[PATCH v2] ARM: S5P: Add System Timer
Lukasz Majewski
l.majewski at samsung.com
Fri May 14 12:08:40 EDT 2010
Hello,
I've following comments:
> -----Original Message-----
> From: linux-samsung-soc-owner at vger.kernel.org [mailto:linux-samsung-
> soc-owner at vger.kernel.org] On Behalf Of Kukjin Kim
> Sent: Friday, May 14, 2010 10:52 AM
> To: linux-arm-kernel at lists.infradead.org; linux-samsung-
> soc at vger.kernel.org
> Cc: ben-linux at fluff.org; Jongpill Lee; Jongpill Lee; Kukjin Kim
> Subject: [PATCH v2] ARM: S5P: Add System Timer
>
> From: Jongpill Lee <boyko at samsung.com>
>
> This patch addes system timer for Samsung S5P series SoCs
>
> Signed-off-by: Jongpill Lee <boyko.lee at samsung.com>
> Signed-off-by: Kukjin Kim <kgene.kim at samsung.com>
> ---
> arch/arm/mach-s5p6442/include/mach/tick.h | 6 +
> arch/arm/mach-s5p6442/mach-smdk6442.c | 2 +-
> arch/arm/mach-s5pv210/include/mach/tick.h | 6 +
> arch/arm/mach-s5pv210/mach-smdkc110.c | 2 +-
> arch/arm/mach-s5pv210/mach-smdkv210.c | 2 +-
> arch/arm/plat-s5p/Kconfig | 7 +
> arch/arm/plat-s5p/Makefile | 1 +
> arch/arm/plat-s5p/include/plat/regs-systimer.h | 75 ++++++
> arch/arm/plat-s5p/s5p-systimer.c | 287
> ++++++++++++++++++++++++
> arch/arm/plat-samsung/include/plat/cpu.h | 3 +
> 10 files changed, 388 insertions(+), 3 deletions(-)
> create mode 100644 arch/arm/plat-s5p/include/plat/regs-systimer.h
> create mode 100644 arch/arm/plat-s5p/s5p-systimer.c
>
> diff --git a/arch/arm/mach-s5p6442/include/mach/tick.h b/arch/arm/mach-
> s5p6442/include/mach/tick.h
> index e1d4cab..1795b43 100644
> --- a/arch/arm/mach-s5p6442/include/mach/tick.h
> +++ b/arch/arm/mach-s5p6442/include/mach/tick.h
> @@ -21,6 +21,12 @@ static inline u32 s3c24xx_ostimer_pending(void)
> return pend & (1 << (IRQ_TIMER4_VIC - S5P_IRQ_VIC0(0)));
> }
>
> +static inline u32 s5p_ostimer_pending(void)
> +{
> + u32 pend = __raw_readl(VA_VIC0 + VIC_RAW_STATUS);
> + return pend & (1 << (IRQ_SYSTIMER - S5P_IRQ_VIC0(0)));
> +}
> +
> #define TICK_MAX (0xffffffff)
>
> #endif /* __ASM_ARCH_TICK_H */
> diff --git a/arch/arm/mach-s5p6442/mach-smdk6442.c b/arch/arm/mach-
> s5p6442/mach-smdk6442.c
> index 0d63371..6c8728b 100644
> --- a/arch/arm/mach-s5p6442/mach-smdk6442.c
> +++ b/arch/arm/mach-s5p6442/mach-smdk6442.c
> @@ -87,5 +87,5 @@ MACHINE_START(SMDK6442, "SMDK6442")
> .init_irq = s5p6442_init_irq,
> .map_io = smdk6442_map_io,
> .init_machine = smdk6442_machine_init,
> - .timer = &s3c24xx_timer,
> + .timer = &s5p_systimer,
> MACHINE_END
> diff --git a/arch/arm/mach-s5pv210/include/mach/tick.h b/arch/arm/mach-
