[PATCH v4 1/3] ARM: S5P: Add s5p_timer support for HRT
Jamie Iles
jamie at jamieiles.com
Wed Mar 9 09:10:16 EST 2011
Hi,
A couple of minor comments inline.
Jamie
On Wed, Mar 09, 2011 at 11:13:31AM +0900, Sangbeom Kim wrote:
> This patch adds support HR-Timer(High Resolution Timer) and dynamic
> tick system for S5P SoCs. There are many clock sources for HR-Timer
> on S5P SoCs. The PWM timer, RTC, System Timer, and MCT can be used
> for clock source.
> This patch can only support PWM timer for clocksource of
> S5P64x0 and S5PV210.
>
> Signed-off-by: Sangbeom Kim <sbkim73 at samsung.com>
> ---
> arch/arm/plat-s5p/Makefile | 1 +
> arch/arm/plat-s5p/include/plat/s5p-time.h | 40 +++
> arch/arm/plat-s5p/s5p-time.c | 449 +++++++++++++++++++++++++++++
> 3 files changed, 490 insertions(+), 0 deletions(-)
> create mode 100644 arch/arm/plat-s5p/include/plat/s5p-time.h
> create mode 100644 arch/arm/plat-s5p/s5p-time.c
>
> diff --git a/arch/arm/plat-s5p/Makefile b/arch/arm/plat-s5p/Makefile
> index 4bd5cf9..588b9b4 100644
> --- a/arch/arm/plat-s5p/Makefile
> +++ b/arch/arm/plat-s5p/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_S5P_GPIO_INT) += irq-gpioint.o
> obj-$(CONFIG_S5P_SYSTEM_MMU) += sysmmu.o
> obj-$(CONFIG_PM) += pm.o
> obj-$(CONFIG_PM) += irq-pm.o
> +obj-$(CONFIG_S5P_HRT) += s5p-time.o
>
> # devices
>
> diff --git a/arch/arm/plat-s5p/include/plat/s5p-time.h b/arch/arm/plat-s5p/include/plat/s5p-time.h
> new file mode 100644
> index 0000000..575e881
> --- /dev/null
> +++ b/arch/arm/plat-s5p/include/plat/s5p-time.h
> @@ -0,0 +1,40 @@
> +/* linux/arch/arm/plat-s5p/include/plat/s5p-time.h
> + *
> + * Copyright 2011 Samsung Electronics Co., Ltd.
> + * http://www.samsung.com/
> + *
> + * Header file for s5p time 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.
> +*/
> +
> +#ifndef __ASM_PLAT_S5P_TIME_H
> +#define __ASM_PLAT_S5P_TIME_H __FILE__
> +
> +/* S5P HR-Timer Clock mode */
> +enum s5p_timer_mode {
> + S5P_PWM0,
> + S5P_PWM1,
> + S5P_PWM2,
> + S5P_PWM3,
> + S5P_PWM4,
> +};
> +
> +struct s5p_timer_source {
> + unsigned int event_id;
> + unsigned int source_id;
> +};
> +
> +/* Be able to sleep for atleast 4 seconds (usually more) */
> +#define S5PTIMER_MIN_RANGE 4
> +
> +#define TCNT_MAX 0xffffffff
> +#define NON_PERIODIC 0
> +#define PERIODIC 1
> +
> +extern void __init s5p_set_timer_source(enum s5p_timer_mode event,
> + enum s5p_timer_mode source);
> +extern struct sys_timer s5p_timer;
> +#endif /* __ASM_PLAT_S5P_TIME_H */
> diff --git a/arch/arm/plat-s5p/s5p-time.c b/arch/arm/plat-s5p/s5p-time.c
> new file mode 100644
> index 0000000..62c079c
> --- /dev/null
> +++ b/arch/arm/plat-s5p/s5p-time.c
> @@ -0,0 +1,449 @@
> +/* linux/arch/arm/plat-s5p/s5p-time.c
> + *
> + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> + * http://www.samsung.com/
> + *
> + * S5P - Common hr-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/platform_device.h>
> +
> +#include <asm/smp_twd.h>
> +#include <asm/mach/time.h>
> +#include <asm/mach/arch.h>
> +#include <asm/mach/map.h>
> +#include <asm/sched_clock.h>
> +
> +#include <mach/map.h>
> +#include <plat/devs.h>
> +#include <plat/regs-timer.h>
> +#include <plat/s5p-time.h>
> +
> +static struct clk *tin_event;
> +static struct clk *tin_source;
> +static struct clk *tdiv_event;
> +static struct clk *tdiv_source;
> +static struct clk *timerclk;
> +static struct s5p_timer_source timer_source;
> +static unsigned long clock_count_per_tick;
