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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/nios2/kernel/time.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/nios2/kernel/time.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/arch/nios2/kernel/time.c b/arch/nios2/kernel/time.c new file mode 100644 index 000000000..54467d008 --- /dev/null +++ b/arch/nios2/kernel/time.c @@ -0,0 +1,359 @@ +/* + * Copyright (C) 2013-2014 Altera Corporation + * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch> + * Copyright (C) 2004 Microtronix Datacom Ltd. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/export.h> +#include <linux/interrupt.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/delay.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/io.h> +#include <linux/slab.h> + +#define ALTR_TIMER_COMPATIBLE "altr,timer-1.0" + +#define ALTERA_TIMER_STATUS_REG 0 +#define ALTERA_TIMER_CONTROL_REG 4 +#define ALTERA_TIMER_PERIODL_REG 8 +#define ALTERA_TIMER_PERIODH_REG 12 +#define ALTERA_TIMER_SNAPL_REG 16 +#define ALTERA_TIMER_SNAPH_REG 20 + +#define ALTERA_TIMER_CONTROL_ITO_MSK (0x1) +#define ALTERA_TIMER_CONTROL_CONT_MSK (0x2) +#define ALTERA_TIMER_CONTROL_START_MSK (0x4) +#define ALTERA_TIMER_CONTROL_STOP_MSK (0x8) + +struct nios2_timer { + void __iomem *base; + unsigned long freq; +}; + +struct nios2_clockevent_dev { + struct nios2_timer timer; + struct clock_event_device ced; +}; + +struct nios2_clocksource { + struct nios2_timer timer; + struct clocksource cs; +}; + +static inline struct nios2_clockevent_dev * + to_nios2_clkevent(struct clock_event_device *evt) +{ + return container_of(evt, struct nios2_clockevent_dev, ced); +} + +static inline struct nios2_clocksource * + to_nios2_clksource(struct clocksource *cs) +{ + return container_of(cs, struct nios2_clocksource, cs); +} + +static u16 timer_readw(struct nios2_timer *timer, u32 offs) +{ + return readw(timer->base + offs); +} + +static void timer_writew(struct nios2_timer *timer, u16 val, u32 offs) +{ + writew(val, timer->base + offs); +} + +static inline unsigned long read_timersnapshot(struct nios2_timer *timer) +{ + unsigned long count; + + timer_writew(timer, 0, ALTERA_TIMER_SNAPL_REG); + count = timer_readw(timer, ALTERA_TIMER_SNAPH_REG) << 16 | + timer_readw(timer, ALTERA_TIMER_SNAPL_REG); + + return count; +} + +static u64 nios2_timer_read(struct clocksource *cs) +{ + struct nios2_clocksource *nios2_cs = to_nios2_clksource(cs); + unsigned long flags; + u32 count; + + local_irq_save(flags); + count = read_timersnapshot(&nios2_cs->timer); + local_irq_restore(flags); + + /* Counter is counting down */ + return ~count; +} + +static struct nios2_clocksource nios2_cs = { + .cs = { + .name = "nios2-clksrc", + .rating = 250, + .read = nios2_timer_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + }, +}; + +cycles_t get_cycles(void) +{ + /* Only read timer if it has been initialized */ + if (nios2_cs.timer.base) + return nios2_timer_read(&nios2_cs.cs); + return 0; +} +EXPORT_SYMBOL(get_cycles); + +static void nios2_timer_start(struct nios2_timer *timer) +{ + u16 ctrl; + + ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG); + ctrl |= ALTERA_TIMER_CONTROL_START_MSK; + timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG); +} + +static void nios2_timer_stop(struct nios2_timer *timer) +{ + u16 ctrl; + + ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG); + ctrl |= ALTERA_TIMER_CONTROL_STOP_MSK; + timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG); +} + +static void nios2_timer_config(struct nios2_timer *timer, unsigned long period, + bool periodic) +{ + u16 ctrl; + + /* The timer's actual period is one cycle greater than the value + * stored in the period register. */ + period--; + + ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG); + /* stop counter */ + timer_writew(timer, ctrl | ALTERA_TIMER_CONTROL_STOP_MSK, + ALTERA_TIMER_CONTROL_REG); + + /* write new count */ + timer_writew(timer, period, ALTERA_TIMER_PERIODL_REG); + timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG); + + ctrl |= ALTERA_TIMER_CONTROL_START_MSK | ALTERA_TIMER_CONTROL_ITO_MSK; + if (periodic) + ctrl |= ALTERA_TIMER_CONTROL_CONT_MSK; + else + ctrl &= ~ALTERA_TIMER_CONTROL_CONT_MSK; + timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG); +} + +static int nios2_timer_set_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); + + nios2_timer_config(&nios2_ced->timer, delta, false); + + return 