> s5pv210/include/mach/tick.h
> index 7993b36..9fc5a8d 100644
> --- a/arch/arm/mach-s5pv210/include/mach/tick.h
> +++ b/arch/arm/mach-s5pv210/include/mach/tick.h
> @@ -21,6 +21,12 @@ static inline u32 s3c24xx_ostimer_pending(void)
> return pend & (1 << (IRQ_TIMER4_VIC - S5P_IRQ_VIC0(0)));
> }
>
> +static inline u32 s5p_ostimer_pending(void)
> +{
> + u32 pend = __raw_readl(VA_VIC0 + VIC_RAW_STATUS);
> + return pend & (1 << (IRQ_SYSTIMER - S5P_IRQ_VIC0(0)));
> +}
> +
> #define TICK_MAX (0xffffffff)
>
> #endif /* __ASM_ARCH_TICK_H */
> diff --git a/arch/arm/mach-s5pv210/mach-smdkc110.c b/arch/arm/mach-
> s5pv210/mach-smdkc110.c
> index ab4869d..b520817 100644
> --- a/arch/arm/mach-s5pv210/mach-smdkc110.c
> +++ b/arch/arm/mach-s5pv210/mach-smdkc110.c
> @@ -94,5 +94,5 @@ MACHINE_START(SMDKC110, "SMDKC110")
> .init_irq = s5pv210_init_irq,
> .map_io = smdkc110_map_io,
> .init_machine = smdkc110_machine_init,
> - .timer = &s3c24xx_timer,
> + .timer = &s5p_systimer,
> MACHINE_END
> diff --git a/arch/arm/mach-s5pv210/mach-smdkv210.c b/arch/arm/mach-
> s5pv210/mach-smdkv210.c
> index a278832..2a29d47 100644
> --- a/arch/arm/mach-s5pv210/mach-smdkv210.c
> +++ b/arch/arm/mach-s5pv210/mach-smdkv210.c
> @@ -94,5 +94,5 @@ MACHINE_START(SMDKV210, "SMDKV210")
> .init_irq = s5pv210_init_irq,
> .map_io = smdkv210_map_io,
> .init_machine = smdkv210_machine_init,
> - .timer = &s3c24xx_timer,
> + .timer = &s5p_systimer,
> MACHINE_END
> diff --git a/arch/arm/plat-s5p/Kconfig b/arch/arm/plat-s5p/Kconfig
> index d400a6a..e152bbc 100644
> --- a/arch/arm/plat-s5p/Kconfig
> +++ b/arch/arm/plat-s5p/Kconfig
> @@ -23,3 +23,10 @@ config PLAT_S5P
> select SAMSUNG_IRQ_UART
> help
> Base platform code for Samsung's S5P series SoC.
> +
> +config S5P_SYSTIMER
> + bool
> + depends on (ARCH_S5P6442 || ARCH_S5PV210)
> + default y
> + help
> + Support System Timer for S5P Series
> diff --git a/arch/arm/plat-s5p/Makefile b/arch/arm/plat-s5p/Makefile
> index 7f44678..dbc6595 100644
> --- a/arch/arm/plat-s5p/Makefile
> +++ b/arch/arm/plat-s5p/Makefile
> @@ -17,3 +17,4 @@ obj-y += cpu.o
> obj-y += clock.o
> obj-y += irq.o
> obj-y += setup-i2c0.o
> +obj-$(CONFIG_S5P_SYSTIMER) += s5p-systimer.o
> diff --git a/arch/arm/plat-s5p/include/plat/regs-systimer.h
> b/arch/arm/plat-s5p/include/plat/regs-systimer.h
> new file mode 100644
> index 0000000..61f1282
> --- /dev/null
> +++ b/arch/arm/plat-s5p/include/plat/regs-systimer.h
> @@ -0,0 +1,75 @@
> +/* linux/arch/arm/plat-s5p/include/plat/regs-systimer.h
> + *
> + * Copyright (c) 2010 Samsung Electronics Co., Ltd.
