From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/clocksource/arc_timer.c | 373 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 373 insertions(+) create mode 100644 drivers/clocksource/arc_timer.c (limited to 'drivers/clocksource/arc_timer.c') diff --git a/drivers/clocksource/arc_timer.c b/drivers/clocksource/arc_timer.c new file mode 100644 index 000000000..cb18524cc --- /dev/null +++ b/drivers/clocksource/arc_timer.c @@ -0,0 +1,373 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2016-17 Synopsys, Inc. (www.synopsys.com) + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + */ + +/* ARC700 has two 32bit independent prog Timers: TIMER0 and TIMER1, Each can be + * programmed to go from @count to @limit and optionally interrupt. + * We've designated TIMER0 for clockevents and TIMER1 for clocksource + * + * ARCv2 based HS38 cores have RTC (in-core) and GFRC (inside ARConnect/MCIP) + * which are suitable for UP and SMP based clocksources respectively + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + + +static unsigned long arc_timer_freq; + +static int noinline arc_get_timer_clk(struct device_node *node) +{ + struct clk *clk; + int ret; + + clk = of_clk_get(node, 0); + if (IS_ERR(clk)) { + pr_err("timer missing clk\n"); + return PTR_ERR(clk); + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("Couldn't enable parent clk\n"); + return ret; + } + + arc_timer_freq = clk_get_rate(clk); + + return 0; +} + +/********** Clock Source Device *********/ + +#ifdef CONFIG_ARC_TIMERS_64BIT + +static u64 arc_read_gfrc(struct clocksource *cs) +{ + unsigned long flags; + u32 l, h; + + /* + * From a programming model pov, there seems to be just one instance of + * MCIP_CMD/MCIP_READBACK however micro-architecturally there's + * an instance PER ARC CORE (not per cluster), and there are dedicated + * hardware decode logic (per core) inside ARConnect to handle + * simultaneous read/write accesses from cores via those two registers. + * So several concurrent commands to ARConnect are OK if they are + * trying to access two different sub-components (like GFRC, + * inter-core interrupt, etc...). HW also supports simultaneously + * accessing GFRC by multiple cores. + * That's why it is safe to disable hard interrupts on the local CPU + * before access to GFRC instead of taking global MCIP spinlock + * defined in arch/arc/kernel/mcip.c + */ + local_irq_save(flags); + + __mcip_cmd(CMD_GFRC_READ_LO, 0); + l = read_aux_reg(ARC_REG_MCIP_READBACK); + + __mcip_cmd(CMD_GFRC_READ_HI, 0); + h = read_aux_reg(ARC_REG_MCIP_READBACK); + + local_irq_restore(flags); + + return (((u64)h) << 32) | l; +} + +static notrace u64 arc_gfrc_clock_read(void) +{ + return arc_read_gfrc(NULL); +} + +static struct clocksource arc_counter_gfrc = { + .name = "ARConnect GFRC", + .rating = 400, + .read = arc_read_gfrc, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init arc_cs_setup_gfrc(struct device_node *node) +{ + struct mcip_bcr mp; + int ret; + + READ_BCR(ARC_REG_MCIP_BCR, mp); + if (!mp.gfrc) { + pr_warn("Global-64-bit-Ctr clocksource not detected\n"); + return -ENXIO; + } + + ret = arc_get_timer_clk(node); + if (ret) + return ret; + + sched_clock_register(arc_gfrc_clock_read, 64, arc_timer_freq); + + return clocksource_register_hz(&arc_counter_gfrc, arc_timer_freq); +} +TIMER_OF_DECLARE(arc_gfrc, "snps,archs-timer-gfrc", arc_cs_setup_gfrc); + +#define AUX_RTC_CTRL 0x103 +#define AUX_RTC_LOW 0x104 +#define AUX_RTC_HIGH 0x105 + +static u64 arc_read_rtc(struct clocksource *cs) +{ + unsigned long status; + u32 l, h; + + /* + * hardware has an internal state machine which tracks readout of + * low/high and updates the CTRL.status if + * - interrupt/exception taken between the two reads + * - high increments after low has been read + */ + do { + l = read_aux_reg(AUX_RTC_LOW); + h = read_aux_reg(AUX_RTC_HIGH); + status = read_aux_reg(AUX_RTC_CTRL); + } while (!(status & BIT(31))); + + return (((u64)h) << 32) | l; +} + +static notrace u64 arc_rtc_clock_read(void) +{ + return arc_read_rtc(NULL); +} + +static struct clocksource arc_counter_rtc = { + .name = "ARCv2 RTC", + .rating = 350, + .read = arc_read_rtc, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init arc_cs_setup_rtc(struct device_node *node) +{ + struct bcr_timer timer; + int ret; + + READ_BCR(ARC_REG_TIMERS_BCR, timer); + if (!timer.rtc) { + pr_warn("Local-64-bit-Ctr clocksource not detected\n"); + return -ENXIO; + } + + /* Local to CPU hence not usable in SMP */ + if (IS_ENABLED(CONFIG_SMP)) { + pr_warn("Local-64-bit-Ctr not usable in SMP\n"); + return -EINVAL; + } + + ret = arc_get_timer_clk(node); + if (ret) + return ret; + + write_aux_reg(AUX_RTC_CTRL, 1); + + sched_clock_register(arc_rtc_clock_read, 