diff options
author | 2016-04-11 10:41:07 +0300 | |
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committer | 2016-04-13 08:17:18 +0300 | |
commit | e09b41010ba33a20a87472ee821fa407a5b8da36 (patch) | |
tree | d10dc367189862e7ca5c592f033dc3726e1df4e3 /kernel/arch/arm/mach-ep93xx/timer-ep93xx.c | |
parent | f93b97fd65072de626c074dbe099a1fff05ce060 (diff) |
These changes are the raw update to linux-4.4.6-rt14. Kernel sources
are taken from kernel.org, and rt patch from the rt wiki download page.
During the rebasing, the following patch collided:
Force tick interrupt and get rid of softirq magic(I70131fb85).
Collisions have been removed because its logic was found on the
source already.
Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'kernel/arch/arm/mach-ep93xx/timer-ep93xx.c')
-rw-r--r-- | kernel/arch/arm/mach-ep93xx/timer-ep93xx.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-ep93xx/timer-ep93xx.c b/kernel/arch/arm/mach-ep93xx/timer-ep93xx.c new file mode 100644 index 000000000..e5f791145 --- /dev/null +++ b/kernel/arch/arm/mach-ep93xx/timer-ep93xx.c @@ -0,0 +1,143 @@ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/sched_clock.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/io.h> +#include <asm/mach/time.h> +#include "soc.h" + +/************************************************************************* + * Timer handling for EP93xx + ************************************************************************* + * The ep93xx has four internal timers. Timers 1, 2 (both 16 bit) and + * 3 (32 bit) count down at 508 kHz, are self-reloading, and can generate + * an interrupt on underflow. Timer 4 (40 bit) counts down at 983.04 kHz, + * is free-running, and can't generate interrupts. + * + * The 508 kHz timers are ideal for use for the timer interrupt, as the + * most common values of HZ divide 508 kHz nicely. We pick the 32 bit + * timer (timer 3) to get as long sleep intervals as possible when using + * CONFIG_NO_HZ. + * + * The higher clock rate of timer 4 makes it a better choice than the + * other timers for use as clock source and for sched_clock(), providing + * a stable 40 bit time base. + ************************************************************************* + */ +#define EP93XX_TIMER_REG(x) (EP93XX_TIMER_BASE + (x)) +#define EP93XX_TIMER1_LOAD EP93XX_TIMER_REG(0x00) +#define EP93XX_TIMER1_VALUE EP93XX_TIMER_REG(0x04) +#define EP93XX_TIMER1_CONTROL EP93XX_TIMER_REG(0x08) +#define EP93XX_TIMER123_CONTROL_ENABLE (1 << 7) +#define EP93XX_TIMER123_CONTROL_MODE (1 << 6) +#define EP93XX_TIMER123_CONTROL_CLKSEL (1 << 3) +#define EP93XX_TIMER1_CLEAR EP93XX_TIMER_REG(0x0c) +#define EP93XX_TIMER2_LOAD EP93XX_TIMER_REG(0x20) +#define EP93XX_TIMER2_VALUE EP93XX_TIMER_REG(0x24) +#define EP93XX_TIMER2_CONTROL EP93XX_TIMER_REG(0x28) +#define EP93XX_TIMER2_CLEAR EP93XX_TIMER_REG(0x2c) +#define EP93XX_TIMER4_VALUE_LOW EP93XX_TIMER_REG(0x60) +#define EP93XX_TIMER4_VALUE_HIGH EP93XX_TIMER_REG(0x64) +#define EP93XX_TIMER4_VALUE_HIGH_ENABLE (1 << 8) +#define EP93XX_TIMER3_LOAD EP93XX_TIMER_REG(0x80) +#define EP93XX_TIMER3_VALUE EP93XX_TIMER_REG(0x84) +#define EP93XX_TIMER3_CONTROL EP93XX_TIMER_REG(0x88) +#define EP93XX_TIMER3_CLEAR EP93XX_TIMER_REG(0x8c) + +#define EP93XX_TIMER123_RATE 508469 +#define EP93XX_TIMER4_RATE 983040 + +static u64 notrace ep93xx_read_sched_clock(void) +{ + u64 ret; + + ret = readl(EP93XX_TIMER4_VALUE_LOW); + ret |= ((u64) (readl(EP93XX_TIMER4_VALUE_HIGH) & 0xff) << 32); + return ret; +} + +cycle_t ep93xx_clocksource_read(struct clocksource *c) +{ + u64 ret; + + ret = readl(EP93XX_TIMER4_VALUE_LOW); + ret |= ((u64) (readl(EP93XX_TIMER4_VALUE_HIGH) & 0xff) << 32); + return (cycle_t) ret; +} + +static int ep93xx_clkevt_set_next_event(unsigned long next, + struct clock_event_device *evt) +{ + /* Default mode: periodic, off, 508 kHz */ + u32 tmode = EP93XX_TIMER123_CONTROL_MODE | + EP93XX_TIMER123_CONTROL_CLKSEL; + + /* Clear timer */ + writel(tmode, EP93XX_TIMER3_CONTROL); + + /* Set next event */ + writel(next, EP93XX_TIMER3_LOAD); + writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE, + EP93XX_TIMER3_CONTROL); + return 0; +} + + +static int ep93xx_clkevt_shutdown(struct clock_event_device *evt) +{ + /* Disable timer */ + writel(0, EP93XX_TIMER3_CONTROL); + + return 0; +} + +static struct clock_event_device ep93xx_clockevent = { + .name = "timer1", + .features = CLOCK_EVT_FEAT_ONESHOT, + .set_state_shutdown = ep93xx_clkevt_shutdown, + .set_state_oneshot = ep93xx_clkevt_shutdown, + .tick_resume = ep93xx_clkevt_shutdown, + .set_next_event = ep93xx_clkevt_set_next_event, + .rating = 300, +}; + +static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + /* Writing any value clears the timer interrupt */ + writel(1, EP93XX_TIMER3_CLEAR); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction ep93xx_timer_irq = { + .name = "ep93xx timer", + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = ep93xx_timer_interrupt, + .dev_id = &ep93xx_clockevent, +}; + +void __init ep93xx_timer_init(void) +{ + /* Enable and register clocksource and sched_clock on timer 4 */ + writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE, + EP93XX_TIMER4_VALUE_HIGH); + clocksource_mmio_init(NULL, "timer4", + EP93XX_TIMER4_RATE, 200, 40, + ep93xx_clocksource_read); + sched_clock_register(ep93xx_read_sched_clock, 40, + EP93XX_TIMER4_RATE); + + /* Set up clockevent on timer 3 */ + setup_irq(IRQ_EP93XX_TIMER3, &ep93xx_timer_irq); + clockevents_config_and_register(&ep93xx_clockevent, + EP93XX_TIMER123_RATE, + 1, + 0xffffffffU); +} |