2 files changed, 23 insertions, 26 deletions

diff --git a/drivers/sn/Kconfig b/drivers/sn/Kconfig
index a34731625877..34d4fde51a79 100644
--- a/drivers/sn/Kconfig
+++ b/drivers/sn/Kconfig
@@ -7,16 +7,15 @@ menu "SN Devices"
 
 config SGI_IOC4
         tristate "SGI IOC4 Base IO support"
-        depends on MMTIMER
         default m
         ---help---
-        This option enables basic support for the SGI IOC4-based Base IO
-        controller card.  This option does not enable any specific
-        functions on such a card, but provides necessary infrastructure
-        for other drivers to utilize.
+        This option enables basic support for the IOC4 chip on certain
+        SGI IO controller cards (IO9, IO10, and PCI-RT).  This option
+        does not enable any specific functions on such a card, but provides
+        necessary infrastructure for other drivers to utilize.
 
-        If you have an SGI Altix with an IOC4-based
-        I/O controller say Y.  Otherwise say N.
+        If you have an SGI Altix with an IOC4-based card say Y.
+        Otherwise say N.
 
 config SGI_IOC3
         tristate "SGI IOC3 Base IO support"
diff --git a/drivers/sn/ioc4.c b/drivers/sn/ioc4.c
index 8562821e6498..83d2e90c581c 100644
--- a/drivers/sn/ioc4.c
+++ b/drivers/sn/ioc4.c
@@ -3,7 +3,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2005 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (C) 2005-2006 Silicon Graphics, Inc.  All Rights Reserved.
  */
 
 /* This file contains the master driver module for use by SGI IOC4 subdrivers.
@@ -29,9 +29,9 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/ioc4.h>
-#include <linux/mmtimer.h>
-#include <linux/rtc.h>
+#include <linux/ktime.h>
 #include <linux/mutex.h>
+#include <linux/time.h>
 #include <asm/sn/addrs.h>
 #include <asm/sn/clksupport.h>
 #include <asm/sn/shub_mmr.h>
@@ -43,7 +43,7 @@
 /* Tweakable values */
 
 /* PCI bus speed detection/calibration */
-#define IOC4_CALIBRATE_COUNT 63 /* Calibration cycle period */
+#define IOC4_CALIBRATE_COUNT 63         /* Calibration cycle period */
 #define IOC4_CALIBRATE_CYCLES 256       /* Average over this many cycles */
 #define IOC4_CALIBRATE_DISCARD 2        /* Discard first few cycles */
 #define IOC4_CALIBRATE_LOW_MHZ 25       /* Lower bound on bus speed sanity */
@@ -143,11 +143,11 @@ ioc4_unregister_submodule(struct ioc4_submodule *is)
 static void
 ioc4_clock_calibrate(struct ioc4_driver_data *idd)
 {
-        extern unsigned long sn_rtc_cycles_per_second;
         union ioc4_int_out int_out;
         union ioc4_gpcr gpcr;
         unsigned int state, last_state = 1;
-        uint64_t start = 0, end, period;
+        struct timespec start_ts, end_ts;
+        uint64_t start, end, period;
         unsigned int count = 0;
 
         /* Enable output */
@@ -175,30 +175,28 @@ ioc4_clock_calibrate(struct ioc4_driver_data *idd)
                 if (!last_state && state) {
                         count++;
                         if (count == IOC4_CALIBRATE_END) {
-                                end = rtc_time();
+                                ktime_get_ts(&end_ts);
                                 break;
                         } else if (count == IOC4_CALIBRATE_DISCARD)
-                                start = rtc_time();
+                                ktime_get_ts(&start_ts);
                 }
                 last_state = state;
         } while (1);
 
         /* Calculation rearranged to preserve intermediate precision.
          * Logically:
-         * 1. "end - start" gives us number of RTC cycles over all the
-         *    square wave cycles measured.
-         * 2. Divide by number of square wave cycles to get number of
-         *    RTC cycles per square wave cycle.
+         * 1. "end - start" gives us the measurement period over all
+         *    the square wave cycles.
+         * 2. Divide by number of square wave cycles to get the period
+         *    of a square wave cycle.
          * 3. Divide by 2*(int_out.fields.count+1), which is the formula
          *    by which the IOC4 generates the square wave, to get the
-         *    number of RTC cycles per IOC4 INT_OUT count.
-         * 4. Divide by sn_rtc_cycles_per_second to get seconds per
-         *    count.
-         * 5. Multiply by 1E9 to get nanoseconds per count.
+         *    period of an IOC4 INT_OUT count.
          */
-        period = ((end - start) * 1000000000) /
-            (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1)
-             * sn_rtc_cycles_per_second);
+        end = end_ts.tv_sec * NSEC_PER_SEC + end_ts.tv_nsec;
+        start = start_ts.tv_sec * NSEC_PER_SEC + start_ts.tv_nsec;
+        period = (end - start) /
+                (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
 
         /* Bounds check the result. */
         if (period > IOC4_CALIBRATE_LOW_LIMIT ||