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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#define pr_fmt(fmt) "tegra-timer: " fmt
#include <linux/clk.h>#include <linux/clockchips.h>#include <linux/cpu.h>#include <linux/cpumask.h>#include <linux/delay.h>#include <linux/err.h>#include <linux/interrupt.h>#include <linux/of_address.h>#include <linux/of_irq.h>#include <linux/percpu.h>#include <linux/sched_clock.h>#include <linux/time.h>
#include "timer-of.h"
#define RTC_SECONDS 0x08#define RTC_SHADOW_SECONDS 0x0c#define RTC_MILLISECONDS 0x10
#define TIMERUS_CNTR_1US 0x10#define TIMERUS_USEC_CFG 0x14#define TIMERUS_CNTR_FREEZE 0x4c
#define TIMER_PTV 0x0#define TIMER_PTV_EN BIT(31)#define TIMER_PTV_PER BIT(30)#define TIMER_PCR 0x4#define TIMER_PCR_INTR_CLR BIT(30)
#define TIMER1_BASE 0x00#define TIMER2_BASE 0x08#define TIMER3_BASE 0x50#define TIMER4_BASE 0x58#define TIMER10_BASE 0x90
#define TIMER1_IRQ_IDX 0#define TIMER10_IRQ_IDX 10
#define TIMER_1MHz 1000000
static u32 usec_config;static void __iomem *timer_reg_base;
static int tegra_timer_set_next_event(unsigned long cycles, struct clock_event_device *evt){ void __iomem *reg_base = timer_of_base(to_timer_of(evt));
/* * Tegra's timer uses n+1 scheme for the counter, i.e. timer will * fire after one tick if 0 is loaded. * * The minimum and maximum numbers of oneshot ticks are defined * by clockevents_config_and_register(1, 0x1fffffff + 1) invocation * below in the code. Hence the cycles (ticks) can't be outside of * a range supportable by hardware. */ writel_relaxed(TIMER_PTV_EN | (cycles - 1), reg_base + TIMER_PTV);
return 0;}
static int tegra_timer_shutdown(struct clock_event_device *evt){ void __iomem *reg_base = timer_of_base(to_timer_of(evt));
writel_relaxed(0, reg_base + TIMER_PTV);
return 0;}
static int tegra_timer_set_periodic(struct clock_event_device *evt){ void __iomem *reg_base = timer_of_base(to_timer_of(evt)); unsigned long period = timer_of_period(to_timer_of(evt));
writel_relaxed(TIMER_PTV_EN | TIMER_PTV_PER | (period - 1), reg_base + TIMER_PTV);
return 0;}
static irqreturn_t tegra_timer_isr(int irq, void *dev_id){ struct clock_event_device *evt = dev_id; void __iomem *reg_base = timer_of_base(to_timer_of(evt));
writel_relaxed(TIMER_PCR_INTR_CLR, reg_base + TIMER_PCR); evt->event_handler(evt);
return IRQ_HANDLED;}
static void tegra_timer_suspend(struct clock_event_device *evt){ void __iomem *reg_base = timer_of_base(to_timer_of(evt));
writel_relaxed(TIMER_PCR_INTR_CLR, reg_base + TIMER_PCR);}
static void tegra_timer_resume(struct clock_event_device *evt){ writel_relaxed(usec_config, timer_reg_base + TIMERUS_USEC_CFG);}
static DEFINE_PER_CPU(struct timer_of, tegra_to) = { .flags = TIMER_OF_CLOCK | TIMER_OF_BASE,
.clkevt = { .name = "tegra_timer", .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, .set_next_event = tegra_timer_set_next_event, .set_state_shutdown = tegra_timer_shutdown, .set_state_periodic = tegra_timer_set_periodic, .set_state_oneshot = tegra_timer_shutdown, .tick_resume = tegra_timer_shutdown, .suspend = tegra_timer_suspend, .resume = tegra_timer_resume, },};
static int tegra_timer_setup(unsigned int cpu){ struct timer_of *to = per_cpu_ptr(&tegra_to, cpu);
writel_relaxed(0, timer_of_base(to) + TIMER_PTV); writel_relaxed(TIMER_PCR_INTR_CLR, timer_of_base(to) + TIMER_PCR);
