[Blackfin] arch: Functional power management support: Add support for cpu frequency scaling

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
This commit is contained in:
Michael Hennerich
2008-04-25 04:58:29 +08:00
committed by Bryan Wu
parent fe44193c55
commit e6c91b64dd
5 changed files with 263 additions and 19 deletions

View File

@@ -6,9 +6,10 @@
* Created:
* Description: This file contains the bfin-specific time handling details.
* Most of the stuff is located in the machine specific files.
* FIXME: (This file is subject for removal)
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
* Copyright 2004-2008 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
@@ -35,6 +36,7 @@
#include <linux/irq.h>
#include <asm/blackfin.h>
#include <asm/time.h>
/* This is an NTP setting */
#define TICK_SIZE (tick_nsec / 1000)
@@ -47,21 +49,6 @@ static struct irqaction bfin_timer_irq = {
.flags = IRQF_DISABLED
};
/*
* The way that the Blackfin core timer works is:
* - CCLK is divided by a programmable 8-bit pre-scaler (TSCALE)
* - Every time TSCALE ticks, a 32bit is counted down (TCOUNT)
*
* If you take the fastest clock (1ns, or 1GHz to make the math work easier)
* 10ms is 10,000,000 clock ticks, which fits easy into a 32-bit counter
* (32 bit counter is 4,294,967,296ns or 4.2 seconds) so, we don't need
* to use TSCALE, and program it to zero (which is pass CCLK through).
* If you feel like using it, try to keep HZ * TIMESCALE to some
* value that divides easy (like power of 2).
*/
#define TIME_SCALE 1
static void
time_sched_init(irq_handler_t timer_routine)
{