--- /dev/null
+/* linux/arch/arm/mach-exynos4/mct.c
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd.
+ * http://www.samsung.com
+ *
+ * EXYNOS4 MCT(Multi-Core Timer) support
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/percpu.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+
+#define EXYNOS4_MCTREG(x) (x)
+#define EXYNOS4_MCT_G_CNT_L EXYNOS4_MCTREG(0x100)
+#define EXYNOS4_MCT_G_CNT_U EXYNOS4_MCTREG(0x104)
+#define EXYNOS4_MCT_G_CNT_WSTAT EXYNOS4_MCTREG(0x110)
+#define EXYNOS4_MCT_G_COMP0_L EXYNOS4_MCTREG(0x200)
+#define EXYNOS4_MCT_G_COMP0_U EXYNOS4_MCTREG(0x204)
+#define EXYNOS4_MCT_G_COMP0_ADD_INCR EXYNOS4_MCTREG(0x208)
+#define EXYNOS4_MCT_G_TCON EXYNOS4_MCTREG(0x240)
+#define EXYNOS4_MCT_G_INT_CSTAT EXYNOS4_MCTREG(0x244)
+#define EXYNOS4_MCT_G_INT_ENB EXYNOS4_MCTREG(0x248)
+#define EXYNOS4_MCT_G_WSTAT EXYNOS4_MCTREG(0x24C)
+#define _EXYNOS4_MCT_L_BASE EXYNOS4_MCTREG(0x300)
+#define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * x))
+#define EXYNOS4_MCT_L_MASK (0xffffff00)
+
+#define MCT_L_TCNTB_OFFSET (0x00)
+#define MCT_L_ICNTB_OFFSET (0x08)
+#define MCT_L_TCON_OFFSET (0x20)
+#define MCT_L_INT_CSTAT_OFFSET (0x30)
+#define MCT_L_INT_ENB_OFFSET (0x34)
+#define MCT_L_WSTAT_OFFSET (0x40)
+#define MCT_G_TCON_START (1 << 8)
+#define MCT_G_TCON_COMP0_AUTO_INC (1 << 1)
+#define MCT_G_TCON_COMP0_ENABLE (1 << 0)
+#define MCT_L_TCON_INTERVAL_MODE (1 << 2)
+#define MCT_L_TCON_INT_START (1 << 1)
+#define MCT_L_TCON_TIMER_START (1 << 0)
+
+#define TICK_BASE_CNT 1
+
+enum {
+ MCT_INT_SPI,
+ MCT_INT_PPI
+};
+
+enum {
+ MCT_G0_IRQ,
+ MCT_G1_IRQ,
+ MCT_G2_IRQ,
+ MCT_G3_IRQ,
+ MCT_L0_IRQ,
+ MCT_L1_IRQ,
+ MCT_L2_IRQ,
+ MCT_L3_IRQ,
+ MCT_L4_IRQ,
+ MCT_L5_IRQ,
+ MCT_L6_IRQ,
+ MCT_L7_IRQ,
+ MCT_NR_IRQS,
+};
+
+static void __iomem *reg_base;
+static unsigned long clk_rate;
+static unsigned int mct_int_type;
+static int mct_irqs[MCT_NR_IRQS];
+
+struct mct_clock_event_device {
+ struct clock_event_device evt;
+ unsigned long base;
+ char name[10];
+};
+
+static void exynos4_mct_write(unsigned int value, unsigned long offset)
+{
+ unsigned long stat_addr;
+ u32 mask;
+ u32 i;
+
+ writel_relaxed(value, reg_base + offset);
+
+ if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
+ stat_addr = (offset & EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
+ switch (offset & ~EXYNOS4_MCT_L_MASK) {
+ case MCT_L_TCON_OFFSET:
+ mask = 1 << 3; /* L_TCON write status */
+ break;
+ case MCT_L_ICNTB_OFFSET:
+ mask = 1 << 1; /* L_ICNTB write status */
+ break;
+ case MCT_L_TCNTB_OFFSET:
+ mask = 1 << 0; /* L_TCNTB write status */
+ break;
+ default:
+ return;
+ }
+ } else {
+ switch (offset) {
+ case EXYNOS4_MCT_G_TCON:
+ stat_addr = EXYNOS4_MCT_G_WSTAT;
+ mask = 1 << 16; /* G_TCON write status */
+ break;
+ case EXYNOS4_MCT_G_COMP0_L:
+ stat_addr = EXYNOS4_MCT_G_WSTAT;
+ mask = 1 << 0; /* G_COMP0_L write status */
+ break;
+ case EXYNOS4_MCT_G_COMP0_U:
+ stat_addr = EXYNOS4_MCT_G_WSTAT;
+ mask = 1 << 1; /* G_COMP0_U write status */
+ break;
+ case EXYNOS4_MCT_G_COMP0_ADD_INCR:
+ stat_addr = EXYNOS4_MCT_G_WSTAT;
+ mask = 1 << 2; /* G_COMP0_ADD_INCR w status */
+ break;
+ case EXYNOS4_MCT_G_CNT_L:
+ stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
+ mask = 1 << 0; /* G_CNT_L write status */
+ break;
+ case EXYNOS4_MCT_G_CNT_U:
+ stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
+ mask = 1 << 1; /* G_CNT_U write status */
