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linux-next/drivers/clocksource/exynos_mct.c
Tomasz Figa 5df718d846 clocksource: exynos_mct: Set IRQ affinity when the CPU goes online 
Some variants of Exynos MCT, namely exynos4210-mct at the moment, use
normal, shared interrupts for local timers. This means that each
interrupt must have correct affinity set to fire only on CPU
corresponding to given local timer.

However after recent conversion of clocksource drivers to not use the
local timer API for local timer initialization any more, the point of
time when local timers get initialized changed and irq_set_affinity()
fails because the CPU is not marked as online yet.

This patch fixes this by moving the call to irq_set_affinity() to
CPU_ONLINE notification, so the affinity is being set when the CPU goes
online.

This fixes a regression introduced by commit
	ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API
which rendered all Exynos4210 based boards unbootable due to
failing irq_set_affinity() making local timers inoperatible.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2013-09-26 02:30:15 +02:00

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/* linux/arch/arm/mach-exynos4/mct.c
*
* Copyright (c) 2011 Samsung Electronics Co., Ltd.
* http://www.samsung.com
*
* EXYNOS4 MCT(Multi-Core Timer) support
*
* 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/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/cpu.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/percpu.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/clocksource.h>
#include <asm/mach/time.h>
#define EXYNOS4_MCTREG(x) (x)
#define EXYNOS4_MCT_G_CNT_L EXYNOS4_MCTREG(0x100)
#define EXYNOS4_MCT_G_CNT_U EXYNOS4_MCTREG(0x104)
#define EXYNOS4_MCT_G_CNT_WSTAT EXYNOS4_MCTREG(0x110)
#define EXYNOS4_MCT_G_COMP0_L EXYNOS4_MCTREG(0x200)
#define EXYNOS4_MCT_G_COMP0_U EXYNOS4_MCTREG(0x204)
#define EXYNOS4_MCT_G_COMP0_ADD_INCR EXYNOS4_MCTREG(0x208)
#define EXYNOS4_MCT_G_TCON EXYNOS4_MCTREG(0x240)
#define EXYNOS4_MCT_G_INT_CSTAT EXYNOS4_MCTREG(0x244)
#define EXYNOS4_MCT_G_INT_ENB EXYNOS4_MCTREG(0x248)
#define EXYNOS4_MCT_G_WSTAT EXYNOS4_MCTREG(0x24C)
#define _EXYNOS4_MCT_L_BASE EXYNOS4_MCTREG(0x300)
#define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * x))
#define EXYNOS4_MCT_L_MASK (0xffffff00)
#define MCT_L_TCNTB_OFFSET (0x00)
#define MCT_L_ICNTB_OFFSET (0x08)
#define MCT_L_TCON_OFFSET (0x20)
#define MCT_L_INT_CSTAT_OFFSET (0x30)
#define MCT_L_INT_ENB_OFFSET (0x34)
#define MCT_L_WSTAT_OFFSET (0x40)
#define MCT_G_TCON_START (1 << 8)
#define MCT_G_TCON_COMP0_AUTO_INC (1 << 1)
#define MCT_G_TCON_COMP0_ENABLE (1 << 0)
#define MCT_L_TCON_INTERVAL_MODE (1 << 2)
#define MCT_L_TCON_INT_START (1 << 1)
#define MCT_L_TCON_TIMER_START (1 << 0)
#define TICK_BASE_CNT 1
enum {
MCT_INT_SPI,
MCT_INT_PPI
};
enum {
MCT_G0_IRQ,
MCT_G1_IRQ,
MCT_G2_IRQ,
MCT_G3_IRQ,
MCT_L0_IRQ,
MCT_L1_IRQ,
MCT_L2_IRQ,
MCT_L3_IRQ,
MCT_NR_IRQS,
};
static void __iomem *reg_base;
static unsigned long clk_rate;
static unsigned int mct_int_type;
static int mct_irqs[MCT_NR_IRQS];
struct mct_clock_event_device {
struct clock_event_device evt;
unsigned long base;
char name[10];
};
static void exynos4_mct_write(unsigned int value, unsigned long offset)
{
unsigned long stat_addr;
u32 mask;
u32 i;
__raw_writel(value, reg_base + offset);
if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
stat_addr = (offset & ~EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
switch (offset & EXYNOS4_MCT_L_MASK) {
case MCT_L_TCON_OFFSET:
mask = 1 << 3; /* L_TCON write status */
break;
case MCT_L_ICNTB_OFFSET:
mask = 1 << 1; /* L_ICNTB write status */
break;
case MCT_L_TCNTB_OFFSET:
mask = 1 << 0; /* L_TCNTB write status */
break;
default:
return;
}
} else {
switch (offset) {
case EXYNOS4_MCT_G_TCON:
stat_addr = EXYNOS4_MCT_G_WSTAT;
mask = 1 << 16; /* G_TCON write status */
break;
case EXYNOS4_MCT_G_COMP0_L:
stat_addr = EXYNOS4_MCT_G_WSTAT;
mask = 1 << 0; /* G_COMP0_L write status */
break;
case EXYNOS4_MCT_G_COMP0_U:
stat_addr = EXYNOS4_MCT_G_WSTAT;
mask = 1 << 1; /* G_COMP0_U write status */
break;
case EXYNOS4_MCT_G_COMP0_ADD_INCR:
stat_addr = EXYNOS4_MCT_G_WSTAT;
mask = 1 << 2; /* G_COMP0_ADD_INCR w status */
break;
case EXYNOS4_MCT_G_CNT_L:
stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
mask = 1 << 0; /* G_CNT_L write status */
break;
case EXYNOS4_MCT_G_CNT_U:
stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
mask = 1 << 1; /* G_CNT_U write status */
break;
default:
return;
}
}
/* Wait maximum 1 ms until written values are applied */
for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