> +static void s5p_timer_resume(void);
> +
> +static void s5p_time_stop(enum s5p_timer_mode mode)
> +{
> + unsigned long tcon;
> +
> + tcon = __raw_readl(S3C2410_TCON);
> +
> + switch (mode) {
> + case S5P_PWM0:
> + tcon &= ~S3C2410_TCON_T0START;
> + break;
> +
> + case S5P_PWM1:
> + tcon &= ~S3C2410_TCON_T1START;
> + break;
> +
> + case S5P_PWM2:
> + tcon &= ~S3C2410_TCON_T2START;
> + break;
> +
> + case S5P_PWM3:
> + tcon &= ~S3C2410_TCON_T3START;
> + break;
> +
> + case S5P_PWM4:
> + tcon &= ~S3C2410_TCON_T4START;
> + break;
> +
> + default:
> + printk(KERN_ERR "Invalid Timer %d\n", mode);
> + break;
> + }
> + __raw_writel(tcon, S3C2410_TCON);
> +}
> +
> +static void s5p_time_setup(enum s5p_timer_mode mode, unsigned long tcnt)
> +{
> + unsigned long tcon;
> +
> + tcon = __raw_readl(S3C2410_TCON);
> +
> + tcnt--;
> +
> + switch (mode) {
> + case S5P_PWM0:
> + tcon &= ~(0x0f << 0);
> + tcon |= S3C2410_TCON_T0MANUALUPD;
> + break;
> +
> + case S5P_PWM1:
> + tcon &= ~(0x0f << 8);
> + tcon |= S3C2410_TCON_T1MANUALUPD;
> + break;
> +
> + case S5P_PWM2:
> + tcon &= ~(0x0f << 12);
> + tcon |= S3C2410_TCON_T2MANUALUPD;
> + break;
> +
> + case S5P_PWM3:
> + tcon &= ~(0x0f << 16);
> + tcon |= S3C2410_TCON_T3MANUALUPD;
> + break;
> +
> + case S5P_PWM4:
> + tcon &= ~(0x07 << 20);
> + tcon |= S3C2410_TCON_T4MANUALUPD;
> + break;
> +
> + default:
> + printk(KERN_ERR "Invalid Timer %d\n", mode);
> + break;
> + }
> +
> + __raw_writel(tcnt, S3C2410_TCNTB(mode));
> + __raw_writel(tcnt, S3C2410_TCMPB(mode));
> + __raw_writel(tcon, S3C2410_TCON);
> +}
> +
> +static void s5p_time_start(enum s5p_timer_mode mode, bool periodic)
> +{
> + unsigned long tcon;
> +
> + tcon = __raw_readl(S3C2410_TCON);
> +
> + switch (mode) {
> + case S5P_PWM0:
> + tcon |= S3C2410_TCON_T0START;
> + tcon &= ~S3C2410_TCON_T0MANUALUPD;
> +
> + if (periodic)
> + tcon |= S3C2410_TCON_T0RELOAD;
> + else
> + tcon &= ~S3C2410_TCON_T0RELOAD;
> + break;
> +
> + case S5P_PWM1:
> + tcon |= S3C2410_TCON_T1START;
> + tcon &= ~S3C2410_TCON_T1MANUALUPD;
> +
> + if (periodic)
> + tcon |= S3C2410_TCON_T1RELOAD;
> + else
> + tcon &= ~S3C2410_TCON_T1RELOAD;
> + break;
> +
> + case S5P_PWM2:
> + tcon |= S3C2410_TCON_T2START;
> + tcon &= ~S3C2410_TCON_T2MANUALUPD;
> +
> + if (periodic)
> + tcon |= S3C2410_TCON_T2RELOAD;
> + else
> + tcon &= ~S3C2410_TCON_T2RELOAD;
> + break;
> +
> + case S5P_PWM3:
> + tcon |= S3C2410_TCON_T3START;
> + tcon &= ~S3C2410_TCON_T3MANUALUPD;
> +
> + if (periodic)
> + tcon |= S3C2410_TCON_T3RELOAD;
> + else
> + tcon &= ~S3C2410_TCON_T3RELOAD;
> + break;
> +
> + case S5P_PWM4:
> + tcon |= S3C2410_TCON_T4START;
> + tcon &= ~S3C2410_TCON_T4MANUALUPD;
> +
> + if (periodic)
> + tcon |= S3C2410_TCON_T4RELOAD;
> + else
> + tcon &= ~S3C2410_TCON_T4RELOAD;
> + break;
> +
> + default:
> + printk(KERN_ERR "Invalid Timer %d\n", mode);
> + break;
> + }
> + __raw_writel(tcon, S3C2410_TCON);
> +}
> +
> +static int s5p_set_next_event(unsigned long cycles,
> + struct clock_event_device *evt)
> +{
> + s5p_time_setup(timer_source.event_id, cycles);
> + s5p_time_start(timer_source.event_id, NON_PERIODIC);
> +
> + return 0;
> +}
> +
> +static void s5p_set_mode(enum clock_event_mode mode,
> + struct clock_event_device *evt)
> +{
> + s5p_time_stop(timer_source.event_id);
> +
> + switch (mode) {
> + case CLOCK_EVT_MODE_PERIODIC:
> + s5p_time_setup(timer_source.event_id, clock_count_per_tick);
