diff --git a/arch/sparc64/kernel/time.c b/arch/sparc64/kernel/time.c
index 6a717d4d2bc5..c60785c046be 100644
--- a/arch/sparc64/kernel/time.c
+++ b/arch/sparc64/kernel/time.c
@@ -48,7 +48,7 @@
 
 DEFINE_SPINLOCK(mostek_lock);
 DEFINE_SPINLOCK(rtc_lock);
-unsigned long mstk48t02_regs = 0UL;
+void * __iomem mstk48t02_regs = 0UL;
 #ifdef CONFIG_PCI
 unsigned long ds1287_regs = 0UL;
 #endif
@@ -59,8 +59,8 @@ u64 jiffies_64 = INITIAL_JIFFIES;
 
 EXPORT_SYMBOL(jiffies_64);
 
-static unsigned long mstk48t08_regs = 0UL;
-static unsigned long mstk48t59_regs = 0UL;
+static void * __iomem mstk48t08_regs;
+static void * __iomem mstk48t59_regs;
 
 static int set_rtc_mmss(unsigned long);
 
@@ -520,7 +520,7 @@ void timer_tick_interrupt(struct pt_regs *regs)
 /* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */
 static void __init kick_start_clock(void)
 {
-	unsigned long regs = mstk48t02_regs;
+	void * __iomem regs = mstk48t02_regs;
 	u8 sec, tmp;
 	int i, count;
 
@@ -604,7 +604,7 @@ static void __init kick_start_clock(void)
 /* Return nonzero if the clock chip battery is low. */
 static int __init has_low_battery(void)
 {
-	unsigned long regs = mstk48t02_regs;
+	void * __iomem regs = mstk48t02_regs;
 	u8 data1, data2;
 
 	spin_lock_irq(&mostek_lock);
@@ -623,7 +623,7 @@ static int __init has_low_battery(void)
 static void __init set_system_time(void)
 {
 	unsigned int year, mon, day, hour, min, sec;
-	unsigned long mregs = mstk48t02_regs;
+	void * __iomem mregs = mstk48t02_regs;
 #ifdef CONFIG_PCI
 	unsigned long dregs = ds1287_regs;
 #else
@@ -843,7 +843,8 @@ void __init clock_probe(void)
 			    !strcmp(model, "m5823")) {
 				ds1287_regs = edev->resource[0].start;
 			} else {
-				mstk48t59_regs = edev->resource[0].start;
+				mstk48t59_regs = (void * __iomem)
+					edev->resource[0].start;
 				mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
 			}
 			break;
@@ -865,7 +866,8 @@ try_isa_clock:
 			    !strcmp(model, "m5823")) {
 				ds1287_regs = isadev->resource.start;
 			} else {
-				mstk48t59_regs = isadev->resource.start;
+				mstk48t59_regs = (void * __iomem)
+					isadev->resource.start;
 				mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
 			}
 			break;
@@ -893,21 +895,24 @@ try_isa_clock:
 		}
 
 		if(model[5] == '0' && model[6] == '2') {
-			mstk48t02_regs = (((u64)clk_reg[0].phys_addr) |
-					  (((u64)clk_reg[0].which_io)<<32UL));
+			mstk48t02_regs = (void * __iomem)
+				(((u64)clk_reg[0].phys_addr) |
+				 (((u64)clk_reg[0].which_io)<<32UL));
 		} else if(model[5] == '0' && model[6] == '8') {
-			mstk48t08_regs = (((u64)clk_reg[0].phys_addr) |
-					  (((u64)clk_reg[0].which_io)<<32UL));
+			mstk48t08_regs = (void * __iomem)
+				(((u64)clk_reg[0].phys_addr) |
+				 (((u64)clk_reg[0].which_io)<<32UL));
 			mstk48t02_regs = mstk48t08_regs + MOSTEK_48T08_48T02;
 		} else {
-			mstk48t59_regs = (((u64)clk_reg[0].phys_addr) |
-					  (((u64)clk_reg[0].which_io)<<32UL));
+			mstk48t59_regs = (void * __iomem)
+				(((u64)clk_reg[0].phys_addr) |
+				 (((u64)clk_reg[0].which_io)<<32UL));
 			mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
 		}
 		break;
 	}
 
