linux/arch/arm/plat-omap/common.c
Aaro Koskinen 80ea3bac3a ARM: OMAP: sched_clock() corrected
After my OMAP3 board has been running for a while, I'm seeing weird
latency traces like this:

      sh-1574    0d.h2  153us : do_timer (tick_do_update_jiffies64)
      sh-1574    0d.h2  153us : update_wall_time (do_timer)
      sh-1574    0d.h2  153us!: omap_32k_read (update_wall_time)
      sh-1574    0d.h2 1883us : update_xtime_cache (update_wall_time)
      sh-1574    0d.h2 1883us : clocksource_get_next (update_wall_time)
      sh-1574    0d.h2 1883us+: _spin_lock_irqsave (clocksource_get_next)

and after a while:

      sh-17818   0d.h3  153us : do_timer (tick_do_update_jiffies64)
      sh-17818   0d.h3  153us : update_wall_time (do_timer)
      sh-17818   0d.h3  153us!: omap_32k_read (update_wall_time)
      sh-17818   0d.h3 1915us : update_xtime_cache (update_wall_time)
      sh-17818   0d.h3 1915us+: clocksource_get_next (update_wall_time)
      sh-17818   0d.h3 1945us : _spin_lock_irqsave (clocksource_get_next)

Turns out that sched_clock() is using cyc2ns(), which returns NTP
adjusted time. The sched_clock() frequency should not be adjusted. The
patch deletes omap_32k_ticks_to_nsecs() and rewrites sched_clock()
to do the conversion using the constant multiplier.

Signed-off-by: Aaro Koskinen <Aaro.Koskinen@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-03-04 10:07:41 -08:00

