remove_group(&class_dev->kobj, &rtc_attr_group);
 }