This fixes several bugs in the code to set just the time (and

not the date as well) on the RTC.  The low level function
x1205_set_datetime always wrote the date, even if it wasn't
given, resulting (typically) in the write of 0 bytes for the
mday,month and year.  It now only write h/m/s if the date is not
given.  The validate_tm API always checked the date, even if it
wasn't given (NOTE: the add of 'epoch' rather than 1900 may be
wrong, but it works at present).

The sync API fails to handle large resets, this problem still
exists, although the API is probably slightly more optimal.

BKrev: 4294039111Q_tc0c6nvKwVJbRiQY_w

2 files changed, 124 insertions, 39 deletions

diff --git a/packages/linux/openslug-kernel-2.6.11.2/x1205-rtc.c b/packages/linux/openslug-kernel-2.6.11.2/x1205-rtc.c
index 9a9831b682..7330037491 100644
--- a/packages/linux/openslug-kernel-2.6.11.2/x1205-rtc.c
+++ b/packages/linux/openslug-kernel-2.6.11.2/x1205-rtc.c
@@ -121,7 +121,7 @@ static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, u8
 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, int datetoo, u8 reg_base);
 static int x1205_attach(struct i2c_adapter *adapter);
 static int x1205_detach(struct i2c_client *client);
-static int x1205_validate_tm(struct rtc_time *tm);
+static int x1205_validate_tm(struct rtc_time *tm, int datetoo);
 static int x1205_command(struct i2c_client *client, unsigned int cmd, void *arg);
 static int x1205_sync_rtc(void);
 static int x1205_read(struct file *file, char *buf, size_t count, loff_t *ptr);
@@ -249,19 +249,21 @@ static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, in
 	
 #else		//do this if page writes aren't working
 
-	int i,xfer;
+	int i,xfer,count;
 	static unsigned char data[3]  = { 0,};
 	static unsigned char buf[8];
 
 	buf[CCR_SEC]  = BIN2BCD(tm->tm_sec);
 	buf[CCR_MIN]  = BIN2BCD(tm->tm_min);
 	buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_MILBIT; // set 24 hour format
+	count = CCR_HOUR+1;
 	if (datetoo == 1) {
 		buf[CCR_MDAY]  = BIN2BCD(tm->tm_mday);
 		buf[CCR_MONTH] = BIN2BCD(tm->tm_mon);		// input is 0-11	
 		buf[CCR_YEAR]  = BIN2BCD((tm->tm_year + epoch - rtc_epoch));	// input is yrs since 1900
 		buf[CCR_WDAY]  = tm->tm_wday & 7;
 		buf[CCR_Y2K]   = BIN2BCD((rtc_epoch/100));
+		count = CCR_Y2K+1;
 	}
 	printk(KERN_DEBUG "rtc_time input - sec-%02d min-%02d hour-%02d mday-%02d mon-%02d year-%02d wday-%02d epoch-%d rtc_epoch-%d\n",
 		tm->tm_sec,tm->tm_min,tm->tm_hour,tm->tm_mday,tm->tm_mon,tm->tm_year,tm->tm_wday, epoch, rtc_epoch);
@@ -276,7 +278,7 @@ static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, in
 	if (xfer != 3)
 		return -EIO;
 
-	for (i = 0; i < 8; i++) {
+	for (i = 0; i < count; i++) {
 		data[1] = i + reg_base;
 		data[2] =  buf[i];
 		xfer = i2c_master_send(client, data, 3);
@@ -288,7 +290,7 @@ static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, in
 	xfer = i2c_master_send(client, diswe, 3);
 	printk(KERN_DEBUG "wdis - %x\n", xfer);
 	if (xfer != 3)
-		return -EIO;		
+		return -EIO;
 	return NOERR;
 #endif
 }
@@ -309,7 +311,16 @@ static int x1205_attach(struct i2c_adapter *adapter)
 	if ((errno = i2c_attach_client(&x1205_i2c_client)) != NOERR)
 		return errno;
 
-	tv.tv_nsec = tm.tm_sec * 10000000;
+	/* IMPORTANT: the RTC only stores whole seconds.  It is arbitrary whether
+	 * it stores the most close value or the value with partial seconds
+	 * truncated, however it is important for x1205_sync_rtc that it be
+	 * defined to store the truncated value.  This is because otherwise it
+	 * is necessary to read both xtime.tv_sec and xtime.tv_nsec in the
+	 * sync function, and atomic reads of >32bits on ARM are not possible.
+	 * So storing the most close value would slow down the sync API.  So
+	 * Here we have the truncated value and the best guess is to add 0.5s
+	 */
+	tv.tv_nsec = NSEC_PER_SEC >> 1;
 	/* WARNING: this is not the C library 'mktime' call, it is a built in
 	 * inline function from include/linux/time.h.  It expects (requires)
 	 * the month to be in the range 1-12
@@ -338,26 +349,64 @@ static int x1205_detach(struct i2c_client *client)
 }
 