> + * http://www.samsung.com/
> + *
> + * S5P System Timer Driver Header information
> + *
> + * 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_REGS_SYSTIMER_H
> +#define __ASM_PLAT_REGS_SYSTIMER_H __FILE__
> +
> +#define S5P_SYSTIMERREG(x) (S5P_VA_SYSTIMER + (x))
> +
> +#define S5P_SYSTIMER_TCFG S5P_SYSTIMERREG(0x00)
> +#define S5P_SYSTIMER_TCON S5P_SYSTIMERREG(0x04)
> +#define S5P_SYSTIMER_TICNTB S5P_SYSTIMERREG(0x08)
> +#define S5P_SYSTIMER_TICNTO S5P_SYSTIMERREG(0x0c)
> +#define S5P_SYSTIMER_TFCNTB S5P_SYSTIMERREG(0x10)
> +#define S5P_SYSTIMER_ICNTB S5P_SYSTIMERREG(0x18)
> +#define S5P_SYSTIMER_ICNTO S5P_SYSTIMERREG(0x1c)
> +#define S5P_SYSTIMER_INT_CSTAT S5P_SYSTIMERREG(0x20)
> +
> +/* Value for TCFG */
> +
> +#define S5P_SYSTIMER_SWRST (1 << 16)
> +
> +#define S5P_SYSTIMER_DIV_GEN (0 << 15)
> +#define S5P_SYSTIMER_DIV_RTC (1 << 15)
> +
> +#define S5P_SYSTIMER_TICK_INT (0 << 14)
> +#define S5P_SYSTIMER_TICK_FRA (1 << 14)
> +
> +#define S5P_SYSTIMER_TCLK_MASK (3 << 12)
> +#define S5P_SYSTIMER_TCLK_XXTI (0 << 12)
> +#define S5P_SYSTIMER_TCLK_RTC (1 << 12)
> +#define S5P_SYSTIMER_TCLK_USB (2 << 12)
> +#define S5P_SYSTIMER_TCLK_PCLK (3 << 12)
> +
> +#define S5P_SYSTIMER_DIV_MASK (7 << 8)
> +#define S5P_SYSTIMER_DIV_1 (0 << 8)
> +#define S5P_SYSTIMER_DIV_2 (1 << 8)
> +#define S5P_SYSTIMER_DIV_4 (2 << 8)
> +#define S5P_SYSTIMER_DIV_8 (3 << 8)
> +#define S5P_SYSTIMER_DIV_16 (4 << 8)
> +
> +#define S5P_SYSTIMER_TARGET_HZ 1000
> +#define S5P_SYSTIMER_PRESCALER 5
> +#define S5P_SYSTIMER_PRESCALER_MASK (0x3f << 0)
> +
> +/* value for TCON */
> +
> +#define S5P_SYSTIMER_INT_AUTO (1 << 5)
> +#define S5P_SYSTIMER_INT_IMM (1 << 4)
> +#define S5P_SYSTIMER_INT_START (1 << 3)
> +#define S5P_SYSTIMER_START (1 << 0)
> +
> +/* Value for INT_CSTAT */
> +
> +#define S5P_SYSTIMER_INT_TWIE (1 << 10)
> +#define S5P_SYSTIMER_INT_IWIE (1 << 9)
> +#define S5P_SYSTIMER_INT_TFWIE (1 << 8)
> +#define S5P_SYSTIMER_INT_TIWIE (1 << 7)
> +#define S5P_SYSTIMER_INT_ICNTEIE (1 << 6)
> +#define S5P_SYSTIMER_INT_TCON (1 << 5)
> +#define S5P_SYSTIMER_INT_ICNTB (1 << 4)
> +#define S5P_SYSTIMER_INT_TFCNTB (1 << 3)
> +#define S5P_SYSTIMER_INT_TICNTB (1 << 2)
> +#define S5P_SYSTIMER_INT_INTCNT (1 << 1)
> +#define S5P_SYSTIMER_INT_INTENABLE (1 << 0)
> +
> +#endif /* __ASM_PLAT_REGS_SYSTIMER_H */
> diff --git a/arch/arm/plat-s5p/s5p-systimer.c b/arch/arm/plat-s5p/s5p-
> systimer.c
> new file mode 100644
> index 0000000..f0e4ec8
> --- /dev/null
> +++ b/arch/arm/plat-s5p/s5p-systimer.c
> @@ -0,0 +1,287 @@
> +/* linux/arch/arm/plat-s5p/s5p-systimer.c
> + *
> + * Copyright (c) 2010 Samsung Electronics Co., Ltd.