64, arc_timer_freq); + + return clocksource_register_hz(&arc_counter_rtc, arc_timer_freq); +} +TIMER_OF_DECLARE(arc_rtc, "snps,archs-timer-rtc", arc_cs_setup_rtc); + +#endif + +/* + * 32bit TIMER1 to keep counting monotonically and wraparound + */ + +static u64 arc_read_timer1(struct clocksource *cs) +{ + return (u64) read_aux_reg(ARC_REG_TIMER1_CNT); +} + +static notrace u64 arc_timer1_clock_read(void) +{ + return arc_read_timer1(NULL); +} + +static struct clocksource arc_counter_timer1 = { + .name = "ARC Timer1", + .rating = 300, + .read = arc_read_timer1, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init arc_cs_setup_timer1(struct device_node *node) +{ + int ret; + + /* Local to CPU hence not usable in SMP */ + if (IS_ENABLED(CONFIG_SMP)) + return -EINVAL; + + ret = arc_get_timer_clk(node); + if (ret) + return ret; + + write_aux_reg(ARC_REG_TIMER1_LIMIT, ARC_TIMERN_MAX); + write_aux_reg(ARC_REG_TIMER1_CNT, 0); + write_aux_reg(ARC_REG_TIMER1_CTRL, ARC_TIMER_CTRL_NH); + + sched_clock_register(arc_timer1_clock_read, 32, arc_timer_freq); + + return clocksource_register_hz(&arc_counter_timer1, arc_timer_freq); +} + +/********** Clock Event Device *********/ + +static int arc_timer_irq; + +/* + * Arm the timer to interrupt after @cycles + * The distinction for oneshot/periodic is done in arc_event_timer_ack() below + */ +static void arc_timer_event_setup(unsigned int cycles) +{ + write_aux_reg(ARC_REG_TIMER0_LIMIT, cycles); + write_aux_reg(ARC_REG_TIMER0_CNT, 0); /* start from 0 */ + + write_aux_reg(ARC_REG_TIMER0_CTRL, ARC_TIMER_CTRL_IE | ARC_TIMER_CTRL_NH); +} + + +static int arc_clkevent_set_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + arc_timer_event_setup(delta); + return 0; +} + +static int arc_clkevent_set_periodic(struct clock_event_device *dev) +{ + /* + * At X Hz, 1 sec = 1000ms -> X cycles; + * 10ms -> X / 100 cycles + */ + arc_timer_event_setup(arc_timer_freq / HZ); + return 0; +} + +static DEFINE_PER_CPU(struct clock_event_device, arc_clockevent_device) = { + .name = "ARC Timer0", + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC, + .rating = 300, + .set_next_event = arc_clkevent_set_next_event, + .set_state_periodic = arc_clkevent_set_periodic, +}; + +static irqreturn_t timer_irq_handler(int irq, void *dev_id) +{ + /* + * Note that generic IRQ core could have passed @evt for @dev_id if + * irq_set_chip_and_handler() asked for handle_percpu_devid_irq() + */ + struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device); + int irq_reenable = clockevent_state_periodic(evt); + + /* + * 1. ACK the interrupt + * - For ARC700, any write to CTRL reg ACKs it, so just rewrite + * Count when [N]ot [H]alted bit. + * - For HS3x, it is a bit subtle. On taken count-down interrupt, + * IP bit [3] is set, which needs to be cleared for ACK'ing. + * The write below can only update the other two bits, hence + * explicitly clears IP bit + * 2. Re-arm interrupt if periodic by writing to IE bit [0] + */ + write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | ARC_TIMER_CTRL_NH); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + + +static int arc_timer_starting_cpu(unsigned int cpu) +{ + struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device); + + evt->cpumask = cpumask_of(smp_processor_id()); + + clockevents_config_and_register(evt, arc_timer_freq, 0, ARC_TIMERN_MAX); + enable_percpu_irq(arc_timer_irq, 0); + return 0; +} + +static int arc_timer_dying_cpu(unsigned int cpu) +{ + disable_percpu_irq(arc_timer_irq); + return 0; +} + +/* + * clockevent setup for boot CPU + */ +static int __init arc_clockevent_setup(struct device_node *node) +{ + struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device); + int ret; + + arc_timer_irq = irq_of_parse_and_map(node, 0); + if (arc_timer_irq <= 0) { + pr_err("clockevent: missing irq\n"); + return -EINVAL; + } + + ret = arc_get_timer_clk(node); + if (ret) + return ret; + + /* Needs apriori irq_set_percpu_devid() done in intc map function */ + ret = request_percpu_irq(arc_timer_irq, timer_irq_handler, + "Timer0 (per-cpu-tick)", evt); + if (ret) { + pr_err("clockevent: unable to request irq\n"); + return ret; + } + + ret = cpuhp_setup_state(CPUHP_AP_ARC_TIMER_STARTING, + "clockevents/arc/timer:starting", + arc_timer_starting_cpu, + arc_timer_dying_cpu); + if (ret) { + pr_err("Failed to setup hotplug state\n"); + return ret; + } + return 0; +} + +static int __init arc_of_timer_init(struct device_node *np) +{ + static int init_count = 0; + int ret; + + if (!init_count) { + init_count = 1; + ret = arc_clockevent_setup(np); + } else { + ret = arc_cs_setup_timer1(np); + } + + return ret; +} +TIMER_OF_DECLARE(arc_clkevt, "snps,arc-timer", arc_of_timer_init); -- cgit v1.2.3