diff options
| author | Mikael Pettersson <mikpe@it.uu.se> | 2009-10-29 11:46:54 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2009-10-29 11:46:54 -0700 |
| commit | a91549a8f27e63e0e537fe1c20d4845581de894f (patch) | |
| tree | 6cf4a9ecf379cc4bdaa8d988c45702135aecdaa3 /arch | |
| parent | 012abeea669ea49636cf952d13298bb68654146a (diff) | |
| download | linux-a91549a8f27e63e0e537fe1c20d4845581de894f.tar.bz2 | |
iop: clocksource support
This updates the IOP platform to expose the free-running
timer 1 as a clocksource object. This timer is now also
properly initialised, which requires a new write_tcr1()
function from the mach-specific code. Apart from the
explicit initialisation, there is no functional change
in how timer 1 is programmed.
Tested on n2100, compile-tested for all plat-iop machines.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/include/asm/hardware/iop3xx.h | 5 | ||||
| -rw-r--r-- | arch/arm/mach-iop13xx/include/mach/time.h | 5 | ||||
| -rw-r--r-- | arch/arm/plat-iop/time.c | 45 |
3 files changed, 55 insertions, 0 deletions
diff --git a/arch/arm/include/asm/hardware/iop3xx.h b/arch/arm/include/asm/hardware/iop3xx.h index 8d60ad267e3a..643b7b95b25b 100644 --- a/arch/arm/include/asm/hardware/iop3xx.h +++ b/arch/arm/include/asm/hardware/iop3xx.h @@ -260,6 +260,11 @@ static inline u32 read_tcr1(void) return val; } +static inline void write_tcr1(u32 val) +{ + asm volatile("mcr p6, 0, %0, c3, c1, 0" : : "r" (val)); +} + static inline void write_trr0(u32 val) { asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (val)); diff --git a/arch/arm/mach-iop13xx/include/mach/time.h b/arch/arm/mach-iop13xx/include/mach/time.h index d6d52527589d..9fb2768c84bb 100644 --- a/arch/arm/mach-iop13xx/include/mach/time.h +++ b/arch/arm/mach-iop13xx/include/mach/time.h @@ -90,6 +90,11 @@ static inline u32 read_tcr1(void) return val; } +static inline void write_tcr1(u32 val) +{ + asm volatile("mcr p6, 0, %0, c3, c9, 0" : : "r" (val)); +} + static inline void write_trr0(u32 val) { asm volatile("mcr p6, 0, %0, c4, c9, 0" : : "r" (val)); diff --git a/arch/arm/plat-iop/time.c b/arch/arm/plat-iop/time.c index 8da95d57c21f..5506c9b45612 100644 --- a/arch/arm/plat-iop/time.c +++ b/arch/arm/plat-iop/time.c @@ -19,6 +19,7 @@ #include <linux/init.h> #include <linux/timex.h> #include <linux/io.h> +#include <linux/clocksource.h> #include <mach/hardware.h> #include <asm/irq.h> #include <asm/uaccess.h> @@ -26,6 +27,43 @@ #include <asm/mach/time.h> #include <mach/time.h> +/* + * IOP clocksource (free-running timer 1). + */ +static cycle_t iop_clocksource_read(struct clocksource *unused) +{ + return 0xffffffffu - read_tcr1(); +} + +static struct clocksource iop_clocksource = { + .name = "iop_timer1", + .rating = 300, + .read = iop_clocksource_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void __init iop_clocksource_set_hz(struct clocksource *cs, unsigned int hz) +{ + u64 temp; + u32 shift; + + /* Find shift and mult values for hz. */ + shift = 32; + do { + temp = (u64) NSEC_PER_SEC << shift; + do_div(temp, hz); + if ((temp >> 32) == 0) + break; + } while (--shift != 0); + + cs->shift = shift; + cs->mult = (u32) temp; + + printk(KERN_INFO "clocksource: %s uses shift %u mult %#x\n", + cs->name, cs->shift, cs->mult); +} + static unsigned long ticks_per_jiffy; static unsigned long ticks_per_usec; static unsigned long next_jiffy_time; @@ -99,8 +137,15 @@ void __init iop_init_time(unsigned long tick_rate) */ write_trr0(ticks_per_jiffy - 1); write_tmr0(timer_ctl); + + /* + * Set up free-running clocksource timer 1. + */ write_trr1(0xffffffff); + write_tcr1(0xffffffff); write_tmr1(timer_ctl); + iop_clocksource_set_hz(&iop_clocksource, tick_rate); + clocksource_register(&iop_clocksource); setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq); } |