linux/arch/arm/mach-omap2/timer.c
Rajendra Nayak 5b5c013591 ARM: OMAP2+: AM43x: Use gptimer as clocksource
The SyncTimer in AM43x is clocked using the following two sources:
1) An inaccuarte 32k clock (CLK_32KHZ) derived from PER DPLL, causing system
   time to go slowly (~10% deviation).
2) external 32KHz RTC clock, which may not always be available on board like
   in the case of ePOS EVM

Use gptimer as clocksource instead, as is done in the case of AM335x
(which does not have a SyncTimer). With this, system time keeping works
accurately.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2014-02-28 15:33:27 -08:00

771 lines
20 KiB
C

/*
* linux/arch/arm/mach-omap2/timer.c
*
* OMAP2 GP timer support.
*
* Copyright (C) 2009 Nokia Corporation
*
* Update to use new clocksource/clockevent layers
* Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
* Copyright (C) 2007 MontaVista Software, Inc.
*
* Original driver:
* Copyright (C) 2005 Nokia Corporation
* Author: Paul Mundt <paul.mundt@nokia.com>
* Juha Yrjölä <juha.yrjola@nokia.com>
* OMAP Dual-mode timer framework support by Timo Teras
*
* Some parts based off of TI's 24xx code:
*
* Copyright (C) 2004-2009 Texas Instruments, Inc.
*
* Roughly modelled after the OMAP1 MPU timer code.
* Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/platform_data/dmtimer-omap.h>
#include <linux/sched_clock.h>
#include <asm/mach/time.h>
#include <asm/smp_twd.h>
#include "omap_hwmod.h"
#include "omap_device.h"
#include <plat/counter-32k.h>
#include <plat/dmtimer.h>
#include "omap-pm.h"
#include "soc.h"
#include "common.h"
#include "powerdomain.h"
#include "omap-secure.h"
#define REALTIME_COUNTER_BASE 0x48243200
#define INCREMENTER_NUMERATOR_OFFSET 0x10
#define INCREMENTER_DENUMERATOR_RELOAD_OFFSET 0x14
#define NUMERATOR_DENUMERATOR_MASK 0xfffff000
/* Clockevent code */
static struct omap_dm_timer clkev;
static struct clock_event_device clockevent_gpt;
#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
static unsigned long arch_timer_freq;
void set_cntfreq(void)
{
omap_smc1(OMAP5_DRA7_MON_SET_CNTFRQ_INDEX, arch_timer_freq);
}
#endif
static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &clockevent_gpt;
__omap_dm_timer_write_status(&clkev, OMAP_TIMER_INT_OVERFLOW);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction omap2_gp_timer_irq = {
.name = "gp_timer",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = omap2_gp_timer_interrupt,
};
static int omap2_gp_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
__omap_dm_timer_load_start(&clkev, OMAP_TIMER_CTRL_ST,
0xffffffff - cycles, OMAP_TIMER_POSTED);
return 0;
}
static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
u32 period;
__omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
period = clkev.rate / HZ;
period -= 1;
/* Looks like we need to first set the load value separately */
__omap_dm_timer_write(&clkev, OMAP_TIMER_LOAD_REG,
0xffffffff - period, OMAP_TIMER_POSTED);
__omap_dm_timer_load_start(&clkev,
OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
0xffffffff - period, OMAP_TIMER_POSTED);
break;
case CLOCK_EVT_MODE_ONESHOT:
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device clockevent_gpt = {
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.rating = 300,
.set_next_event = omap2_gp_timer_set_next_event,
.set_mode = omap2_gp_timer_set_mode,
};
static struct property device_disabled = {
.name = "status",
.length = sizeof("disabled"),
.value = "disabled",
};
static struct of_device_id omap_timer_match[] __initdata = {
{ .compatible = "ti,omap2420-timer", },
{ .compatible = "ti,omap3430-timer", },
{ .compatible = "ti,omap4430-timer", },
{ .compatible = "ti,omap5430-timer", },
{ .compatible = "ti,am335x-timer", },
{ .compatible = "ti,am335x-timer-1ms", },
{ }
};
/**
* omap_get_timer_dt - get a timer using device-tree
* @match - device-tree match structure for matching a device type
* @property - optional timer property to match
*
* Helper function to get a timer during early boot using device-tree for use
* as kernel system timer. Optionally, the property argument can be used to
* select a timer with a specific property. Once a timer is found then mark
* the timer node in device-tree as disabled, to prevent the kernel from
* registering this timer as a platform device and so no one else can use it.
