hw/intc/ibex_plic.c - qemu - Git at Google

 /*
  * QEMU RISC-V lowRISC Ibex PLIC
  *
  * Copyright (c) 2020 Western Digital
  *
  * Documentation avaliable: https://docs.opentitan.org/hw/ip/rv_plic/doc/
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2 or later, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include "qemu/osdep.h"
 #include "qemu/log.h"
 #include "hw/qdev-properties.h"
 #include "hw/core/cpu.h"
 #include "hw/boards.h"
 #include "hw/pci/msi.h"
 #include "target/riscv/cpu_bits.h"
 #include "target/riscv/cpu.h"
 #include "hw/intc/ibex_plic.h"

 static bool addr_between(uint32_t addr, uint32_t base, uint32_t num)
 {
     uint32_t end = base + (num * 0x04);

     if (addr >= base && addr < end) {
         return true;
     }

     return false;
 }

 static void ibex_plic_irqs_set_pending(IbexPlicState *s, int irq, bool level)
 {
     int pending_num = irq / 32;

     if (!level) {
         /*
          * If the level is low make sure we clear the hidden_pending.
          */
         s->hidden_pending[pending_num] &= ~(1 << (irq % 32));
     }

     if (s->claimed[pending_num] & 1 << (irq % 32)) {
         /*
          * The interrupt has been claimed, but not completed.
          * The pending bit can't be set.
          * Save the pending level for after the interrupt is completed.
          */
         s->hidden_pending[pending_num] |= level << (irq % 32);
     } else {
         s->pending[pending_num] |= level << (irq % 32);
     }
 }

 static bool ibex_plic_irqs_pending(IbexPlicState *s, uint32_t context)
 {
     int i;
     uint32_t max_irq = 0;
     uint32_t max_prio = s->threshold;

     for (i = 0; i < s->pending_num; i++) {
         uint32_t irq_num = ctz64(s->pending[i]) + (i * 32);

         if (!(s->pending[i] & s->enable[i])) {
             /* No pending and enabled IRQ */
             continue;
         }

         if (s->priority[irq_num] > max_prio) {
             max_irq = irq_num;
             max_prio = s->priority[irq_num];
         }
     }

     if (max_irq) {
         s->claim = max_irq;
         return true;
     }

     return false;
 }

 static void ibex_plic_update(IbexPlicState *s)
 {
     CPUState *cpu;
     int level, i;

     for (i = 0; i < s->num_cpus; i++) {
         cpu = qemu_get_cpu(i);

         if (!cpu) {
             continue;
         }

         level = ibex_plic_irqs_pending(s, 0);

         riscv_cpu_update_mip(RISCV_CPU(cpu), MIP_MEIP, BOOL_TO_MASK(level));
     }
 }

 static void ibex_plic_reset(DeviceState *dev)
 {
     IbexPlicState *s = IBEX_PLIC(dev);

     s->threshold = 0x00000000;
     s->claim = 0x00000000;
 }

 static uint64_t ibex_plic_read(void *opaque, hwaddr addr,
                                unsigned int size)
 {
     IbexPlicState *s = opaque;
     int offset;
     uint32_t ret = 0;

     if (addr_between(addr, s->pending_base, s->pending_num)) {
         offset = (addr - s->pending_base) / 4;
         ret = s->pending[offset];
     } else if (addr_between(addr, s->source_base, s->source_num)) {
         qemu_log_mask(LOG_UNIMP,
                       "%s: Interrupt source mode not supported\n", __func__);
     } else if (addr_between(addr, s->priority_base, s->priority_num)) {
         offset = (addr - s->priority_base) / 4;
         ret = s->priority[offset];
     } else if (addr_between(addr, s->enable_base, s->enable_num)) {
         offset = (addr - s->enable_base) / 4;
         ret = s->enable[offset];
     } else if (addr_between(addr, s->threshold_base, 1)) {
         ret = s->threshold;
     } else if (addr_between(addr, s->claim_base, 1)) {
         int pending_num = s->claim / 32;
         s->pending[pending_num] &= ~(1 << (s->claim % 32));