> + s5p_time_start(timer_source.event_id, PERIODIC);
> + break;
> +
> + case CLOCK_EVT_MODE_ONESHOT:
> + break;
> +
> + case CLOCK_EVT_MODE_UNUSED:
> + case CLOCK_EVT_MODE_SHUTDOWN:
> + break;
> +
> + case CLOCK_EVT_MODE_RESUME:
> + s5p_timer_resume();
> + break;
> + }
> +}
> +
> +static void s5p_timer_resume(void)
> +{
> + /* event timer restart */
> + s5p_time_setup(timer_source.event_id, clock_count_per_tick);
> + s5p_time_start(timer_source.event_id, PERIODIC);
> +
> + /* source timer restart */
> + s5p_time_setup(timer_source.source_id, TCNT_MAX);
> + s5p_time_start(timer_source.source_id, PERIODIC);
> +}
> +
> +void __init s5p_set_timer_source(enum s5p_timer_mode event,
> + enum s5p_timer_mode source)
> +{
> + s3c_device_timer[event].dev.bus = &platform_bus_type;
> + s3c_device_timer[source].dev.bus = &platform_bus_type;
> +
> + timer_source.event_id = event;
> + timer_source.source_id = source;
> +}
> +
> +static struct clock_event_device time_event_device = {
> + .name = "s5p_event_timer",
> + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
> + .rating = 200,
> + .shift = 32,
You are using clockevents_calc_mult_shift so you don't need to specify
.shift here.
> + .set_next_event = s5p_set_next_event,
> + .set_mode = s5p_set_mode,
> +};
> +
> +static irqreturn_t s5p_clock_event_isr(int irq, void *dev_id)
> +{
> + struct clock_event_device *evt = dev_id;
> +
> + evt->event_handler(evt);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static struct irqaction s5p_clock_event_irq = {
> + .name = "s5p_time_irq",
> + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
> + .handler = s5p_clock_event_isr,
> + .dev_id = &time_event_device,
> +};
> +
> +static void __init s5p_clockevent_init(void)
> +{
> + unsigned long pclk;
> + unsigned long clock_rate;
> + unsigned int irq_number;
> + struct clk *tscaler;
> +
> + pclk = clk_get_rate(timerclk);
> +
> + tscaler = clk_get_parent(tdiv_event);
> +
> + clk_set_rate(tscaler, pclk / 2);
> + clk_set_rate(tdiv_event, pclk / 2);
> + clk_set_parent(tin_event, tdiv_event);
> +
> + clock_rate = clk_get_rate(tin_event);
> + clock_count_per_tick = clock_rate / HZ;
> +
> + clockevents_calc_mult_shift(&time_event_device,
> + clock_rate, S5PTIMER_MIN_RANGE);
> + time_event_device.max_delta_ns =
> + clockevent_delta2ns(-1, &time_event_device);
> + time_event_device.min_delta_ns =
> + clockevent_delta2ns(1, &time_event_device);
> +
> + time_event_device.cpumask = cpumask_of(0);
> + clockevents_register_device(&time_event_device);
> +
> + irq_number = timer_source.event_id + IRQ_TIMER0;
> + setup_irq(irq_number, &s5p_clock_event_irq);
> +}
> +
> +static cycle_t s5p_timer_read(struct clocksource *cs)
> +{
> + unsigned long offset = 0;
> +
> + switch (timer_source.source_id) {
> + case S5P_PWM0:
> + case S5P_PWM1:
> + case S5P_PWM2:
> + case S5P_PWM3:
> + offset = (timer_source.source_id * 0x0c) + 0x14;
> + break;
> +
> + case S5P_PWM4:
> + offset = 0x40;
> + break;
> +
> + default:
> + printk(KERN_ERR "Invalid Timer %d\n", timer_source.source_id);
> + return 0;
> + }
> +
> + return (cycle_t) ~__raw_readl(S3C_TIMERREG(offset));
> +}
> +
> +/*
> + * Override the global weak sched_clock symbol with this
> + * local implementation which uses the clocksource to get some
> + * better resolution when scheduling the kernel. We accept that
> + * this wraps around for now, since it is just a relative time
> + * stamp. (Inspired by U300 implementation.)
