hw/timer/ibex_timer.c - qemu - Git at Google

 /*
  * QEMU lowRISC Ibex Timer device
  *
  * Copyright (c) 2021 Western Digital
  *
  * For details check the documentation here:
  *    https://docs.opentitan.org/hw/ip/rv_timer/doc/
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include "qemu/osdep.h"
 #include "qemu/log.h"
 #include "qemu/timer.h"
 #include "hw/timer/ibex_timer.h"
 #include "hw/irq.h"
 #include "hw/qdev-properties.h"
 #include "target/riscv/cpu.h"
 #include "migration/vmstate.h"

 REG32(ALERT_TEST, 0x00)
     FIELD(ALERT_TEST, FATAL_FAULT, 0, 1)
 REG32(CTRL, 0x04)
     FIELD(CTRL, ACTIVE, 0, 1)
 REG32(CFG0, 0x100)
     FIELD(CFG0, PRESCALE, 0, 12)
     FIELD(CFG0, STEP, 16, 8)
 REG32(LOWER0, 0x104)
 REG32(UPPER0, 0x108)
 REG32(COMPARE_LOWER0, 0x10C)
 REG32(COMPARE_UPPER0, 0x110)
 REG32(INTR_ENABLE, 0x114)
     FIELD(INTR_ENABLE, IE_0, 0, 1)
 REG32(INTR_STATE, 0x118)
     FIELD(INTR_STATE, IS_0, 0, 1)
 REG32(INTR_TEST, 0x11C)
     FIELD(INTR_TEST, T_0, 0, 1)

 static uint64_t cpu_riscv_read_rtc(uint32_t timebase_freq)
 {
     return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
                     timebase_freq, NANOSECONDS_PER_SECOND);
 }

 static void ibex_timer_update_irqs(IbexTimerState *s)
 {
     CPUState *cs = qemu_get_cpu(0);
     RISCVCPU *cpu = RISCV_CPU(cs);
     uint64_t value = s->timer_compare_lower0 |
                          ((uint64_t)s->timer_compare_upper0 << 32);
     uint64_t next, diff;
     uint64_t now = cpu_riscv_read_rtc(s->timebase_freq);

     if (!(s->timer_ctrl & R_CTRL_ACTIVE_MASK)) {
         /* Timer isn't active */
         return;
     }

     /* Update the CPUs mtimecmp */
     cpu->env.timecmp = value;

     if (cpu->env.timecmp <= now) {
         /*
          * If the mtimecmp was in the past raise the interrupt now.
          */
         qemu_irq_raise(s->m_timer_irq);
         if (s->timer_intr_enable & R_INTR_ENABLE_IE_0_MASK) {
             s->timer_intr_state |= R_INTR_STATE_IS_0_MASK;
             qemu_set_irq(s->irq, true);
         }
         return;
     }

     /* Setup a timer to trigger the interrupt in the future */
     qemu_irq_lower(s->m_timer_irq);
     qemu_set_irq(s->irq, false);

     diff = cpu->env.timecmp - now;
     next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
                                  muldiv64(diff,
                                           NANOSECONDS_PER_SECOND,
                                           s->timebase_freq);

     if (next < qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)) {
         /* We overflowed the timer, just set it as large as we can */
         timer_mod(cpu->env.timer, 0x7FFFFFFFFFFFFFFF);
     } else {
         timer_mod(cpu->env.timer, next);
     }
 }

 static void ibex_timer_cb(void *opaque)
 {
     IbexTimerState *s = opaque;

     qemu_irq_raise(s->m_timer_irq);
     if (s->timer_intr_enable & R_INTR_ENABLE_IE_0_MASK) {
         s->timer_intr_state |= R_INTR_STATE_IS_0_MASK;
         qemu_set_irq(s->irq, true);
     }
 }

 static void ibex_timer_reset(DeviceState *dev)
 {
     IbexTimerState *s = IBEX_TIMER(dev);

