diff options
| -rw-r--r-- | arch/arm/mach-ep93xx/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm/mach-ep93xx/core.c | 109 | ||||
| -rw-r--r-- | arch/arm/mach-ep93xx/timer-ep93xx.c | 112 |
3 files changed, 113 insertions, 110 deletions
diff --git a/arch/arm/mach-ep93xx/Makefile b/arch/arm/mach-ep93xx/Makefile index 78d427b34b1f..b7ae4345ac08 100644 --- a/arch/arm/mach-ep93xx/Makefile +++ b/arch/arm/mach-ep93xx/Makefile @@ -1,7 +1,7 @@ # # 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 diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c index 0e571f1749d6..5e2151bcc0c5 100644 --- a/arch/arm/mach-ep93xx/core.c +++ b/arch/arm/mach-ep93xx/core.c @@ -22,7 +22,6 @@ #include <linux/interrupt.h> #include <linux/dma-mapping.h> #include <linux/sys_soc.h> -#include <linux/timex.h> #include <linux/irq.h> #include <linux/io.h> #include <linux/gpio.h> @@ -47,7 +46,6 @@ #include <asm/mach/arch.h> #include <asm/mach/map.h> -#include <asm/mach/time.h> #include "soc.h" @@ -73,113 +71,6 @@ void __init ep93xx_map_io(void) 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 *************************************************************************/ diff --git a/arch/arm/mach-ep93xx/timer-ep93xx.c b/arch/arm/mach-ep93xx/timer-ep93xx.c new file mode 100644 index 000000000000..978252c52661 --- /dev/null +++ b/arch/arm/mach-ep93xx/timer-ep93xx.c @@ -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); +} |