*/
static struct device_node * __init omap_get_timer_dt(struct of_device_id *match,
const char *property)
{
struct device_node *np;
for_each_matching_node(np, match) {
if (!of_device_is_available(np))
continue;
if (property && !of_get_property(np, property, NULL))
continue;
if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
of_get_property(np, "ti,timer-dsp", NULL) ||
of_get_property(np, "ti,timer-pwm", NULL) ||
of_get_property(np, "ti,timer-secure", NULL)))
continue;
of_add_property(np, &device_disabled);
return np;
}
return NULL;
}
/**
* omap_dmtimer_init - initialisation function when device tree is used
*
* For secure OMAP3 devices, timers with device type "timer-secure" cannot
* be used by the kernel as they are reserved. Therefore, to prevent the
* kernel registering these devices remove them dynamically from the device
* tree on boot.
*/
static void __init omap_dmtimer_init(void)
{
struct device_node *np;
if (!cpu_is_omap34xx())
return;
/* If we are a secure device, remove any secure timer nodes */
if ((omap_type() != OMAP2_DEVICE_TYPE_GP)) {
np = omap_get_timer_dt(omap_timer_match, "ti,timer-secure");
if (np)
of_node_put(np);
}
}
/**
* omap_dm_timer_get_errata - get errata flags for a timer
*
* Get the timer errata flags that are specific to the OMAP device being used.
*/
static u32 __init omap_dm_timer_get_errata(void)
{
if (cpu_is_omap24xx())
return 0;
return OMAP_TIMER_ERRATA_I103_I767;
}
static int __init omap_dm_timer_init_one(struct omap_dm_timer *timer,
const char *fck_source,
const char *property,
const char **timer_name,
int posted)
{
char name[10]; /* 10 = sizeof("gptXX_Xck0") */
const char *oh_name = NULL;
struct device_node *np;
struct omap_hwmod *oh;
struct resource irq, mem;
struct clk *src;
int r = 0;
if (of_have_populated_dt()) {
np = omap_get_timer_dt(omap_timer_match, property);
if (!np)
return -ENODEV;
of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
if (!oh_name)
return -ENODEV;
timer->irq = irq_of_parse_and_map(np, 0);
if (!timer->irq)
return -ENXIO;
timer->io_base = of_iomap(np, 0);
of_node_put(np);
} else {
if (omap_dm_timer_reserve_systimer(timer->id))
return -ENODEV;
sprintf(name, "timer%d", timer->id);
oh_name = name;
}
oh = omap_hwmod_lookup(oh_name);
if (!oh)
return -ENODEV;
*timer_name = oh->name;
if (!of_have_populated_dt()) {
r = omap_hwmod_get_resource_byname(oh, IORESOURCE_IRQ, NULL,
&irq);
if (r)
return -ENXIO;
timer->irq = irq.start;
r = omap_hwmod_get_resource_byname(oh, IORESOURCE_MEM, NULL,
&mem);
if (r)
return -ENXIO;
/* Static mapping, never released */
timer->io_base = ioremap(mem.start, mem.end - mem.start);
}
if (!timer->io_base)
return -ENXIO;
/* After the dmtimer is using hwmod these clocks won't be needed */
timer->fclk = clk_get(NULL, omap_hwmod_get_main_clk(oh));
if (IS_ERR(timer->fclk))
return PTR_ERR(timer->fclk);
src = clk_get(NULL, fck_source);
if (IS_ERR(src))
return PTR_ERR(src);
if (clk_get_parent(timer->fclk) != src) {
r = clk_set_parent(timer->fclk, src);
if (r < 0) {
pr_warn("%s: %s cannot set source\n", __func__,
oh->name);
clk_put(src);
return r;
}
}
clk_put(src);
omap_hwmod_setup_one(oh_name);
omap_hwmod_enable(oh);
__omap_dm_timer_init_regs(timer);
if (posted)
__omap_dm_timer_enable_posted(timer);
/* Check that the intended posted configuration matches the actual */
if (posted != timer->posted)
return -EINVAL;
timer->rate = clk_get_rate(timer->fclk);
timer->reserved = 1;
return r;
}
static void __init omap2_gp_clockevent_init(int gptimer_id,
const char *fck_source,
const char *property)
{
int res;
clkev.id = gptimer_id;
clkev.errata = omap_dm_timer_get_errata();
/*
* For clock-event timers we never read the timer counter and
* so we are not impacted by errata i103 and i767. Therefore,
* we can safely ignore this errata for clock-event timers.
