Something went wrong. Try again.
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
6.9 kB · 277 lines
C
at master
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2020 Western Digital Corporation or its affiliates. * * Most of the M-mode (i.e. NoMMU) RISC-V systems usually have a * CLINT MMIO timer device. */
#define pr_fmt(fmt) "clint: " fmt#include <linux/bitops.h>#include <linux/clocksource.h>#include <linux/clockchips.h>#include <linux/cpu.h>#include <linux/delay.h>#include <linux/module.h>#include <linux/of_address.h>#include <linux/sched_clock.h>#include <linux/io-64-nonatomic-lo-hi.h>#include <linux/interrupt.h>#include <linux/irq.h>#include <linux/irqchip/chained_irq.h>#include <linux/irqdomain.h>#include <linux/of_irq.h>#include <linux/smp.h>#include <linux/timex.h>
#ifndef CONFIG_RISCV_M_MODE#include <asm/clint.h>#endif
#define CLINT_IPI_OFF 0#define CLINT_TIMER_CMP_OFF 0x4000#define CLINT_TIMER_VAL_OFF 0xbff8
/* CLINT manages IPI and Timer for RISC-V M-mode */static u32 __iomem *clint_ipi_base;static unsigned int clint_ipi_irq;static u64 __iomem *clint_timer_cmp;static u64 __iomem *clint_timer_val;static unsigned long clint_timer_freq;static unsigned int clint_timer_irq;
#ifdef CONFIG_RISCV_M_MODEu64 __iomem *clint_time_val;EXPORT_SYMBOL(clint_time_val);#endif
#ifdef CONFIG_SMPstatic void clint_send_ipi(unsigned int cpu){ writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));}
static void clint_clear_ipi(void){ writel(0, clint_ipi_base + cpuid_to_hartid_map(smp_processor_id()));}
static void clint_ipi_interrupt(struct irq_desc *desc){ struct irq_chip *chip = irq_desc_get_chip(desc);
chained_irq_enter(chip, desc);
clint_clear_ipi(); ipi_mux_process();
chained_irq_exit(chip, desc);}#endif
#ifdef CONFIG_64BIT#define clint_get_cycles() readq_relaxed(clint_timer_val)#else#define clint_get_cycles() readl_relaxed(clint_timer_val)#define clint_get_cycles_hi() readl_relaxed(((u32 *)clint_timer_val) + 1)#endif
#ifdef CONFIG_64BITstatic u64 notrace clint_get_cycles64(void){ return clint_get_cycles();}#else /* CONFIG_64BIT */static u64 notrace clint_get_cycles64(void){ u32 hi, lo;
do { hi = clint_get_cycles_hi(); lo = clint_get_cycles(); } while (hi != clint_get_cycles_hi());
return ((u64)hi << 32) | lo;}#endif /* CONFIG_64BIT */
static u64 clint_rdtime(struct clocksource *cs){ return clint_get_cycles64();}
static struct clocksource clint_clocksource = { .name = "clint_clocksource", .rating = 300, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS, .read = clint_rdtime,};
static int clint_clock_next_event(unsigned long delta, struct clock_event_device *ce){ void __iomem *r = clint_timer_cmp + cpuid_to_hartid_map(smp_processor_id());
csr_set(CSR_IE, IE_TIE); writeq_relaxed(clint_get_cycles64() + delta, r); return 0;}
static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = { .name = "clint_clockevent", .features = CLOCK_EVT_FEAT_ONESHOT, .rating = 100, .set_next_event = clint_clock_next_event,};
static int clint_timer_starting_cpu(unsigned int cpu){ struct clock_event_device *ce = per_cpu_ptr(&clint_clock_event, cpu);
ce->cpumask = cpumask_of(cpu); clockevents_config_and_register(ce, clint_timer_freq, 100, ULONG_MAX);
enable_percpu_irq(clint_timer_irq, irq_get_trigger_type(clint_timer_irq)); enable_percpu_irq(clint_ipi_irq, irq_get_trigger_type(clint_ipi_irq)); return 0;}
