projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 778eeb1b SH |
1 | /* |
| 2 | * This file is subject to the terms and conditions of the GNU General Public | |
| 3 | * License. See the file "COPYING" in the main directory of this archive | |
| 4 | * for more details. | |
| 5 | * | |
| 6 | * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. | |
| 7 | */ | |
| 8 | #include <linux/clocksource.h> | |
| 9 | #include <linux/init.h> | |
| 10 | ||
| 11 | #include <asm/time.h> | |
| 12 | #include <asm/gic.h> | |
| 13 | ||
| 14 | static cycle_t gic_hpt_read(struct clocksource *cs) | |
| 15 | { | |
| 16 | unsigned int hi, hi2, lo; | |
| 17 | ||
| 18 | do { | |
| 19 | GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_63_32), hi); | |
| 20 | GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), lo); | |
| 21 | GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_63_32), hi2); | |
| 22 | } while (hi2 != hi); | |
| 23 | ||
| 24 | return (((cycle_t) hi) << 32) + lo; | |
| 25 | } | |
| 26 | ||
| 27 | static struct clocksource gic_clocksource = { | |
| 28 | .name = "GIC", | |
| 29 | .read = gic_hpt_read, | |
| 30 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
| 31 | }; | |
| 32 | ||
| 33 | void __init gic_clocksource_init(unsigned int frequency) | |
| 34 | { | |
| 35 | unsigned int config, bits; | |
| 36 | ||
| 37 | /* Calculate the clocksource mask. */ | |
| 38 | GICREAD(GIC_REG(SHARED, GIC_SH_CONFIG), config); | |
| 39 | bits = 32 + ((config & GIC_SH_CONFIG_COUNTBITS_MSK) >> | |
| 40 | (GIC_SH_CONFIG_COUNTBITS_SHF - 2)); | |
| 41 | ||
| 42 | /* Set clocksource mask. */ | |
| 43 | gic_clocksource.mask = CLOCKSOURCE_MASK(bits); | |
| 44 | ||
| 45 | /* Calculate a somewhat reasonable rating value. */ | |
| 46 | gic_clocksource.rating = 200 + frequency / 10000000; | |
| 47 | ||
| 48 | clocksource_register_hz(&gic_clocksource, frequency); | |
| 49 | } |