projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 442c8176 RK |
1 | /* |
| 2 | * Generic MMIO clocksource support | |
| 3 | * | |
| 4 | * This program is free software; you can redistribute it and/or modify | |
| 5 | * it under the terms of the GNU General Public License version 2 as | |
| 6 | * published by the Free Software Foundation. | |
| 7 | */ | |
| 8 | #include <linux/clocksource.h> | |
| 9 | #include <linux/errno.h> | |
| 10 | #include <linux/init.h> | |
| 11 | #include <linux/slab.h> | |
| 12 | ||
| 13 | struct clocksource_mmio { | |
| 14 | void __iomem *reg; | |
| 15 | struct clocksource clksrc; | |
| 16 | }; | |
| 17 | ||
| 18 | static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c) | |
| 19 | { | |
| 20 | return container_of(c, struct clocksource_mmio, clksrc); | |
| 21 | } | |
| 22 | ||
| 23 | cycle_t clocksource_mmio_readl_up(struct clocksource *c) | |
| 24 | { | |
| 4a3ae074 | 25 | return (cycle_t)readl_relaxed(to_mmio_clksrc(c)->reg); |
| 442c8176 RK |
26 | } |
| 27 | ||
| 28 | cycle_t clocksource_mmio_readl_down(struct clocksource *c) | |
| 29 | { | |
| 95c19a06 | 30 | return ~(cycle_t)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask; |
| 442c8176 RK |
31 | } |
| 32 | ||
| 33 | cycle_t clocksource_mmio_readw_up(struct clocksource *c) | |
| 34 | { | |
| 4a3ae074 | 35 | return (cycle_t)readw_relaxed(to_mmio_clksrc(c)->reg); |
| 442c8176 RK |
36 | } |
| 37 | ||
| 38 | cycle_t clocksource_mmio_readw_down(struct clocksource *c) | |
| 39 | { | |
| 95c19a06 | 40 | return ~(cycle_t)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask; |
| 442c8176 RK |
41 | } |
| 42 | ||
| 43 | /** | |
| 44 | * clocksource_mmio_init - Initialize a simple mmio based clocksource | |
| 45 | * @base: Virtual address of the clock readout register | |
| 46 | * @name: Name of the clocksource | |
| 47 | * @hz: Frequency of the clocksource in Hz | |
| 48 | * @rating: Rating of the clocksource | |
| 49 | * @bits: Number of valid bits | |
| 50 | * @read: One of clocksource_mmio_read*() above | |
| 51 | */ | |
| 52 | int __init clocksource_mmio_init(void __iomem *base, const char *name, | |
| 53 | unsigned long hz, int rating, unsigned bits, | |
| 54 | cycle_t (*read)(struct clocksource *)) | |
| 55 | { | |
| 56 | struct clocksource_mmio *cs; | |
| 57 | ||
| 58 | if (bits > 32 || bits < 16) | |
| 59 | return -EINVAL; | |
| 60 | ||
| 61 | cs = kzalloc(sizeof(struct clocksource_mmio), GFP_KERNEL); | |
| 62 | if (!cs) | |
| 63 | return -ENOMEM; | |
| 64 | ||
| 65 | cs->reg = base; | |
| 66 | cs->clksrc.name = name; | |
| 67 | cs->clksrc.rating = rating; | |
| 68 | cs->clksrc.read = read; | |
| 69 | cs->clksrc.mask = CLOCKSOURCE_MASK(bits); | |
| 70 | cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS; | |
| 71 | ||
| 72 | return clocksource_register_hz(&cs->clksrc, hz); | |
| 73 | } |