         /* Set the interrupt as claimed, but not completed */
         s->claimed[pending_num] |= 1 << (s->claim % 32);

         /* Return the current claimed interrupt */
         ret = s->claim;

         /* Clear the claimed interrupt */
         s->claim = 0x00000000;

         /* Update the interrupt status after the claim */
         ibex_plic_update(s);
     }

     return ret;
 }

 static void ibex_plic_write(void *opaque, hwaddr addr,
                             uint64_t value, unsigned int size)
 {
     IbexPlicState *s = opaque;

     if (addr_between(addr, s->pending_base, s->pending_num)) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: Pending registers are read only\n", __func__);
     } else if (addr_between(addr, s->source_base, s->source_num)) {
         qemu_log_mask(LOG_UNIMP,
                       "%s: Interrupt source mode not supported\n", __func__);
     } else if (addr_between(addr, s->priority_base, s->priority_num)) {
         uint32_t irq = ((addr - s->priority_base) >> 2) + 1;
         s->priority[irq] = value & 7;
         ibex_plic_update(s);
     } else if (addr_between(addr, s->enable_base, s->enable_num)) {
         uint32_t enable_reg = (addr - s->enable_base) / 4;

         s->enable[enable_reg] = value;
     } else if (addr_between(addr, s->threshold_base, 1)) {
         s->threshold = value & 3;
     } else if (addr_between(addr, s->claim_base, 1)) {
         if (s->claim == value) {
             /* Interrupt was completed */
             s->claim = 0;
         }
         if (s->claimed[value / 32] & 1 << (value % 32)) {
             int pending_num = value / 32;

             /* This value was already claimed, clear it. */
             s->claimed[pending_num] &= ~(1 << (value % 32));

             if (s->hidden_pending[pending_num] & (1 << (value % 32))) {
                 /*
                  * If the bit in hidden_pending is set then that means we
                  * received an interrupt between claiming and completing
                  * the interrupt that hasn't since been de-asserted.
                  * On hardware this would trigger an interrupt, so let's
                  * trigger one here as well.
                  */
                 s->pending[pending_num] |= 1 << (value % 32);
             }
         }
     }

     ibex_plic_update(s);
 }

 static const MemoryRegionOps ibex_plic_ops = {
     .read = ibex_plic_read,
     .write = ibex_plic_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
     .valid = {
         .min_access_size = 4,
         .max_access_size = 4
     }
 };

 static void ibex_plic_irq_request(void *opaque, int irq, int level)
 {
     IbexPlicState *s = opaque;

     ibex_plic_irqs_set_pending(s, irq, level > 0);
     ibex_plic_update(s);
 }

 static Property ibex_plic_properties[] = {
     DEFINE_PROP_UINT32("num-cpus", IbexPlicState, num_cpus, 1),
     DEFINE_PROP_UINT32("num-sources", IbexPlicState, num_sources, 176),

     DEFINE_PROP_UINT32("pending-base", IbexPlicState, pending_base, 0),
     DEFINE_PROP_UINT32("pending-num", IbexPlicState, pending_num, 6),

     DEFINE_PROP_UINT32("source-base", IbexPlicState, source_base, 0x18),
     DEFINE_PROP_UINT32("source-num", IbexPlicState, source_num, 6),

     DEFINE_PROP_UINT32("priority-base", IbexPlicState, priority_base, 0x30),
     DEFINE_PROP_UINT32("priority-num", IbexPlicState, priority_num, 177),

     DEFINE_PROP_UINT32("enable-base", IbexPlicState, enable_base, 0x300),
     DEFINE_PROP_UINT32("enable-num", IbexPlicState, enable_num, 6),