     CPUState *cpu = qemu_get_cpu(0);
     CPURISCVState *env = cpu->env_ptr;
     env->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                               &ibex_timer_cb, s);
     env->timecmp = 0;

     s->timer_ctrl = 0x00000000;
     s->timer_cfg0 = 0x00010000;
     s->timer_compare_lower0 = 0xFFFFFFFF;
     s->timer_compare_upper0 = 0xFFFFFFFF;
     s->timer_intr_enable = 0x00000000;
     s->timer_intr_state = 0x00000000;

     ibex_timer_update_irqs(s);
 }

 static uint64_t ibex_timer_read(void *opaque, hwaddr addr,
                                        unsigned int size)
 {
     IbexTimerState *s = opaque;
     uint64_t now = cpu_riscv_read_rtc(s->timebase_freq);
     uint64_t retvalue = 0;

     switch (addr >> 2) {
     case R_ALERT_TEST:
         qemu_log_mask(LOG_GUEST_ERROR,
                         "Attempted to read ALERT_TEST, a write only register");
         break;
     case R_CTRL:
         retvalue = s->timer_ctrl;
         break;
     case R_CFG0:
         retvalue = s->timer_cfg0;
         break;
     case R_LOWER0:
         retvalue = now;
         break;
     case R_UPPER0:
         retvalue = now >> 32;
         break;
     case R_COMPARE_LOWER0:
         retvalue = s->timer_compare_lower0;
         break;
     case R_COMPARE_UPPER0:
         retvalue = s->timer_compare_upper0;
         break;
     case R_INTR_ENABLE:
         retvalue = s->timer_intr_enable;
         break;
     case R_INTR_STATE:
         retvalue = s->timer_intr_state;
         break;
     case R_INTR_TEST:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "Attempted to read INTR_TEST, a write only register");
         break;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
         return 0;
     }

     return retvalue;
 }

 static void ibex_timer_write(void *opaque, hwaddr addr,
                              uint64_t val64, unsigned int size)
 {
     IbexTimerState *s = opaque;
     uint32_t val = val64;

     switch (addr >> 2) {
     case R_ALERT_TEST:
         qemu_log_mask(LOG_UNIMP, "Alert triggering not supported");
         break;
     case R_CTRL:
         s->timer_ctrl = val;
         break;
     case R_CFG0:
         qemu_log_mask(LOG_UNIMP, "Changing prescale or step not supported");
         s->timer_cfg0 = val;
         break;
     case R_LOWER0:
         qemu_log_mask(LOG_UNIMP, "Changing timer value is not supported");
         break;
     case R_UPPER0:
         qemu_log_mask(LOG_UNIMP, "Changing timer value is not supported");
         break;
     case R_COMPARE_LOWER0:
         s->timer_compare_lower0 = val;
         ibex_timer_update_irqs(s);
         break;
     case R_COMPARE_UPPER0:
         s->timer_compare_upper0 = val;
         ibex_timer_update_irqs(s);
         break;
     case R_INTR_ENABLE:
         s->timer_intr_enable = val;
         break;
     case R_INTR_STATE:
         /* Write 1 to clear */
         s->timer_intr_state &= ~val;
         break;
     case R_INTR_TEST:
         if (s->timer_intr_enable & val & R_INTR_ENABLE_IE_0_MASK) {
             s->timer_intr_state |= R_INTR_STATE_IS_0_MASK;
             qemu_set_irq(s->irq, true);
         }
         break;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
     }
 }

 static const MemoryRegionOps ibex_timer_ops = {
     .read = ibex_timer_read,
     .write = ibex_timer_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
     .impl.min_access_size = 4,
     .impl.max_access_size = 4,
 };

 static int ibex_timer_post_load(void *opaque, int version_id)
 {
     IbexTimerState *s = opaque;

