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-rw-r--r--drivers/clocksource/Kconfig3
-rw-r--r--drivers/clocksource/Makefile1
-rw-r--r--drivers/clocksource/mmio.c73
-rw-r--r--include/linux/clocksource.h8
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 */