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70 lines
1.7 KiB
70 lines
1.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Generic MMIO clocksource support |
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*/ |
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#include <linux/clocksource.h> |
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#include <linux/errno.h> |
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#include <linux/init.h> |
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#include <linux/slab.h> |
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struct clocksource_mmio { |
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void __iomem *reg; |
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struct clocksource clksrc; |
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}; |
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static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c) |
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{ |
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return container_of(c, struct clocksource_mmio, clksrc); |
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} |
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u64 clocksource_mmio_readl_up(struct clocksource *c) |
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{ |
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return (u64)readl_relaxed(to_mmio_clksrc(c)->reg); |
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} |
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u64 clocksource_mmio_readl_down(struct clocksource *c) |
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{ |
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return ~(u64)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask; |
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} |
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u64 clocksource_mmio_readw_up(struct clocksource *c) |
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{ |
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return (u64)readw_relaxed(to_mmio_clksrc(c)->reg); |
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} |
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u64 clocksource_mmio_readw_down(struct clocksource *c) |
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{ |
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return ~(u64)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask; |
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} |
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/** |
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* clocksource_mmio_init - Initialize a simple mmio based clocksource |
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* @base: Virtual address of the clock readout register |
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* @name: Name of the clocksource |
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* @hz: Frequency of the clocksource in Hz |
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* @rating: Rating of the clocksource |
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* @bits: Number of valid bits |
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* @read: One of clocksource_mmio_read*() above |
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*/ |
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int __init clocksource_mmio_init(void __iomem *base, const char *name, |
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unsigned long hz, int rating, unsigned bits, |
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u64 (*read)(struct clocksource *)) |
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{ |
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struct clocksource_mmio *cs; |
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if (bits > 64 || bits < 16) |
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return -EINVAL; |
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cs = kzalloc(sizeof(struct clocksource_mmio), GFP_KERNEL); |
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if (!cs) |
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return -ENOMEM; |
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cs->reg = base; |
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cs->clksrc.name = name; |
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cs->clksrc.rating = rating; |
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cs->clksrc.read = read; |
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cs->clksrc.mask = CLOCKSOURCE_MASK(bits); |
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cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS; |
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return clocksource_register_hz(&cs->clksrc, hz); |
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}
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