 // make sure the rtc_time values are in bounds
-static int x1205_validate_tm(struct rtc_time *tm)
+static int x1205_validate_tm(struct rtc_time *tm, int datetoo)
 {
-	tm->tm_year += 1900;
+	int result = NOERR;
 
-	if (tm->tm_year < 1970)
-		return -EINVAL;
+	tm->tm_year += epoch;
+
+	/* The RTC uses a byte containing a BCD year value, so this is
+	 * limited to the range 0..99 from rtc_epoch.
+	 */
+	if (tm->tm_year < rtc_epoch || tm->tm_year > rtc_epoch + 99)
+		goto baddate;
 
 	if ((tm->tm_mon > 11) || tm->tm_mon < 0 || (tm->tm_mday == 0))
-		return -EINVAL;
+		goto baddate;
+
+	if (tm->tm_mday < 0)
+		goto baddate;
 
 	if (tm->tm_mday > (days_in_mo[tm->tm_mon] + ( (tm->tm_mon == 1) && 
 		((!(tm->tm_year % 4) && (tm->tm_year % 100) ) || !(tm->tm_year % 400)))))
-		return -EINVAL;
+		goto baddate;
 
-	if ((tm->tm_year -= epoch) > 255)
-		return -EINVAL;
-			
+	/* This special check shouldn't fire, it's here to detect a possible invalid
+	 * input which seems to happen to the clock on shutdown (detach?)
+	 */
+	if (tm->tm_year == rtc_epoch && tm->tm_mon == 0 && tm->tm_mday == 0) {
+		printk(KERN_DEBUG "x1205_validate_tm: date is being zapped\n");
+		/* FIXME: this is a hack to test the problem. */
+		tm->tm_year = rtc_epoch+45-epoch;
+		return NOERR;
+
+	baddate:
+		if (datetoo) {
+			printk(KERN_DEBUG "x1205_validate_tm: invalid date:\t%04d,%02d,%02d\n",
+				tm->tm_year, tm->tm_mon, tm->tm_mday);
+			return -EINVAL;
+		} else {
+			/* I believe this case is the one where the kernel crashed
+			 * because tm_mon is large and negative (uninitialised).
+			 */
+			printk(KERN_DEBUG "x1205_validate_tm: unset date:\t%04d,%02d,%02d\n",
+				tm->tm_year, tm->tm_mon, tm->tm_mday);
+		}
+	}
+
+	tm->tm_year -= epoch;
+
+	if ((tm->tm_hour < 0) || (tm->tm_min < 0) || (tm->tm_sec < 0))
+		result = -EINVAL;
 	if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) || (tm->tm_sec >= 60))
-		return -EINVAL;
-	return NOERR;
+		result = -EINVAL;
+
+	if (result == -EINVAL) {
+		printk(KERN_DEBUG "x1205_validate_tm: invalid time:\t%02d,%02d,%02d\n",
+			tm->tm_hour, tm->tm_min, tm->tm_sec);
+	}
+
+	return result;
 }
 
 static int x1205_command(struct i2c_client *client, unsigned int cmd, void *tm)
@@ -378,7 +427,7 @@ static int x1205_command(struct i2c_client *client, unsigned int cmd, void *tm)
 	case RTC_SETTIME:		// note fall thru
 		dodate = RTC_NODATE;
 	case RTC_SETDATETIME:
-		if ((errno = x1205_validate_tm(tm)) < NOERR)
+		if ((errno = x1205_validate_tm(tm, dodate)) < NOERR)
 			return errno;
 		return x1205_set_datetime(client, tm, dodate, X1205_CCR_BASE);
 
@@ -389,33 +438,69 @@ static int x1205_command(struct i2c_client *client, unsigned int cmd, void *tm)
 
 static int x1205_sync_rtc(void)
 {
-	struct rtc_time new_tm, old_tm;
-	unsigned long cur_secs = xtime.tv_sec;
+	/* sync to xtime, tv_nsec is ignored (see the command above about
+	 * use of the truncated value) so this is pretty easy.  kas11's
+	 * code took are to do RTC_SETTIME - i.e. not set the date.  My
+	 * assumption is that this may be because date setting is slow, so
+	 * this feature is retained.  NTP does a sync when the time is
+	 * changed, including significant changes.  The sync needs to
+	 * set the date correctly if necessary.
+	 */
+	struct rtc_time tm;
+	time_t new_s, old_s, div, rem;
+	unsigned int cmd;
 
 	printk(KERN_DEBUG "x1205_sync_rtc entry\n");
 
