Restore 'loongarch_ipi.c' for LoongArch.

This reverts commit 5f82fb2a3a71bb510b3e1b7229929d468c01740a.
---
 hw/intc/loongarch_ipi.c | 347 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 347 insertions(+)
 create mode 100644 hw/intc/loongarch_ipi.c

diff --git a/hw/intc/loongarch_ipi.c b/hw/intc/loongarch_ipi.c
new file mode 100644
index 0000000000..44b3b9c138
--- /dev/null
+++ b/hw/intc/loongarch_ipi.c
@@ -0,0 +1,347 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * LoongArch ipi interrupt support
+ *
+ * Copyright (C) 2021 Loongson Technology Corporation Limited
+ */
+
+#include "qemu/osdep.h"
+#include "hw/boards.h"
+#include "hw/sysbus.h"
+#include "hw/intc/loongarch_ipi.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "qapi/error.h"
+#include "qemu/log.h"
+#include "exec/address-spaces.h"
+#include "migration/vmstate.h"
+#include "target/loongarch/cpu.h"
+#include "trace.h"
+
+static MemTxResult loongarch_ipi_readl(void *opaque, hwaddr addr,
+                                       uint64_t *data,
+                                       unsigned size, MemTxAttrs attrs)
+{
+    IPICore *s;
+    LoongArchIPI *ipi = opaque;
+    uint64_t ret = 0;
+    int index = 0;
+
+    s = &ipi->cpu[attrs.requester_id];
+    addr &= 0xff;
+    switch (addr) {
+    case CORE_STATUS_OFF:
+        ret = s->status;
+        break;
+    case CORE_EN_OFF:
+        ret = s->en;
+        break;
+    case CORE_SET_OFF:
+        ret = 0;
+        break;
+    case CORE_CLEAR_OFF:
+        ret = 0;
+        break;
+    case CORE_BUF_20 ... CORE_BUF_38 + 4:
+        index = (addr - CORE_BUF_20) >> 2;
+        ret = s->buf[index];
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "invalid read: %x", (uint32_t)addr);
+        break;
+    }
+
+    trace_loongarch_ipi_read(size, (uint64_t)addr, ret);
+    *data = ret;
+    return MEMTX_OK;
+}
+
+static void send_ipi_data(CPULoongArchState *env, uint64_t val, hwaddr addr,
+                          MemTxAttrs attrs)
+{
+    int i, mask = 0, data = 0;
+
+    /*
+     * bit 27-30 is mask for byte writing,
+     * if the mask is 0, we need not to do anything.
+     */
+    if ((val >> 27) & 0xf) {
+        data = address_space_ldl(env->address_space_iocsr, addr,
+                                 attrs, NULL);
+        for (i = 0; i < 4; i++) {
+            /* get mask for byte writing */
+            if (val & (0x1 << (27 + i))) {
+                mask |= 0xff << (i * 8);
+            }
+        }
+    }
+
+    data &= mask;
+    data |= (val >> 32) & ~mask;
+    address_space_stl(env->address_space_iocsr, addr,
+                      data, attrs, NULL);
+}
+
+static int archid_cmp(const void *a, const void *b)
+{
+   CPUArchId *archid_a = (CPUArchId *)a;
+   CPUArchId *archid_b = (CPUArchId *)b;
+
+   return archid_a->arch_id - archid_b->arch_id;
+}
+
+static CPUArchId *find_cpu_by_archid(MachineState *ms, uint32_t id)
+{
+    CPUArchId apic_id, *found_cpu;
+
+    apic_id.arch_id = id;
+    found_cpu = bsearch(&apic_id, ms->possible_cpus->cpus,
+        ms->possible_cpus->len, sizeof(*ms->possible_cpus->cpus),
+        archid_cmp);
+
+    return found_cpu;
+}
+
+static CPUState *ipi_getcpu(int arch_id)
+{
+    MachineState *machine = MACHINE(qdev_get_machine());