-	if (mstk48t02_regs != 0UL) {
+	if (mstk48t02_regs != NULL) {
 		/* Report a low battery voltage condition. */
 		if (has_low_battery())
 			prom_printf("NVRAM: Low battery voltage!\n");
@@ -1087,7 +1092,7 @@ unsigned long long sched_clock(void)
 static int set_rtc_mmss(unsigned long nowtime)
 {
 	int real_seconds, real_minutes, chip_minutes;
-	unsigned long mregs = mstk48t02_regs;
+	void * __iomem mregs = mstk48t02_regs;
 #ifdef CONFIG_PCI
 	unsigned long dregs = ds1287_regs;
 #else
diff --git a/drivers/sbus/char/rtc.c b/drivers/sbus/char/rtc.c
index bf3273eb1c8b..49d1cd99d5ac 100644
--- a/drivers/sbus/char/rtc.c
+++ b/drivers/sbus/char/rtc.c
@@ -28,6 +28,42 @@
 
 static int rtc_busy = 0;
 
+/* This is the structure layout used by drivers/char/rtc.c, we
+ * support that driver's ioctls so that things are less messy in
+ * userspace.
+ */
+struct rtc_time_generic {
+	int tm_sec;
+	int tm_min;
+	int tm_hour;
+	int tm_mday;
+	int tm_mon;
+	int tm_year;
+	int tm_wday;
+	int tm_yday;
+	int tm_isdst;
+};
+#define RTC_AIE_ON	_IO('p', 0x01)	/* Alarm int. enable on		*/
+#define RTC_AIE_OFF	_IO('p', 0x02)	/* ... off			*/
+#define RTC_UIE_ON	_IO('p', 0x03)	/* Update int. enable on	*/
+#define RTC_UIE_OFF	_IO('p', 0x04)	/* ... off			*/
+#define RTC_PIE_ON	_IO('p', 0x05)	/* Periodic int. enable on	*/
+#define RTC_PIE_OFF	_IO('p', 0x06)	/* ... off			*/
+#define RTC_WIE_ON	_IO('p', 0x0f)  /* Watchdog int. enable on	*/
+#define RTC_WIE_OFF	_IO('p', 0x10)  /* ... off			*/
+#define RTC_RD_TIME	_IOR('p', 0x09, struct rtc_time_generic) /* Read RTC time   */
+#define RTC_SET_TIME	_IOW('p', 0x0a, struct rtc_time_generic) /* Set RTC time    */
+#define RTC_ALM_SET	_IOW('p', 0x07, struct rtc_time) /* Set alarm time  */
+#define RTC_ALM_READ	_IOR('p', 0x08, struct rtc_time) /* Read alarm time */
+#define RTC_IRQP_READ	_IOR('p', 0x0b, unsigned long)	 /* Read IRQ rate   */
+#define RTC_IRQP_SET	_IOW('p', 0x0c, unsigned long)	 /* Set IRQ rate    */
+#define RTC_EPOCH_READ	_IOR('p', 0x0d, unsigned long)	 /* Read epoch      */
+#define RTC_EPOCH_SET	_IOW('p', 0x0e, unsigned long)	 /* Set epoch       */
+#define RTC_WKALM_SET	_IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/
+#define RTC_WKALM_RD	_IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/
+#define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
+#define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */
+
 /* Retrieve the current date and time from the real time clock. */
 static void get_rtc_time(struct rtc_time *t)
 {
@@ -82,29 +118,87 @@ void set_rtc_time(struct rtc_time *t)
 	spin_unlock_irq(&mostek_lock);
 }
 
