[MIPS] Fixup migration to GENERIC_TIME

Since we already moved to GENERIC_TIME, we should implement alternatives
of old do_gettimeoffset routines to get sub-jiffies resolution from
gettimeofday().  This patch includes:

 * MIPS clocksource support (based on works by Manish Lachwani).
 * remove unused gettimeoffset routines and related codes.
 * remove unised 64bit do_div64_32().
 * simplify mips_hpt_init. (no argument needed, __init tag)
 * simplify c0_hpt_timer_init. (no need to write to c0_count)
 * remove some hpt_init routines.
 * mips_hpt_mask variable to specify bitmask of hpt value.
 * convert jmr3927_do_gettimeoffset to jmr3927_hpt_read.
 * convert ip27_do_gettimeoffset to ip27_hpt_read.
 * convert bcm1480_do_gettimeoffset to bcm1480_hpt_read.
 * simplify sb1250 hpt functions. (no need to subtract and shift)
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 15 insertions, 18 deletions

diff --git a/arch/mips/sibyte/bcm1480/time.c b/arch/mips/sibyte/bcm1480/time.c
index bf12af46132e..e136bde5248e 100644
--- a/arch/mips/sibyte/bcm1480/time.c
+++ b/arch/mips/sibyte/bcm1480/time.c
@@ -47,6 +47,12 @@
 #define IMR_IP3_VAL     K_BCM1480_INT_MAP_I1
 #define IMR_IP4_VAL     K_BCM1480_INT_MAP_I2
 
+#ifdef CONFIG_SIMULATION
+#define BCM1480_HPT_VALUE       50000
+#else
+#define BCM1480_HPT_VALUE       1000000
+#endif
+
 extern int bcm1480_steal_irq(int irq);
 
 void bcm1480_time_init(void)
@@ -59,11 +65,6 @@ void bcm1480_time_init(void)
                 BUG();
         }
 
-        if (!cpu) {
-                /* Use our own gettimeoffset() routine */
-                do_gettimeoffset = bcm1480_gettimeoffset;
-        }
-
         bcm1480_mask_irq(cpu, irq);
 
         /* Map the timer interrupt to ip[4] of this cpu */
@@ -74,11 +75,7 @@ void bcm1480_time_init(void)
         /* Disable the timer and set up the count */
         __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
         __raw_writeq(
-#ifndef CONFIG_SIMULATION
-                1000000/HZ
-#else
-                50000/HZ
-#endif
+                BCM1480_HPT_VALUE/HZ
                 , IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
 
         /* Set the timer running */
@@ -122,16 +119,16 @@ void bcm1480_timer_interrupt(void)
         }
 }
 
-/*
- * We use our own do_gettimeoffset() instead of the generic one,
- * because the generic one does not work for SMP case.
- * In addition, since we use general timer 0 for system time,
- * we can get accurate intra-jiffy offset without calibration.
- */
-unsigned long bcm1480_gettimeoffset(void)
+static unsigned int bcm1480_hpt_read(void)
 {
+        /* We assume this function is called xtime_lock held. */
         unsigned long count =
                 __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
+        return (jiffies + 1) * (BCM1480_HPT_VALUE / HZ) - count;
+}
 
-        return 1000000/HZ - count;
+void __init bcm1480_hpt_setup(void)
+{
+        mips_hpt_read = bcm1480_hpt_read;
+        mips_hpt_frequency = BCM1480_HPT_VALUE;
 }