[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, 8 insertions, 31 deletions

diff --git a/Documentation/mips/time.README b/Documentation/mips/time.README
index e1304b6bc483..a4ce603ed3b3 100644
--- a/Documentation/mips/time.README
+++ b/Documentation/mips/time.README
@@ -38,19 +38,14 @@ The new time code provide the following services:
 
   a) Implements functions required by Linux common code:
         time_init
-        do_gettimeofday
-        do_settimeofday
 
   b) provides an abstraction of RTC and null RTC implementation as default.
         extern unsigned long (*rtc_get_time)(void);
         extern int (*rtc_set_time)(unsigned long);
 
-  c) a set of gettimeoffset functions for different CPUs and different
-     needs.
-
-  d) high-level and low-level timer interrupt routines where the timer 
-     interrupt source  may or may not be the CPU timer.  The high-level 
-     routine is dispatched through do_IRQ() while the low-level is 
+  c) high-level and low-level timer interrupt routines where the timer
+     interrupt source  may or may not be the CPU timer.  The high-level
+     routine is dispatched through do_IRQ() while the low-level is
      dispatched in assemably code (usually int-handler.S)
 
 
@@ -73,8 +68,7 @@ the following functions or values:
   c) (optional) board-specific RTC routines.
 
   d) (optional) mips_hpt_frequency - It must be definied if the board
-     is using CPU counter for timer interrupt or it is using fixed rate
-     gettimeoffset().
+     is using CPU counter for timer interrupt.
 
 
 PORTING GUIDE
@@ -89,16 +83,6 @@ Step 1: decide how you like to implement the time services.
      If the answer is no, you need a timer to provide the timer interrupt
      at 100 HZ speed.
 
-     You cannot use the fast gettimeoffset functions, i.e.,
-
-        unsigned long fixed_rate_gettimeoffset(void);
-        unsigned long calibrate_div32_gettimeoffset(void);
-        unsigned long calibrate_div64_gettimeoffset(void);
-
-    You can use null_gettimeoffset() will gives the same time resolution as
-    jiffy.  Or you can implement your own gettimeoffset (probably based on 
-    some ad hoc hardware on your machine.)
-
   c) The following sub steps assume your CPU has counter register.
      Do you plan to use the CPU counter register as the timer interrupt
      or use an exnternal timer?
@@ -123,8 +107,8 @@ Step 3: implement rtc routines, board_time_init() and plat_timer_setup()
   board_time_init() -
         a) (optional) set up RTC routines,
         b) (optional) calibrate and set the mips_hpt_frequency
-            (only needed if you intended to use fixed_rate_gettimeoffset
-             or use cpu counter as timer interrupt source)
+            (only needed if you intended to use cpu counter as timer interrupt
+             source)
 
   plat_timer_setup() -
         a) (optional) over-write any choices made above by time_init().
@@ -154,8 +138,8 @@ for some of the functions in time.c.
 For example, you may define your own timer interrupt routine, which does
 some of its own processing and then calls timer_interrupt().
 
-You can also over-ride any of the built-in functions (gettimeoffset,
-RTC routines and/or timer interrupt routine).
+You can also over-ride any of the built-in functions (RTC routines
+and/or timer interrupt routine).
 
 
 PORTING NOTES FOR SMP
@@ -187,10 +171,3 @@ You need to decide on your timer interrupt sources.
 
         You can also do the low-level version of those interrupt routines,
         following similar dispatching routes described above.
-
-Note about do_gettimeoffset():
-
-  It is very likely the CPU counter registers are not sync'ed up in a SMP box.
-  Therefore you cannot really use the many of the existing routines that
-  are based on CPU counter.  You should wirte your own gettimeoffset rouinte
-  if you want intra-jiffy resolution.