+ break;
+ default:
+ return;
+ }
+ }
+
+ /* Wait maximum 1 ms until written values are applied */
+ for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
+ if (readl_relaxed(reg_base + stat_addr) & mask) {
+ writel_relaxed(mask, reg_base + stat_addr);
+ return;
+ }
+
+ panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
+}
+
+/* Clocksource handling */
+static void exynos4_mct_frc_start(void)
+{
+ u32 reg;
+
+ reg = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
+ reg |= MCT_G_TCON_START;
+ exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
+}
+
+/**
+ * exynos4_read_count_64 - Read all 64-bits of the global counter
+ *
+ * This will read all 64-bits of the global counter taking care to make sure
+ * that the upper and lower half match. Note that reading the MCT can be quite
+ * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half
+ * only) version when possible.
+ *
+ * Returns the number of cycles in the global counter.
+ */
+static u64 exynos4_read_count_64(void)
+{
+ unsigned int lo, hi;
+ u32 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
+
+ do {
+ hi = hi2;
+ lo = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
+ hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
+ } while (hi != hi2);
+
+ return ((cycle_t)hi << 32) | lo;
+}
+
+/**
+ * exynos4_read_count_32 - Read the lower 32-bits of the global counter
+ *
+ * This will read just the lower 32-bits of the global counter. This is marked
+ * as notrace so it can be used by the scheduler clock.
+ *
+ * Returns the number of cycles in the global counter (lower 32 bits).
+ */
+static u32 notrace exynos4_read_count_32(void)
+{
+ return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
+}
+
+static cycle_t exynos4_frc_read(struct clocksource *cs)
+{
+ return exynos4_read_count_32();
+}
+
+static void exynos4_frc_resume(struct clocksource *cs)
+{
+ exynos4_mct_frc_start();
+}
+
+struct clocksource mct_frc = {
+ .name = "mct-frc",
+ .rating = 400,
+ .read = exynos4_frc_read,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .resume = exynos4_frc_resume,
+};
+
+static u64 notrace exynos4_read_sched_clock(void)
+{
+ return exynos4_read_count_32();
+}
+
+static struct delay_timer exynos4_delay_timer;
+
+static cycles_t exynos4_read_current_timer(void)
+{
+ BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32),
+ "cycles_t needs to move to 32-bit for ARM64 usage");
+ return exynos4_read_count_32();
+}
+
+static void __init exynos4_clocksource_init(void)
+{
+ exynos4_mct_frc_start();
+
+ exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
+ exynos4_delay_timer.freq = clk_rate;
+ register_current_timer_delay(&exynos4_delay_timer);
+
+ if (clocksource_register_hz(&mct_frc, clk_rate))
+ panic("%s: can't register clocksource\n", mct_frc.name);
+
+ sched_clock_register(exynos4_read_sched_clock, 32, clk_rate);
+}
+
+static void exynos4_mct_comp0_stop(void)
+{
+ unsigned int tcon;
+
+ tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
+ tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
+
+ exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
+ exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
+}
+
+static void exynos4_mct_comp0_start(enum clock_event_mode mode,
+ unsigned long cycles)
+{
+ unsigned int tcon;
+ cycle_t comp_cycle;
+
+ tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
+
