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
......@@ -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;
}
......
......@@ -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;
}
......
......@@ -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;
}
......
......@@ -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;
}
......
......@@ -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;
}
......
......@@ -135,7 +135,9 @@ void setup_wired_tlb_entries(void)
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;
......@@ -152,6 +154,7 @@ 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);
}
......@@ -159,11 +162,13 @@ 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;
......@@ -187,6 +192,7 @@ int m48t37y_set_time(unsigned long sec)
/* disable writing */
rtc_base[0x7ff8] = 0x00;
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
......
......@@ -140,7 +140,9 @@ unsigned long m48t37y_get_time(void)
unsigned char* rtc_base = (unsigned char*)0xfc800000;
#endif
unsigned int year, month, day, hour, min, sec;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
/* stop the update */
rtc_base[0x7ff8] = 0x40;
......@@ -157,6 +159,7 @@ 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);
}
......@@ -169,11 +172,13 @@ int m48t37y_set_time(unsigned long sec)
unsigned char* rtc_base = (unsigned char*)0xfc800000;
#endif
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;
......@@ -197,6 +202,7 @@ int m48t37y_set_time(unsigned long sec)
/* disable writing */
rtc_base[0x7ff8] = 0x00;
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
......
......@@ -73,7 +73,9 @@ void __init bus_error_init(void)
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 to the time */
m48t37_base->control = 0x40;
......@@ -88,6 +90,7 @@ unsigned long m48t37y_get_time(void)
/* Start the update to the time again */
m48t37_base->control = 0x00;
spin_unlock_irqrestore(&rtc_lock, flags);
return mktime(year, month, day, hour, min, sec);
}
......@@ -95,11 +98,13 @@ 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 */
m48t37_base->control = 0x80;
......@@ -123,6 +128,7 @@ int m48t37y_set_time(unsigned long sec)
/* disable writing */
m48t37_base->control = 0x00;
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
......
......@@ -35,7 +35,9 @@ static unsigned long indy_rtc_get_time(void)
{
unsigned int yrs, mon, day, hrs, min, sec;
unsigned int save_control;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;
......@@ -47,6 +49,7 @@ static unsigned long indy_rtc_get_time(void)
yrs = BCD2BIN(hpc3c0->rtcregs[RTC_YEAR] & 0xff);
hpc3c0->rtcregs[RTC_CMD] = save_control;
spin_unlock_irqrestore(&rtc_lock, flags);
if (yrs < 45)
yrs += 30;
......@@ -60,6 +63,7 @@ static int indy_rtc_set_time(unsigned long tim)
{
struct rtc_time tm;
unsigned int save_control;
unsigned long flags;
to_tm(tim, &tm);
......@@ -68,6 +72,7 @@ static int indy_rtc_set_time(unsigned long tim)
if (tm.tm_year >= 100)
tm.tm_year -= 100;
spin_lock_irqsave(&rtc_lock, flags);
save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;
......@@ -80,6 +85,7 @@ static int indy_rtc_set_time(unsigned long tim)
hpc3c0->rtcregs[RTC_HUNDREDTH_SECOND] = 0;
hpc3c0->rtcregs[RTC_CMD] = save_control;
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
......
......@@ -144,6 +144,7 @@ static int m41t81_write(uint8_t addr, int b)
int m41t81_set_time(unsigned long t)
{
struct rtc_time tm;
unsigned long flags;
to_tm(t, &tm);
......@@ -153,6 +154,7 @@ int m41t81_set_time(unsigned long t)
* believe we should finish writing min within a second.
*/
spin_lock_irqsave(&rtc_lock, flags);
tm.tm_sec = BIN2BCD(tm.tm_sec);
m41t81_write(M41T81REG_SC, tm.tm_sec);
......@@ -180,6 +182,7 @@ int m41t81_set_time(unsigned long t)
tm.tm_year %= 100;
tm.tm_year = BIN2BCD(tm.tm_year);
m41t81_write(M41T81REG_YR, tm.tm_year);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
......@@ -187,19 +190,23 @@ int m41t81_set_time(unsigned long t)
unsigned long m41t81_get_time(void)
{
unsigned int year, mon, day, hour, min, sec;
unsigned long flags;
/*
* min is valid if two reads of sec are the same.
*/
for (;;) {
spin_lock_irqsave(&rtc_lock, flags);
sec = m41t81_read(M41T81REG_SC);
min = m41t81_read(M41T81REG_MN);
if (sec == m41t81_read(M41T81REG_SC)) break;
spin_unlock_irqrestore(&rtc_lock, flags);
}
hour = m41t81_read(M41T81REG_HR) & 0x3f;
day = m41t81_read(M41T81REG_DT);
mon = m41t81_read(M41T81REG_MO);
year = m41t81_read(M41T81REG_YR);
spin_unlock_irqrestore(&rtc_lock, flags);
sec = BCD2BIN(sec);
min = BCD2BIN(min);
......
......@@ -113,9 +113,11 @@ int xicor_set_time(unsigned long t)
{
struct rtc_time tm;
int tmp;
unsigned long flags;
to_tm(t, &tm);
spin_lock_irqsave(&rtc_lock, flags);
/* unlock writes to the CCR */
xicor_write(X1241REG_SR, X1241REG_SR_WEL);
xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);
......@@ -160,6 +162,7 @@ int xicor_set_time(unsigned long t)
xicor_write(X1241REG_HR, tmp);
xicor_write(X1241REG_SR, 0);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
......@@ -167,7 +170,9 @@ int xicor_set_time(unsigned long t)
unsigned long xicor_get_time(void)
{
unsigned int year, mon, day, hour, min, sec, y2k;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
sec = xicor_read(X1241REG_SC);
min = xicor_read(X1241REG_MN);
hour = xicor_read(X1241REG_HR);
......@@ -183,6 +188,7 @@ unsigned long xicor_get_time(void)
mon = xicor_read(X1241REG_MO);
year = xicor_read(X1241REG_YR);
y2k = xicor_read(X1241REG_Y2K);
spin_unlock_irqrestore(&rtc_lock, flags);
sec = BCD2BIN(sec);
min = BCD2BIN(min);
......
......@@ -33,7 +33,9 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime)
int real_seconds, real_minutes, cmos_minutes;
unsigned char save_control, save_freq_select;
int retval = 0;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
......@@ -79,14 +81,30 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime)
*/
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
spin_unlock_irqrestore(&rtc_lock, flags);
return retval;
}
/*
* Returns true if a clock update is in progress
*/
static inline unsigned char 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 inline unsigned long mc146818_get_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int i;
unsigned long flags;
/*
* The Linux interpretation of the CMOS clock register contents:
......@@ -97,12 +115,13 @@ static inline unsigned long mc146818_get_cmos_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 (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 (!rtc_is_updating())
break;
spin_lock_irqsave(&rtc_lock, flags);
do { /* Isn't this overkill ? UIP above should guarantee consistency */
sec = CMOS_READ(RTC_SECONDS);
min = CMOS_READ(RTC_MINUTES);
......@@ -120,6 +139,7 @@ static inline unsigned long mc146818_get_cmos_time(void)
BCD_TO_BIN(mon);
BCD_TO_BIN(year);
}
spin_unlock_irqrestore(&rtc_lock, flags);
year = mc146818_decode_year(year);
return mktime(year, mon, day, hour, min, sec);
......
......@@ -20,6 +20,9 @@
#include <linux/linkage.h>
#include <linux/ptrace.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
extern spinlock_t rtc_lock;
/*
* RTC ops. By default, they point to no-RTC functions.
......
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