+    CPUArchId *archid;
+
+    archid = find_cpu_by_archid(machine, arch_id);
+    if (archid) {
+        return CPU(archid->cpu);
+    }
+
+    return NULL;
+}
+
+static MemTxResult mail_send(uint64_t val, MemTxAttrs attrs)
+{
+    uint32_t cpuid;
+    hwaddr addr;
+    CPUState *cs;
+
+    cpuid = extract32(val, 16, 10);
+    cs = ipi_getcpu(cpuid);
+    if (cs == NULL) {
+        return MEMTX_DECODE_ERROR;
+    }
+
+    /* override requester_id */
+    addr = SMP_IPI_MAILBOX + CORE_BUF_20 + (val & 0x1c);
+    attrs.requester_id = cs->cpu_index;
+    send_ipi_data(&LOONGARCH_CPU(cs)->env, val, addr, attrs);
+    return MEMTX_OK;
+}
+
+static MemTxResult any_send(uint64_t val, MemTxAttrs attrs)
+{
+    uint32_t cpuid;
+    hwaddr addr;
+    CPUState *cs;
+
+    cpuid = extract32(val, 16, 10);
+    cs = ipi_getcpu(cpuid);
+    if (cs == NULL) {
+        return MEMTX_DECODE_ERROR;
+    }
+
+    /* override requester_id */
+    addr = val & 0xffff;
+    attrs.requester_id = cs->cpu_index;
+    send_ipi_data(&LOONGARCH_CPU(cs)->env, val, addr, attrs);
+    return MEMTX_OK;
+}
+
+static MemTxResult loongarch_ipi_writel(void *opaque, hwaddr addr, uint64_t val,
+                                        unsigned size, MemTxAttrs attrs)
+{
+    LoongArchIPI *ipi = opaque;
+    IPICore *s;
+    int index = 0;
+    uint32_t cpuid;
+    uint8_t vector;
+    CPUState *cs;
+
+    s = &ipi->cpu[attrs.requester_id];
+    addr &= 0xff;
+    trace_loongarch_ipi_write(size, (uint64_t)addr, val);
+    switch (addr) {
+    case CORE_STATUS_OFF:
+        qemu_log_mask(LOG_GUEST_ERROR, "can not be written");
+        break;
+    case CORE_EN_OFF:
+        s->en = val;
+        break;
+    case CORE_SET_OFF:
+        s->status |= val;
+        if (s->status != 0 && (s->status & s->en) != 0) {
+            qemu_irq_raise(s->irq);
+        }
+        break;
+    case CORE_CLEAR_OFF:
+        s->status &= ~val;
+        if (s->status == 0 && s->en != 0) {
+            qemu_irq_lower(s->irq);
+        }
+        break;
+    case CORE_BUF_20 ... CORE_BUF_38 + 4:
+        index = (addr - CORE_BUF_20) >> 2;
+        s->buf[index] = val;
+        break;
+    case IOCSR_IPI_SEND:
+        cpuid = extract32(val, 16, 10);
+        /* IPI status vector */
+        vector = extract8(val, 0, 5);
+        cs = ipi_getcpu(cpuid);
+        if (cs == NULL) {
+            return MEMTX_DECODE_ERROR;
+        }
+
+        /* override requester_id */
+        attrs.requester_id = cs->cpu_index;
+        loongarch_ipi_writel(ipi, CORE_SET_OFF, BIT(vector), 4, attrs);
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "invalid write: %x", (uint32_t)addr);
+        break;
+    }
+
+    return MEMTX_OK;
+}
+
+static const MemoryRegionOps loongarch_ipi_ops = {
+    .read_with_attrs = loongarch_ipi_readl,
+    .write_with_attrs = loongarch_ipi_writel,
+    .impl.min_access_size = 4,
+    .impl.max_access_size = 4,
+    .valid.min_access_size = 4,
+    .valid.max_access_size = 8,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+/* mail send and any send only support writeq */
+static MemTxResult loongarch_ipi_writeq(void *opaque, hwaddr addr, uint64_t val,
+                                        unsigned size, MemTxAttrs attrs)