> + * http://www.samsung.com/
> + *
> + * S5P System Timer
> + *
> + * Based on linux/arch/arm/plat-samsung/time.c
> + *
> + * 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/kernel.h>
> +#include <linux/sched.h>
> +#include <linux/init.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/err.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +
> +#include <asm/system.h>
> +#include <asm/mach-types.h>
> +
> +#include <asm/irq.h>
> +#include <asm/mach/time.h>
> +
> +#include <mach/map.h>
> +#include <mach/regs-irq.h>
> +#include <mach/tick.h>
> +
> +#include <plat/regs-systimer.h>
> +#include <plat/clock.h>
> +#include <plat/cpu.h>
> +
> +#include <mach/regs-clock.h>
> +
> +static unsigned long timer_startval;
> +static unsigned long timer_usec_ticks;
> +static unsigned long timer_icnt;
> +
> +#define TICK_MAX (0xffffffff)
> +#define TIMER_USEC_SHIFT 16
> +
> +static unsigned int systimer_write_done(unsigned int value)
> +{
> + unsigned int cnt;
> + unsigned int tmp_reg;
> +
> + cnt = 1000;
> +
> + do {
> + if (__raw_readl(S5P_SYSTIMER_INT_CSTAT) & value) {
> + tmp_reg = __raw_readl(S5P_SYSTIMER_INT_CSTAT);
> + tmp_reg |= value;
> + __raw_writel(tmp_reg , S5P_SYSTIMER_INT_CSTAT);
> +
> + return 0;
> + }
> + } while (--cnt > 0);
> +
> + printk(KERN_ERR "%s : %d : Timer Expired\n", __func__, value);
> +
> + return -ETIME;
> +}
> +
> +static unsigned int s5p_systimer_write(void __iomem *reg,
> + unsigned int value)
> +{
> + unsigned int int_cstat;
> + unsigned int ret = 0;
> +
> + __raw_writel(value, reg);
> +
> + int_cstat = __raw_readl(S5P_SYSTIMER_INT_CSTAT);
> +
> + if (reg == S5P_SYSTIMER_TCON) {
> + if (int_cstat & S5P_SYSTIMER_INT_TWIE)
> + ret = systimer_write_done(S5P_SYSTIMER_INT_TCON);
> +
> + } else if (reg == S5P_SYSTIMER_ICNTB) {
> + if (int_cstat & S5P_SYSTIMER_INT_IWIE)
> + ret = systimer_write_done(S5P_SYSTIMER_INT_ICNTB);
> +
> + } else if (reg == S5P_SYSTIMER_TFCNTB) {
> + if (int_cstat & S5P_SYSTIMER_INT_TFWIE)
> + ret = systimer_write_done(S5P_SYSTIMER_INT_TFCNTB);
> +
> + } else if (reg == S5P_SYSTIMER_TICNTB) {
> + if (int_cstat & S5P_SYSTIMER_INT_TIWIE)
> + ret = systimer_write_done(S5P_SYSTIMER_INT_TICNTB);
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * S5P has system timer to use as OS tick Timer.
> + * System Timer provides two distincive feature. Accurate timer which
> provides
> + * exact 1ms time tick at any power mode except sleep mode.
> + * interrupt interval without stopping reference tick timer.
> + */
> +
> +/*
> + * timer_mask_usec_ticks
> + *
> + * given a clock and divisor, make the value to pass into
> timer_ticks_to_usec
> + * to scale the ticks into usecs
> + */
> +static inline unsigned long timer_mask_usec_ticks(unsigned long
> scaler,
> + unsigned long pclk)
> +{
> + unsigned long den = pclk / 1000;
> +
> + return ((1000 << TIMER_USEC_SHIFT) * scaler + (den >> 1)) / den;
> +}
> +
> +/*
> + * timer_ticks_to_usec
> + *
> + * convert timer ticks to usec.
