Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / clocksource / mmio.c

diff --git a/kernel/drivers/clocksource/mmio.c b/kernel/drivers/clocksource/mmio.c
new file mode 100644 (file)
index 0000000..1593ade
--- /dev/null
+++ b/kernel/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 (cycle_t)readl_relaxed(to_mmio_clksrc(c)->reg);
+}
+
+cycle_t clocksource_mmio_readl_down(struct clocksource *c)
+{
+       return ~(cycle_t)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
+}
+
+cycle_t clocksource_mmio_readw_up(struct clocksource *c)
+{
+       return (cycle_t)readw_relaxed(to_mmio_clksrc(c)->reg);
+}
+
+cycle_t clocksource_mmio_readw_down(struct clocksource *c)
+{
+       return ~(cycle_t)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
+}
+
+/**
+ * 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);
+}