diff options
| -rw-r--r-- | drivers/clocksource/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
| -rw-r--r-- | drivers/clocksource/mmio.c | 73 | ||||
| -rw-r--r-- | include/linux/clocksource.h | 8 |
4 files changed, 85 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 110aeeb52f9a..96c921910469 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -1,2 +1,5 @@ config CLKSRC_I8253 bool + +config CLKSRC_MMIO + bool diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index cfb6383b543a..b995942a5060 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o obj-$(CONFIG_CLKSRC_I8253) += i8253.o +obj-$(CONFIG_CLKSRC_MMIO) += mmio.o diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c new file mode 100644 index 000000000000..c0e25125a55e --- /dev/null +++ b/drivers/clocksource/mmio.c @@ -0,0 +1,73 @@ +/* + * Generic MMIO clocksource support + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/clocksource.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/slab.h> + +struct clocksource_mmio { + void __iomem *reg; + struct clocksource clksrc; +}; + +static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c) +{ + return container_of(c, struct clocksource_mmio, clksrc); +} + +cycle_t clocksource_mmio_readl_up(struct clocksource *c) +{ + return readl_relaxed(to_mmio_clksrc(c)->reg); +} + +cycle_t clocksource_mmio_readl_down(struct clocksource *c) +{ + return ~readl_relaxed(to_mmio_clksrc(c)->reg); +} + +cycle_t clocksource_mmio_readw_up(struct clocksource *c) +{ + return readw_relaxed(to_mmio_clksrc(c)->reg); +} + +cycle_t clocksource_mmio_readw_down(struct clocksource *c) +{ + return ~(unsigned)readw_relaxed(to_mmio_clksrc(c)->reg); +} + +/** + * clocksource_mmio_init - Initialize a simple mmio based clocksource + * @base: Virtual address of the clock readout register + * @name: Name of the clocksource + * @hz: Frequency of the clocksource in Hz + * @rating: Rating of the clocksource + * @bits: Number of valid bits + * @read: One of clocksource_mmio_read*() above + */ +int __init clocksource_mmio_init(void __iomem *base, const char *name, + unsigned long hz, int rating, unsigned bits, + cycle_t (*read)(struct clocksource *)) +{ + struct clocksource_mmio *cs; + + if (bits > 32 || bits < 16) + return -EINVAL; + + cs = kzalloc(sizeof(struct clocksource_mmio), GFP_KERNEL); + if (!cs) + return -ENOMEM; + + cs->reg = base; + cs->clksrc.name = name; + cs->clksrc.rating = rating; + cs->clksrc.read = read; + cs->clksrc.mask = CLOCKSOURCE_MASK(bits); + cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + return clocksource_register_hz(&cs->clksrc, hz); +} diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index c918fbd33ee5..d4646b48dc4a 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -337,6 +337,14 @@ static inline void update_vsyscall_tz(void) extern void timekeeping_notify(struct clocksource *clock); +extern cycle_t clocksource_mmio_readl_up(struct clocksource *); +extern cycle_t clocksource_mmio_readl_down(struct clocksource *); +extern cycle_t clocksource_mmio_readw_up(struct clocksource *); +extern cycle_t clocksource_mmio_readw_down(struct clocksource *); + +extern int clocksource_mmio_init(void __iomem *, const char *, + unsigned long, int, unsigned, cycle_t (*)(struct clocksource *)); + extern int clocksource_i8253_init(void); #endif /* _LINUX_CLOCKSOURCE_H */ |