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kernel-ark/drivers/clocksource/qcom-timer.c
Stephen Boyd 013be5adf5 clocksource: qcom: Implement read_current_timer for udelay 
Setup the same timer used as the clocksource to be used as the
read_current_timer implementation. This allows us to support a
stable udelay implementation on MSMs where it's possible for the
CPUs to scale speeds independently of one another.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2014-05-19 11:30:11 +02:00

344 lines
8.1 KiB
C
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/*
*
* Copyright (C) 2007 Google, Inc.
* Copyright (c) 2009-2012,2014, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <asm/delay.h>
#define TIMER_MATCH_VAL 0x0000
#define TIMER_COUNT_VAL 0x0004
#define TIMER_ENABLE 0x0008
#define TIMER_ENABLE_CLR_ON_MATCH_EN BIT(1)
#define TIMER_ENABLE_EN BIT(0)
#define TIMER_CLEAR 0x000C
#define DGT_CLK_CTL 0x10
#define DGT_CLK_CTL_DIV_4 0x3
#define TIMER_STS_GPT0_CLR_PEND BIT(10)
#define GPT_HZ 32768
#define MSM_DGT_SHIFT 5
static void __iomem *event_base;
static void __iomem *sts_base;
static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
/* Stop the timer tick */
if (evt->mode == CLOCK_EVT_MODE_ONESHOT) {
u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
ctrl &= ~TIMER_ENABLE_EN;
writel_relaxed(ctrl, event_base + TIMER_ENABLE);
}
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int msm_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
u32 ctrl = readl_relaxed(event_base + TIMER_ENABLE);
ctrl &= ~TIMER_ENABLE_EN;
writel_relaxed(ctrl, event_base + TIMER_ENABLE);
writel_relaxed(ctrl, event_base + TIMER_CLEAR);
writel_relaxed(cycles, event_base + TIMER_MATCH_VAL);
if (sts_base)
while (readl_relaxed(sts_base) & TIMER_STS_GPT0_CLR_PEND)
cpu_relax();
writel_relaxed(ctrl | TIMER_ENABLE_EN, event_base + TIMER_ENABLE);
return 0;
}
static void msm_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
u32 ctrl;
ctrl = readl_relaxed(event_base + TIMER_ENABLE);
ctrl &= ~(TIMER_ENABLE_EN | TIMER_ENABLE_CLR_ON_MATCH_EN);
switch (mode) {
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
case CLOCK_EVT_MODE_ONESHOT:
/* Timer is enabled in set_next_event */
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
break;
}
writel_relaxed(ctrl, event_base + TIMER_ENABLE);
}
static struct clock_event_device __percpu *msm_evt;
static void __iomem *source_base;
static notrace cycle_t msm_read_timer_count(struct clocksource *cs)
{
return readl_relaxed(source_base + TIMER_COUNT_VAL);
}
static struct clocksource msm_clocksource = {
.name = "dg_timer",
.rating = 300,
.read = msm_read_timer_count,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static int msm_timer_irq;
static int msm_timer_has_ppi;
static int msm_local_timer_setup(struct clock_event_device *evt)
{
int cpu = smp_processor_id();
int err;
evt->irq = msm_timer_irq;
evt->name = "msm_timer";
evt->features = CLOCK_EVT_FEAT_ONESHOT;
evt->rating = 200;
evt->set_mode = msm_timer_set_mode;
evt->set_next_event = msm_timer_set_next_event;
evt->cpumask = cpumask_of(cpu);
clockevents_config_and_register(evt, GPT_HZ, 4, 0xffffffff);
if (msm_timer_has_ppi) {
enable_percpu_irq(evt->irq, IRQ_TYPE_EDGE_RISING);
} else {
err = request_irq(evt->irq, msm_timer_interrupt,
IRQF_TIMER | IRQF_NOBALANCING |
IRQF_TRIGGER_RISING, "gp_timer", evt);
if (err)
pr_err("request_irq failed\n");
}
return 0;
}
static void msm_local_timer_stop(struct clock_event_device *evt)
{
evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
disable_percpu_irq(evt->irq);
}
static int msm_timer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
/*
* Grab cpu pointer in each case to avoid spurious
* preemptible warnings
*/
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
msm_local_timer_setup(this_cpu_ptr(msm_evt));
break;
case CPU_DYING:
