diff options
Diffstat (limited to 'arch/ppc/kernel/smp-tbsync.c')
-rw-r--r-- | arch/ppc/kernel/smp-tbsync.c | 180 |
1 files changed, 0 insertions, 180 deletions
diff --git a/arch/ppc/kernel/smp-tbsync.c b/arch/ppc/kernel/smp-tbsync.c deleted file mode 100644 index d0cf3f8..0000000 --- a/arch/ppc/kernel/smp-tbsync.c +++ /dev/null @@ -1,180 +0,0 @@ -/* - * Smp timebase synchronization for ppc. - * - * Copyright (C) 2003 Samuel Rydh (samuel@ibrium.se) - * - */ - -#include <linux/kernel.h> -#include <linux/sched.h> -#include <linux/smp.h> -#include <linux/unistd.h> -#include <linux/init.h> -#include <asm/atomic.h> -#include <asm/smp.h> -#include <asm/time.h> - -#define NUM_ITER 300 - -enum { - kExit=0, kSetAndTest, kTest -}; - -static struct { - volatile int tbu; - volatile int tbl; - volatile int mark; - volatile int cmd; - volatile int handshake; - int filler[3]; - - volatile int ack; - int filler2[7]; - - volatile int race_result; -} *tbsync; - -static volatile int running; - -static void __devinit -enter_contest( int mark, int add ) -{ - while( (int)(get_tbl() - mark) < 0 ) - tbsync->race_result = add; -} - -void __devinit -smp_generic_take_timebase( void ) -{ - int cmd, tbl, tbu; - unsigned long flags; - - local_irq_save(flags); - while( !running ) - ; - rmb(); - - for( ;; ) { - tbsync->ack = 1; - while( !tbsync->handshake ) - ; - rmb(); - - cmd = tbsync->cmd; - tbl = tbsync->tbl; - tbu = tbsync->tbu; - tbsync->ack = 0; - if( cmd == kExit ) - break; - - if( cmd == kSetAndTest ) { - while( tbsync->handshake ) - ; - asm volatile ("mttbl %0" :: "r" (tbl) ); - asm volatile ("mttbu %0" :: "r" (tbu) ); - } else { - while( tbsync->handshake ) - ; - } - enter_contest( tbsync->mark, -1 ); - } - local_irq_restore(flags); -} - -static int __devinit -start_contest( int cmd, int offset, int num ) -{ - int i, tbu, tbl, mark, score=0; - - tbsync->cmd = cmd; - - local_irq_disable(); - for( i=-3; i<num; ) { - tbl = get_tbl() + 400; - tbsync->tbu = tbu = get_tbu(); - tbsync->tbl = tbl + offset; - tbsync->mark = mark = tbl + 400; - - wmb(); - - tbsync->handshake = 1; - while( tbsync->ack ) - ; - - while( (int)(get_tbl() - tbl) <= 0 ) - ; - tbsync->handshake = 0; - enter_contest( mark, 1 ); - - while( !tbsync->ack ) - ; - - if( tbsync->tbu != get_tbu() || ((tbsync->tbl ^ get_tbl()) & 0x80000000) ) - continue; - if( i++ > 0 ) - score += tbsync->race_result; - } - local_irq_enable(); - return score; -} - -void __devinit -smp_generic_give_timebase( void ) -{ - int i, score, score2, old, min=0, max=5000, offset=1000; - - printk("Synchronizing timebase\n"); - - /* if this fails then this kernel won't work anyway... */ - tbsync = kzalloc( sizeof(*tbsync), GFP_KERNEL ); - mb(); - running = 1; - - while( !tbsync->ack ) - ; - - /* binary search */ - for( old=-1 ; old != offset ; offset=(min+max)/2 ) { - score = start_contest( kSetAndTest, offset, NUM_ITER ); - - printk("score %d, offset %d\n", score, offset ); - - if( score > 0 ) - max = offset; - else - min = offset; - old = offset; - } - score = start_contest( kSetAndTest, min, NUM_ITER ); - score2 = start_contest( kSetAndTest, max, NUM_ITER ); - - printk( "Min %d (score %d), Max %d (score %d)\n", min, score, max, score2 ); - score = abs( score ); - score2 = abs( score2 ); - offset = (score < score2) ? min : max; - - /* guard against inaccurate mttb */ - for( i=0; i<10; i++ ) { - start_contest( kSetAndTest, offset, NUM_ITER/10 ); - - if( (score2=start_contest(kTest, offset, NUM_ITER)) < 0 ) - score2 = -score2; - if( score2 <= score || score2 < 20 ) - break; - } - printk("Final offset: %d (%d/%d)\n", offset, score2, NUM_ITER ); - - /* exiting */ - tbsync->cmd = kExit; - wmb(); - tbsync->handshake = 1; - while( tbsync->ack ) - ; - tbsync->handshake = 0; - kfree( tbsync ); - tbsync = NULL; - running = 0; - - /* all done */ - smp_tb_synchronized = 1; -} |