| 1 | |
| 2 | |
| 3 | * Generic MMIO clocksource support
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| 4 |
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| 5 | #include <linux/clocksource.h>
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| 6 | #include <linux/errno.h>
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| 7 | #include <linux/init.h>
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| 8 | #include <linux/slab.h>
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| 9 |
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| 10 | struct clocksource_mmio {
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| 11 | void __iomem *reg;
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| 12 | struct clocksource clksrc;
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| 13 | };
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| 14 |
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| 15 | static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c)
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| 16 | {
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| 17 | return container_of(c, struct clocksource_mmio, clksrc);
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| 18 | }
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| 19 |
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| 20 | u64 clocksource_mmio_readl_up(struct clocksource *c)
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| 21 | {
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| 22 | return (u64)readl_relaxed(to_mmio_clksrc(c)->reg);
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| 23 | }
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| 24 | EXPORT_SYMBOL_GPL(clocksource_mmio_readl_up);
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| 25 |
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| 26 | u64 clocksource_mmio_readl_down(struct clocksource *c)
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| 27 | {
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| 28 | return ~(u64)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
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| 29 | }
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| 30 | EXPORT_SYMBOL_GPL(clocksource_mmio_readl_down);
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| 31 |
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| 32 | u64 clocksource_mmio_readw_up(struct clocksource *c)
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| 33 | {
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| 34 | return (u64)readw_relaxed(to_mmio_clksrc(c)->reg);
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| 35 | }
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| 36 | EXPORT_SYMBOL_GPL(clocksource_mmio_readw_up);
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| 37 |
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| 38 | u64 clocksource_mmio_readw_down(struct clocksource *c)
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| 39 | {
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| 40 | return ~(u64)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
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| 41 | }
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| 42 | EXPORT_SYMBOL_GPL(clocksource_mmio_readw_down);
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| 43 |
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| 44 | |
| 45 | * clocksource_mmio_init - Initialize a simple mmio based clocksource
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| 46 | * @base: Virtual address of the clock readout register
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| 47 | * @name: Name of the clocksource
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| 48 | * @hz: Frequency of the clocksource in Hz
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| 49 | * @rating: Rating of the clocksource
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| 50 | * @bits: Number of valid bits
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| 51 | * @read: One of clocksource_mmio_read*() above
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| 52 |
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| 53 | int clocksource_mmio_init(void __iomem *base, const char *name,
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| 54 | unsigned long hz, int rating, unsigned bits,
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| 55 | u64 (*read)(struct clocksource *))
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| 56 | {
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| 57 | struct clocksource_mmio *cs;
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| 58 |
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| 59 | if (bits > 64 || bits < 16)
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| 60 | return -EINVAL;
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| 61 |
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| 62 | cs = kzalloc_obj(struct clocksource_mmio);
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| 63 | if (!cs)
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| 64 | return -ENOMEM;
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| 65 |
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| 66 | cs->reg = base;
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| 67 | cs->clksrc.name = name;
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| 68 | cs->clksrc.rating = rating;
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| 69 | cs->clksrc.read = read;
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| 70 | cs->clksrc.mask = CLOCKSOURCE_MASK(bits);
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| 71 | cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
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| 72 |
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| 73 | return clocksource_register_hz(&cs->clksrc, hz);
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| 74 | }
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| 75 | EXPORT_SYMBOL_GPL(clocksource_mmio_init);
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