msm_local_timer_stop(this_cpu_ptr(msm_evt));
break;
}
return NOTIFY_OK;
}
static struct notifier_block msm_timer_cpu_nb = {
.notifier_call = msm_timer_cpu_notify,
};
static u64 notrace msm_sched_clock_read(void)
{
return msm_clocksource.read(&msm_clocksource);
}
static unsigned long msm_read_current_timer(void)
{
return msm_clocksource.read(&msm_clocksource);
}
static struct delay_timer msm_delay_timer = {
.read_current_timer = msm_read_current_timer,
};
static void __init msm_timer_init(u32 dgt_hz, int sched_bits, int irq,
bool percpu)
{
struct clocksource *cs = &msm_clocksource;
int res = 0;
msm_timer_irq = irq;
msm_timer_has_ppi = percpu;
msm_evt = alloc_percpu(struct clock_event_device);
if (!msm_evt) {
pr_err("memory allocation failed for clockevents\n");
goto err;
}
if (percpu)
res = request_percpu_irq(irq, msm_timer_interrupt,
"gp_timer", msm_evt);
if (res) {
pr_err("request_percpu_irq failed\n");
} else {
res = register_cpu_notifier(&msm_timer_cpu_nb);
if (res) {
free_percpu_irq(irq, msm_evt);
goto err;
}
/* Immediately configure the timer on the boot CPU */
msm_local_timer_setup(__this_cpu_ptr(msm_evt));
}
err:
writel_relaxed(TIMER_ENABLE_EN, source_base + TIMER_ENABLE);
res = clocksource_register_hz(cs, dgt_hz);
if (res)
pr_err("clocksource_register failed\n");
sched_clock_register(msm_sched_clock_read, sched_bits, dgt_hz);
msm_delay_timer.freq = dgt_hz;
register_current_timer_delay(&msm_delay_timer);
}
#ifdef CONFIG_ARCH_QCOM
static void __init msm_dt_timer_init(struct device_node *np)
{
u32 freq;
int irq;
struct resource res;
u32 percpu_offset;
void __iomem *base;
void __iomem *cpu0_base;
base = of_iomap(np, 0);
if (!base) {
pr_err("Failed to map event base\n");
return;
}
/* We use GPT0 for the clockevent */
irq = irq_of_parse_and_map(np, 1);
if (irq <= 0) {
pr_err("Can't get irq\n");
return;
}
/* We use CPU0's DGT for the clocksource */
if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
percpu_offset = 0;
if (of_address_to_resource(np, 0, &res)) {
pr_err("Failed to parse DGT resource\n");
return;
}
cpu0_base = ioremap(res.start + percpu_offset, resource_size(&res));
if (!cpu0_base) {
pr_err("Failed to map source base\n");
return;
}
if (of_property_read_u32(np, "clock-frequency", &freq)) {
pr_err("Unknown frequency\n");
return;
}
event_base = base + 0x4;
sts_base = base + 0x88;
source_base = cpu0_base + 0x24;
freq /= 4;
writel_relaxed(DGT_CLK_CTL_DIV_4, source_base + DGT_CLK_CTL);
msm_timer_init(freq, 32, irq, !!percpu_offset);
}
CLOCKSOURCE_OF_DECLARE(kpss_timer, "qcom,kpss-timer", msm_dt_timer_init);
CLOCKSOURCE_OF_DECLARE(scss_timer, "qcom,scss-timer", msm_dt_timer_init);
#else
static int __init msm_timer_map(phys_addr_t addr, u32 event, u32 source,
u32 sts)
{
void __iomem *base;
base = ioremap(addr, SZ_256);
if (!base) {
pr_err("Failed to map timer base\n");
return -ENOMEM;
}
event_base = base + event;
source_base = base + source;
if (sts)
sts_base = base + sts;
return 0;
}
static notrace cycle_t msm_read_timer_count_shift(struct clocksource *cs)
{
/*
* Shift timer count down by a constant due to unreliable lower bits
* on some targets.
*/
return msm_read_timer_count(cs) >> MSM_DGT_SHIFT;
}
void __init msm7x01_timer_init(void)
{
struct clocksource *cs = &msm_clocksource;
if (msm_timer_map(0xc0100000, 0x0, 0x10, 0x0))
return;
cs->read = msm_read_timer_count_shift;
cs->mask = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT));
/* 600 KHz */
msm_timer_init(19200000 >> MSM_DGT_SHIFT, 32 - MSM_DGT_SHIFT, 7,
false);
}
void __init msm7x30_timer_init(void)
{
if (msm_timer_map(0xc0100000, 0x4, 0x24, 0x80))
return;
msm_timer_init(24576000 / 4, 32, 1, false);
}
void __init qsd8x50_timer_init(void)
{
if (msm_timer_map(0xAC100000, 0x0, 0x10, 0x34))
return;
msm_timer_init(19200000 / 4, 32, 7, false);
}
#endif
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