[PATCH] ppc64 iSeries: fix boot time setting

For quite a while, there has existed a hypervisor bug on legacy iSeries
which means that we do not get the boot time set in the kernel. This
patch works around that bug. This was most noticable when the root
partition needed to be checked at every boot as the kernel thought it
was some time in 1905 until user mode reset the time correctly.

Signed-off-by: Stephen Rothwell <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/ppc64/kernel/mf.c

···
 /*
   * mf.c
   * Copyright (C) 2001 Troy D. Armstrong  IBM Corporation
-  * Copyright (C) 2004 Stephen Rothwell  IBM Corporation
+  * Copyright (C) 2004-2005 Stephen Rothwell  IBM Corporation
   *
   * This modules exists as an interface between a Linux secondary partition
   * running on an iSeries and the primary partition's Virtual Service
···
 
 #include <asm/time.h>
 #include <asm/uaccess.h>
+#include <asm/paca.h>
 #include <asm/iSeries/vio.h>
 #include <asm/iSeries/mf.h>
 #include <asm/iSeries/HvLpConfig.h>
 #include <asm/iSeries/ItSpCommArea.h>
+#include <asm/iSeries/ItLpQueue.h>
 
 /*
  * This is the structure layout for the Machine Facilites LPAR event
···
 	complete(&rtc->com);
 }
 
-int mf_get_rtc(struct rtc_time *tm)
+static int rtc_set_tm(int rc, u8 *ce_msg, struct rtc_time *tm)
 {
-	struct ce_msg_comp_data ce_complete;
-	struct rtc_time_data rtc_data;
-	int rc;
-
-	memset(&ce_complete, 0, sizeof(ce_complete));
-	memset(&rtc_data, 0, sizeof(rtc_data));
-	init_completion(&rtc_data.com);
-	ce_complete.handler = &get_rtc_time_complete;
-	ce_complete.token = &rtc_data;
-	rc = signal_ce_msg_simple(0x40, &ce_complete);
-	if (rc)
-		return rc;
-	wait_for_completion(&rtc_data.com);
 	tm->tm_wday = 0;
 	tm->tm_yday = 0;
 	tm->tm_isdst = 0;
-	if (rtc_data.rc) {
+	if (rc) {
 		tm->tm_sec = 0;
 		tm->tm_min = 0;
 		tm->tm_hour = 0;
 		tm->tm_mday = 15;
 		tm->tm_mon = 5;
 		tm->tm_year = 52;
-		return rtc_data.rc;
+		return rc;
 	}
 
-	if ((rtc_data.ce_msg.ce_msg[2] == 0xa9) ||
-	    (rtc_data.ce_msg.ce_msg[2] == 0xaf)) {
+	if ((ce_msg[2] == 0xa9) ||
+	    (ce_msg[2] == 0xaf)) {
 		/* TOD clock is not set */
 		tm->tm_sec = 1;
 		tm->tm_min = 1;
···
 		mf_set_rtc(tm);
 	}
 	{
-		u8 *ce_msg = rtc_data.ce_msg.ce_msg;
 		u8 year = ce_msg[5];
 		u8 sec = ce_msg[6];
 		u8 min = ce_msg[7];
···
 	}
 
