1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-tegra.c b/drivers/clocksource/timer-tegra.c
new file mode 100644
index 000000000000..ed1454000ea9
--- /dev/null
+++ b/drivers/clocksource/timer-tegra.c
@@ -0,0 +1,386 @@
+// 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
+
+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));
+
+	writel_relaxed(TIMER_PTV_EN |
+		       ((cycles > 1) ? (cycles - 1) : 0), /* n+1 scheme */
+		       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));
+
+	writel_relaxed(TIMER_PTV_EN | TIMER_PTV_PER |
+		       ((timer_of_rate(to_timer_of(evt)) / HZ) - 1),
+		       reg_base + TIMER_PTV);
+
+	return 0;
+}
+
+static irqreturn_t tegra_timer_isr(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = (struct clock_event_device *)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);
+
+	clockevents_config_and_register(&to->clkevt, timer_of_rate(to),
+					1, /* min */
+					0x1fffffff); /* 29 bits */
+
+	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 = 1000000,
+};
+#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 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 int base = tegra_base_for_cpu(cpu, tegra20);
+		unsigned int idx = tegra_irq_idx_for_cpu(cpu, tegra20);
+
+		/*
+		 * TIMER1-9 are fixed to 1MHz, TIMER10-13 are running off the
+		 * parent clock.
+		 */
+		if (tegra20)
+			cpu_to->of_clk.rate = 1000000;
+
+		cpu_to = per_cpu_ptr(&tegra_to, cpu);
+		cpu_to->of_base.base = timer_reg_base + base;
+		cpu_to->clkevt.rating = rating;
+		cpu_to->clkevt.cpumask = cpumask_of(cpu);
+		cpu_to->clkevt.irq = irq_of_parse_and_map(np, idx);
+		if (!cpu_to->clkevt.irq) {
+			pr_err("failed to map irq for cpu%d\n", cpu);
+			ret = -EINVAL;
+			goto out_irq;
+		}
+
+		irq_set_status_flags(cpu_to->clkevt.irq, IRQ_NOAUTOEN);
+		ret = request_irq(cpu_to->clkevt.irq, tegra_timer_isr,
+				  IRQF_TIMER | IRQF_NOBALANCING,
+				  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, 1000000);
+
+	ret = clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
+				    "timer_us", 1000000,
+				    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);
+		}
+	}
+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);