-	if (x1205_command(&x1205_i2c_client, RTC_GETDATETIME, &old_tm))
-		return 0;
+	{
+		int err = x1205_command(&x1205_i2c_client, RTC_GETDATETIME, &tm);
+		if (err != NOERR) {
+			printk(KERN_DEBUG "x1205_sync_rtc exit (failed to get date)\n");
+			return err;
+		}
+	}
+
+	old_s = mktime(tm.tm_year+epoch, tm.tm_mon+1, tm.tm_mday,
+			tm.tm_hour, tm.tm_min, tm.tm_sec);
+	new_s = xtime.tv_sec;
 
-//	xtime.tv_nsec = old_tm.tm_sec * 10000000;   //FIXME:
-	new_tm.tm_sec  = cur_secs % 60;
-	cur_secs /= 60;
-	new_tm.tm_min  = cur_secs % 60;
-	cur_secs /= 60;
-	new_tm.tm_hour = cur_secs % 24;
-
-	/*
-	 * avoid writing when we're going to change the day
-	 * of the month.  We will retry in the next minute.
-	 * This basically means that if the RTC must not drift
-	 * by more than 1 minute in 11 minutes.
+	/* Optimisation, the clock only stores seconds so it's pointless
+	 * to reset it if it is within 1s of now.
 	 */
-	if ((old_tm.tm_hour == 23 && old_tm.tm_min == 59) ||
-	    (new_tm.tm_hour == 23 && new_tm.tm_min == 59))
+	if (old_s - 1 <= new_s && new_s <= old_s + 1) {
+		printk(KERN_DEBUG "x1205_sync_rtc exit (RTC in sync)\n");
+		return NOERR;
+	}
+
+	div = new_s / 60;
+	tm.tm_sec = new_s - div*60;
+	rem = div;
+	div /= 60;
+	tm.tm_min = rem - div*60;
+	rem = div;
+	div /= 24;
+	tm.tm_hour = rem - div*24;
+
+	/* Now subtract the result from the original 'new' value.  This
+	 * should be zero, if not an mday change is required.  Notice
+	 * that this will tend to fire for small drifts close to UTC midnight.
+	 */
+	cmd = RTC_SETTIME;
+	div = new_s - mktime(tm.tm_year+epoch, tm.tm_mon+1, tm.tm_mday,
+				tm.tm_hour, tm.tm_min, tm.tm_sec);
+	if (div != 0) {
+		/* Convert to days. */
+		printk(KERN_DEBUG "x1205_sync_rtc exit (change tm_mday %d)\n",
+			div);
+		div /= 86400;
+		if (div <= 0) --div;
+		cmd = RTC_SETDATETIME;
 		return 1;
-	printk(KERN_DEBUG "x1205_sync_rtc exit\n");
+	}
+
+	printk(KERN_DEBUG "x1205_sync_rtc exit (change seconds %d)\n", new_s-old_s);
 
-	return x1205_command(&x1205_i2c_client, RTC_SETTIME, &new_tm);
+	return x1205_command(&x1205_i2c_client, cmd, &tm);
 }
 
 static int x1205_read(struct file *file, char *buf, size_t count, loff_t *ptr)
@@ -449,7 +534,7 @@ static int x1205_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 
 		if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time))) 
 			return -EFAULT;
-		if ((errno = x1205_validate_tm(&tm)) < NOERR)
+		if ((errno = x1205_validate_tm(&tm, RTC_DATETOO)) < NOERR)
 			return errno;
 		return x1205_set_datetime(&x1205_i2c_client, &tm, RTC_DATETOO, X1205_CCR_BASE);
 
diff --git a/packages/linux/openslug-kernel_2.6.11.2.bb b/packages/linux/openslug-kernel_2.6.11.2.bb
index b1111180df..0bf4317ec4 100644
--- a/packages/linux/openslug-kernel_2.6.11.2.bb
+++ b/packages/linux/openslug-kernel_2.6.11.2.bb
@@ -2,7 +2,7 @@ SECTION = "kernel"
 DESCRIPTION = "Linux kernel for the Linksys NSLU2 device"
 LICENSE = "GPL"
 MAINTAINER = "Chris Larson <kergoth@handhelds.org>"
-PR = "r7"
+PR = "r8"
 
 KERNEL_SUFFIX = "openslug"