[PATCH] [RESEND] scsi: ips: fix firmware timestamps for 32-bit

[Arnd Bergmann <arnd@arndb.de>]

do_gettimeofday() is deprecated since it will stop working in 2038 on
32-bit platforms. The firmware interface here actually supports times
until year 25500, so we should use longer timestamps.

Using ktime_get_real_seconds() to get a 64-bit seconds value
and time64_to_tm() to convert it into the right format also has
the advantage of greatly simplifying the time management code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Submitted originally in November 2017. The aacraid@adaptec.com
apparently bounced. Trying again now with a few people on Cc
that previously reviewed patches to this driver.
---
 drivers/scsi/ips.c | 78 +++++++++++-------------------------------------------
 drivers/scsi/ips.h |  2 +-
 2 files changed, 17 insertions(+), 63 deletions(-)

diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c
index 67621308eb9c..887843a465e1 100644
--- a/drivers/scsi/ips.c
+++ b/drivers/scsi/ips.c
@@ -293,7 +293,7 @@ static void ips_freescb(ips_ha_t *, ips_scb_t *);
 static void ips_setup_funclist(ips_ha_t *);
 static void ips_statinit(ips_ha_t *);
 static void ips_statinit_memio(ips_ha_t *);
-static void ips_fix_ffdc_time(ips_ha_t *, ips_scb_t *, time_t);
+static void ips_fix_ffdc_time(ips_ha_t *, ips_scb_t *, time64_t);
 static void ips_ffdc_reset(ips_ha_t *, int);
 static void ips_ffdc_time(ips_ha_t *);
 static uint32_t ips_statupd_copperhead(ips_ha_t *);
@@ -989,10 +989,7 @@ static int __ips_eh_reset(struct scsi_cmnd *SC)
 
 	/* FFDC */
 	if (le32_to_cpu(ha->subsys->param[3]) & 0x300000) {
-		struct timeval tv;
-
-		do_gettimeofday(&tv);
-		ha->last_ffdc = tv.tv_sec;
+		ha->last_ffdc = ktime_get_real_seconds();
 		ha->reset_count++;
 		ips_ffdc_reset(ha, IPS_INTR_IORL);
 	}
@@ -2396,7 +2393,6 @@ static int
 ips_hainit(ips_ha_t * ha)
 {
 	int i;
-	struct timeval tv;
 
 	METHOD_TRACE("ips_hainit", 1);
 
@@ -2411,8 +2407,7 @@ ips_hainit(ips_ha_t * ha)
 
 	/* Send FFDC */
 	ha->reset_count = 1;
-	do_gettimeofday(&tv);
-	ha->last_ffdc = tv.tv_sec;
+	ha->last_ffdc = ktime_get_real_seconds();
 	ips_ffdc_reset(ha, IPS_INTR_IORL);
 
 	if (!ips_read_config(ha, IPS_INTR_IORL)) {
@@ -2552,12 +2547,9 @@ ips_next(ips_ha_t * ha, int intr)
 
 	if ((ha->subsys->param[3] & 0x300000)
 	    && (ha->scb_activelist.count == 0)) {
-		struct timeval tv;
-
-		do_gettimeofday(&tv);
-
-		if (tv.tv_sec - ha->last_ffdc > IPS_SECS_8HOURS) {
-			ha->last_ffdc = tv.tv_sec;
+		time64_t now = ktime_get_real_seconds();
+		if (now - ha->last_ffdc > IPS_SECS_8HOURS) {
+			ha->last_ffdc = now;
 			ips_ffdc_time(ha);
 		}
 	}
@@ -5992,59 +5984,21 @@ ips_ffdc_time(ips_ha_t * ha)
 /*                                                                          */
 /****************************************************************************/
 static void
-ips_fix_ffdc_time(ips_ha_t * ha, ips_scb_t * scb, time_t current_time)
+ips_fix_ffdc_time(ips_ha_t * ha, ips_scb_t * scb, time64_t current_time)
 {
-	long days;
-	long rem;
-	int i;
-	int year;
-	int yleap;
-	int year_lengths[2] = { IPS_DAYS_NORMAL_YEAR, IPS_DAYS_LEAP_YEAR };
-	int month_lengths[12][2] = { {31, 31},
-	{28, 29},
-	{31, 31},
-	{30, 30},
-	{31, 31},
-	{30, 30},
-	{31, 31},
-	{31, 31},
-	{30, 30},
-	{31, 31},
-	{30, 30},
-	{31, 31}
-	};
+	struct tm tm;
 
 	METHOD_TRACE("ips_fix_ffdc_time", 1);
 
-	days = current_time / IPS_SECS_DAY;
-	rem = current_time % IPS_SECS_DAY;
-
-	scb->cmd.ffdc.hour = (rem / IPS_SECS_HOUR);
-	rem = rem % IPS_SECS_HOUR;
-	scb->cmd.ffdc.minute = (rem / IPS_SECS_MIN);
-	scb->cmd.ffdc.second = (rem % IPS_SECS_MIN);
-
-	year = IPS_EPOCH_YEAR;
-	while (days < 0 || days >= year_lengths[yleap = IPS_IS_LEAP_YEAR(year)]) {
-		int newy;
-
-		newy = year + (days / IPS_DAYS_NORMAL_YEAR);
-		if (days < 0)
-			--newy;
-		days -= (newy - year) * IPS_DAYS_NORMAL_YEAR +
-		    IPS_NUM_LEAP_YEARS_THROUGH(newy - 1) -
-		    IPS_NUM_LEAP_YEARS_THROUGH(year - 1);
-		year = newy;
-	}
-
-	scb->cmd.ffdc.yearH = year / 100;
-	scb->cmd.ffdc.yearL = year % 100;
-
-	for (i = 0; days >= month_lengths[i][yleap]; ++i)
-		days -= month_lengths[i][yleap];
+	time64_to_tm(current_time, 0, &tm);
 
-	scb->cmd.ffdc.month = i + 1;
-	scb->cmd.ffdc.day = days + 1;
+	scb->cmd.ffdc.hour   = tm.tm_hour;
+	scb->cmd.ffdc.minute = tm.tm_min;
+	scb->cmd.ffdc.second = tm.tm_sec;
+	scb->cmd.ffdc.yearH  = tm.tm_year / 100 + 1900;
+	scb->cmd.ffdc.yearL  = tm.tm_year % 100;
+	scb->cmd.ffdc.month  = tm.tm_mon + 1;
+	scb->cmd.ffdc.day    = tm.tm_mday;
 }
 
 /****************************************************************************
diff --git a/drivers/scsi/ips.h b/drivers/scsi/ips.h
index 366be3b2f9b4..b43a1ae75660 100644
--- a/drivers/scsi/ips.h
+++ b/drivers/scsi/ips.h
@@ -1054,7 +1054,7 @@ typedef struct ips_ha {
    uint8_t            active;
    int                ioctl_reset;        /* IOCTL Requested Reset Flag */
    uint16_t           reset_count;        /* number of resets           */
-   time_t             last_ffdc;          /* last time we sent ffdc info*/
+   time64_t           last_ffdc;          /* last time we sent ffdc info*/
    uint8_t            slot_num;           /* PCI Slot Number            */
    int                ioctl_len;          /* size of ioctl buffer       */
    dma_addr_t         ioctl_busaddr;      /* dma address of ioctl buffer*/
-- 
2.9.0