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-rw-r--r--drivers/clocksource/timer-tegra.c416
1 files changed, 416 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-tegra.c b/drivers/clocksource/timer-tegra.c
new file mode 100644
index 000000000..e9635c25e
--- /dev/null
+++ b/drivers/clocksource/timer-tegra.c
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ * Colin Cross <ccross@google.com>
+ */
+
+#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);
+
+ to->clkevt.set_state_shutdown(&to->clkevt);
+ 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_ARM
+static 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);