312 lines
7.7 KiB
C

/*
* linux/arch/arm/plat-omap/common.c
*
* Code common to all OMAP machines.
*
* 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.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/pm.h>
#include <linux/console.h>
#include <linux/serial.h>
#include <linux/tty.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/mach/map.h>
#include <asm/setup.h>
#include <mach/common.h>
#include <mach/board.h>
#include <mach/control.h>
#include <mach/mux.h>
#include <mach/fpga.h>
#include <mach/clock.h>
#if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3)
# include "../mach-omap2/sdrc.h"
#endif
#define NO_LENGTH_CHECK 0xffffffff
unsigned char omap_bootloader_tag[512];
int omap_bootloader_tag_len;
struct omap_board_config_kernel *omap_board_config;
int omap_board_config_size;
static const void *get_config(u16 tag, size_t len, int skip, size_t *len_out)
{
struct omap_board_config_kernel *kinfo = NULL;
int i;
#ifdef CONFIG_OMAP_BOOT_TAG
struct omap_board_config_entry *info = NULL;
if (omap_bootloader_tag_len > 4)
info = (struct omap_board_config_entry *) omap_bootloader_tag;
while (info != NULL) {
u8 *next;
if (info->tag == tag) {
if (skip == 0)
break;
skip--;
}
if ((info->len & 0x03) != 0) {
/* We bail out to avoid an alignment fault */
printk(KERN_ERR "OMAP peripheral config: Length (%d) not word-aligned (tag %04x)\n",
info->len, info->tag);
return NULL;
}
next = (u8 *) info + sizeof(*info) + info->len;
if (next >= omap_bootloader_tag + omap_bootloader_tag_len)
info = NULL;
else
info = (struct omap_board_config_entry *) next;
}
if (info != NULL) {
/* Check the length as a lame attempt to check for
* binary inconsistency. */
if (len != NO_LENGTH_CHECK) {
/* Word-align len */
if (len & 0x03)
len = (len + 3) & ~0x03;
if (info->len != len) {
printk(KERN_ERR "OMAP peripheral config: Length mismatch with tag %x (want %d, got %d)\n",
tag, len, info->len);
return NULL;
}
}
if (len_out != NULL)
*len_out = info->len;
return info->data;
}
#endif
/* Try to find the config from the board-specific structures
* in the kernel. */
for (i = 0; i < omap_board_config_size; i++) {
if (omap_board_config[i].tag == tag) {
if (skip == 0) {
kinfo = &omap_board_config[i];
break;
} else {
skip--;
}
}
}
if (kinfo == NULL)
return NULL;
return kinfo->data;
}
const void *__omap_get_config(u16 tag, size_t len, int nr)
{
return get_config(tag, len, nr, NULL);
}
EXPORT_SYMBOL(__omap_get_config);
const void *omap_get_var_config(u16 tag, size_t *len)
{
return get_config(tag, NO_LENGTH_CHECK, 0, len);
}
EXPORT_SYMBOL(omap_get_var_config);
static int __init omap_add_serial_console(void)
{
const struct omap_serial_console_config *con_info;
const struct omap_uart_config *uart_info;
static char speed[11], *opt = NULL;
int line, i, uart_idx;
uart_info = omap_get_config(OMAP_TAG_UART, struct omap_uart_config);
con_info = omap_get_config(OMAP_TAG_SERIAL_CONSOLE,
struct omap_serial_console_config);
if (uart_info == NULL || con_info == NULL)
return 0;
if (con_info->console_uart == 0)
return 0;
if (con_info->console_speed) {
snprintf(speed, sizeof(speed), "%u", con_info->console_speed);
opt = speed;
}
uart_idx = con_info->console_uart - 1;
if (uart_idx >= OMAP_MAX_NR_PORTS) {
printk(KERN_INFO "Console: external UART#%d. "
"Not adding it as console this time.\n",
uart_idx + 1);
return 0;
}
if (!(uart_info->enabled_uarts & (1 << uart_idx))) {
printk(KERN_ERR "Console: Selected UART#%d is "
"not enabled for this platform\n",
uart_idx + 1);
return -1;
}
line = 0;
for (i = 0; i < uart_idx; i++) {
if (uart_info->enabled_uarts & (1 << i))
line++;
}
return add_preferred_console("ttyS", line, opt);
}
console_initcall(omap_add_serial_console);
/*
* 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.
*/
#if defined(CONFIG_ARCH_OMAP16XX)
#define TIMER_32K_SYNCHRONIZED 0xfffbc410
#elif defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
#define TIMER_32K_SYNCHRONIZED (OMAP2_32KSYNCT_BASE + 0x10)
#endif
#ifdef TIMER_32K_SYNCHRONIZED
#include <linux/clocksource.h>
static cycle_t omap_32k_read(void)
{
return omap_readl(TIMER_32K_SYNCHRONIZED);
}
static struct clocksource clocksource_32k = {
.name = "32k_counter",
.rating = 250,
.read = omap_32k_read,
.mask = CLOCKSOURCE_MASK(32),
.shift = 10,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* 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.
*/
unsigned long long sched_clock(void)
{
unsigned long long ret;
ret = (unsigned long long)omap_32k_read();
ret = (ret * clocksource_32k.mult_orig) >> clocksource_32k.shift;
return ret;
}
static 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()) {
struct clk *sync_32k_ick;
sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
if (sync_32k_ick)
clk_enable(sync_32k_ick);
clocksource_32k.mult = clocksource_hz2mult(32768,
clocksource_32k.shift);
if (clocksource_register(&clocksource_32k))
printk(err, clocksource_32k.name);
}
return 0;
}
arch_initcall(omap_init_clocksource_32k);
#endif /* TIMER_32K_SYNCHRONIZED */
/* Global address base setup code */
#if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3)
static struct omap_globals *omap2_globals;
static void __init __omap2_set_globals(void)
{
omap2_set_globals_tap(omap2_globals);
omap2_set_globals_memory(omap2_globals);
omap2_set_globals_control(omap2_globals);
omap2_set_globals_prcm(omap2_globals);
}
#endif
#if defined(CONFIG_ARCH_OMAP2420)
static struct omap_globals omap242x_globals = {
.class = OMAP242X_CLASS,
.tap = OMAP2_IO_ADDRESS(0x48014000),
.sdrc = OMAP2_IO_ADDRESS(OMAP2420_SDRC_BASE),
.sms = OMAP2_IO_ADDRESS(OMAP2420_SMS_BASE),
.ctrl = OMAP2_IO_ADDRESS(OMAP2420_CTRL_BASE),
.prm = OMAP2_IO_ADDRESS(OMAP2420_PRM_BASE),
.cm = OMAP2_IO_ADDRESS(OMAP2420_CM_BASE),
};
void __init omap2_set_globals_242x(void)
{
omap2_globals = &omap242x_globals;
__omap2_set_globals();
}
#endif
#if defined(CONFIG_ARCH_OMAP2430)
static struct omap_globals omap243x_globals = {
.class = OMAP243X_CLASS,
.tap = OMAP2_IO_ADDRESS(0x4900a000),
.sdrc = OMAP2_IO_ADDRESS(OMAP243X_SDRC_BASE),
.sms = OMAP2_IO_ADDRESS(OMAP243X_SMS_BASE),
.ctrl = OMAP2_IO_ADDRESS(OMAP243X_CTRL_BASE),
.prm = OMAP2_IO_ADDRESS(OMAP2430_PRM_BASE),
.cm = OMAP2_IO_ADDRESS(OMAP2430_CM_BASE),
};
void __init omap2_set_globals_243x(void)
{
omap2_globals = &omap243x_globals;
__omap2_set_globals();
}
#endif
#if defined(CONFIG_ARCH_OMAP3430)
static struct omap_globals omap343x_globals = {
.class = OMAP343X_CLASS,
.tap = OMAP2_IO_ADDRESS(0x4830A000),
.sdrc = OMAP2_IO_ADDRESS(OMAP343X_SDRC_BASE),
.sms = OMAP2_IO_ADDRESS(OMAP343X_SMS_BASE),
.ctrl = OMAP2_IO_ADDRESS(OMAP343X_CTRL_BASE),
.prm = OMAP2_IO_ADDRESS(OMAP3430_PRM_BASE),
.cm = OMAP2_IO_ADDRESS(OMAP3430_CM_BASE),
};
void __init omap2_set_globals_343x(void)
{
omap2_globals = &omap343x_globals;
__omap2_set_globals();
}
#endif