static int clint_timer_dying_cpu(unsigned int cpu){ disable_percpu_irq(clint_timer_irq); /* * Don't disable IPI when CPU goes offline because * the masking/unmasking of virtual IPIs is done * via generic IPI-Mux */ return 0;}
static irqreturn_t clint_timer_interrupt(int irq, void *dev_id){ struct clock_event_device *evdev = this_cpu_ptr(&clint_clock_event);
csr_clear(CSR_IE, IE_TIE); evdev->event_handler(evdev);
return IRQ_HANDLED;}
static int __init clint_timer_init_dt(struct device_node *np){ int rc; u32 i, nr_irqs; void __iomem *base; struct of_phandle_args oirq;
/* * Ensure that CLINT device interrupts are either RV_IRQ_TIMER or * RV_IRQ_SOFT. If it's anything else then we ignore the device. */ nr_irqs = of_irq_count(np); for (i = 0; i < nr_irqs; i++) { if (of_irq_parse_one(np, i, &oirq)) { pr_err("%pOFP: failed to parse irq %d.\n", np, i); continue; }
if ((oirq.args_count != 1) || (oirq.args[0] != RV_IRQ_TIMER && oirq.args[0] != RV_IRQ_SOFT)) { pr_err("%pOFP: invalid irq %d (hwirq %d)\n", np, i, oirq.args[0]); return -ENODEV; }
/* Find parent irq domain and map ipi irq */ if (!clint_ipi_irq && oirq.args[0] == RV_IRQ_SOFT && irq_find_host(oirq.np)) clint_ipi_irq = irq_of_parse_and_map(np, i);
/* Find parent irq domain and map timer irq */ if (!clint_timer_irq && oirq.args[0] == RV_IRQ_TIMER && irq_find_host(oirq.np)) clint_timer_irq = irq_of_parse_and_map(np, i); }
/* If CLINT ipi or timer irq not found then fail */ if (!clint_ipi_irq || !clint_timer_irq) { pr_err("%pOFP: ipi/timer irq not found\n", np); return -ENODEV; }
base = of_iomap(np, 0); if (!base) { pr_err("%pOFP: could not map registers\n", np); return -ENODEV; }
clint_ipi_base = base + CLINT_IPI_OFF; clint_timer_cmp = base + CLINT_TIMER_CMP_OFF; clint_timer_val = base + CLINT_TIMER_VAL_OFF; clint_timer_freq = riscv_timebase;
#ifdef CONFIG_RISCV_M_MODE /* * Yes, that's an odd naming scheme. time_val is public, but hopefully * will die in favor of something cleaner. */ clint_time_val = clint_timer_val;#endif
pr_info("%pOFP: timer running at %ld Hz\n", np, clint_timer_freq);
rc = clocksource_register_hz(&clint_clocksource, clint_timer_freq); if (rc) { pr_err("%pOFP: clocksource register failed [%d]\n", np, rc); goto fail_iounmap; }
sched_clock_register(clint_get_cycles64, 64, clint_timer_freq);
rc = request_percpu_irq(clint_timer_irq, clint_timer_interrupt, "clint-timer", &clint_clock_event); if (rc) { pr_err("registering percpu irq failed [%d]\n", rc); goto fail_iounmap; }
#ifdef CONFIG_SMP rc = ipi_mux_create(BITS_PER_BYTE, clint_send_ipi); if (rc <= 0) { pr_err("unable to create muxed IPIs\n"); rc = (rc < 0) ? rc : -ENODEV; goto fail_free_irq; }
irq_set_chained_handler(clint_ipi_irq, clint_ipi_interrupt); riscv_ipi_set_virq_range(rc, BITS_PER_BYTE); clint_clear_ipi();#endif
rc = cpuhp_setup_state(CPUHP_AP_CLINT_TIMER_STARTING, "clockevents/clint/timer:starting", clint_timer_starting_cpu, clint_timer_dying_cpu); if (rc) { pr_err("%pOFP: cpuhp setup state failed [%d]\n", np, rc); goto fail_free_irq; }
return 0;
fail_free_irq: free_percpu_irq(clint_timer_irq, &clint_clock_event);fail_iounmap: iounmap(base); return rc;}
TIMER_OF_DECLARE(clint_timer, "riscv,clint0", clint_timer_init_dt);TIMER_OF_DECLARE(clint_timer1, "sifive,clint0", clint_timer_init_dt);