     DEFINE_PROP_UINT32("threshold-base", IbexPlicState, threshold_base, 0x318),

     DEFINE_PROP_UINT32("claim-base", IbexPlicState, claim_base, 0x31c),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void ibex_plic_init(Object *obj)
 {
     IbexPlicState *s = IBEX_PLIC(obj);

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

 static void ibex_plic_realize(DeviceState *dev, Error **errp)
 {
     IbexPlicState *s = IBEX_PLIC(dev);
     int i;

     s->pending = g_new0(uint32_t, s->pending_num);
     s->hidden_pending = g_new0(uint32_t, s->pending_num);
     s->claimed = g_new0(uint32_t, s->pending_num);
     s->source = g_new0(uint32_t, s->source_num);
     s->priority = g_new0(uint32_t, s->priority_num);
     s->enable = g_new0(uint32_t, s->enable_num);

     qdev_init_gpio_in(dev, ibex_plic_irq_request, s->num_sources);

     /*
      * We can't allow the supervisor to control SEIP as this would allow the
      * supervisor to clear a pending external interrupt which will result in
      * a lost interrupt in the case a PLIC is attached. The SEIP bit must be
      * hardware controlled when a PLIC is attached.
      */
     MachineState *ms = MACHINE(qdev_get_machine());
     unsigned int smp_cpus = ms->smp.cpus;
     for (i = 0; i < smp_cpus; i++) {
         RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(i));
         if (riscv_cpu_claim_interrupts(cpu, MIP_SEIP) < 0) {
             error_report("SEIP already claimed");
             exit(1);
         }
     }

     msi_nonbroken = true;
 }

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

     dc->reset = ibex_plic_reset;
     device_class_set_props(dc, ibex_plic_properties);
     dc->realize = ibex_plic_realize;
 }

 static const TypeInfo ibex_plic_info = {
     .name          = TYPE_IBEX_PLIC,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(IbexPlicState),
     .instance_init = ibex_plic_init,
     .class_init    = ibex_plic_class_init,
 };

 static void ibex_plic_register_types(void)
 {
     type_register_static(&ibex_plic_info);
 }

 type_init(ibex_plic_register_types)
	/*
	* QEMU RISC-V lowRISC Ibex PLIC
	*
	* Copyright (c) 2020 Western Digital
	*
	* Documentation avaliable: https://docs.opentitan.org/hw/ip/rv_plic/doc/
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2 or later, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include "qemu/osdep.h"
	#include "qemu/log.h"
	#include "hw/qdev-properties.h"
	#include "hw/core/cpu.h"
	#include "hw/boards.h"
	#include "hw/pci/msi.h"
	#include "target/riscv/cpu_bits.h"
	#include "target/riscv/cpu.h"
	#include "hw/intc/ibex_plic.h"

	static bool addr_between(uint32_t addr, uint32_t base, uint32_t num)
	{
	uint32_t end = base + (num * 0x04);

	if (addr >= base && addr < end) {
	return true;
	}

	return false;
	}

	static void ibex_plic_irqs_set_pending(IbexPlicState *s, int irq, bool level)
	{
	int pending_num = irq / 32;

	if (!level) {
	/*
	* If the level is low make sure we clear the hidden_pending.
	*/
	s->hidden_pending[pending_num] &= ~(1 << (irq % 32));
	}

	if (s->claimed[pending_num] & 1 << (irq % 32)) {
	/*
	* The interrupt has been claimed, but not completed.
	* The pending bit can't be set.
	* Save the pending level for after the interrupt is completed.
	*/
	s->hidden_pending[pending_num] \|= level << (irq % 32);
	} else {
	s->pending[pending_num] \|= level << (irq % 32);
	}
	}

	static bool ibex_plic_irqs_pending(IbexPlicState *s, uint32_t context)
	{
	int i;
	uint32_t max_irq = 0;
	uint32_t max_prio = s->threshold;

	for (i = 0; i < s->pending_num; i++) {
	uint32_t irq_num = ctz64(s->pending[i]) + (i * 32);

	if (!(s->pending[i] & s->enable[i])) {
	/* No pending and enabled IRQ */
	continue;
	}