+ if (mode == CLOCK_EVT_MODE_PERIODIC) {
+ tcon |= MCT_G_TCON_COMP0_AUTO_INC;
+ exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
+ }
+
+ comp_cycle = exynos4_read_count_64() + cycles;
+ exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
+ exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
+
+ exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
+
+ tcon |= MCT_G_TCON_COMP0_ENABLE;
+ exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
+}
+
+static int exynos4_comp_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ exynos4_mct_comp0_start(evt->mode, cycles);
+
+ return 0;
+}
+
+static void exynos4_comp_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ unsigned long cycles_per_jiffy;
+ exynos4_mct_comp0_stop();
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ cycles_per_jiffy =
+ (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
+ exynos4_mct_comp0_start(mode, cycles_per_jiffy);
+ break;
+
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+static struct clock_event_device mct_comp_device = {
+ .name = "mct-comp",
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 250,
+ .set_next_event = exynos4_comp_set_next_event,
+ .set_mode = exynos4_comp_set_mode,
+};
+
+static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction mct_comp_event_irq = {
+ .name = "mct_comp_irq",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = exynos4_mct_comp_isr,
+ .dev_id = &mct_comp_device,
+};
+
+static void exynos4_clockevent_init(void)
+{
+ mct_comp_device.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&mct_comp_device, clk_rate,
+ 0xf, 0xffffffff);
+ setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
+}
+
+static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
+
+/* Clock event handling */
+static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
+{
+ unsigned long tmp;
+ unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
+ unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
+
+ tmp = readl_relaxed(reg_base + offset);
+ if (tmp & mask) {
+ tmp &= ~mask;
+ exynos4_mct_write(tmp, offset);
+ }
+}
+
+static void exynos4_mct_tick_start(unsigned long cycles,
+ struct mct_clock_event_device *mevt)
+{
+ unsigned long tmp;
+
+ exynos4_mct_tick_stop(mevt);
+
+ tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
+
+ /* update interrupt count buffer */
+ exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
+
+ /* enable MCT tick interrupt */
+ exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
+
+ tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
+ tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
+ MCT_L_TCON_INTERVAL_MODE;
+ exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
+}
+
+static int exynos4_tick_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+
+ exynos4_mct_tick_start(cycles, mevt);
+
+ return 0;
+}
+
+static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ unsigned long cycles_per_jiffy;
+
+ exynos4_mct_tick_stop(mevt);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ cycles_per_jiffy =
+ (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
+ exynos4_mct_tick_start(cycles_per_jiffy, mevt);
+ break;
+
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
+{
+ struct clock_event_device *evt = &mevt->evt;
+
+ /*
+ * This is for supporting oneshot mode.
+ * Mct would generate interrupt periodically
+ * without explicit stopping.