> + */
> +static inline unsigned long timer_ticks_to_usec(unsigned long ticks)
> +{
> + unsigned long res;
> +
> + res = ticks * timer_usec_ticks;
> + res += 1 << (TIMER_USEC_SHIFT - 4); /* round up slightly */
> +
> + return res >> TIMER_USEC_SHIFT;
> +}
> +
> +/*
> + * Returns microsecond since last clock interrupt. Note that
> interrupts
> + * will have been disabled by do_gettimeoffset()
> + * IRQs are disabled before entering here from do_gettimeofday()
> + */
> +static unsigned long s5p_gettimeoffset(void)
> +{
> + unsigned long tdone;
> + unsigned long tval;
> + unsigned long clk_tick_totcnt;
> +
> + clk_tick_totcnt = (timer_icnt + 1) * timer_startval;
> +
> + /* work out how many ticks have gone since last timer interrupt
> */
> + tval = __raw_readl(S5P_SYSTIMER_ICNTO) * timer_startval;
> + tval += __raw_readl(S5P_SYSTIMER_TICNTO);
> +
> + tdone = clk_tick_totcnt - tval;
> +
> + /* check to see if there is an interrupt pending */
> + if (s5p_ostimer_pending()) {
> + /* re-read the timer, and try and fix up for the missed
> + * interrupt. Note, the interrupt may go off before the
> + * timer has re-loaded from wrapping.
> + */
> +
> + tval = __raw_readl(S5P_SYSTIMER_ICNTO) * timer_startval;
> + tval += __raw_readl(S5P_SYSTIMER_TICNTO);
> +
> + tdone = clk_tick_totcnt - tval;
> +
> + if (tval != 0)
> + tdone += clk_tick_totcnt;
> + }
> +
> + return timer_ticks_to_usec(tdone);
> +}
> +
> +/*
> + * IRQ handler for the timer
> + */
> +static irqreturn_t s5p_systimer_interrupt(int irq, void *dev_id)
> +{
> + unsigned int temp_cstat;
> +
> + temp_cstat = __raw_readl(S5P_SYSTIMER_INT_CSTAT);
> + temp_cstat |= S5P_SYSTIMER_INT_INTCNT;
> + s5p_systimer_write(S5P_SYSTIMER_INT_CSTAT, temp_cstat);
> +
> + timer_tick();
> +
> + return IRQ_HANDLED;
> +}
> +
> +static struct irqaction s5p_systimer_irq = {
> + .name = "S5P System Timer",
> + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
> + .handler = s5p_systimer_interrupt,
> +};
> +
> +/*
> + * Set up timer interrupt, and return the current time in seconds.
> + */
> +static void s5p_systimer_setup(void)
> +{
> + unsigned long tcon;
> + unsigned long tcnt;
> + unsigned long tcfg;
> + unsigned long int_csata;
> +
> + /* clock configuration setting and enable */
> + unsigned long pclk;
> + struct clk *clk;
> +
> + clk = clk_get(NULL, "systimer");
> + if (IS_ERR(clk))
> + panic("failed to get clock for system timer");
> +
> + clk_enable(clk);
> +
> + pclk = clk_get_rate(clk);
> +
> + tcfg = __raw_readl(S5P_SYSTIMER_TCFG);
> + tcfg |= S5P_SYSTIMER_SWRST;
> + s5p_systimer_write(S5P_SYSTIMER_TCFG, tcfg);
> +
> + tcnt = TICK_MAX; /* default value for tcnt */
> +
> + /* initialize system timer clock */
> + tcfg = __raw_readl(S5P_SYSTIMER_TCFG);
> +
> + tcfg &= ~S5P_SYSTIMER_TCLK_MASK;
> + tcfg |= S5P_SYSTIMER_TCLK_PCLK;
> +
> + s5p_systimer_write(S5P_SYSTIMER_TCFG, tcfg);
> +
> + /* TCFG must not be changed at run-time.
