Modified: trunk/drivers/rtc/rtc-bfin.c (3880 => 3881)
--- trunk/drivers/rtc/rtc-bfin.c 2007-11-16 02:11:57 UTC (rev 3880)
+++ trunk/drivers/rtc/rtc-bfin.c 2007-11-16 04:57:56 UTC (rev 3881)
@@ -32,16 +32,16 @@
* writes to clear status registers complete immediately.
*/
-#include <linux/module.h>
-#include <linux/kernel.h>
#include <linux/bcd.h>
-#include <linux/rtc.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
#include <linux/platform_device.h>
+#include <linux/rtc.h>
#include <linux/seq_file.h>
-#include <linux/interrupt.h>
-#include <linux/spinlock.h>
-#include <linux/delay.h>
#include <asm/blackfin.h>
@@ -50,7 +50,7 @@
struct bfin_rtc {
struct rtc_device *rtc_dev;
struct rtc_time rtc_alarm;
- spinlock_t lock;
+ u16 rtc_wrote_regs;
};
/* Bit values for the ISTAT / ICTL registers */
@@ -96,7 +96,10 @@
rtc_time_to_tm(rtc_bfin_to_time(rtc_bfin), tm);
}
-/* Wait for the previous write to a RTC register to complete.
+/**
+ * bfin_rtc_sync_pending - make sure pending writes have complete
+ *
+ * Wait for the previous write to a RTC register to complete.
* Unfortunately, we can't sleep here as that introduces a race condition when
* turning on interrupt events. Consider this:
* - process sets alarm
@@ -117,64 +120,102 @@
* inc rate for all RTC registers from 1HZ to 32.768kHZ ...
* - use the write complete IRQ
*/
-static void rtc_bfin_sync_pending(void)
+/*
+static void bfin_rtc_sync_pending_polled(void)
{
- while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_COMPLETE)) {
+ while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_COMPLETE))
if (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING))
break;
- }
bfin_write_RTC_ISTAT(RTC_ISTAT_WRITE_COMPLETE);
}
+*/
+static DECLARE_COMPLETION(bfin_write_complete);
+static void bfin_rtc_sync_pending(struct device *dev)
+{
+ dev_dbg_stamp(dev);
+ while (bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING)
+ wait_for_completion_timeout(&bfin_write_complete, HZ * 5);
+ dev_dbg_stamp(dev);
+}
-static void rtc_bfin_reset(struct device *dev)
+/**
+ * bfin_rtc_reset - set RTC to sane/known state
+ *
+ * Initialize the RTC. Enable pre-scaler to scale RTC clock
+ * to 1Hz and clear interrupt/status registers.
+ */
+static void bfin_rtc_reset(struct device *dev)
{
struct bfin_rtc *rtc = dev_get_drvdata(dev);
- /* Initialize the RTC. Enable pre-scaler to scale RTC clock
- * to 1Hz and clear interrupt/status registers. */
- spin_lock_irq(&rtc->lock);
- rtc_bfin_sync_pending();
+ dev_dbg_stamp(dev);
+ bfin_rtc_sync_pending(dev);
bfin_write_RTC_PREN(0x1);
- bfin_write_RTC_ICTL(0);
+ bfin_write_RTC_ICTL(RTC_ISTAT_WRITE_COMPLETE);
bfin_write_RTC_SWCNT(0);
bfin_write_RTC_ALARM(0);
bfin_write_RTC_ISTAT(0xFFFF);
- spin_unlock_irq(&rtc->lock);
+ rtc->rtc_wrote_regs = 0;
}
+/**
+ * bfin_rtc_interrupt - handle interrupt from RTC
+ *
+ * Since we handle all RTC events here, we have to make sure the requested
+ * interrupt is enabled (in RTC_ICTL) as the event status register (RTC_ISTAT)
+ * always gets updated regardless of the interrupt being enabled. So when one
+ * even we care about (e.g. stopwatch) goes off, we don't want to turn around
+ * and say that other events have happened as well (e.g. second). We do not
+ * have to worry about pending writes to the RTC_ICTL register as interrupts
+ * only fire if they are enabled in the RTC_ICTL register.