     ibex_timer_update_irqs(s);
     return 0;
 }

 static const VMStateDescription vmstate_ibex_timer = {
     .name = TYPE_IBEX_TIMER,
     .version_id = 2,
     .minimum_version_id = 2,
     .post_load = ibex_timer_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(timer_ctrl, IbexTimerState),
         VMSTATE_UINT32(timer_cfg0, IbexTimerState),
         VMSTATE_UINT32(timer_compare_lower0, IbexTimerState),
         VMSTATE_UINT32(timer_compare_upper0, IbexTimerState),
         VMSTATE_UINT32(timer_intr_enable, IbexTimerState),
         VMSTATE_UINT32(timer_intr_state, IbexTimerState),
         VMSTATE_END_OF_LIST()
     }
 };

 static Property ibex_timer_properties[] = {
     DEFINE_PROP_UINT32("timebase-freq", IbexTimerState, timebase_freq, 10000),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void ibex_timer_init(Object *obj)
 {
     IbexTimerState *s = IBEX_TIMER(obj);

     sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);

     memory_region_init_io(&s->mmio, obj, &ibex_timer_ops, s,
                           TYPE_IBEX_TIMER, 0x400);
     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
 }

 static void ibex_timer_realize(DeviceState *dev, Error **errp)
 {
     IbexTimerState *s = IBEX_TIMER(dev);

     qdev_init_gpio_out(dev, &s->m_timer_irq, 1);
 }


 static void ibex_timer_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->reset = ibex_timer_reset;
     dc->vmsd = &vmstate_ibex_timer;
     dc->realize = ibex_timer_realize;
     device_class_set_props(dc, ibex_timer_properties);
 }

 static const TypeInfo ibex_timer_info = {
     .name          = TYPE_IBEX_TIMER,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(IbexTimerState),
     .instance_init = ibex_timer_init,
     .class_init    = ibex_timer_class_init,
 };

 static void ibex_timer_register_types(void)
 {
     type_register_static(&ibex_timer_info);
 }

 type_init(ibex_timer_register_types)
	/*
	* QEMU lowRISC Ibex Timer device
	*
	* Copyright (c) 2021 Western Digital
	*
	* For details check the documentation here:
	* https://docs.opentitan.org/hw/ip/rv_timer/doc/
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include "qemu/osdep.h"
	#include "qemu/log.h"
	#include "qemu/timer.h"
	#include "hw/timer/ibex_timer.h"
	#include "hw/irq.h"
	#include "hw/qdev-properties.h"
	#include "target/riscv/cpu.h"
	#include "migration/vmstate.h"

	REG32(ALERT_TEST, 0x00)
	FIELD(ALERT_TEST, FATAL_FAULT, 0, 1)
	REG32(CTRL, 0x04)
	FIELD(CTRL, ACTIVE, 0, 1)
	REG32(CFG0, 0x100)
	FIELD(CFG0, PRESCALE, 0, 12)
	FIELD(CFG0, STEP, 16, 8)
	REG32(LOWER0, 0x104)
	REG32(UPPER0, 0x108)
	REG32(COMPARE_LOWER0, 0x10C)
	REG32(COMPARE_UPPER0, 0x110)
	REG32(INTR_ENABLE, 0x114)
	FIELD(INTR_ENABLE, IE_0, 0, 1)
	REG32(INTR_STATE, 0x118)
	FIELD(INTR_STATE, IS_0, 0, 1)
	REG32(INTR_TEST, 0x11C)
	FIELD(INTR_TEST, T_0, 0, 1)

	static uint64_t cpu_riscv_read_rtc(uint32_t timebase_freq)
	{
	return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
	timebase_freq, NANOSECONDS_PER_SECOND);
	}

	static void ibex_timer_update_irqs(IbexTimerState *s)
	{
	CPUState *cs = qemu_get_cpu(0);
	RISCVCPU *cpu = RISCV_CPU(cs);
	uint64_t value = s->timer_compare_lower0 \|
	((uint64_t)s->timer_compare_upper0 << 32);
	uint64_t next, diff;
	uint64_t now = cpu_riscv_read_rtc(s->timebase_freq);

	if (!(s->timer_ctrl & R_CTRL_ACTIVE_MASK)) {
	/* Timer isn't active */
	return;
	}