irq_force_affinity(to->clkevt.irq, cpumask_of(cpu)); enable_irq(to->clkevt.irq);
/* * Tegra's timer uses n+1 scheme for the counter, i.e. timer will * fire after one tick if 0 is loaded and thus minimum number of * ticks is 1. In result both of the clocksource's tick limits are * higher than a minimum and maximum that hardware register can * take by 1, this is then taken into account by set_next_event * callback. */ clockevents_config_and_register(&to->clkevt, timer_of_rate(to), 1, /* min */ 0x1fffffff + 1); /* max 29 bits + 1 */
return 0;}
static int tegra_timer_stop(unsigned int cpu){ struct timer_of *to = per_cpu_ptr(&tegra_to, cpu);
disable_irq_nosync(to->clkevt.irq);
return 0;}
static u64 notrace tegra_read_sched_clock(void){ return readl_relaxed(timer_reg_base + TIMERUS_CNTR_1US);}
#ifdef CONFIG_ARMstatic unsigned long tegra_delay_timer_read_counter_long(void){ return readl_relaxed(timer_reg_base + TIMERUS_CNTR_1US);}
static struct delay_timer tegra_delay_timer = { .read_current_timer = tegra_delay_timer_read_counter_long, .freq = TIMER_1MHz,};#endif
static struct timer_of suspend_rtc_to = { .flags = TIMER_OF_BASE | TIMER_OF_CLOCK,};
/* * tegra_rtc_read - Reads the Tegra RTC registers * Care must be taken that this function is not called while the * tegra_rtc driver could be executing to avoid race conditions * on the RTC shadow register */static u64 tegra_rtc_read_ms(struct clocksource *cs){ void __iomem *reg_base = timer_of_base(&suspend_rtc_to);
u32 ms = readl_relaxed(reg_base + RTC_MILLISECONDS); u32 s = readl_relaxed(reg_base + RTC_SHADOW_SECONDS);
return (u64)s * MSEC_PER_SEC + ms;}
static struct clocksource suspend_rtc_clocksource = { .name = "tegra_suspend_timer", .rating = 200, .read = tegra_rtc_read_ms, .mask = CLOCKSOURCE_MASK(32), .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,};
static inline unsigned int tegra_base_for_cpu(int cpu, bool tegra20){ if (tegra20) { switch (cpu) { case 0: return TIMER1_BASE; case 1: return TIMER2_BASE; case 2: return TIMER3_BASE; default: return TIMER4_BASE; } }
return TIMER10_BASE + cpu * 8;}
static inline unsigned int tegra_irq_idx_for_cpu(int cpu, bool tegra20){ if (tegra20) return TIMER1_IRQ_IDX + cpu;
return TIMER10_IRQ_IDX + cpu;}
static inline unsigned long tegra_rate_for_timer(struct timer_of *to, bool tegra20){ /* * TIMER1-9 are fixed to 1MHz, TIMER10-13 are running off the * parent clock. */ if (tegra20) return TIMER_1MHz;
return timer_of_rate(to);}
static int __init tegra_init_timer(struct device_node *np, bool tegra20, int rating){ struct timer_of *to; int cpu, ret;
to = this_cpu_ptr(&tegra_to); ret = timer_of_init(np, to); if (ret) goto out;
timer_reg_base = timer_of_base(to);
/* * Configure microsecond timers to have 1MHz clock * Config register is 0xqqww, where qq is "dividend", ww is "divisor" * Uses n+1 scheme */ switch (timer_of_rate(to)) { case 12000000: usec_config = 0x000b; /* (11+1)/(0+1) */ break; case 12800000: usec_config = 0x043f; /* (63+1)/(4+1) */ break; case 13000000: usec_config = 0x000c; /* (12+1)/(0+1) */ break; case 16800000: usec_config = 0x0453; /* (83+1)/(4+1) */ break; case 19200000: usec_config = 0x045f; /* (95+1)/(4+1) */ break; case 26000000: usec_config = 0x0019; /* (25+1)/(0+1) */ break; case 38400000: usec_config = 0x04bf; /* (191+1)/(4+1) */ break; case 48000000: usec_config = 0x002f; /* (47+1)/(0+1) */ break; default: ret = -EINVAL; goto out; }
