[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>

2 files changed, 19 insertions, 42 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;
 }
diff --git a/arch/mips/sibyte/sb1250/time.c b/arch/mips/sibyte/sb1250/time.c
index 0ccf1796dd78..bcb74f2c1948 100644
--- a/arch/mips/sibyte/sb1250/time.c
+++ b/arch/mips/sibyte/sb1250/time.c
@@ -47,15 +47,11 @@
 
 #define SB1250_HPT_NUM          3
 #define SB1250_HPT_VALUE        M_SCD_TIMER_CNT /* max value */
-#define SB1250_HPT_SHIFT        ((sizeof(unsigned int)*8)-V_SCD_TIMER_WIDTH)
 
 
 extern int sb1250_steal_irq(int irq);
 
 static unsigned int sb1250_hpt_read(void);
-static void sb1250_hpt_init(unsigned int);
-
-static unsigned int hpt_offset;
 
 void __init sb1250_hpt_setup(void)
 {
@@ -69,13 +65,9 @@ void __init sb1250_hpt_setup(void)
                 __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
                              IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
 
-                /*
-                 * we need to fill 32 bits, so just use the upper 23 bits and pretend
-                 * the timer is going 512Mhz instead of 1Mhz
-                 */
-                mips_hpt_frequency = V_SCD_TIMER_FREQ << SB1250_HPT_SHIFT;
-                mips_hpt_init = sb1250_hpt_init;
+                mips_hpt_frequency = V_SCD_TIMER_FREQ;
                 mips_hpt_read = sb1250_hpt_read;
+                mips_hpt_mask = M_SCD_TIMER_INIT;
         }
 }
 
@@ -149,11 +141,7 @@ void sb1250_timer_interrupt(void)
 
 /*
  * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
- * again. There's no easy way to set to a specific value so store init value
- * in hpt_offset and subtract each time.
- *
- * Note: Timer isn't full 32bits so shift it into the upper part making
- *       it appear to run at a higher frequency.
+ * again.
  */
 static unsigned int sb1250_hpt_read(void)
 {
@@ -161,13 +149,5 @@ static unsigned int sb1250_hpt_read(void)
 
         count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));
 
-        count = (SB1250_HPT_VALUE - count) << SB1250_HPT_SHIFT;
-
-        return count - hpt_offset;
-}
-
-static void sb1250_hpt_init(unsigned int count)
-{
-        hpt_offset = count;
-        return;
+        return SB1250_HPT_VALUE - count;
 }