*/
__omap_dm_timer_override_errata(&clkev, OMAP_TIMER_ERRATA_I103_I767);
res = omap_dm_timer_init_one(&clkev, fck_source, property,
&clockevent_gpt.name, OMAP_TIMER_POSTED);
BUG_ON(res);
omap2_gp_timer_irq.dev_id = &clkev;
setup_irq(clkev.irq, &omap2_gp_timer_irq);
__omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
clockevent_gpt.cpumask = cpu_possible_mask;
clockevent_gpt.irq = omap_dm_timer_get_irq(&clkev);
clockevents_config_and_register(&clockevent_gpt, clkev.rate,
3, /* Timer internal resynch latency */
0xffffffff);
pr_info("OMAP clockevent source: %s at %lu Hz\n", clockevent_gpt.name,
clkev.rate);
}
/* Clocksource code */
static struct omap_dm_timer clksrc;
static bool use_gptimer_clksrc;
/*
* clocksource
*/
static cycle_t clocksource_read_cycles(struct clocksource *cs)
{
return (cycle_t)__omap_dm_timer_read_counter(&clksrc,
OMAP_TIMER_NONPOSTED);
}
static struct clocksource clocksource_gpt = {
.rating = 300,
.read = clocksource_read_cycles,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static u64 notrace dmtimer_read_sched_clock(void)
{
if (clksrc.reserved)
return __omap_dm_timer_read_counter(&clksrc,
OMAP_TIMER_NONPOSTED);
return 0;
}
static struct of_device_id omap_counter_match[] __initdata = {
{ .compatible = "ti,omap-counter32k", },
{ }
};
/* Setup free-running counter for clocksource */
static int __init __maybe_unused omap2_sync32k_clocksource_init(void)
{
int ret;
struct device_node *np = NULL;
struct omap_hwmod *oh;
void __iomem *vbase;
const char *oh_name = "counter_32k";
/*
* If device-tree is present, then search the DT blob
* to see if the 32kHz counter is supported.
*/
if (of_have_populated_dt()) {
np = omap_get_timer_dt(omap_counter_match, NULL);
if (!np)
return -ENODEV;
of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
if (!oh_name)
return -ENODEV;
}
/*
* First check hwmod data is available for sync32k counter
*/
oh = omap_hwmod_lookup(oh_name);
if (!oh || oh->slaves_cnt == 0)
return -ENODEV;
omap_hwmod_setup_one(oh_name);
if (np) {
vbase = of_iomap(np, 0);
of_node_put(np);
} else {
vbase = omap_hwmod_get_mpu_rt_va(oh);
}
if (!vbase) {
pr_warn("%s: failed to get counter_32k resource\n", __func__);
return -ENXIO;
}
ret = omap_hwmod_enable(oh);
if (ret) {
pr_warn("%s: failed to enable counter_32k module (%d)\n",
__func__, ret);
return ret;
}
ret = omap_init_clocksource_32k(vbase);
if (ret) {
pr_warn("%s: failed to initialize counter_32k as a clocksource (%d)\n",
__func__, ret);
omap_hwmod_idle(oh);
}
return ret;
}
static void __init omap2_gptimer_clocksource_init(int gptimer_id,
const char *fck_source,
const char *property)
{
int res;
clksrc.id = gptimer_id;
clksrc.errata = omap_dm_timer_get_errata();
res = omap_dm_timer_init_one(&clksrc, fck_source, property,
&clocksource_gpt.name,
OMAP_TIMER_NONPOSTED);
BUG_ON(res);
__omap_dm_timer_load_start(&clksrc,
OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0,
OMAP_TIMER_NONPOSTED);
sched_clock_register(dmtimer_read_sched_clock, 32, clksrc.rate);
if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
pr_err("Could not register clocksource %s\n",
clocksource_gpt.name);
else
pr_info("OMAP clocksource: %s at %lu Hz\n",
clocksource_gpt.name, clksrc.rate);
}
#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
/*
* The realtime counter also called master counter, is a free-running
* counter, which is related to real time. It produces the count used
* by the CPU local timer peripherals in the MPU cluster. The timer counts
* at a rate of 6.144 MHz. Because the device operates on different clocks
* in different power modes, the master counter shifts operation between
* clocks, adjusting the increment per clock in hardware accordingly to
* maintain a constant count rate.
