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ARM: ep93xx: move timer to its own file 

This breaks the timer code out of the core file in preparation
for refactoring.

Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2015-06-15 13:15:26 +02:00
parent d770e558e2
commit 361c81f996
3 changed files with 113 additions and 110 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm/mach-ep93xx/Makefile
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@ -1,7 +1,7 @@
# #
# Makefile for the linux kernel. # Makefile for the linux kernel.
# #
obj-y := core.o clock.o obj-y := core.o clock.o timer-ep93xx.o
obj-$(CONFIG_EP93XX_DMA) += dma.o obj-$(CONFIG_EP93XX_DMA) += dma.o

109
arch/arm/mach-ep93xx/core.c
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@ -22,7 +22,6 @@
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/dma-mapping.h> #include <linux/dma-mapping.h>
#include <linux/sys_soc.h> #include <linux/sys_soc.h>
#include <linux/timex.h>
#include <linux/irq.h> #include <linux/irq.h>
#include <linux/io.h> #include <linux/io.h>
#include <linux/gpio.h> #include <linux/gpio.h>
@ -47,7 +46,6 @@
#include <asm/mach/arch.h> #include <asm/mach/arch.h>
#include <asm/mach/map.h> #include <asm/mach/map.h>
#include <asm/mach/time.h>
#include "soc.h" #include "soc.h"
@ -73,113 +71,6 @@ void __init ep93xx_map_io(void)
iotable_init(ep93xx_io_desc, ARRAY_SIZE(ep93xx_io_desc)); iotable_init(ep93xx_io_desc, ARRAY_SIZE(ep93xx_io_desc));
} }
/*************************************************************************
* 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 one of the 16
* bit timers (timer 1) since we don't need more than 16 bits of reload
* value as long as HZ >= 8.
*
* The higher clock rate of timer 4 makes it a better choice than the
* other timers for use in gettimeoffset(), while the fact that it can't
* generate interrupts means we don't have to worry about not being able
* to use this timer for something else. We also use timer 4 for keeping
* track of lost jiffies.
*/
#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_CLOCK 508469
#define EP93XX_TIMER4_CLOCK 983040
#define TIMER1_RELOAD ((EP93XX_TIMER123_CLOCK / HZ) - 1)
#define TIMER4_TICKS_PER_JIFFY DIV_ROUND_CLOSEST(EP93XX_TIMER4_CLOCK, HZ)
static unsigned int last_jiffy_time;
static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id)
{
/* Writing any value clears the timer interrupt */
__raw_writel(1, EP93XX_TIMER1_CLEAR);
/* Recover lost jiffies */
while ((signed long)
(__raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time)
>= TIMER4_TICKS_PER_JIFFY) {
last_jiffy_time += TIMER4_TICKS_PER_JIFFY;
timer_tick();
}
return IRQ_HANDLED;
}
static struct irqaction ep93xx_timer_irq = {
.name = "ep93xx timer",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = ep93xx_timer_interrupt,
};
static u32 ep93xx_gettimeoffset(void)
{
int offset;
offset = __raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time;
/*
* Timer 4 is based on a 983.04 kHz reference clock,
* so dividing by 983040 gives the fraction of a second,
* so dividing by 0.983040 converts to uS.
* Refactor the calculation to avoid overflow.
* Finally, multiply by 1000 to give nS.
*/
return (offset + (53 * offset / 3072)) * 1000;
}
void __init ep93xx_timer_init(void)
{
u32 tmode = EP93XX_TIMER123_CONTROL_MODE |
EP93XX_TIMER123_CONTROL_CLKSEL;
arch_gettimeoffset = ep93xx_gettimeoffset;
/* Enable periodic HZ timer. */
__raw_writel(tmode, EP93XX_TIMER1_CONTROL);
__raw_writel(TIMER1_RELOAD, EP93XX_TIMER1_LOAD);
__raw_writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE,
EP93XX_TIMER1_CONTROL);
/* Enable lost jiffy timer. */
__raw_writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE,
EP93XX_TIMER4_VALUE_HIGH);
setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq);
}
/************************************************************************* /*************************************************************************
* EP93xx IRQ handling * EP93xx IRQ handling
*************************************************************************/ *************************************************************************/

112
arch/arm/mach-ep93xx/timer-ep93xx.c Normal file
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@ -0,0 +1,112 @@
#include <linux/kernel.h>
#include <linux/init.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 one of the 16
* bit timers (timer 1) since we don't need more than 16 bits of reload
* value as long as HZ >= 8.
*
* The higher clock rate of timer 4 makes it a better choice than the
* other timers for use in gettimeoffset(), while the fact that it can't
* generate interrupts means we don't have to worry about not being able
* to use this timer for something else. We also use timer 4 for keeping
* track of lost jiffies.
*/
#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_CLOCK 508469
#define EP93XX_TIMER4_CLOCK 983040
#define TIMER1_RELOAD ((EP93XX_TIMER123_CLOCK / HZ) - 1)
#define TIMER4_TICKS_PER_JIFFY DIV_ROUND_CLOSEST(EP93XX_TIMER4_CLOCK, HZ)
static unsigned int last_jiffy_time;
static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id)
{
/* Writing any value clears the timer interrupt */
__raw_writel(1, EP93XX_TIMER1_CLEAR);
/* Recover lost jiffies */
while ((signed long)
(__raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time)
>= TIMER4_TICKS_PER_JIFFY) {
last_jiffy_time += TIMER4_TICKS_PER_JIFFY;
timer_tick();
}
return IRQ_HANDLED;
}
static struct irqaction ep93xx_timer_irq = {
.name = "ep93xx timer",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = ep93xx_timer_interrupt,
};
static u32 ep93xx_gettimeoffset(void)
{
int offset;
offset = __raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time;
/*
* Timer 4 is based on a 983.04 kHz reference clock,
* so dividing by 983040 gives the fraction of a second,
* so dividing by 0.983040 converts to uS.
* Refactor the calculation to avoid overflow.
* Finally, multiply by 1000 to give nS.
*/
return (offset + (53 * offset / 3072)) * 1000;
}
void __init ep93xx_timer_init(void)
{
u32 tmode = EP93XX_TIMER123_CONTROL_MODE |
EP93XX_TIMER123_CONTROL_CLKSEL;
arch_gettimeoffset = ep93xx_gettimeoffset;
/* Enable periodic HZ timer. */
__raw_writel(tmode, EP93XX_TIMER1_CONTROL);
__raw_writel(TIMER1_RELOAD, EP93XX_TIMER1_LOAD);
__raw_writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE,
EP93XX_TIMER1_CONTROL);
/* Enable lost jiffy timer. */
__raw_writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE,
EP93XX_TIMER4_VALUE_HIGH);
setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq);
}