	if (s->priority[irq_num] > max_prio) {
	max_irq = irq_num;
	max_prio = s->priority[irq_num];
	}
	}

	if (max_irq) {
	s->claim = max_irq;
	return true;
	}

	return false;
	}

	static void ibex_plic_update(IbexPlicState *s)
	{
	CPUState *cpu;
	int level, i;

	for (i = 0; i < s->num_cpus; i++) {
	cpu = qemu_get_cpu(i);

	if (!cpu) {
	continue;
	}

	level = ibex_plic_irqs_pending(s, 0);

	riscv_cpu_update_mip(RISCV_CPU(cpu), MIP_MEIP, BOOL_TO_MASK(level));
	}
	}

	static void ibex_plic_reset(DeviceState *dev)
	{
	IbexPlicState *s = IBEX_PLIC(dev);

	s->threshold = 0x00000000;
	s->claim = 0x00000000;
	}

	static uint64_t ibex_plic_read(void *opaque, hwaddr addr,
	unsigned int size)
	{
	IbexPlicState *s = opaque;
	int offset;
	uint32_t ret = 0;

	if (addr_between(addr, s->pending_base, s->pending_num)) {
	offset = (addr - s->pending_base) / 4;
	ret = s->pending[offset];
	} else if (addr_between(addr, s->source_base, s->source_num)) {
	qemu_log_mask(LOG_UNIMP,
	"%s: Interrupt source mode not supported\n", __func__);
	} else if (addr_between(addr, s->priority_base, s->priority_num)) {
	offset = (addr - s->priority_base) / 4;
	ret = s->priority[offset];
	} else if (addr_between(addr, s->enable_base, s->enable_num)) {
	offset = (addr - s->enable_base) / 4;
	ret = s->enable[offset];
	} else if (addr_between(addr, s->threshold_base, 1)) {
	ret = s->threshold;
	} else if (addr_between(addr, s->claim_base, 1)) {
	int pending_num = s->claim / 32;
	s->pending[pending_num] &= ~(1 << (s->claim % 32));

	/* Set the interrupt as claimed, but not completed */
	s->claimed[pending_num] \|= 1 << (s->claim % 32);

	/* Return the current claimed interrupt */
	ret = s->claim;

	/* Clear the claimed interrupt */
	s->claim = 0x00000000;

	/* Update the interrupt status after the claim */
	ibex_plic_update(s);
	}

	return ret;
	}

	static void ibex_plic_write(void *opaque, hwaddr addr,
	uint64_t value, unsigned int size)
	{
	IbexPlicState *s = opaque;

	if (addr_between(addr, s->pending_base, s->pending_num)) {
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: Pending registers are read only\n", __func__);
	} else if (addr_between(addr, s->source_base, s->source_num)) {
	qemu_log_mask(LOG_UNIMP,
	"%s: Interrupt source mode not supported\n", __func__);
	} else if (addr_between(addr, s->priority_base, s->priority_num)) {
	uint32_t irq = ((addr - s->priority_base) >> 2) + 1;
	s->priority[irq] = value & 7;
	ibex_plic_update(s);
	} else if (addr_between(addr, s->enable_base, s->enable_num)) {
	uint32_t enable_reg = (addr - s->enable_base) / 4;

	s->enable[enable_reg] = value;
	} else if (addr_between(addr, s->threshold_base, 1)) {
	s->threshold = value & 3;
	} else if (addr_between(addr, s->claim_base, 1)) {
	if (s->claim == value) {
	/* Interrupt was completed */
	s->claim = 0;
	}
	if (s->claimed[value / 32] & 1 << (value % 32)) {
	int pending_num = value / 32;