*/
static void __init realtime_counter_init(void)
{
void __iomem *base;
static struct clk *sys_clk;
unsigned long rate;
unsigned int reg, num, den;
base = ioremap(REALTIME_COUNTER_BASE, SZ_32);
if (!base) {
pr_err("%s: ioremap failed\n", __func__);
return;
}
sys_clk = clk_get(NULL, "sys_clkin");
if (IS_ERR(sys_clk)) {
pr_err("%s: failed to get system clock handle\n", __func__);
iounmap(base);
return;
}
rate = clk_get_rate(sys_clk);
/* Numerator/denumerator values refer TRM Realtime Counter section */
switch (rate) {
case 1200000:
num = 64;
den = 125;
break;
case 1300000:
num = 768;
den = 1625;
break;
case 19200000:
num = 8;
den = 25;
break;
case 20000000:
num = 192;
den = 625;
break;
case 2600000:
num = 384;
den = 1625;
break;
case 2700000:
num = 256;
den = 1125;
break;
case 38400000:
default:
/* Program it for 38.4 MHz */
num = 4;
den = 25;
break;
}
/* Program numerator and denumerator registers */
reg = __raw_readl(base + INCREMENTER_NUMERATOR_OFFSET) &
NUMERATOR_DENUMERATOR_MASK;
reg |= num;
__raw_writel(reg, base + INCREMENTER_NUMERATOR_OFFSET);
reg = __raw_readl(base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET) &
NUMERATOR_DENUMERATOR_MASK;
reg |= den;
__raw_writel(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);
arch_timer_freq = (rate / den) * num;
set_cntfreq();
iounmap(base);
}
#else
static inline void __init realtime_counter_init(void)
{}
#endif
#define OMAP_SYS_GP_TIMER_INIT(name, clkev_nr, clkev_src, clkev_prop, \
clksrc_nr, clksrc_src, clksrc_prop) \
void __init omap##name##_gptimer_timer_init(void) \
{ \
omap_clk_init(); \
omap_dmtimer_init(); \
omap2_gp_clockevent_init((clkev_nr), clkev_src, clkev_prop); \
omap2_gptimer_clocksource_init((clksrc_nr), clksrc_src, \
clksrc_prop); \
}
#define OMAP_SYS_32K_TIMER_INIT(name, clkev_nr, clkev_src, clkev_prop, \
clksrc_nr, clksrc_src, clksrc_prop) \
void __init omap##name##_sync32k_timer_init(void) \
{ \
omap_clk_init(); \
omap_dmtimer_init(); \
omap2_gp_clockevent_init((clkev_nr), clkev_src, clkev_prop); \
/* Enable the use of clocksource="gp_timer" kernel parameter */ \
if (use_gptimer_clksrc) \
omap2_gptimer_clocksource_init((clksrc_nr), clksrc_src, \
clksrc_prop); \
else \
omap2_sync32k_clocksource_init(); \
}
#ifdef CONFIG_ARCH_OMAP2
OMAP_SYS_32K_TIMER_INIT(2, 1, "timer_32k_ck", "ti,timer-alwon",
2, "timer_sys_ck", NULL);
#endif /* CONFIG_ARCH_OMAP2 */
#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM43XX)
OMAP_SYS_32K_TIMER_INIT(3, 1, "timer_32k_ck", "ti,timer-alwon",
2, "timer_sys_ck", NULL);
OMAP_SYS_32K_TIMER_INIT(3_secure, 12, "secure_32k_fck", "ti,timer-secure",
2, "timer_sys_ck", NULL);
#endif /* CONFIG_ARCH_OMAP3 */
#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) || \
defined(CONFIG_SOC_AM43XX)
OMAP_SYS_GP_TIMER_INIT(3, 2, "timer_sys_ck", NULL,
1, "timer_sys_ck", "ti,timer-alwon");
#endif
#if defined(CONFIG_ARCH_OMAP4) || defined(CONFIG_SOC_OMAP5) || \
defined(CONFIG_SOC_DRA7XX)
static OMAP_SYS_32K_TIMER_INIT(4, 1, "timer_32k_ck", "ti,timer-alwon",
2, "sys_clkin_ck", NULL);
#endif
#ifdef CONFIG_ARCH_OMAP4
#ifdef CONFIG_HAVE_ARM_TWD
static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, OMAP44XX_LOCAL_TWD_BASE, 29);
void __init omap4_local_timer_init(void)
{
omap4_sync32k_timer_init();
/* Local timers are not supprted on OMAP4430 ES1.0 */
if (omap_rev() != OMAP4430_REV_ES1_0) {
int err;
if (of_have_populated_dt()) {
clocksource_of_init();
return;
}
err = twd_local_timer_register(&twd_local_timer);
if (err)
pr_err("twd_local_timer_register failed %d\n", err);
}
}
#else
void __init omap4_local_timer_init(void)
{
omap4_sync32k_timer_init();