+static int put_rtc_time_generic(void __user *argp, struct rtc_time *tm)
+{
+	struct rtc_time_generic __user *utm = argp;
+
+	if (__put_user(tm->sec, &utm->tm_sec) ||
+	    __put_user(tm->min, &utm->tm_min) ||
+	    __put_user(tm->hour, &utm->tm_hour) ||
+	    __put_user(tm->dom, &utm->tm_mday) ||
+	    __put_user(tm->month, &utm->tm_mon) ||
+	    __put_user(tm->year, &utm->tm_year) ||
+	    __put_user(tm->dow, &utm->tm_wday) ||
+	    __put_user(0, &utm->tm_yday) ||
+	    __put_user(0, &utm->tm_isdst))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int get_rtc_time_generic(struct rtc_time *tm, void __user *argp)
+{
+	struct rtc_time_generic __user *utm = argp;
+
+	if (__get_user(tm->sec, &utm->tm_sec) ||
+	    __get_user(tm->min, &utm->tm_min) ||
+	    __get_user(tm->hour, &utm->tm_hour) ||
+	    __get_user(tm->dom, &utm->tm_mday) ||
+	    __get_user(tm->month, &utm->tm_mon) ||
+	    __get_user(tm->year, &utm->tm_year) ||
+	    __get_user(tm->dow, &utm->tm_wday))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	unsigned long arg)
 {
 	struct rtc_time rtc_tm;
 	void __user *argp = (void __user *)arg;
 
-	switch (cmd)
-	{
+	switch (cmd) {
+	/* No interrupt support, return an error
+	 * compatible with drivers/char/rtc.c
+	 */
+	case RTC_AIE_OFF:
+	case RTC_AIE_ON:
+	case RTC_PIE_OFF:
+	case RTC_PIE_ON:
+	case RTC_UIE_OFF:
+	case RTC_UIE_ON:
+	case RTC_IRQP_READ:
+	case RTC_IRQP_SET:
+	case RTC_EPOCH_SET:
+	case RTC_EPOCH_READ:
+		return -EINVAL;
+
 	case RTCGET:
+	case RTC_RD_TIME:
 		memset(&rtc_tm, 0, sizeof(struct rtc_time));
 		get_rtc_time(&rtc_tm);
 
-		if (copy_to_user(argp, &rtc_tm, sizeof(struct rtc_time)))
+		if (cmd == RTCGET) {
+			if (copy_to_user(argp, &rtc_tm,
+					 sizeof(struct rtc_time)))
+				return -EFAULT;
+		} else if (put_rtc_time_generic(argp, &rtc_tm))
 			return -EFAULT;
 
 		return 0;
 
 
 	case RTCSET:
+	case RTC_SET_TIME:
 		if (!capable(CAP_SYS_TIME))
 			return -EPERM;
 
-		if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
+		if (cmd == RTCSET) {
+			if (copy_from_user(&rtc_tm, argp,
+					   sizeof(struct rtc_time)))
+				return -EFAULT;
+		} else if (get_rtc_time_generic(&rtc_tm, argp))
 			return -EFAULT;
 
 		set_rtc_time(&rtc_tm);
@@ -164,6 +258,7 @@ static int __init rtc_sun_init(void)
 		printk(KERN_ERR "rtc: unable to get misc minor for Mostek\n");
 		return error;
 	}
+	printk("rtc_sun_init: Registered Mostek RTC driver.\n");
 
 	return 0;
 }
diff --git a/include/asm-sparc64/mostek.h b/include/asm-sparc64/mostek.h
index ccf2f5f82d7f..1f9b1356a48e 100644
--- a/include/asm-sparc64/mostek.h
+++ b/include/asm-sparc64/mostek.h
@@ -38,7 +38,7 @@
  *
  * We now deal with physical addresses for I/O to the chip. -DaveM
  */
-static __inline__ u8 mostek_read(unsigned long addr)
+static __inline__ u8 mostek_read(void * __iomem addr)
 {
 	u8 ret;
 
@@ -48,7 +48,7 @@ static __inline__ u8 mostek_read(unsigned long addr)
 	return ret;
 }
 
-static __inline__ void mostek_write(unsigned long addr, u8 val)
+static __inline__ void mostek_write(void * __iomem addr, u8 val)
 {
 	__asm__ __volatile__("stba	%0, [%1] %2"
 			     : /* no outputs */
@@ -67,7 +67,7 @@ static __inline__ void mostek_write(unsigned long addr, u8 val)
 #define MOSTEK_YEAR		0x07ffUL
 
 extern spinlock_t mostek_lock;
-extern unsigned long mstk48t02_regs;
+extern void *__iomem mstk48t02_regs;
 
 /* Control register values. */
 #define	MSTK_CREG_WRITE	0x80	/* Must set this before placing values. */