	/* Update the CPUs mtimecmp */
	cpu->env.timecmp = value;

	if (cpu->env.timecmp <= now) {
	/*
	* If the mtimecmp was in the past raise the interrupt now.
	*/
	qemu_irq_raise(s->m_timer_irq);
	if (s->timer_intr_enable & R_INTR_ENABLE_IE_0_MASK) {
	s->timer_intr_state \|= R_INTR_STATE_IS_0_MASK;
	qemu_set_irq(s->irq, true);
	}
	return;
	}

	/* Setup a timer to trigger the interrupt in the future */
	qemu_irq_lower(s->m_timer_irq);
	qemu_set_irq(s->irq, false);

	diff = cpu->env.timecmp - now;
	next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
	muldiv64(diff,
	NANOSECONDS_PER_SECOND,
	s->timebase_freq);

	if (next < qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)) {
	/* We overflowed the timer, just set it as large as we can */
	timer_mod(cpu->env.timer, 0x7FFFFFFFFFFFFFFF);
	} else {
	timer_mod(cpu->env.timer, next);
	}
	}

	static void ibex_timer_cb(void *opaque)
	{
	IbexTimerState *s = opaque;

	qemu_irq_raise(s->m_timer_irq);
	if (s->timer_intr_enable & R_INTR_ENABLE_IE_0_MASK) {
	s->timer_intr_state \|= R_INTR_STATE_IS_0_MASK;
	qemu_set_irq(s->irq, true);
	}
	}

	static void ibex_timer_reset(DeviceState *dev)
	{
	IbexTimerState *s = IBEX_TIMER(dev);

	CPUState *cpu = qemu_get_cpu(0);
	CPURISCVState *env = cpu->env_ptr;
	env->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
	&ibex_timer_cb, s);
	env->timecmp = 0;

	s->timer_ctrl = 0x00000000;
	s->timer_cfg0 = 0x00010000;
	s->timer_compare_lower0 = 0xFFFFFFFF;
	s->timer_compare_upper0 = 0xFFFFFFFF;
	s->timer_intr_enable = 0x00000000;
	s->timer_intr_state = 0x00000000;

	ibex_timer_update_irqs(s);
	}

	static uint64_t ibex_timer_read(void *opaque, hwaddr addr,
	unsigned int size)
	{
	IbexTimerState *s = opaque;
	uint64_t now = cpu_riscv_read_rtc(s->timebase_freq);
	uint64_t retvalue = 0;

	switch (addr >> 2) {
	case R_ALERT_TEST:
	qemu_log_mask(LOG_GUEST_ERROR,
	"Attempted to read ALERT_TEST, a write only register");
	break;
	case R_CTRL:
	retvalue = s->timer_ctrl;
	break;
	case R_CFG0:
	retvalue = s->timer_cfg0;
	break;
	case R_LOWER0:
	retvalue = now;
	break;
	case R_UPPER0:
	retvalue = now >> 32;
	break;
	case R_COMPARE_LOWER0:
	retvalue = s->timer_compare_lower0;
	break;
	case R_COMPARE_UPPER0:
	retvalue = s->timer_compare_upper0;
	break;
	case R_INTR_ENABLE:
	retvalue = s->timer_intr_enable;
	break;
	case R_INTR_STATE:
	retvalue = s->timer_intr_state;
	break;
	case R_INTR_TEST:
	qemu_log_mask(LOG_GUEST_ERROR,
	"Attempted to read INTR_TEST, a write only register");
	break;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
	return 0;
	}

	return retvalue;
	}

	static void ibex_timer_write(void *opaque, hwaddr addr,
	uint64_t val64, unsigned int size)
	{
	IbexTimerState *s = opaque;
	uint32_t val = val64;