> + */
> +static DEFINE_CLOCK_DATA(cd);
> +
> +unsigned long long notrace sched_clock(void)
> +{
> + u32 cyc;
> + unsigned long offset = 0;
> +
> + switch (timer_source.source_id) {
> + case S5P_PWM0:
> + case S5P_PWM1:
> + case S5P_PWM2:
> + case S5P_PWM3:
> + offset = (timer_source.source_id * 0x0c) + 0x14;
> + break;
> +
> + case S5P_PWM4:
> + offset = 0x40;
> + break;
> +
> + default:
> + printk(KERN_ERR "Invalid Timer %d\n", timer_source.source_id);
> + return 0;
> + }
> +
> + cyc = ~__raw_readl(S3C_TIMERREG(offset));
> + return cyc_to_sched_clock(&cd, cyc, (u32)~0);
> +}
> +
> +static void notrace s5p_update_sched_clock(void)
> +{
> + u32 cyc;
> + unsigned long offset = 0;
> +
> + switch (timer_source.source_id) {
> + case S5P_PWM0:
> + case S5P_PWM1:
> + case S5P_PWM2:
> + case S5P_PWM3:
> + offset = (timer_source.source_id * 0x0c) + 0x14;
> + break;
> +
> + case S5P_PWM4:
> + offset = 0x40;
> + break;
> +
> + default:
> + printk(KERN_ERR "Invalid Timer %d\n", timer_source.source_id);
> + }
> +
> + cyc = ~__raw_readl(S3C_TIMERREG(offset));
> + update_sched_clock(&cd, cyc, (u32)~0);
> +}
> +
> +struct clocksource time_clocksource = {
> + .name = "s5p_clocksource_timer",
> + .rating = 250,
> + .read = s5p_timer_read,
> + .mask = CLOCKSOURCE_MASK(32),
> + .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> +};
> +
> +static void __init s5p_clocksource_init(void)
> +{
> + unsigned long pclk;
> + unsigned long clock_rate;
> +
> + pclk = clk_get_rate(timerclk);
> +
> + clk_set_rate(tdiv_source, pclk / 2);
> + clk_set_parent(tin_source, tdiv_source);
> +
> + clock_rate = clk_get_rate(tin_source);
> +
> + init_sched_clock(&cd, s5p_update_sched_clock, 32, clock_rate);
> +
> + s5p_time_setup(timer_source.source_id, TCNT_MAX);
> + s5p_time_start(timer_source.source_id, PERIODIC);
> +
> + if (clocksource_register_hz(&time_clocksource, clock_rate))
> + panic("%s: can't register clocksource\n", time_clocksource.name);
> +}
> +
> +static void __init s5p_timer_resources(void)
> +{
> +
> + unsigned long event_id = timer_source.event_id;
> + unsigned long source_id = timer_source.source_id;
> +
> + timerclk = clk_get(NULL, "timers");
> + if (IS_ERR(timerclk))
> + panic("failed to get timers clock for timer");
> +
> + clk_enable(timerclk);
clk_enable() can fail, should you be checking the return here and the
other clk_enable() calls?
Jamie
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