+ */
+ if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
+ exynos4_mct_tick_stop(mevt);
+
+ /* Clear the MCT tick interrupt */
+ if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) {
+ exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
+ return 1;
+ } else {
+ return 0;
+ }
+}
+
+static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
+{
+ struct mct_clock_event_device *mevt = dev_id;
+ struct clock_event_device *evt = &mevt->evt;
+
+ exynos4_mct_tick_clear(mevt);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static int exynos4_local_timer_setup(struct clock_event_device *evt)
+{
+ struct mct_clock_event_device *mevt;
+ unsigned int cpu = smp_processor_id();
+
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
+
+ mevt->base = EXYNOS4_MCT_L_BASE(cpu);
+ snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
+
+ evt->name = mevt->name;
+ evt->cpumask = cpumask_of(cpu);
+ evt->set_next_event = exynos4_tick_set_next_event;
+ evt->set_mode = exynos4_tick_set_mode;
+ evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ evt->rating = 450;
+
+ exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
+
+ if (mct_int_type == MCT_INT_SPI) {
+ evt->irq = mct_irqs[MCT_L0_IRQ + cpu];
+ if (request_irq(evt->irq, exynos4_mct_tick_isr,
+ IRQF_TIMER | IRQF_NOBALANCING,
+ evt->name, mevt)) {
+ pr_err("exynos-mct: cannot register IRQ %d\n",
+ evt->irq);
+ return -EIO;
+ }
+ irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu));
+ } else {
+ enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
+ }
+ clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
+ 0xf, 0x7fffffff);
+
+ return 0;
+}
+
+static void exynos4_local_timer_stop(struct clock_event_device *evt)
+{
+ evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+ if (mct_int_type == MCT_INT_SPI)
+ free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick));
+ else
+ disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
+}
+
+static int exynos4_mct_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ struct mct_clock_event_device *mevt;
+
+ /*
+ * Grab cpu pointer in each case to avoid spurious
+ * preemptible warnings
+ */
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ mevt = this_cpu_ptr(&percpu_mct_tick);
+ exynos4_local_timer_setup(&mevt->evt);
+ break;
+ case CPU_DYING:
+ mevt = this_cpu_ptr(&percpu_mct_tick);
+ exynos4_local_timer_stop(&mevt->evt);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block exynos4_mct_cpu_nb = {
+ .notifier_call = exynos4_mct_cpu_notify,
+};
+
+static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
+{
+ int err;
+ struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct clk *mct_clk, *tick_clk;
+
+ tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
+ clk_get(NULL, "fin_pll");
+ if (IS_ERR(tick_clk))
+ panic("%s: unable to determine tick clock rate\n", __func__);
+ clk_rate = clk_get_rate(tick_clk);
+
+ mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
+ if (IS_ERR(mct_clk))
+ panic("%s: unable to retrieve mct clock instance\n", __func__);
+ clk_prepare_enable(mct_clk);
+
+ reg_base = base;
+ if (!reg_base)
+ panic("%s: unable to ioremap mct address space\n", __func__);
+
+ if (mct_int_type == MCT_INT_PPI) {
+
+ err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
+ exynos4_mct_tick_isr, "MCT",
+ &percpu_mct_tick);
+ WARN(err, "MCT: can't request IRQ %d (%d)\n",
+ mct_irqs[MCT_L0_IRQ], err);
+ } else {
+ irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));
+ }
+
+ err = register_cpu_notifier(&exynos4_mct_cpu_nb);
+ if (err)
+ goto out_irq;
+
+ /* Immediately configure the timer on the boot CPU */
+ exynos4_local_timer_setup(&mevt->evt);
+ return;
+
+out_irq:
+ free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
+}
+
+void __init mct_init(void __iomem *base, int irq_g0, int irq_l0, int irq_l1)
+{
+ mct_irqs[MCT_G0_IRQ] = irq_g0;
+ mct_irqs[MCT_L0_IRQ] = irq_l0;
+ mct_irqs[MCT_L1_IRQ] = irq_l1;
+ mct_int_type = MCT_INT_SPI;
+
+ exynos4_timer_resources(NULL, base);
+ exynos4_clocksource_init();
+ exynos4_clockevent_init();
+}
+
+static void __init mct_init_dt(struct device_node *np, unsigned int int_type)
+{
+ u32 nr_irqs, i;
+
+ mct_int_type = int_type;
+
+ /* This driver uses only one global timer interrupt */
+ mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
+
+ /*
+ * Find out the number of local irqs specified. The local
+ * timer irqs are specified after the four global timer
+ * irqs are specified.
+ */
+#ifdef CONFIG_OF
+ nr_irqs = of_irq_count(np);
+#else
+ nr_irqs = 0;
+#endif
+ for (i = MCT_L0_IRQ; i < nr_irqs; i++)
+ mct_irqs[i] = irq_of_parse_and_map(np, i);
+
+ exynos4_timer_resources(np, of_iomap(np, 0));
+ exynos4_clocksource_init();
+ exynos4_clockevent_init();
+}
+
+
+static void __init mct_init_spi(struct device_node *np)
+{
+ return mct_init_dt(np, MCT_INT_SPI);
+}
+
+static void __init mct_init_ppi(struct device_node *np)
+{
+ return mct_init_dt(np, MCT_INT_PPI);
+}
+CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
+CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
Code Review / kvmfornfv.git / blobdiff