> + * If you want to change TCFG, stop timer(TCON[0] = 0)
> + */
> +
> + s5p_systimer_write(S5P_SYSTIMER_TCON, 0);
> +
> + /* read the current timer configuration bits */
> + tcon = __raw_readl(S5P_SYSTIMER_TCON);
> + tcfg = __raw_readl(S5P_SYSTIMER_TCFG);
> +
> + /* configure clock tick */
> + timer_usec_ticks = timer_mask_usec_ticks(S5P_SYSTIMER_PRESCALER,
> pclk);
> +
> + tcfg &= ~S5P_SYSTIMER_TCLK_MASK;
> + tcfg |= S5P_SYSTIMER_TCLK_PCLK;
Here the PCLK clock is used to feed the SYSTEM TIMER.
Maybe it would be worth to use other (not system dependent and always
available)
clock source - for instance the main processor clock?
And additionally it would be welcome to add this clock selection to the
overall clock API? (with use of e.g. clock_set/get_parent)
Is there any plan to do that?
> + tcfg &= ~S5P_SYSTIMER_PRESCALER_MASK;
> + tcfg |= S5P_SYSTIMER_PRESCALER - 1;
> +
> + tcnt = ((pclk / S5P_SYSTIMER_PRESCALER) / S5P_SYSTIMER_TARGET_HZ)
> - 1;
> +
> + /* check to see if timer is within 16bit range... */
> + if (tcnt > TICK_MAX) {
> + panic("setup_timer: HZ is too small, cannot configure
> timer!");
> + return;
> + }
> +
> + s5p_systimer_write(S5P_SYSTIMER_TCFG, tcfg);
> +
> + timer_startval = tcnt;
> + s5p_systimer_write(S5P_SYSTIMER_TICNTB, tcnt);
> +
> + /* set Interrupt tick value */
> + timer_icnt = (S5P_SYSTIMER_TARGET_HZ / HZ) - 1;
> + s5p_systimer_write(S5P_SYSTIMER_ICNTB, timer_icnt);
> +
> + tcon = (S5P_SYSTIMER_INT_AUTO | S5P_SYSTIMER_START
> + | S5P_SYSTIMER_INT_START);
> + s5p_systimer_write(S5P_SYSTIMER_TCON, tcon);
> +
> + /* Interrupt Start and Enable */
> + int_csata = __raw_readl(S5P_SYSTIMER_INT_CSTAT);
> + int_csata |= (S5P_SYSTIMER_INT_ICNTEIE |
> S5P_SYSTIMER_INT_INTENABLE);
> + s5p_systimer_write(S5P_SYSTIMER_INT_CSTAT, int_csata);
> +}
> +
> +static void __init s5p_systimer_init(void)
> +{
> + s5p_systimer_setup();
> + setup_irq(IRQ_SYSTIMER, &s5p_systimer_irq);
> +}
> +
> +struct sys_timer s5p_systimer = {
> + .init = s5p_systimer_init,
> + .offset = s5p_gettimeoffset,
> + .resume = s5p_systimer_setup
> +};
> diff --git a/arch/arm/plat-samsung/include/plat/cpu.h b/arch/arm/plat-
> samsung/include/plat/cpu.h
> index c54f318..d1ec201 100644
> --- a/arch/arm/plat-samsung/include/plat/cpu.h
> +++ b/arch/arm/plat-samsung/include/plat/cpu.h
> @@ -68,6 +68,9 @@ extern void s3c24xx_init_uartdevs(char *name,
> struct sys_timer;
> extern struct sys_timer s3c24xx_timer;
>
> +/* timer for s5p */
> +extern struct sys_timer s5p_systimer;
> +
> /* system device classes */
>
> extern struct sysdev_class s3c2410_sysclass;
> --
> 1.6.2.5
>
> --
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Best regards,
Lukasz Majewski
Samsung Poland R&D Center
Platform Group
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