	switch (addr >> 2) {
	case R_ALERT_TEST:
	qemu_log_mask(LOG_UNIMP, "Alert triggering not supported");
	break;
	case R_CTRL:
	s->timer_ctrl = val;
	break;
	case R_CFG0:
	qemu_log_mask(LOG_UNIMP, "Changing prescale or step not supported");
	s->timer_cfg0 = val;
	break;
	case R_LOWER0:
	qemu_log_mask(LOG_UNIMP, "Changing timer value is not supported");
	break;
	case R_UPPER0:
	qemu_log_mask(LOG_UNIMP, "Changing timer value is not supported");
	break;
	case R_COMPARE_LOWER0:
	s->timer_compare_lower0 = val;
	ibex_timer_update_irqs(s);
	break;
	case R_COMPARE_UPPER0:
	s->timer_compare_upper0 = val;
	ibex_timer_update_irqs(s);
	break;
	case R_INTR_ENABLE:
	s->timer_intr_enable = val;
	break;
	case R_INTR_STATE:
	/* Write 1 to clear */
	s->timer_intr_state &= ~val;
	break;
	case R_INTR_TEST:
	if (s->timer_intr_enable & val & R_INTR_ENABLE_IE_0_MASK) {
	s->timer_intr_state \|= R_INTR_STATE_IS_0_MASK;
	qemu_set_irq(s->irq, true);
	}
	break;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
	}
	}

	static const MemoryRegionOps ibex_timer_ops = {
	.read = ibex_timer_read,
	.write = ibex_timer_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.impl.min_access_size = 4,
	.impl.max_access_size = 4,
	};

	static int ibex_timer_post_load(void *opaque, int version_id)
	{
	IbexTimerState *s = opaque;

	ibex_timer_update_irqs(s);
	return 0;
	}

	static const VMStateDescription vmstate_ibex_timer = {
	.name = TYPE_IBEX_TIMER,
	.version_id = 2,
	.minimum_version_id = 2,
	.post_load = ibex_timer_post_load,
	.fields = (VMStateField[]) {
	VMSTATE_UINT32(timer_ctrl, IbexTimerState),
	VMSTATE_UINT32(timer_cfg0, IbexTimerState),
	VMSTATE_UINT32(timer_compare_lower0, IbexTimerState),
	VMSTATE_UINT32(timer_compare_upper0, IbexTimerState),
	VMSTATE_UINT32(timer_intr_enable, IbexTimerState),
	VMSTATE_UINT32(timer_intr_state, IbexTimerState),
	VMSTATE_END_OF_LIST()
	}
	};

	static Property ibex_timer_properties[] = {
	DEFINE_PROP_UINT32("timebase-freq", IbexTimerState, timebase_freq, 10000),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void ibex_timer_init(Object *obj)
	{
	IbexTimerState *s = IBEX_TIMER(obj);

	sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);

	memory_region_init_io(&s->mmio, obj, &ibex_timer_ops, s,
	TYPE_IBEX_TIMER, 0x400);
	sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
	}

	static void ibex_timer_realize(DeviceState dev, Error *errp)
	{
	IbexTimerState *s = IBEX_TIMER(dev);

	qdev_init_gpio_out(dev, &s->m_timer_irq, 1);
	}


	static void ibex_timer_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->reset = ibex_timer_reset;
	dc->vmsd = &vmstate_ibex_timer;
	dc->realize = ibex_timer_realize;
	device_class_set_props(dc, ibex_timer_properties);
	}

	static const TypeInfo ibex_timer_info = {
	.name = TYPE_IBEX_TIMER,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(IbexTimerState),
	.instance_init = ibex_timer_init,
	.class_init = ibex_timer_class_init,
	};

	static void ibex_timer_register_types(void)
	{
	type_register_static(&ibex_timer_info);
	}

	type_init(ibex_timer_register_types)