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qemu-e2k/hw/intc/ibex_plic.c

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/*
* 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, 80),
DEFINE_PROP_UINT32("pending-base", IbexPlicState, pending_base, 0),
DEFINE_PROP_UINT32("pending-num", IbexPlicState, pending_num, 3),
DEFINE_PROP_UINT32("source-base", IbexPlicState, source_base, 0x0c),
DEFINE_PROP_UINT32("source-num", IbexPlicState, source_num, 3),
DEFINE_PROP_UINT32("priority-base", IbexPlicState, priority_base, 0x18),
DEFINE_PROP_UINT32("priority-num", IbexPlicState, priority_num, 80),
DEFINE_PROP_UINT32("enable-base", IbexPlicState, enable_base, 0x200),
DEFINE_PROP_UINT32("enable-num", IbexPlicState, enable_num, 3),
DEFINE_PROP_UINT32("threshold-base", IbexPlicState, threshold_base, 0x20c),
DEFINE_PROP_UINT32("claim-base", IbexPlicState, claim_base, 0x210),
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)
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