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: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

11 files changed, 86 insertions, 2 deletions

diff --git a/arch/mips/ddb5xxx/common/rtc_ds1386.c b/arch/mips/ddb5xxx/common/rtc_ds1386.c
index f5b11508ff2f..995896ac0e39 100644
--- a/arch/mips/ddb5xxx/common/rtc_ds1386.c
+++ b/arch/mips/ddb5xxx/common/rtc_ds1386.c
@@ -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;
 }
diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index dc7091caa7aa..174822344131 100644
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -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;
 }
diff --git a/arch/mips/jmr3927/common/rtc_ds1742.c b/arch/mips/jmr3927/common/rtc_ds1742.c
index 1ae4318e1358..8b407d7dc460 100644
--- a/arch/mips/jmr3927/common/rtc_ds1742.c
+++ b/arch/mips/jmr3927/common/rtc_ds1742.c
@@ -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;
 }
diff --git a/arch/mips/lasat/ds1603.c b/arch/mips/lasat/ds1603.c
index 9d7812e03dcd..7dced67c55eb 100644
--- a/arch/mips/lasat/ds1603.c
+++ b/arch/mips/lasat/ds1603.c
@@ -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;
 }
diff --git a/arch/mips/momentum/jaguar_atx/setup.c b/arch/mips/momentum/jaguar_atx/setup.c
index 768bf4406452..bab192ddc185 100644
--- a/arch/mips/momentum/jaguar_atx/setup.c
+++ b/arch/mips/momentum/jaguar_atx/setup.c
@@ -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;
 }
diff --git a/arch/mips/momentum/ocelot_3/setup.c b/arch/mips/momentum/ocelot_3/setup.c
index a7803e08f9db..c9b7ff8148ec 100644
--- a/arch/mips/momentum/ocelot_3/setup.c
+++ b/arch/mips/momentum/ocelot_3/setup.c
@@ -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;
 }
diff --git a/arch/mips/momentum/ocelot_c/setup.c b/arch/mips/momentum/ocelot_c/setup.c
index ce70fc96f160..2755c1547473 100644
--- a/arch/mips/momentum/ocelot_c/setup.c
+++ b/arch/mips/momentum/ocelot_c/setup.c
@@ -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;
 }
diff --git a/arch/mips/pmc-sierra/yosemite/setup.c b/arch/mips/pmc-sierra/yosemite/setup.c
index bdc2ab55bed6..059755b5ed57 100644
--- a/arch/mips/pmc-sierra/yosemite/setup.c
+++ b/arch/mips/pmc-sierra/yosemite/setup.c
@@ -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;
 }
diff --git a/arch/mips/sgi-ip22/ip22-time.c b/arch/mips/sgi-ip22/ip22-time.c
index df9b5694328a..b7300cc5c5ad 100644
--- a/arch/mips/sgi-ip22/ip22-time.c
+++ b/arch/mips/sgi-ip22/ip22-time.c
@@ -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;
 }
diff --git a/arch/mips/sibyte/swarm/rtc_m41t81.c b/arch/mips/sibyte/swarm/rtc_m41t81.c
index 5b4fc26c1b36..c13914bdda59 100644
--- a/arch/mips/sibyte/swarm/rtc_m41t81.c
+++ b/arch/mips/sibyte/swarm/rtc_m41t81.c
@@ -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);
diff --git a/arch/mips/sibyte/swarm/rtc_xicor1241.c b/arch/mips/sibyte/swarm/rtc_xicor1241.c
index d9ff9323f24e..f4a178836415 100644
--- a/arch/mips/sibyte/swarm/rtc_xicor1241.c
+++ b/arch/mips/sibyte/swarm/rtc_xicor1241.c
@@ -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);