if (__raw_readl(reg_base + stat_addr) & mask) {
__raw_writel(mask, reg_base + stat_addr);
return;
}
panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
}
/* Clocksource handling */
static void exynos4_mct_frc_start(u32 hi, u32 lo)
{
u32 reg;
exynos4_mct_write(lo, EXYNOS4_MCT_G_CNT_L);
exynos4_mct_write(hi, EXYNOS4_MCT_G_CNT_U);
reg = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
reg |= MCT_G_TCON_START;
exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
}
static cycle_t exynos4_frc_read(struct clocksource *cs)
{
unsigned int lo, hi;
u32 hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U);
do {
hi = hi2;
lo = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_L);
hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U);
} while (hi != hi2);
return ((cycle_t)hi << 32) | lo;
}
static void exynos4_frc_resume(struct clocksource *cs)
{
exynos4_mct_frc_start(0, 0);
}
struct clocksource mct_frc = {
.name = "mct-frc",
.rating = 400,
.read = exynos4_frc_read,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.resume = exynos4_frc_resume,
};
static void __init exynos4_clocksource_init(void)
{
exynos4_mct_frc_start(0, 0);
if (clocksource_register_hz(&mct_frc, clk_rate))
panic("%s: can't register clocksource\n", mct_frc.name);
}
static void exynos4_mct_comp0_stop(void)
{
unsigned int tcon;
tcon = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
}
static void exynos4_mct_comp0_start(enum clock_event_mode mode,
unsigned long cycles)
{
unsigned int tcon;
cycle_t comp_cycle;
tcon = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
if (mode == CLOCK_EVT_MODE_PERIODIC) {
tcon |= MCT_G_TCON_COMP0_AUTO_INC;
exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
}
comp_cycle = exynos4_frc_read(&mct_frc) + cycles;
exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
tcon |= MCT_G_TCON_COMP0_ENABLE;
exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
}
static int exynos4_comp_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
exynos4_mct_comp0_start(evt->mode, cycles);
return 0;
}
static void exynos4_comp_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned long cycles_per_jiffy;
exynos4_mct_comp0_stop();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
cycles_per_jiffy =
(((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
exynos4_mct_comp0_start(mode, cycles_per_jiffy);
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device mct_comp_device = {
.name = "mct-comp",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.rating = 250,
.set_next_event = exynos4_comp_set_next_event,
.set_mode = exynos4_comp_set_mode,
};
static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction mct_comp_event_irq = {
.name = "mct_comp_irq",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = exynos4_mct_comp_isr,
.dev_id = &mct_comp_device,
};
static void exynos4_clockevent_init(void)
{
mct_comp_device.cpumask = cpumask_of(0);
clockevents_config_and_register(&mct_comp_device, clk_rate,
0xf, 0xffffffff);
setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
}
static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
/* Clock event handling */
static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
{
unsigned long tmp;
unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
tmp = __raw_readl(reg_base + offset);
if (tmp & mask) {
tmp &= ~mask;
exynos4_mct_write(tmp, offset);
}
}
static void exynos4_mct_tick_start(unsigned long cycles,
struct mct_clock_event_device *mevt)
{
unsigned long tmp;
exynos4_mct_tick_stop(mevt);
tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
/* update interrupt count buffer */
exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
/* enable MCT tick interrupt */
exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
tmp = __raw_readl(reg_base + mevt->base + MCT_L_TCON_OFFSET);
tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
MCT_L_TCON_INTERVAL_MODE;
exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
}
static int exynos4_tick_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
exynos4_mct_tick_start(cycles, mevt);
return 0;
}
static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
unsigned long cycles_per_jiffy;
exynos4_mct_tick_stop(mevt);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
cycles_per_jiffy =
(((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
exynos4_mct_tick_start(cycles_per_jiffy, mevt);
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
{
struct clock_event_device *evt = &mevt->evt;
/*
* This is for supporting oneshot mode.
* Mct would generate interrupt periodically
* without explicit stopping.
