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From:   Baolin Wang <baolin.wang@linaro.org>
To:     macro@linux-mips.org, ralf@linux-mips.org, jhogan@kernel.org,
        chenhc@lemote.com
Cc:     kstewart@linuxfoundation.org, gregkh@linuxfoundation.org,
        tglx@linutronix.de, pombredanne@nexb.com, arnd@arndb.de,
        broonie@kernel.org, paul.burton@mips.com, heiko@sntech.de,
        daniel.lezcano@linaro.org, viresh.kumar@linaro.org,
        baolin.wang@linaro.org, linux-mips@linux-mips.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v3 2/2] MIPS: Convert update_persistent_clock() to update_persistent_clock64()
Date:   Mon,  7 May 2018 17:28:28 +0800
Message-Id: <0ca2517277b997bdacf17a4994498f0dc5c2b4ff.1525682212.git.baolin.wang@linaro.org>
In-Reply-To: <c26982955db16b8f790e7f5f2a5b63e42bc78192.1525682212.git.baolin.wang@linaro.org>
References: <c26982955db16b8f790e7f5f2a5b63e42bc78192.1525682212.git.baolin.wang@linaro.org>
In-Reply-To: <c26982955db16b8f790e7f5f2a5b63e42bc78192.1525682212.git.baolin.wang@linaro.org>
References: <c26982955db16b8f790e7f5f2a5b63e42bc78192.1525682212.git.baolin.wang@linaro.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Since struct timespec is not y2038 safe on 32bit machines, this patch
converts update_persistent_clock() to update_persistent_clock64() using
struct timespec64.

The rtc_mips_set_time() and rtc_mips_set_mmss() interfaces were using
'unsigned long' type that is not y2038 safe on 32bit machines, moreover
there is only one platform implementing rtc_mips_set_time() and two
platforms implementing rtc_mips_set_mmss(), so we can just make them each
implement update_persistent_clock64() directly, to get that helper out
of the common mips code by removing rtc_mips_set_time() and
rtc_mips_set_mmss() interfaces.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
Changes since v2:
 - Use div_u64_rem() to calculate the min/sec.
 - Add some comments.

Changes since v1:
 - Remove rtc_mips_set_time() and rtc_mips_set_mmss() interfaces.
---
 arch/mips/dec/time.c                   |    8 ++++----
 arch/mips/include/asm/time.h           |    9 ---------
 arch/mips/kernel/time.c                |   15 ---------------
 arch/mips/lasat/ds1603.c               |    9 +++++++--
 arch/mips/lasat/sysctl.c               |   12 ++++++++++--
 arch/mips/sibyte/swarm/rtc_m41t81.c    |    4 ++--
 arch/mips/sibyte/swarm/rtc_xicor1241.c |    4 ++--
 arch/mips/sibyte/swarm/setup.c         |    8 +++++---
 8 files changed, 30 insertions(+), 39 deletions(-)

diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index 9e992cf..c38686f 100644
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -59,14 +59,15 @@ void read_persistent_clock64(struct timespec64 *ts)
 }
 
 /*
- * In order to set the CMOS clock precisely, rtc_mips_set_mmss has to
+ * In order to set the CMOS clock precisely, update_persistent_clock64 has to
  * be called 500 ms after the second nowtime has started, because when
  * nowtime is written into the registers of the CMOS clock, it will
  * jump to the next second precisely 500 ms later.  Check the Dallas
  * DS1287 data sheet for details.
  */
-int rtc_mips_set_mmss(unsigned long nowtime)
+int update_persistent_clock64(struct timespec64 now)
 {
+	time64_t nowtime = now.tv_sec;
 	int retval = 0;
 	int real_seconds, real_minutes, cmos_minutes;
 	unsigned char save_control, save_freq_select;
@@ -91,8 +92,7 @@ int rtc_mips_set_mmss(unsigned long nowtime)
 	 * messing with unknown time zones but requires your
 	 * RTC not to be off by more than 15 minutes
 	 */
-	real_seconds = nowtime % 60;
-	real_minutes = nowtime / 60;
+	real_minutes = div_s64_rem(nowtime, 60, &real_seconds);
 	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
 		real_minutes += 30;	/* correct for half hour time zone */
 	real_minutes %= 60;
diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h
index 17d4cd2..b85ec64 100644
--- a/arch/mips/include/asm/time.h
+++ b/arch/mips/include/asm/time.h
@@ -22,15 +22,6 @@
 extern spinlock_t rtc_lock;
 
 /*
- * RTC ops.  By default, they point to weak no-op RTC functions.
- *	rtc_mips_set_time - reverse the above translation and set time to RTC.
- *	rtc_mips_set_mmss - similar to rtc_set_time, but only min and sec need
- *			to be set.  Used by RTC sync-up.
- */
-extern int rtc_mips_set_time(unsigned long);
-extern int rtc_mips_set_mmss(unsigned long);
-
-/*
  * board specific routines required by time_init().
  */
 extern void plat_time_init(void);
diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c
index a6ebc81..bfe02de 100644
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -34,21 +34,6 @@
 DEFINE_SPINLOCK(rtc_lock);
 EXPORT_SYMBOL(rtc_lock);
 
