[U-Boot] [PATCH resend] armv7/ltimer: Add support for local timer on armv7 cpus

Vipin Kumar
2012-12-12T10:01:44Z

ping

On 12/6/2012 2:52 PM, Vipin KUMAR wrote:
> Certain ARMV7 cpus eg. CortexA9 contains a local and a global timer within the
> CPU core itself. This patch adds generic support for local timer.
>
> Signed-off-by: Vipin Kumar<vipin.kumar@st.com>
> ---
> arch/arm/cpu/armv7/Makefile | 11 ++-
> arch/arm/cpu/armv7/ca9_ltimer.c | 152 ++++++++++++++++++++++++++++++++++++++
> arch/arm/include/asm/ca9_ltimer.h | 40 ++++++++++
> 3 files changed, 199 insertions(+), 4 deletions(-)
> create mode 100644 arch/arm/cpu/armv7/ca9_ltimer.c
> create mode 100644 arch/arm/include/asm/ca9_ltimer.h
>
> diff --git a/arch/arm/cpu/armv7/Makefile b/arch/arm/cpu/armv7/Makefile
> index 4fdbee4..3ef01f6 100644
> --- a/arch/arm/cpu/armv7/Makefile
> +++ b/arch/arm/cpu/armv7/Makefile
> @@ -27,15 +27,18 @@ LIB = $(obj)lib$(CPU).o
>
> START := start.o
>
> -COBJS += cache_v7.o
> +COBJS-y += cache_v7.o
>
> -COBJS += cpu.o
> -COBJS += syslib.o
> +COBJS-y += cpu.o
> +COBJS-y += syslib.o
> +COBJS-$(CONFIG_ARMV7_CA9LTIMER) += ca9_ltimer.o
>
> ifneq ($(CONFIG_AM33XX)$(CONFIG_OMAP44XX)$(CONFIG_OMAP54XX)$(CONFIG_TEGRA20),)
> -SOBJS += lowlevel_init.o
> +SOBJS-y += lowlevel_init.o
> endif
>
> +COBJS := $(sort $(COBJS-y))
> +SOBJS := $(sort $(SOBJS-y))
> SRCS := $(START:.o=.S) $(COBJS:.o=.c)
> OBJS := $(addprefix $(obj),$(COBJS) $(SOBJS))
> START := $(addprefix $(obj),$(START))
> diff --git a/arch/arm/cpu/armv7/ca9_ltimer.c b/arch/arm/cpu/armv7/ca9_ltimer.c
> new file mode 100644
> index 0000000..cbf1552
> --- /dev/null
> +++ b/arch/arm/cpu/armv7/ca9_ltimer.c
> @@ -0,0 +1,152 @@
> +/*
> + * (C) Copyright 2012
> + * Vipin Kumar, ST Micoelectronics, vipin.kumar at st.com.
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include<common.h>
> +#include<asm/io.h>
> +#include<asm/ca9_ltimer.h>
> +#include<asm/arch/hardware.h>
> +
> +#define READ_TIMER() readl(&ca9_timer_p->count)
> +
> +static struct ca9_timer_regs *const ca9_timer_p =
> + (struct ca9_timer_regs *)CONFIG_ARMV7_LTIMER_BASE;
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +#define timestamp gd->tbl
> +#define lastdec gd->lastinc
> +#define tickshz gd->timer_rate_hz
> +#define ticksper10usec gd->tbu
> +
> +int timer_init(void)
> +{
> + u32 prescaler, timertickshz;
> + /*
> + * Genrally, CortexA9 MPUs are operating from 500MHz to 1500MHz which
> + * means that CA9 local timer clock would be in the range of 250 MHz to
> + * 750MHz.
> + * Try to find a prescaler which can perfectly divide the local timer
> + * clock. Take prescaler as 200 if nothing is found
> + */
> + for (prescaler = 255; prescaler> 1; prescaler--) {
> + if (CONFIG_ARMV7_LTMR_CLK ==
> + (CONFIG_ARMV7_LTMR_CLK / prescaler) * prescaler)
> + break;
> + }
> +
> + if (prescaler == 1)
> + prescaler = 200;
> + timertickshz = CONFIG_ARMV7_LTMR_CLK / prescaler;
> + ticksper10usec = timertickshz / (100 * 1000);
> + tickshz = timertickshz / CONFIG_SYS_HZ;
> +
> + /* disable timers */
> + writel(((prescaler - 1)<< 8) | AUTO_RELOAD,&ca9_timer_p->control);
> +
> + /* load value for free running */
> + writel(FREE_RUNNING,&ca9_timer_p->load);
> +
> + /* auto reload, start timer */
> + setbits_le32(&ca9_timer_p->control, TIMER_ENABLE);
> +
> + reset_timer_masked();
> +
> + return 0;
> +}
> +
> +/*
> + * timer without interrupts
> + */
> +
> +void reset_timer(void)
> +{
> + reset_timer_masked();
> +}
> +
> +ulong get_timer(ulong base)
> +{
> + return (get_timer_masked() / tickshz) - base;
> +}
> +
> +void set_timer(ulong t)
> +{
> + timestamp = t;
> +}
> +
> +void __udelay(unsigned long usec)
> +{
> + ulong tmo;
> + ulong start = get_timer_masked();
> + ulong rndoff;
> +
> + rndoff = (usec % 10) ? 1 : 0;
> + tmo = ((usec / 10) + rndoff) * ticksper10usec;
> +
> + while ((ulong) (get_timer_masked() - start)< tmo);
> +}
> +
> +void reset_timer_masked(void)
> +{
> + /* reset time */
> + lastdec = READ_TIMER();
> + timestamp = 0;
> +}
> +
> +ulong get_timer_masked(void)
> +{
> + ulong now = READ_TIMER();
> +
> + if (now<= lastdec) {
> + /* normal mode */
> + timestamp += lastdec - now;
> + } else {
> + /* we have an overflow ... */
> + timestamp += lastdec + FREE_RUNNING - now;
> + }
> + lastdec = now;
> +
> + return timestamp;
> +}
> +
> +void udelay_masked(unsigned long usec)
> +{
> + return udelay(usec);
> +}
> +
> +/*
> + * This function is derived from PowerPC code (read timebase as long long).
> + * On ARM it just returns the timer value.
> + */
> +unsigned long long get_ticks(void)
> +{
> + return get_timer(0);
> +}
> +
> +/*
> + * This function is derived from PowerPC code (timebase clock frequency).
> + * On ARM it returns the number of timer ticks per second.
> + */
> +ulong get_tbclk(void)
> +{
> + return CONFIG_SYS_HZ;
> +}
> diff --git a/arch/arm/include/asm/ca9_ltimer.h b/arch/arm/include/asm/ca9_ltimer.h
> new file mode 100644
> index 0000000..8833853
> --- /dev/null
> +++ b/arch/arm/include/asm/ca9_ltimer.h
> @@ -0,0 +1,40 @@
> +/*
> + * (C) Copyright 2012
> + * Vipin Kumar, ST Micoelectronics, vipin.kumar at st.com.
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#ifndef __ARCH_ARM_CA9TIMER_H
> +#define __ARCH_ARM_CA9TIMER_H
> +
> +struct ca9_timer_regs {
> + u32 load;
> + u32 count;
> + u32 control;
> +};
> +
> +/* control related definitions */
> +#define AUTO_RELOAD (1<< 1)
> +#define TIMER_ENABLE (1<< 0)
> +
> +/* load related definitions */
> +#define FREE_RUNNING (0xFFFFFFFF)
> +
> +#endif