0; +} + +static int nios2_timer_shutdown(struct clock_event_device *evt) +{ + struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); + struct nios2_timer *timer = &nios2_ced->timer; + + nios2_timer_stop(timer); + return 0; +} + +static int nios2_timer_set_periodic(struct clock_event_device *evt) +{ + unsigned long period; + struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); + struct nios2_timer *timer = &nios2_ced->timer; + + period = DIV_ROUND_UP(timer->freq, HZ); + nios2_timer_config(timer, period, true); + return 0; +} + +static int nios2_timer_resume(struct clock_event_device *evt) +{ + struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); + struct nios2_timer *timer = &nios2_ced->timer; + + nios2_timer_start(timer); + return 0; +} + +irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = (struct clock_event_device *) dev_id; + struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); + + /* Clear the interrupt condition */ + timer_writew(&nios2_ced->timer, 0, ALTERA_TIMER_STATUS_REG); + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static int __init nios2_timer_get_base_and_freq(struct device_node *np, + void __iomem **base, u32 *freq) +{ + *base = of_iomap(np, 0); + if (!*base) { + pr_crit("Unable to map reg for %pOFn\n", np); + return -ENXIO; + } + + if (of_property_read_u32(np, "clock-frequency", freq)) { + pr_crit("Unable to get %pOFn clock frequency\n", np); + return -EINVAL; + } + + return 0; +} + +static struct nios2_clockevent_dev nios2_ce = { + .ced = { + .name = "nios2-clkevent", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .rating = 250, + .shift = 32, + .set_next_event = nios2_timer_set_next_event, + .set_state_shutdown = nios2_timer_shutdown, + .set_state_periodic = nios2_timer_set_periodic, + .set_state_oneshot = nios2_timer_shutdown, + .tick_resume = nios2_timer_resume, + }, +}; + +static __init int nios2_clockevent_init(struct device_node *timer) +{ + void __iomem *iobase; + u32 freq; + int irq, ret; + + ret = nios2_timer_get_base_and_freq(timer, &iobase, &freq); + if (ret) + return ret; + + irq = irq_of_parse_and_map(timer, 0); + if (!irq) { + pr_crit("Unable to parse timer irq\n"); + return -EINVAL; + } + + nios2_ce.timer.base = iobase; + nios2_ce.timer.freq = freq; + + nios2_ce.ced.cpumask = cpumask_of(0); + nios2_ce.ced.irq = irq; + + nios2_timer_stop(&nios2_ce.timer); + /* clear pending interrupt */ + timer_writew(&nios2_ce.timer, 0, ALTERA_TIMER_STATUS_REG); + + ret = request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name, + &nios2_ce.ced); + if (ret) { + pr_crit("Unable to setup timer irq\n"); + return ret; + } + + clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX); + + return 0; +} + +static __init int nios2_clocksource_init(struct device_node *timer) +{ + unsigned int ctrl; + void __iomem *iobase; + u32 freq; + int ret; + + ret = nios2_timer_get_base_and_freq(timer, &iobase, &freq); + if (ret) + return ret; + + nios2_cs.timer.base = iobase; + nios2_cs.timer.freq = freq; + + ret = clocksource_register_hz(&nios2_cs.cs, freq); + if (ret) + return ret; + + timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODL_REG); + timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG); + + /* interrupt disable + continuous + start */ + ctrl = ALTERA_TIMER_CONTROL_CONT_MSK | ALTERA_TIMER_CONTROL_START_MSK; + timer_writew(&nios2_cs.timer, ctrl, ALTERA_TIMER_CONTROL_REG); + + /* Calibrate the delay loop directly */ + lpj_fine = freq / HZ; + + return 0; +} + +/* + * The first timer instance will use as a clockevent. If there are two or + * more instances, the second one gets used as clocksource and all + * others are unused. +*/ +static int __init nios2_time_init(struct device_node *timer) +{ + static int num_called; + int ret; + + switch (num_called) { + case 0: + ret = nios2_clockevent_init(timer); + break; + case 1: + ret = nios2_clocksource_init(timer); + break; + default: + ret = 0; + break; + } + + num_called++; + + return ret; +} + +void read_persistent_clock64(struct timespec64 *ts) +{ + ts->tv_sec = mktime64(2007, 1, 1, 0, 0, 0); + ts->tv_nsec = 0; +} + +void __init time_init(void) +{ + struct device_node *np; + int count = 0; + + for_each_compatible_node(np, NULL, ALTR_TIMER_COMPATIBLE) + count++; + + if (count < 2) + panic("%d timer is found, it needs 2 timers in system\n", count); + + timer_probe(); +} + +TIMER_OF_DECLARE(nios2_timer, ALTR_TIMER_COMPATIBLE, nios2_time_init); |