-int __weak rtc_mips_set_time(unsigned long sec)
-{
-	return -ENODEV;
-}
-
-int __weak rtc_mips_set_mmss(unsigned long nowtime)
-{
-	return rtc_mips_set_time(nowtime);
-}
-
-int update_persistent_clock(struct timespec now)
-{
-	return rtc_mips_set_mmss(now.tv_sec);
-}
-
 static int null_perf_irq(void)
 {
 	return 0;
diff --git a/arch/mips/lasat/ds1603.c b/arch/mips/lasat/ds1603.c
index d75c887..e6ce39f 100644
--- a/arch/mips/lasat/ds1603.c
+++ b/arch/mips/lasat/ds1603.c
@@ -152,14 +152,19 @@ void read_persistent_clock64(struct timespec64 *ts)
 	ts->tv_nsec = 0;
 }
 
-int rtc_mips_set_mmss(unsigned long time)
+int update_persistent_clock64(struct timespec64 now)
 {
+	time64_t time = now.tv_sec;
 	unsigned long flags;
 
 	spin_lock_irqsave(&rtc_lock, flags);
 	rtc_init_op();
 	rtc_write_byte(SET_TIME_CMD);
-	rtc_write_word(time);
+	/*
+	 * Due to the hardware limitation, we cast to 'unsigned long' type,
+	 * so it will overflow in year 2106 on 32-bit machine.
+	 */
+	rtc_write_word((unsigned long)time);
 	rtc_end_op();
 	spin_unlock_irqrestore(&rtc_lock, flags);
 
diff --git a/arch/mips/lasat/sysctl.c b/arch/mips/lasat/sysctl.c
index 6f74224..ead07c2 100644
--- a/arch/mips/lasat/sysctl.c
+++ b/arch/mips/lasat/sysctl.c
@@ -73,8 +73,16 @@ int proc_dolasatrtc(struct ctl_table *table, int write,
 	if (r)
 		return r;
 
-	if (write)
-		rtc_mips_set_mmss(rtctmp);
+	if (write) {
+		/*
+		 * Due to the RTC hardware limitation, we can not actually
+		 * use the full 64-bit range here.
+		 */
+		ts.tv_sec = rtctmp;
+		ts.tv_nsec = 0;
+
+		update_persistent_clock64(ts);
+	}
 
 	return 0;
 }
diff --git a/arch/mips/sibyte/swarm/rtc_m41t81.c b/arch/mips/sibyte/swarm/rtc_m41t81.c
index aa27a22..4ac8ccd 100644
--- a/arch/mips/sibyte/swarm/rtc_m41t81.c
+++ b/arch/mips/sibyte/swarm/rtc_m41t81.c
@@ -141,13 +141,13 @@ static int m41t81_write(uint8_t addr, int b)
 	return 0;
 }
 
-int m41t81_set_time(unsigned long t)
+int m41t81_set_time(time64_t t)
 {
 	struct rtc_time tm;
 	unsigned long flags;
 
 	/* Note we don't care about the century */
-	rtc_time_to_tm(t, &tm);
+	rtc_time64_to_tm(t, &tm);
 
 	/*
 	 * Note the write order matters as it ensures the correctness.
diff --git a/arch/mips/sibyte/swarm/rtc_xicor1241.c b/arch/mips/sibyte/swarm/rtc_xicor1241.c
index a2121c1..2dcaaa7 100644
--- a/arch/mips/sibyte/swarm/rtc_xicor1241.c
+++ b/arch/mips/sibyte/swarm/rtc_xicor1241.c
@@ -109,13 +109,13 @@ static int xicor_write(uint8_t addr, int b)
 	}
 }
 
-int xicor_set_time(unsigned long t)
+int xicor_set_time(time64_t t)
 {
 	struct rtc_time tm;
 	int tmp;
 	unsigned long flags;
 
-	rtc_time_to_tm(t, &tm);
+	rtc_time64_to_tm(t, &tm);
 	tm.tm_year += 1900;
 
 	spin_lock_irqsave(&rtc_lock, flags);
diff --git a/arch/mips/sibyte/swarm/setup.c b/arch/mips/sibyte/swarm/setup.c
index 7073940..152ca71 100644
--- a/arch/mips/sibyte/swarm/setup.c
+++ b/arch/mips/sibyte/swarm/setup.c
@@ -57,11 +57,11 @@
 #endif
 
 extern int xicor_probe(void);
-extern int xicor_set_time(unsigned long);
+extern int xicor_set_time(time64_t);
 extern time64_t xicor_get_time(void);
 
 extern int m41t81_probe(void);
-extern int m41t81_set_time(unsigned long);
+extern int m41t81_set_time(time64_t);
 extern time64_t m41t81_get_time(void);
 
 const char *get_system_type(void)
@@ -109,8 +109,10 @@ void read_persistent_clock64(struct timespec64 *ts)
 	ts->tv_nsec = 0;
 }
 
-int rtc_mips_set_time(unsigned long sec)
+int update_persistent_clock64(struct timespec64 now)
 {
+	time64_t sec = now.tv_sec;
+
 	switch (swarm_rtc_type) {
 	case RTC_XICOR:
 		return xicor_set_time(sec);
-- 
1.7.9.5