 	return 0;
+}
+
+int mf_get_rtc(struct rtc_time *tm)
+{
+	struct ce_msg_comp_data ce_complete;
+	struct rtc_time_data rtc_data;
+	int rc;
+
+	memset(&ce_complete, 0, sizeof(ce_complete));
+	memset(&rtc_data, 0, sizeof(rtc_data));
+	init_completion(&rtc_data.com);
+	ce_complete.handler = &get_rtc_time_complete;
+	ce_complete.token = &rtc_data;
+	rc = signal_ce_msg_simple(0x40, &ce_complete);
+	if (rc)
+		return rc;
+	wait_for_completion(&rtc_data.com);
+	return rtc_set_tm(rtc_data.rc, rtc_data.ce_msg.ce_msg, tm);
+}
+
+struct boot_rtc_time_data {
+	int busy;
+	struct ce_msg_data ce_msg;
+	int rc;
+};
+
+static void get_boot_rtc_time_complete(void *token, struct ce_msg_data *ce_msg)
+{
+	struct boot_rtc_time_data *rtc = token;
+
+	memcpy(&rtc->ce_msg, ce_msg, sizeof(rtc->ce_msg));
+	rtc->rc = 0;
+	rtc->busy = 0;
+}
+
+int mf_get_boot_rtc(struct rtc_time *tm)
+{
+	struct ce_msg_comp_data ce_complete;
+	struct boot_rtc_time_data rtc_data;
+	int rc;
+
+	memset(&ce_complete, 0, sizeof(ce_complete));
+	memset(&rtc_data, 0, sizeof(rtc_data));
+	rtc_data.busy = 1;
+	ce_complete.handler = &get_boot_rtc_time_complete;
+	ce_complete.token = &rtc_data;
+	rc = signal_ce_msg_simple(0x40, &ce_complete);
+	if (rc)
+		return rc;
+	/* We need to poll here as we are not yet taking interrupts */
+	while (rtc_data.busy) {
+		extern unsigned long lpevent_count;
+		struct ItLpQueue *lpq = get_paca()->lpqueue_ptr;
+		if (lpq && ItLpQueue_isLpIntPending(lpq))
+			lpevent_count += ItLpQueue_process(lpq, NULL);
+	}
+	return rtc_set_tm(rtc_data.rc, rtc_data.ce_msg.ce_msg, tm);
 }
 
 int mf_set_rtc(struct rtc_time *tm)

arch/ppc64/kernel/rtc.c

···
 
 void iSeries_get_boot_time(struct rtc_time *tm)
 {
-	unsigned long time;
-	static unsigned long lastsec = 1;
-
-	u32 dataWord1 = *((u32 *)(&xSpCommArea.xBcdTimeAtIplStart));
-	u32 dataWord2 = *(((u32 *)&(xSpCommArea.xBcdTimeAtIplStart)) + 1);
-	int year = 1970;
-	int year1 = ( dataWord1 >> 24 ) & 0x000000FF;
-	int year2 = ( dataWord1 >> 16 ) & 0x000000FF;
-	int sec = ( dataWord1 >> 8 ) & 0x000000FF;
-	int min = dataWord1 & 0x000000FF;
-	int hour = ( dataWord2 >> 24 ) & 0x000000FF;
-	int day = ( dataWord2 >> 8 ) & 0x000000FF;
-	int mon = dataWord2 & 0x000000FF;
-
 	if ( piranha_simulator )
 		return;
 
-	BCD_TO_BIN(sec);
-	BCD_TO_BIN(min);
-	BCD_TO_BIN(hour);
-	BCD_TO_BIN(day);
-	BCD_TO_BIN(mon);
-	BCD_TO_BIN(year1);
-	BCD_TO_BIN(year2);
-	year = year1 * 100 + year2;
-
-	time = mktime(year, mon, day, hour, min, sec);
-	time += ( jiffies / HZ );
-
-	/* Now THIS is a nasty hack!
-	* It ensures that the first two calls get different answers.  
-	* That way the loop in init_time (time.c) will not think
-	* the clock is stuck.
-	*/
-	if ( lastsec ) {
-		time -= lastsec;
-		--lastsec;
-	}
-
-	to_tm(time, tm); 
-	tm->tm_year -= 1900;
+	mf_get_boot_rtc(tm);
 	tm->tm_mon  -= 1;
 }
 #endif

include/asm-ppc64/iSeries/mf.h

···
 extern void mf_init(void);
 
 extern int mf_get_rtc(struct rtc_time *tm);
+extern int mf_get_boot_rtc(struct rtc_time *tm);
 extern int mf_set_rtc(struct rtc_time *tm);
 
 #endif /* _ASM_PPC64_ISERIES_MF_H */