+ */
static irqreturn_t bfin_rtc_interrupt(int irq, void *dev_id)
{
struct device *dev = dev_id;
struct bfin_rtc *rtc = dev_get_drvdata(dev);
unsigned long events = 0;
- u16 rtc_istat;
+ bool write_complete = false;
+ u16 rtc_istat, rtc_ictl;
dev_dbg_stamp(dev);
- spin_lock_irq(&rtc->lock);
-
rtc_istat = bfin_read_RTC_ISTAT();
+ rtc_ictl = bfin_read_RTC_ICTL();
- if (rtc_istat & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) {
- bfin_write_RTC_ISTAT(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY);
- events |= RTC_AF | RTC_IRQF;
+ if (rtc_istat & RTC_ISTAT_WRITE_COMPLETE) {
+ bfin_write_RTC_ISTAT(RTC_ISTAT_WRITE_COMPLETE);
+ write_complete = true;
+ complete(&bfin_write_complete);
}
- if (rtc_istat & RTC_ISTAT_STOPWATCH) {
- bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH);
- events |= RTC_PF | RTC_IRQF;
- bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
+ if (rtc_ictl & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) {
+ if (rtc_istat & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) {
+ bfin_write_RTC_ISTAT(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY);
+ events |= RTC_AF | RTC_IRQF;
+ }
}
- if (rtc_istat & RTC_ISTAT_SEC) {
- bfin_write_RTC_ISTAT(RTC_ISTAT_SEC);
- events |= RTC_UF | RTC_IRQF;
+ if (rtc_ictl & RTC_ISTAT_STOPWATCH) {
+ if (rtc_istat & RTC_ISTAT_STOPWATCH) {
+ bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH);
+ events |= RTC_PF | RTC_IRQF;
+ bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
+ }
}
- rtc_update_irq(rtc->rtc_dev, 1, events);
+ if (rtc_ictl & RTC_ISTAT_SEC) {
+ if (rtc_istat & RTC_ISTAT_SEC) {
+ bfin_write_RTC_ISTAT(RTC_ISTAT_SEC);
+ events |= RTC_UF | RTC_IRQF;
+ }
+ }
- spin_unlock_irq(&rtc->lock);
+ if (events)
+ rtc_update_irq(rtc->rtc_dev, 1, events);
- return IRQ_HANDLED;
+ if (write_complete || events)
+ return IRQ_HANDLED;
+ else
+ return IRQ_NONE;
}
static int bfin_rtc_open(struct device *dev)
@@ -183,21 +224,17 @@
dev_dbg_stamp(dev);
- ret = request_irq(IRQ_RTC, bfin_rtc_interrupt, IRQF_DISABLED, "rtc-bfin", dev);
- if (unlikely(ret)) {
- dev_err(dev, "request RTC IRQ failed with %d\n", ret);
- return ret;
- }
+ ret = request_irq(IRQ_RTC, bfin_rtc_interrupt, IRQF_SHARED, to_platform_device(dev)->name, dev);
+ if (!ret)
+ bfin_rtc_reset(dev);
- rtc_bfin_reset(dev);
-
return ret;
}
static void bfin_rtc_release(struct device *dev)
{
dev_dbg_stamp(dev);
- rtc_bfin_reset(dev);
+ bfin_rtc_reset(dev);
free_irq(IRQ_RTC, dev);
}
@@ -224,8 +261,7 @@
dev_dbg_stamp(dev);
- spin_lock_irq(&rtc->lock);
- rtc_bfin_sync_pending();
+ bfin_rtc_sync_pending(dev);
switch (cmd) {
case RTC_PIE_ON:
@@ -257,11 +293,10 @@
break;
default:
+ dev_dbg_stamp(dev);
ret = -ENOIOCTLCMD;
}
- spin_unlock_irq(&rtc->lock);
-
return ret;
}
@@ -271,10 +306,10 @@
dev_dbg_stamp(dev);
- spin_lock_irq(&rtc->lock);
- rtc_bfin_sync_pending();
+ if (rtc->rtc_wrote_regs & 0x1)
+ bfin_rtc_sync_pending(dev);
+
rtc_bfin_to_tm(bfin_read_RTC_STAT(), tm);
- spin_unlock_irq(&rtc->lock);
return 0;
}
@@ -287,13 +322,13 @@
dev_dbg_stamp(dev);
- spin_lock_irq(&rtc->lock);
ret = rtc_tm_to_time(tm, &now);
if (ret == 0) {
- rtc_bfin_sync_pending();
+ if (rtc->rtc_wrote_regs & 0x1)
+ bfin_rtc_sync_pending(dev);
bfin_write_RTC_STAT(rtc_time_to_bfin(now));
+ rtc->rtc_wrote_regs = 0x1;
}
- spin_unlock_irq(&rtc->lock);
return ret;
}
@@ -303,7 +338,7 @@
struct bfin_rtc *rtc = dev_get_drvdata(dev);
dev_dbg_stamp(dev);
alrm->time = rtc->rtc_alarm;
- rtc_bfin_sync_pending();
+ bfin_rtc_sync_pending(dev);
alrm->enabled = !!(bfin_read_RTC_ICTL() & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY));
return 0;
}
@@ -320,12 +355,10 @@
rtc->rtc_alarm = alrm->time;
- spin_lock_irq(&rtc->lock);
- rtc_bfin_sync_pending();
+ bfin_rtc_sync_pending(dev);
bfin_write_RTC_ALARM(rtc_time_to_bfin(rtc_alarm));
if (alrm->enabled)
bfin_rtc_int_set_alarm(rtc);
- spin_unlock_irq(&rtc->lock);
return 0;
}
@@ -385,8 +418,6 @@
if (unlikely(!rtc))
return -ENOMEM;
- spin_lock_init(&rtc->lock);
-
rtc->rtc_dev = rtc_device_register(pdev->name, &pdev->dev, &bfin_rtc_ops, THIS_MODULE);
if (unlikely(IS_ERR(rtc))) {
ret = PTR_ERR(rtc->rtc_dev);