writel_relaxed(usec_config, timer_reg_base + TIMERUS_USEC_CFG);
for_each_possible_cpu(cpu) { struct timer_of *cpu_to = per_cpu_ptr(&tegra_to, cpu); unsigned long flags = IRQF_TIMER | IRQF_NOBALANCING; unsigned long rate = tegra_rate_for_timer(to, tegra20); unsigned int base = tegra_base_for_cpu(cpu, tegra20); unsigned int idx = tegra_irq_idx_for_cpu(cpu, tegra20); unsigned int irq = irq_of_parse_and_map(np, idx);
if (!irq) { pr_err("failed to map irq for cpu%d\n", cpu); ret = -EINVAL; goto out_irq; }
cpu_to->clkevt.irq = irq; cpu_to->clkevt.rating = rating; cpu_to->clkevt.cpumask = cpumask_of(cpu); cpu_to->of_base.base = timer_reg_base + base; cpu_to->of_clk.period = rate / HZ; cpu_to->of_clk.rate = rate;
irq_set_status_flags(cpu_to->clkevt.irq, IRQ_NOAUTOEN);
ret = request_irq(cpu_to->clkevt.irq, tegra_timer_isr, flags, cpu_to->clkevt.name, &cpu_to->clkevt); if (ret) { pr_err("failed to set up irq for cpu%d: %d\n", cpu, ret); irq_dispose_mapping(cpu_to->clkevt.irq); cpu_to->clkevt.irq = 0; goto out_irq; } }
sched_clock_register(tegra_read_sched_clock, 32, TIMER_1MHz);
ret = clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US, "timer_us", TIMER_1MHz, 300, 32, clocksource_mmio_readl_up); if (ret) pr_err("failed to register clocksource: %d\n", ret);
#ifdef CONFIG_ARM register_current_timer_delay(&tegra_delay_timer);#endif
ret = cpuhp_setup_state(CPUHP_AP_TEGRA_TIMER_STARTING, "AP_TEGRA_TIMER_STARTING", tegra_timer_setup, tegra_timer_stop); if (ret) pr_err("failed to set up cpu hp state: %d\n", ret);
return ret;
out_irq: for_each_possible_cpu(cpu) { struct timer_of *cpu_to;
cpu_to = per_cpu_ptr(&tegra_to, cpu); if (cpu_to->clkevt.irq) { free_irq(cpu_to->clkevt.irq, &cpu_to->clkevt); irq_dispose_mapping(cpu_to->clkevt.irq); } }
to->of_base.base = timer_reg_base;out: timer_of_cleanup(to);
return ret;}
static int __init tegra210_init_timer(struct device_node *np){ /* * Arch-timer can't survive across power cycle of CPU core and * after CPUPORESET signal due to a system design shortcoming, * hence tegra-timer is more preferable on Tegra210. */ return tegra_init_timer(np, false, 460);}TIMER_OF_DECLARE(tegra210_timer, "nvidia,tegra210-timer", tegra210_init_timer);
static int __init tegra20_init_timer(struct device_node *np){ int rating;
/* * Tegra20 and Tegra30 have Cortex A9 CPU that has a TWD timer, * that timer runs off the CPU clock and hence is subjected to * a jitter caused by DVFS clock rate changes. Tegra-timer is * more preferable for older Tegra's, while later SoC generations * have arch-timer as a main per-CPU timer and it is not affected * by DVFS changes. */ if (of_machine_is_compatible("nvidia,tegra20") || of_machine_is_compatible("nvidia,tegra30")) rating = 460; else rating = 330;
return tegra_init_timer(np, true, rating);}TIMER_OF_DECLARE(tegra20_timer, "nvidia,tegra20-timer", tegra20_init_timer);
static int __init tegra20_init_rtc(struct device_node *np){ int ret;
ret = timer_of_init(np, &suspend_rtc_to); if (ret) return ret;
return clocksource_register_hz(&suspend_rtc_clocksource, 1000);}TIMER_OF_DECLARE(tegra20_rtc, "nvidia,tegra20-rtc", tegra20_init_rtc);