mirror of
https://github.com/torvalds/linux.git
synced 2024-12-21 18:42:44 +00:00
354a183f53
clocksource support. This achieves several things: 1. It means we get rid of all these helper functions which frankly should never have been necessary. 2. It means omap_readl() inside these helper functions does not appear in ftrace output. Another plus is that we avoid the overhead of calculating the address to read each time, but a minus is that we use readl() which has a barrier. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> [tony@atomide.com: updated to use ioremap] Signed-off-by: Tony Lindgren <tony@atomide.com>
155 lines
4.2 KiB
C
155 lines
4.2 KiB
C
/*
|
|
* OMAP 32ksynctimer/counter_32k-related code
|
|
*
|
|
* Copyright (C) 2009 Texas Instruments
|
|
* Copyright (C) 2010 Nokia Corporation
|
|
* Tony Lindgren <tony@atomide.com>
|
|
* Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* NOTE: This timer is not the same timer as the old OMAP1 MPU timer.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/err.h>
|
|
#include <linux/io.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/clocksource.h>
|
|
|
|
#include <asm/sched_clock.h>
|
|
|
|
#include <plat/common.h>
|
|
#include <plat/board.h>
|
|
|
|
#include <plat/clock.h>
|
|
|
|
/*
|
|
* 32KHz clocksource ... always available, on pretty most chips except
|
|
* OMAP 730 and 1510. Other timers could be used as clocksources, with
|
|
* higher resolution in free-running counter modes (e.g. 12 MHz xtal),
|
|
* but systems won't necessarily want to spend resources that way.
|
|
*/
|
|
static void __iomem *timer_32k_base;
|
|
|
|
#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410
|
|
|
|
/*
|
|
* Returns current time from boot in nsecs. It's OK for this to wrap
|
|
* around for now, as it's just a relative time stamp.
|
|
*/
|
|
static DEFINE_CLOCK_DATA(cd);
|
|
|
|
/*
|
|
* Constants generated by clocks_calc_mult_shift(m, s, 32768, NSEC_PER_SEC, 60).
|
|
* This gives a resolution of about 30us and a wrap period of about 36hrs.
|
|
*/
|
|
#define SC_MULT 4000000000u
|
|
#define SC_SHIFT 17
|
|
|
|
static inline unsigned long long notrace _omap_32k_sched_clock(void)
|
|
{
|
|
u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
|
|
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
|
|
}
|
|
|
|
#if defined(CONFIG_OMAP_32K_TIMER) && !defined(CONFIG_OMAP_MPU_TIMER)
|
|
unsigned long long notrace sched_clock(void)
|
|
{
|
|
return _omap_32k_sched_clock();
|
|
}
|
|
#else
|
|
unsigned long long notrace omap_32k_sched_clock(void)
|
|
{
|
|
return _omap_32k_sched_clock();
|
|
}
|
|
#endif
|
|
|
|
static void notrace omap_update_sched_clock(void)
|
|
{
|
|
u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
|
|
update_sched_clock(&cd, cyc, (u32)~0);
|
|
}
|
|
|
|
/**
|
|
* read_persistent_clock - Return time from a persistent clock.
|
|
*
|
|
* Reads the time from a source which isn't disabled during PM, the
|
|
* 32k sync timer. Convert the cycles elapsed since last read into
|
|
* nsecs and adds to a monotonically increasing timespec.
|
|
*/
|
|
static struct timespec persistent_ts;
|
|
static cycles_t cycles, last_cycles;
|
|
static unsigned int persistent_mult, persistent_shift;
|
|
void read_persistent_clock(struct timespec *ts)
|
|
{
|
|
unsigned long long nsecs;
|
|
cycles_t delta;
|
|
struct timespec *tsp = &persistent_ts;
|
|
|
|
last_cycles = cycles;
|
|
cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
|
|
delta = cycles - last_cycles;
|
|
|
|
nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift);
|
|
|
|
timespec_add_ns(tsp, nsecs);
|
|
*ts = *tsp;
|
|
}
|
|
|
|
int __init omap_init_clocksource_32k(void)
|
|
{
|
|
static char err[] __initdata = KERN_ERR
|
|
"%s: can't register clocksource!\n";
|
|
|
|
if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
|
|
u32 pbase;
|
|
unsigned long size = SZ_4K;
|
|
void __iomem *base;
|
|
struct clk *sync_32k_ick;
|
|
|
|
if (cpu_is_omap16xx()) {
|
|
pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
|
|
size = SZ_1K;
|
|
} else if (cpu_is_omap2420())
|
|
pbase = OMAP2420_32KSYNCT_BASE + 0x10;
|
|
else if (cpu_is_omap2430())
|
|
pbase = OMAP2430_32KSYNCT_BASE + 0x10;
|
|
else if (cpu_is_omap34xx())
|
|
pbase = OMAP3430_32KSYNCT_BASE + 0x10;
|
|
else if (cpu_is_omap44xx())
|
|
pbase = OMAP4430_32KSYNCT_BASE + 0x10;
|
|
else
|
|
return -ENODEV;
|
|
|
|
/* For this to work we must have a static mapping in io.c for this area */
|
|
base = ioremap(pbase, size);
|
|
if (!base)
|
|
return -ENODEV;
|
|
|
|
sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
|
|
if (!IS_ERR(sync_32k_ick))
|
|
clk_enable(sync_32k_ick);
|
|
|
|
timer_32k_base = base;
|
|
|
|
/*
|
|
* 120000 rough estimate from the calculations in
|
|
* __clocksource_updatefreq_scale.
|
|
*/
|
|
clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
|
|
32768, NSEC_PER_SEC, 120000);
|
|
|
|
if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
|
|
clocksource_mmio_readl_up))
|
|
printk(err, "32k_counter");
|
|
|
|
init_fixed_sched_clock(&cd, omap_update_sched_clock, 32,
|
|
32768, SC_MULT, SC_SHIFT);
|
|
}
|
|
return 0;
|
|
}
|