	/* This value was already claimed, clear it. */
	s->claimed[pending_num] &= ~(1 << (value % 32));

	if (s->hidden_pending[pending_num] & (1 << (value % 32))) {
	/*
	* If the bit in hidden_pending is set then that means we
	* received an interrupt between claiming and completing
	* the interrupt that hasn't since been de-asserted.
	* On hardware this would trigger an interrupt, so let's
	* trigger one here as well.
	*/
	s->pending[pending_num] \|= 1 << (value % 32);
	}
	}
	}

	ibex_plic_update(s);
	}

	static const MemoryRegionOps ibex_plic_ops = {
	.read = ibex_plic_read,
	.write = ibex_plic_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.valid = {
	.min_access_size = 4,
	.max_access_size = 4
	}
	};

	static void ibex_plic_irq_request(void *opaque, int irq, int level)
	{
	IbexPlicState *s = opaque;

	ibex_plic_irqs_set_pending(s, irq, level > 0);
	ibex_plic_update(s);
	}

	static Property ibex_plic_properties[] = {
	DEFINE_PROP_UINT32("num-cpus", IbexPlicState, num_cpus, 1),
	DEFINE_PROP_UINT32("num-sources", IbexPlicState, num_sources, 176),

	DEFINE_PROP_UINT32("pending-base", IbexPlicState, pending_base, 0),
	DEFINE_PROP_UINT32("pending-num", IbexPlicState, pending_num, 6),

	DEFINE_PROP_UINT32("source-base", IbexPlicState, source_base, 0x18),
	DEFINE_PROP_UINT32("source-num", IbexPlicState, source_num, 6),

	DEFINE_PROP_UINT32("priority-base", IbexPlicState, priority_base, 0x30),
	DEFINE_PROP_UINT32("priority-num", IbexPlicState, priority_num, 177),

	DEFINE_PROP_UINT32("enable-base", IbexPlicState, enable_base, 0x300),
	DEFINE_PROP_UINT32("enable-num", IbexPlicState, enable_num, 6),

	DEFINE_PROP_UINT32("threshold-base", IbexPlicState, threshold_base, 0x318),

	DEFINE_PROP_UINT32("claim-base", IbexPlicState, claim_base, 0x31c),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void ibex_plic_init(Object *obj)
	{
	IbexPlicState *s = IBEX_PLIC(obj);

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

	static void ibex_plic_realize(DeviceState dev, Error *errp)
	{
	IbexPlicState *s = IBEX_PLIC(dev);
	int i;

	s->pending = g_new0(uint32_t, s->pending_num);
	s->hidden_pending = g_new0(uint32_t, s->pending_num);
	s->claimed = g_new0(uint32_t, s->pending_num);
	s->source = g_new0(uint32_t, s->source_num);
	s->priority = g_new0(uint32_t, s->priority_num);
	s->enable = g_new0(uint32_t, s->enable_num);

	qdev_init_gpio_in(dev, ibex_plic_irq_request, s->num_sources);

	/*
	* We can't allow the supervisor to control SEIP as this would allow the
	* supervisor to clear a pending external interrupt which will result in
	* a lost interrupt in the case a PLIC is attached. The SEIP bit must be
	* hardware controlled when a PLIC is attached.
	*/
	MachineState *ms = MACHINE(qdev_get_machine());
	unsigned int smp_cpus = ms->smp.cpus;
	for (i = 0; i < smp_cpus; i++) {
	RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(i));
	if (riscv_cpu_claim_interrupts(cpu, MIP_SEIP) < 0) {
	error_report("SEIP already claimed");
	exit(1);
	}
	}

	msi_nonbroken = true;
	}

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

	dc->reset = ibex_plic_reset;
	device_class_set_props(dc, ibex_plic_properties);
	dc->realize = ibex_plic_realize;
	}

	static const TypeInfo ibex_plic_info = {
	.name = TYPE_IBEX_PLIC,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(IbexPlicState),
	.instance_init = ibex_plic_init,
	.class_init = ibex_plic_class_init,
	};

	static void ibex_plic_register_types(void)
	{
	type_register_static(&ibex_plic_info);
	}

	type_init(ibex_plic_register_types)