[ 19/64] Revert "drivers/rtc/rtc-at91rm9200.c: use a variable for storing IMR"

From: Greg Kroah-Hartman
Date: Wed Apr 10 2013 - 19:17:57 EST


3.8-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hovold <jhovold@xxxxxxxxx>

commit e24b0bfa2f0446ffaad2661040be23668133aef8 upstream.

This reverts commit 0ef1594c017521ea89278e80fe3f80dafb17abde.

This patch introduced a few races which cannot be easily fixed with a
small follow-up patch. Furthermore, the SoC with the broken hardware
register, which this patch intended to add support for, can only be used
with device trees, which this driver currently does not support.

[ Here is the discussion that led to this "revert" patch:
https://lkml.org/lkml/2013/4/3/176 ]

Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/rtc/rtc-at91rm9200.c | 50 ++++++++++++++++---------------------------
drivers/rtc/rtc-at91rm9200.h | 1
2 files changed, 20 insertions(+), 31 deletions(-)

--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -44,7 +44,6 @@ static DECLARE_COMPLETION(at91_rtc_updat
static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
static void __iomem *at91_rtc_regs;
static int irq;
-static u32 at91_rtc_imr;

/*
* Decode time/date into rtc_time structure
@@ -109,11 +108,9 @@ static int at91_rtc_settime(struct devic
cr = at91_rtc_read(AT91_RTC_CR);
at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);

- at91_rtc_imr |= AT91_RTC_ACKUPD;
at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
- at91_rtc_imr &= ~AT91_RTC_ACKUPD;

at91_rtc_write(AT91_RTC_TIMR,
bin2bcd(tm->tm_sec) << 0
@@ -145,7 +142,7 @@ static int at91_rtc_readalarm(struct dev
tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
tm->tm_year = at91_alarm_year - 1900;

- alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM)
+ alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
? 1 : 0;

pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
@@ -171,7 +168,6 @@ static int at91_rtc_setalarm(struct devi
tm.tm_sec = alrm->time.tm_sec;

at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
- at91_rtc_imr &= ~AT91_RTC_ALARM;
at91_rtc_write(AT91_RTC_TIMALR,
bin2bcd(tm.tm_sec) << 0
| bin2bcd(tm.tm_min) << 8
@@ -184,7 +180,6 @@ static int at91_rtc_setalarm(struct devi

if (alrm->enabled) {
at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
- at91_rtc_imr |= AT91_RTC_ALARM;
at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
}

@@ -201,12 +196,9 @@ static int at91_rtc_alarm_irq_enable(str

if (enabled) {
at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
- at91_rtc_imr |= AT91_RTC_ALARM;
at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
- } else {
+ } else
at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
- at91_rtc_imr &= ~AT91_RTC_ALARM;
- }

return 0;
}
@@ -215,10 +207,12 @@ static int at91_rtc_alarm_irq_enable(str
*/
static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
{
+ unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
+
seq_printf(seq, "update_IRQ\t: %s\n",
- (at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
+ (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
seq_printf(seq, "periodic_IRQ\t: %s\n",
- (at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
+ (imr & AT91_RTC_SECEV) ? "yes" : "no");

return 0;
}
@@ -233,7 +227,7 @@ static irqreturn_t at91_rtc_interrupt(in
unsigned int rtsr;
unsigned long events = 0;

- rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr;
+ rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
if (rtsr) { /* this interrupt is shared! Is it ours? */
if (rtsr & AT91_RTC_ALARM)
events |= (RTC_AF | RTC_IRQF);
@@ -297,7 +291,6 @@ static int __init at91_rtc_probe(struct
at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
AT91_RTC_SECEV | AT91_RTC_TIMEV |
AT91_RTC_CALEV);
- at91_rtc_imr = 0;

ret = request_irq(irq, at91_rtc_interrupt,
IRQF_SHARED,
@@ -337,7 +330,6 @@ static int __exit at91_rtc_remove(struct
at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
AT91_RTC_SECEV | AT91_RTC_TIMEV |
AT91_RTC_CALEV);
- at91_rtc_imr = 0;
free_irq(irq, pdev);

rtc_device_unregister(rtc);
@@ -350,35 +342,31 @@ static int __exit at91_rtc_remove(struct

/* AT91RM9200 RTC Power management control */

-static u32 at91_rtc_bkpimr;
-
+static u32 at91_rtc_imr;

static int at91_rtc_suspend(struct device *dev)
{
/* this IRQ is shared with DBGU and other hardware which isn't
* necessarily doing PM like we are...
*/
- at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
- if (at91_rtc_bkpimr) {
- if (device_may_wakeup(dev)) {
+ at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
+ & (AT91_RTC_ALARM|AT91_RTC_SECEV);
+ if (at91_rtc_imr) {
+ if (device_may_wakeup(dev))
enable_irq_wake(irq);
- } else {
- at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
- at91_rtc_imr &= ~at91_rtc_bkpimr;
- }
-}
+ else
+ at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
+ }
return 0;
}

static int at91_rtc_resume(struct device *dev)
{
- if (at91_rtc_bkpimr) {
- if (device_may_wakeup(dev)) {
+ if (at91_rtc_imr) {
+ if (device_may_wakeup(dev))
disable_irq_wake(irq);
- } else {
- at91_rtc_imr |= at91_rtc_bkpimr;
- at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
- }
+ else
+ at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
}
return 0;
}
--- a/drivers/rtc/rtc-at91rm9200.h
+++ b/drivers/rtc/rtc-at91rm9200.h
@@ -64,6 +64,7 @@
#define AT91_RTC_SCCR 0x1c /* Status Clear Command Register */
#define AT91_RTC_IER 0x20 /* Interrupt Enable Register */
#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
+#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */

#define AT91_RTC_VER 0x2c /* Valid Entry Register */
#define AT91_RTC_NVTIM (1 << 0) /* Non valid Time */


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