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Commit 53c2df2f authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Ralf Baechle
Browse files

Use rtc_lock to protect RTC operations 


    
Many RTC routines were not protected against each other, so there are
potential races, for example, ntp-update against /dev/rtc.  This patch
fixes them using rtc_lock.
    
Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent e329331a

arch/mips/ddb5xxx/common/rtc_ds1386.c

+6 −0
Original line number Diff line number Diff line
@@ -41,7 +41,9 @@ rtc_ds1386_get_time(void) 
	u8 byte;

	u8 temp;

	unsigned int year, month, day, hour, minute, second;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	/* let us freeze external registers */

	byte = READ_RTC(0xB);

	byte &= 0x3f;
@@ -60,6 +62,7 @@ rtc_ds1386_get_time(void) 
	/* enable time transfer */

	byte |= 0x80;

	WRITE_RTC(0xB, byte);

	spin_unlock_irqrestore(&rtc_lock, flags);



	/* calc hour */

	if (temp & 0x40) {
@@ -81,7 +84,9 @@ rtc_ds1386_set_time(unsigned long t) 
	u8 byte;

	u8 temp;

	u8 year, month, day, hour, minute, second;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	/* let us freeze external registers */

	byte = READ_RTC(0xB);

	byte &= 0x3f;
@@ -133,6 +138,7 @@ rtc_ds1386_set_time(unsigned long t) 
	if (second != READ_RTC(0x1)) {

		WRITE_RTC(0x1, second);

	}

	spin_unlock_irqrestore(&rtc_lock, flags);



	return 0;

}

arch/mips/dec/time.c

+22 −2
Original line number Diff line number Diff line
@@ -37,10 +37,25 @@ 
#include <asm/dec/machtype.h>





/*

 * Returns true if a clock update is in progress

 */

static inline unsigned char dec_rtc_is_updating(void)

{

	unsigned char uip;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);

	spin_unlock_irqrestore(&rtc_lock, flags);

	return uip;

}



static unsigned long dec_rtc_get_time(void)

{

	unsigned int year, mon, day, hour, min, sec, real_year;

	int i;

	unsigned long flags;



	/* The Linux interpretation of the DS1287 clock register contents:

	 * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
@@ -49,11 +64,12 @@ static unsigned long dec_rtc_get_time(void) 
	 */

	/* read RTC exactly on falling edge of update flag */

	for (i = 0; i < 1000000; i++)	/* may take up to 1 second... */

		if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)

		if (dec_rtc_is_updating())

			break;

	for (i = 0; i < 1000000; i++)	/* must try at least 2.228 ms */

		if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))

		if (!dec_rtc_is_updating())

			break;

	spin_lock_irqsave(&rtc_lock, flags);

	/* Isn't this overkill?  UIP above should guarantee consistency */

	do {

		sec = CMOS_READ(RTC_SECONDS);
@@ -77,6 +93,7 @@ static unsigned long dec_rtc_get_time(void) 
	 * of unused BBU RAM locations.

	 */

	real_year = CMOS_READ(RTC_DEC_YEAR);

	spin_unlock_irqrestore(&rtc_lock, flags);

	year += real_year - 72 + 2000;



	return mktime(year, mon, day, hour, min, sec);
@@ -95,6 +112,8 @@ static int dec_rtc_set_mmss(unsigned long nowtime) 
	int real_seconds, real_minutes, cmos_minutes;

	unsigned char save_control, save_freq_select;



	/* irq are locally disabled here */

	spin_lock(&rtc_lock);

	/* tell the clock it's being set */

	save_control = CMOS_READ(RTC_CONTROL);

	CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL);
@@ -141,6 +160,7 @@ static int dec_rtc_set_mmss(unsigned long nowtime) 
	 */

	CMOS_WRITE(save_control, RTC_CONTROL);

	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);

	spin_unlock(&rtc_lock);



	return retval;