}
#endif /* CONFIG_HAVE_ARM_TWD */
#endif /* CONFIG_ARCH_OMAP4 */
#if defined(CONFIG_SOC_OMAP5) || defined(CONFIG_SOC_DRA7XX)
void __init omap5_realtime_timer_init(void)
{
omap4_sync32k_timer_init();
realtime_counter_init();
clocksource_of_init();
}
#endif /* CONFIG_SOC_OMAP5 || CONFIG_SOC_DRA7XX */
/**
* omap_timer_init - build and register timer device with an
* associated timer hwmod
* @oh: timer hwmod pointer to be used to build timer device
* @user: parameter that can be passed from calling hwmod API
*
* Called by omap_hwmod_for_each_by_class to register each of the timer
* devices present in the system. The number of timer devices is known
* by parsing through the hwmod database for a given class name. At the
* end of function call memory is allocated for timer device and it is
* registered to the framework ready to be proved by the driver.
*/
static int __init omap_timer_init(struct omap_hwmod *oh, void *unused)
{
int id;
int ret = 0;
char *name = "omap_timer";
struct dmtimer_platform_data *pdata;
struct platform_device *pdev;
struct omap_timer_capability_dev_attr *timer_dev_attr;
pr_debug("%s: %s\n", __func__, oh->name);
/* on secure device, do not register secure timer */
timer_dev_attr = oh->dev_attr;
if (omap_type() != OMAP2_DEVICE_TYPE_GP && timer_dev_attr)
if (timer_dev_attr->timer_capability == OMAP_TIMER_SECURE)
return ret;
pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
if (!pdata) {
pr_err("%s: No memory for [%s]\n", __func__, oh->name);
return -ENOMEM;
}
/*
* Extract the IDs from name field in hwmod database
* and use the same for constructing ids' for the
* timer devices. In a way, we are avoiding usage of
* static variable witin the function to do the same.
* CAUTION: We have to be careful and make sure the
* name in hwmod database does not change in which case
* we might either make corresponding change here or
* switch back static variable mechanism.
*/
sscanf(oh->name, "timer%2d", &id);
if (timer_dev_attr)
pdata->timer_capability = timer_dev_attr->timer_capability;
pdata->timer_errata = omap_dm_timer_get_errata();
pdata->get_context_loss_count = omap_pm_get_dev_context_loss_count;
pdev = omap_device_build(name, id, oh, pdata, sizeof(*pdata));
if (IS_ERR(pdev)) {
pr_err("%s: Can't build omap_device for %s: %s.\n",
__func__, name, oh->name);
ret = -EINVAL;
}
kfree(pdata);
return ret;
}
/**
* omap2_dm_timer_init - top level regular device initialization
*
* Uses dedicated hwmod api to parse through hwmod database for
* given class name and then build and register the timer device.
*/
static int __init omap2_dm_timer_init(void)
{
int ret;
/* If dtb is there, the devices will be created dynamically */
if (of_have_populated_dt())
return -ENODEV;
ret = omap_hwmod_for_each_by_class("timer", omap_timer_init, NULL);
if (unlikely(ret)) {
pr_err("%s: device registration failed.\n", __func__);
return -EINVAL;
}
return 0;
}
omap_arch_initcall(omap2_dm_timer_init);
/**
* omap2_override_clocksource - clocksource override with user configuration
*
* Allows user to override default clocksource, using kernel parameter
* clocksource="gp_timer" (For all OMAP2PLUS architectures)
*
* Note that, here we are using same standard kernel parameter "clocksource=",
* and not introducing any OMAP specific interface.
*/
static int __init omap2_override_clocksource(char *str)
{
if (!str)
return 0;
/*
* For OMAP architecture, we only have two options
* - sync_32k (default)
* - gp_timer (sys_clk based)
*/
if (!strcmp(str, "gp_timer"))
use_gptimer_clksrc = true;
return 0;
}
early_param("clocksource", omap2_override_clocksource);