From mboxrd@z Thu Jan 1 00:00:00 1970 From: kgene.kim@samsung.com (Kukjin Kim) Date: Mon, 10 Oct 2011 18:57:58 +0900 Subject: [PATCH 2/5] ARM: s3c64xx: Add generic high resolution time support using PWM timers. In-Reply-To: <3260808.zUY9bHslbC@flatron> References: <1731819.jJi37IsjvJ@flatron> <3260808.zUY9bHslbC@flatron> Message-ID: <039d01cc8733$16c5ded0$44519c70$%kim@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Tomasz Figa wrote: > > From d1fa581f09d8f8a3cc24d05420e9e65112fd8c12 Mon Sep 17 00:00:00 2001 > From: Tomasz Figa > Date: Sun, 28 Aug 2011 02:45:06 +0200 > Subject: [PATCH 2/5] ARM: s3c64xx: Add generic high resolution time support > using PWM timers. > > This patch adds a sys_timer implementing generic clock source and clock event > device on S3C64xx using PWM timers 3 and 4. It can be enabled by a Kconfig > option, based on which either the new sys_timer is used as s3c64xx_timer or > s3c64xx_timer is defined to s3c24xx_timer which is the old tick timer. > > Signed-off-by: Tomasz Figa > --- > arch/arm/Kconfig | 1 - > arch/arm/mach-s3c64xx/Kconfig | 12 ++ > arch/arm/mach-s3c64xx/Makefile | 3 + > arch/arm/mach-s3c64xx/time.c | 320 > ++++++++++++++++++++++++++++++ > arch/arm/plat-samsung/include/plat/cpu.h | 7 + > 5 files changed, 342 insertions(+), 1 deletions(-) > create mode 100644 arch/arm/mach-s3c64xx/time.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 9adc278..05941f6 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -700,7 +700,6 @@ config ARCH_S3C64XX > select ARM_VIC > select HAVE_CLK > select NO_IOPORT > - select ARCH_USES_GETTIMEOFFSET > select ARCH_HAS_CPUFREQ > select ARCH_REQUIRE_GPIOLIB > select SAMSUNG_CLKSRC > diff --git a/arch/arm/mach-s3c64xx/Kconfig b/arch/arm/mach-s3c64xx/Kconfig > index e4177e2..2db76fd 100644 > --- a/arch/arm/mach-s3c64xx/Kconfig > +++ b/arch/arm/mach-s3c64xx/Kconfig > @@ -25,6 +25,18 @@ config CPU_S3C6410 > help > Enable S3C6410 CPU support > > +config S3C64XX_GENERIC_CLOCKEVENTS > + bool "Enable high resolution generic time support using PWM timers" > + select GENERIC_CLOCKEVENTS > + help > + This option enables high resolution generic time support > + on S3C6400/S3C6410 SoCs using PWM timers 3 and 4 instead > + of standard periodic tick using PWM timer 4. > + > +config S3C64XX_ARCH_USES_GETTIMEOFFSET > + def_bool y if !S3C64XX_GENERIC_CLOCKEVENTS > + select ARCH_USES_GETTIMEOFFSET > + > config S3C64XX_DMA > bool "S3C64XX DMA" > select S3C_DMA > diff --git a/arch/arm/mach-s3c64xx/Makefile b/arch/arm/mach-s3c64xx/Makefile > index 4657363..a152002 100644 > --- a/arch/arm/mach-s3c64xx/Makefile > +++ b/arch/arm/mach-s3c64xx/Makefile > @@ -15,6 +15,9 @@ obj-y += cpu.o > obj-y += clock.o > obj-y += gpiolib.o > > +# Generic clockevents > +obj-$(CONFIG_S3C64XX_GENERIC_CLOCKEVENTS) += time.o > + > # Core support for S3C6400 system > > obj-$(CONFIG_CPU_S3C6400) += s3c6400.o > diff --git a/arch/arm/mach-s3c64xx/time.c b/arch/arm/mach-s3c64xx/time.c > new file mode 100644 > index 0000000..4fa57f0 > --- /dev/null > +++ b/arch/arm/mach-s3c64xx/time.c > @@ -0,0 +1,320 @@ > +/* linux/arch/arm/mach-s3c64xx/time.c > + * > + * Copyright (c) 2011 Tomasz Figa > + * > + * based on linux/arch/arm/plat-samsung/s5p-time.c > + * > + * S3C64XX generic high resolution time support using PWM 3 and PWM 4 timers. > + * > + * 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. > + * > + * Notes: > + * - Frequency divisors are currently hardcoded to make both timers operate > + * at 1/6 the frequency of PCLK, so with the usual PCLK frequency of 66 MHz, > + * the timers are clocked at 11 MHz giving us the operating range from > + * 90 nsec to 386 sec. > + * - PWM registers, especially TCON, are shared with PWM driver, but since > + * all the clock event callbacks are run in atomic context synchronization > + * is not needed. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > +#include > + > +#define PWM_EVENT (3) > +#define PWM_SOURCE (4) > + > +#define ONESHOT (0) > +#define PERIODIC (1) > + > +#define TCNT_MAX (0xffffffff) > + > +static struct clk *timerclk; > + > +/* > + * PWM timers setup code > + */ > + > +static inline void s3c64xx_pwm_stop(unsigned int pwm_id) > +{ > + unsigned long tcon = __raw_readl(S3C2410_TCON); > + > + switch (pwm_id) { > + case 3: > + tcon &= ~S3C2410_TCON_T3START; > + break; > + case 4: > + tcon &= ~S3C2410_TCON_T4START; > + break; > + } > + > + __raw_writel(tcon, S3C2410_TCON); > +} > + > +static inline void s3c64xx_pwm_init(unsigned int pwm_id, unsigned long tcnt) > +{ > + unsigned long tcon = __raw_readl(S3C2410_TCON); > + > + /* timers reload after counting zero, so reduce the count by 1 */ > + --tcnt; > + > + /* stop the timer and ask it to load the new value */ > + switch (pwm_id) { > + case 3: > + tcon &= ~(0xf<<16); > + tcon |= S3C2410_TCON_T3MANUALUPD; > + break; > + case 4: > + tcon &= ~(7<<20); > + tcon |= S3C2410_TCON_T4MANUALUPD; > + break; > + } > + > + __raw_writel(tcnt, S3C2410_TCNTB(pwm_id)); > + __raw_writel(tcnt, S3C2410_TCMPB(pwm_id)); > + __raw_writel(tcon, S3C2410_TCON); > +} > + > +static inline void s3c64xx_pwm_start(unsigned int pwm_id, bool periodic) > +{ > + unsigned long tcon = __raw_readl(S3C2410_TCON); > + > + switch (pwm_id) { > + case 3: > + tcon |= S3C2410_TCON_T3START; > + tcon &= ~S3C2410_TCON_T3MANUALUPD; > + > + if (periodic) > + tcon |= S3C2410_TCON_T3RELOAD; > + else > + tcon &= ~S3C2410_TCON_T3RELOAD; > + break; > + case 4: > + tcon |= S3C2410_TCON_T4START; > + tcon &= ~S3C2410_TCON_T4MANUALUPD; > + > + if (periodic) > + tcon |= S3C2410_TCON_T4RELOAD; > + else > + tcon &= ~S3C2410_TCON_T4RELOAD; > + break; > + } > + > + __raw_writel(tcon, S3C2410_TCON); > +} > + > +/* > + * Clock event > + */ > + > +static struct clk *event_in; > +static struct clk *event_div; > + > +static unsigned long clock_count_per_tick; > + > +static int s3c64xx_clock_event_set_next_event(unsigned long cycles, > + struct clock_event_device > *evt) > +{ > + s3c64xx_pwm_init(PWM_EVENT, cycles); > + s3c64xx_pwm_start(PWM_EVENT, ONESHOT); > + return 0; > +} > + > +static void s3c64xx_clock_event_resume(void) > +{ > + unsigned long pclk; > + struct clk *tscaler; > + > + pclk = clk_get_rate(timerclk); > + tscaler = clk_get_parent(event_div); > + clk_set_rate(tscaler, pclk / 3); > + > + clk_set_rate(event_div, pclk / 6); > + clk_set_parent(event_in, event_div); > + > + s3c64xx_pwm_init(PWM_EVENT, clock_count_per_tick); > + s3c64xx_pwm_start(PWM_EVENT, PERIODIC); > +} > + > +static void s3c64xx_clock_event_set_mode(enum clock_event_mode mode, > + struct clock_event_device > *evt) > +{ > + s3c64xx_pwm_stop(PWM_EVENT); > + > + switch (mode) { > + case CLOCK_EVT_MODE_PERIODIC: > + s3c64xx_pwm_init(PWM_EVENT, clock_count_per_tick); > + s3c64xx_pwm_start(PWM_EVENT, PERIODIC); > + break; > + case CLOCK_EVT_MODE_ONESHOT: > + break; > + case CLOCK_EVT_MODE_UNUSED: > + case CLOCK_EVT_MODE_SHUTDOWN: > + break; > + case CLOCK_EVT_MODE_RESUME: > + s3c64xx_clock_event_resume(); > + break; > + } > +} > + > +static struct clock_event_device s3c64xx_clock_event_device = { > + .name = "s3c64xx_clkevt", > + .features = CLOCK_EVT_FEAT_PERIODIC | > CLOCK_EVT_FEAT_ONESHOT, > + .rating = 200, > + .shift = 32, > + .set_next_event = s3c64xx_clock_event_set_next_event, > + .set_mode = s3c64xx_clock_event_set_mode, > +}; > + > +static irqreturn_t s3c64xx_clock_event_isr(int irq, void *dev_id) > +{ > + struct clock_event_device *evt = &s3c64xx_clock_event_device; > + > + evt->event_handler(evt); > + > + return IRQ_HANDLED; > +} > + > +static struct irqaction s3c64xx_clock_event_irq = { > + .name = "s3c64xx_clkevt_irq", > + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, > + .handler = s3c64xx_clock_event_isr, > +}; > + > +static void __init s3c64xx_clock_event_init(void) > +{ > + unsigned long clock_rate; > + > + clock_rate = clk_get_rate(event_in); > + > + clock_count_per_tick = clock_rate / HZ; > + > + s3c64xx_clock_event_device.mult = div_sc(clock_rate, > + NSEC_PER_SEC, s3c64xx_clock_event_device.shift); > + s3c64xx_clock_event_device.max_delta_ns = > + clockevent_delta2ns(-1, &s3c64xx_clock_event_device); > + s3c64xx_clock_event_device.min_delta_ns = > + clockevent_delta2ns(1, &s3c64xx_clock_event_device); > + > + s3c64xx_clock_event_device.cpumask = cpumask_of(0); > + clockevents_register_device(&s3c64xx_clock_event_device); > + > + setup_irq(IRQ_TIMER3, &s3c64xx_clock_event_irq); > +} > + > +/* > + * Clock source > + */ > + > +static struct clk *source_in; > +static struct clk *source_div; > + > +static cycle_t s3c64xx_clocksource_read(struct clocksource *cs) > +{ > + return (cycle_t) ~__raw_readl(S3C2410_TCNTO(PWM_SOURCE)); > +} > + > +static void s3c64xx_clocksource_resume(struct clocksource *cs) > +{ > + unsigned long pclk; > + struct clk *tscaler; > + > + pclk = clk_get_rate(timerclk); > + tscaler = clk_get_parent(source_div); > + clk_set_rate(tscaler, pclk / 3); > + > + clk_set_rate(source_div, pclk / 6); > + clk_set_parent(source_in, source_div); > + > + s3c64xx_pwm_init(PWM_SOURCE, TCNT_MAX); > + s3c64xx_pwm_start(PWM_SOURCE, PERIODIC); > +} > + > +static struct clocksource pwm_clocksource = { > + .name = "s3c64xx_clksrc", > + .rating = 250, > + .read = s3c64xx_clocksource_read, > + .mask = CLOCKSOURCE_MASK(32), > + .flags = CLOCK_SOURCE_IS_CONTINUOUS, > + .resume = s3c64xx_clocksource_resume, > +}; > + > +static void __init s3c64xx_clocksource_init(void) > +{ > + unsigned long clock_rate; > + > + clock_rate = clk_get_rate(source_in); > + > + s3c64xx_pwm_init(PWM_SOURCE, TCNT_MAX); > + s3c64xx_pwm_start(PWM_SOURCE, PERIODIC); > + > + if (clocksource_register_hz(&pwm_clocksource, clock_rate)) > + panic("%s: can't register clocksource\n", > pwm_clocksource.name); > +} > + > +static void __init s3c64xx_timer_init_common(void) > +{ > + struct platform_device tmpdev; > + unsigned long pclk; > + struct clk *tscaler; > + > + tmpdev.dev.bus = &platform_bus_type; > + > + timerclk = clk_get(NULL, "timers"); > + if (IS_ERR(timerclk)) > + panic("failed to get timers clock for system timer"); > + > + tmpdev.id = PWM_EVENT; > + event_in = clk_get(&tmpdev.dev, "pwm-tin"); > + if (IS_ERR(event_in)) > + panic("failed to get pwm-event_in clock for system timer"); > + > + event_div = clk_get(&tmpdev.dev, "pwm-tdiv"); > + if (IS_ERR(event_div)) > + panic("failed to get pwm-event_div clock for system timer"); > + > + tmpdev.id = PWM_SOURCE; > + source_in = clk_get(&tmpdev.dev, "pwm-tin"); > + if (IS_ERR(source_in)) > + panic("failed to get pwm-source_in clock for system timer"); > + > + source_div = clk_get(&tmpdev.dev, "pwm-tdiv"); > + if (IS_ERR(source_div)) > + panic("failed to get pwm-source_div clock for system timer"); > + > + pclk = clk_get_rate(timerclk); > + tscaler = clk_get_parent(event_div); > + clk_set_rate(tscaler, pclk / 3); > + > + clk_set_rate(event_div, pclk / 6); > + clk_set_parent(event_in, event_div); > + > + clk_set_rate(source_div, pclk / 6); > + clk_set_parent(source_in, source_div); > + > + clk_enable(timerclk); > + clk_enable(event_in); > + clk_enable(source_in); > +} > + > +static void __init s3c64xx_timer_init(void) > +{ > + s3c64xx_timer_init_common(); > + s3c64xx_clock_event_init(); > + s3c64xx_clocksource_init(); > +} > + > +struct sys_timer s3c64xx_timer = { > + .init = s3c64xx_timer_init, > +}; > diff --git a/arch/arm/plat-samsung/include/plat/cpu.h b/arch/arm/plat- > samsung/include/plat/cpu.h > index c0a5741..e1fcad0 100644 > --- a/arch/arm/plat-samsung/include/plat/cpu.h > +++ b/arch/arm/plat-samsung/include/plat/cpu.h > @@ -74,6 +74,13 @@ extern struct syscore_ops s3c2416_pm_syscore_ops; > extern struct syscore_ops s3c244x_pm_syscore_ops; > extern struct syscore_ops s3c64xx_irq_syscore_ops; > > +/* timer for 64xx */ > +#ifdef CONFIG_S3C64XX_GENERIC_CLOCKEVENTS > +extern struct sys_timer s3c64xx_timer; > +#else > +#define s3c64xx_timer s3c24xx_timer > +#endif > + > /* system device classes */ > > extern struct sysdev_class s3c2410_sysclass; > -- > 1.7.6.1 Hi Tomasz Figa, Sorry for late response, probably I'm missing this......and I couldn't review this in detail :( But as you know above mach-s3c64xx/time.c is similar with plat-s5p/s5p-time.c so I'd prefer that you could consolidate them, samsung_timer into plat-samsung directory. In addition, if you need to implement SoC specific feature, you can use soc_is_xxxx() like soc_is_s3c64xx() there. If any problems, please let me know. Thanks. Best regards, Kgene. -- Kukjin Kim , Senior Engineer, SW Solution Development Team, Samsung Electronics Co., Ltd.