}

arch/mips/jmr3927/common/rtc_ds1742.c

+6 −0
Original line number Diff line number Diff line
@@ -57,7 +57,9 @@ rtc_ds1742_get_time(void) 
{

	unsigned int year, month, day, hour, minute, second;

	unsigned int century;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	CMOS_WRITE(RTC_READ, RTC_CONTROL);

	second = BCD2BIN(CMOS_READ(RTC_SECONDS) & RTC_SECONDS_MASK);

	minute = BCD2BIN(CMOS_READ(RTC_MINUTES));
@@ -67,6 +69,7 @@ rtc_ds1742_get_time(void) 
	year = BCD2BIN(CMOS_READ(RTC_YEAR));

	century = BCD2BIN(CMOS_READ(RTC_CENTURY) & RTC_CENTURY_MASK);

	CMOS_WRITE(0, RTC_CONTROL);

	spin_unlock_irqrestore(&rtc_lock, flags);



	year += century * 100;
@@ -81,7 +84,9 @@ rtc_ds1742_set_time(unsigned long t) 
	u8 year, month, day, hour, minute, second;

	u8 cmos_year, cmos_month, cmos_day, cmos_hour, cmos_minute, cmos_second;

	int cmos_century;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	CMOS_WRITE(RTC_READ, RTC_CONTROL);

	cmos_second = (u8)(CMOS_READ(RTC_SECONDS) & RTC_SECONDS_MASK);

	cmos_minute = (u8)CMOS_READ(RTC_MINUTES);
@@ -139,6 +144,7 @@ rtc_ds1742_set_time(unsigned long t) 


	/* RTC_CENTURY and RTC_CONTROL share same address... */

	CMOS_WRITE(cmos_century, RTC_CONTROL);

	spin_unlock_irqrestore(&rtc_lock, flags);



	return 0;

}

arch/mips/lasat/ds1603.c

+9 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <asm/lasat/lasat.h>

#include <linux/delay.h>

#include <asm/lasat/ds1603.h>

#include <asm/time.h>



#include "ds1603.h"
@@ -138,19 +139,27 @@ static void rtc_end_op(void) 
unsigned long ds1603_read(void)

{

	unsigned long word;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	rtc_init_op();

	rtc_write_byte(READ_TIME_CMD);

	word = rtc_read_word();

	rtc_end_op();

	spin_unlock_irqrestore(&rtc_lock, flags);

	return word;

}



int ds1603_set(unsigned long time)

{

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	rtc_init_op();

	rtc_write_byte(SET_TIME_CMD);

	rtc_write_word(time);

	rtc_end_op();

	spin_unlock_irqrestore(&rtc_lock, flags);



	return 0;

}

arch/mips/momentum/jaguar_atx/setup.c

+6 −0
Original line number Diff line number Diff line
@@ -149,7 +149,9 @@ arch_initcall(per_cpu_mappings); 
unsigned long m48t37y_get_time(void)

{

	unsigned int year, month, day, hour, min, sec;

	unsigned long flags;



	spin_lock_irqsave(&rtc_lock, flags);

	/* stop the update */

	rtc_base[0x7ff8] = 0x40;
@@ -166,6 +168,7 @@ unsigned long m48t37y_get_time(void) 


	/* start the update */

	rtc_base[0x7ff8] = 0x00;

	spin_unlock_irqrestore(&rtc_lock, flags);



	return mktime(year, month, day, hour, min, sec);

}
@@ -173,11 +176,13 @@ unsigned long m48t37y_get_time(void) 
int m48t37y_set_time(unsigned long sec)

{

	struct rtc_time tm;

	unsigned long flags;



	/* convert to a more useful format -- note months count from 0 */

	to_tm(sec, &tm);

	tm.tm_mon += 1;



	spin_lock_irqsave(&rtc_lock, flags);

	/* enable writing */

	rtc_base[0x7ff8] = 0x80;
@@ -201,6 +206,7 @@ int m48t37y_set_time(unsigned long sec) 


	/* disable writing */

	rtc_base[0x7ff8] = 0x00;

	spin_unlock_irqrestore(&rtc_lock, flags);



	return 0;

}