diff options
Diffstat (limited to 'arch/mips/kernel/csrc-gic.c')
| -rw-r--r-- | arch/mips/kernel/csrc-gic.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/arch/mips/kernel/csrc-gic.c b/arch/mips/kernel/csrc-gic.c new file mode 100644 index 000000000000..5dca24bce51b --- /dev/null +++ b/arch/mips/kernel/csrc-gic.c @@ -0,0 +1,49 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. + */ +#include <linux/clocksource.h> +#include <linux/init.h> + +#include <asm/time.h> +#include <asm/gic.h> + +static cycle_t gic_hpt_read(struct clocksource *cs) +{ + unsigned int hi, hi2, lo; + + do { + GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_63_32), hi); + GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), lo); + GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_63_32), hi2); + } while (hi2 != hi); + + return (((cycle_t) hi) << 32) + lo; +} + +static struct clocksource gic_clocksource = { + .name = "GIC", + .read = gic_hpt_read, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +void __init gic_clocksource_init(unsigned int frequency) +{ + unsigned int config, bits; + + /* Calculate the clocksource mask. */ + GICREAD(GIC_REG(SHARED, GIC_SH_CONFIG), config); + bits = 32 + ((config & GIC_SH_CONFIG_COUNTBITS_MSK) >> + (GIC_SH_CONFIG_COUNTBITS_SHF - 2)); + + /* Set clocksource mask. */ + gic_clocksource.mask = CLOCKSOURCE_MASK(bits); + + /* Calculate a somewhat reasonable rating value. */ + gic_clocksource.rating = 200 + frequency / 10000000; + + clocksource_register_hz(&gic_clocksource, frequency); +} |