*/
if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
exynos4_mct_tick_stop(mevt);
/* Clear the MCT tick interrupt */
if (__raw_readl(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) {
exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
return 1;
} else {
return 0;
}
}
static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
{
struct mct_clock_event_device *mevt = dev_id;
struct clock_event_device *evt = &mevt->evt;
exynos4_mct_tick_clear(mevt);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int exynos4_local_timer_setup(struct clock_event_device *evt)
{
struct mct_clock_event_device *mevt;
unsigned int cpu = smp_processor_id();
mevt = container_of(evt, struct mct_clock_event_device, evt);
mevt->base = EXYNOS4_MCT_L_BASE(cpu);
sprintf(mevt->name, "mct_tick%d", cpu);
evt->name = mevt->name;
evt->cpumask = cpumask_of(cpu);
evt->set_next_event = exynos4_tick_set_next_event;
evt->set_mode = exynos4_tick_set_mode;
evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
evt->rating = 450;
clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
0xf, 0x7fffffff);
exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
if (mct_int_type == MCT_INT_SPI) {
evt->irq = mct_irqs[MCT_L0_IRQ + cpu];
if (request_irq(evt->irq, exynos4_mct_tick_isr,
IRQF_TIMER | IRQF_NOBALANCING,
evt->name, mevt)) {
pr_err("exynos-mct: cannot register IRQ %d\n",
evt->irq);
return -EIO;
}
} else {
enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
}
return 0;
}
static void exynos4_local_timer_stop(struct clock_event_device *evt)
{
evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
if (mct_int_type == MCT_INT_SPI)
free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick));
else
disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
}
static int exynos4_mct_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
struct mct_clock_event_device *mevt;
unsigned int cpu;
/*
* Grab cpu pointer in each case to avoid spurious
* preemptible warnings
*/
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
mevt = this_cpu_ptr(&percpu_mct_tick);
exynos4_local_timer_setup(&mevt->evt);
break;
case CPU_ONLINE:
cpu = (unsigned long)hcpu;
if (mct_int_type == MCT_INT_SPI)
irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu],
cpumask_of(cpu));
break;
case CPU_DYING:
mevt = this_cpu_ptr(&percpu_mct_tick);
exynos4_local_timer_stop(&mevt->evt);
break;
}
return NOTIFY_OK;
}
static struct notifier_block exynos4_mct_cpu_nb = {
.notifier_call = exynos4_mct_cpu_notify,
};
static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
{
int err;
struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
struct clk *mct_clk, *tick_clk;
tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
clk_get(NULL, "fin_pll");
if (IS_ERR(tick_clk))
panic("%s: unable to determine tick clock rate\n", __func__);
clk_rate = clk_get_rate(tick_clk);
mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
if (IS_ERR(mct_clk))
panic("%s: unable to retrieve mct clock instance\n", __func__);
clk_prepare_enable(mct_clk);
reg_base = base;
if (!reg_base)
panic("%s: unable to ioremap mct address space\n", __func__);
if (mct_int_type == MCT_INT_PPI) {
err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
exynos4_mct_tick_isr, "MCT",
&percpu_mct_tick);
WARN(err, "MCT: can't request IRQ %d (%d)\n",
mct_irqs[MCT_L0_IRQ], err);
} else {
irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));
}
err = register_cpu_notifier(&exynos4_mct_cpu_nb);
if (err)
goto out_irq;
/* Immediately configure the timer on the boot CPU */
exynos4_local_timer_setup(&mevt->evt);
return;
out_irq:
free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
}
void __init mct_init(void __iomem *base, int irq_g0, int irq_l0, int irq_l1)
{
mct_irqs[MCT_G0_IRQ] = irq_g0;
mct_irqs[MCT_L0_IRQ] = irq_l0;
mct_irqs[MCT_L1_IRQ] = irq_l1;
mct_int_type = MCT_INT_SPI;
exynos4_timer_resources(NULL, base);
exynos4_clocksource_init();
exynos4_clockevent_init();
}
static void __init mct_init_dt(struct device_node *np, unsigned int int_type)
{
u32 nr_irqs, i;
mct_int_type = int_type;
/* This driver uses only one global timer interrupt */
mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
/*
* Find out the number of local irqs specified. The local
* timer irqs are specified after the four global timer
* irqs are specified.
*/
#ifdef CONFIG_OF
nr_irqs = of_irq_count(np);
#else
nr_irqs = 0;
#endif
for (i = MCT_L0_IRQ; i < nr_irqs; i++)
mct_irqs[i] = irq_of_parse_and_map(np, i);
exynos4_timer_resources(np, of_iomap(np, 0));
exynos4_clocksource_init();
exynos4_clockevent_init();
}
static void __init mct_init_spi(struct device_node *np)
{
return mct_init_dt(np, MCT_INT_SPI);
}
static void __init mct_init_ppi(struct device_node *np)
{
return mct_init_dt(np, MCT_INT_PPI);
}
CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
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