+{
+    MemTxResult ret = MEMTX_OK;
+
+    addr &= 0xfff;
+    switch (addr) {
+    case MAIL_SEND_OFFSET:
+        ret = mail_send(val, attrs);
+        break;
+    case ANY_SEND_OFFSET:
+        ret = any_send(val, attrs);
+        break;
+    default:
+       break;
+    }
+
+    return ret;
+}
+
+static const MemoryRegionOps loongarch_ipi64_ops = {
+    .write_with_attrs = loongarch_ipi_writeq,
+    .impl.min_access_size = 8,
+    .impl.max_access_size = 8,
+    .valid.min_access_size = 8,
+    .valid.max_access_size = 8,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void loongarch_ipi_realize(DeviceState *dev, Error **errp)
+{
+    LoongArchIPI *s = LOONGARCH_IPI(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    int i;
+
+    if (s->num_cpu == 0) {
+        error_setg(errp, "num-cpu must be at least 1");
+        return;
+    }
+
+    memory_region_init_io(&s->ipi_iocsr_mem, OBJECT(dev), &loongarch_ipi_ops,
+                          s, "loongarch_ipi_iocsr", 0x48);
+
+    /* loongarch_ipi_iocsr performs re-entrant IO through ipi_send */
+    s->ipi_iocsr_mem.disable_reentrancy_guard = true;
+
+    sysbus_init_mmio(sbd, &s->ipi_iocsr_mem);
+
+    memory_region_init_io(&s->ipi64_iocsr_mem, OBJECT(dev),
+                          &loongarch_ipi64_ops,
+                          s, "loongarch_ipi64_iocsr", 0x118);
+    sysbus_init_mmio(sbd, &s->ipi64_iocsr_mem);
+
+    s->cpu = g_new0(IPICore, s->num_cpu);
+    if (s->cpu == NULL) {
+        error_setg(errp, "Memory allocation for ExtIOICore faile");
+        return;
+    }
+
+    for (i = 0; i < s->num_cpu; i++) {
+        qdev_init_gpio_out(dev, &s->cpu[i].irq, 1);
+    }
+}
+
+static const VMStateDescription vmstate_ipi_core = {
+    .name = "ipi-single",
+    .version_id = 2,
+    .minimum_version_id = 2,
+    .fields = (const VMStateField[]) {
+        VMSTATE_UINT32(status, IPICore),
+        VMSTATE_UINT32(en, IPICore),
+        VMSTATE_UINT32(set, IPICore),
+        VMSTATE_UINT32(clear, IPICore),
+        VMSTATE_UINT32_ARRAY(buf, IPICore, IPI_MBX_NUM * 2),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_loongarch_ipi = {
+    .name = TYPE_LOONGARCH_IPI,
+    .version_id = 2,
+    .minimum_version_id = 2,
+    .fields = (const VMStateField[]) {
+        VMSTATE_STRUCT_VARRAY_POINTER_UINT32(cpu, LoongArchIPI, num_cpu,
+                         vmstate_ipi_core, IPICore),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static Property ipi_properties[] = {
+    DEFINE_PROP_UINT32("num-cpu", LoongArchIPI, num_cpu, 1),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void loongarch_ipi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = loongarch_ipi_realize;
+    device_class_set_props(dc, ipi_properties);
+    dc->vmsd = &vmstate_loongarch_ipi;
+}
+
+static void loongarch_ipi_finalize(Object *obj)
+{
+    LoongArchIPI *s = LOONGARCH_IPI(obj);
+
+    g_free(s->cpu);
+}
+
+static const TypeInfo loongarch_ipi_info = {
+    .name          = TYPE_LOONGARCH_IPI,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(LoongArchIPI),
+    .class_init    = loongarch_ipi_class_init,
+    .instance_finalize = loongarch_ipi_finalize,
+};
+
+static void loongarch_ipi_register_types(void)
+{
+    type_register_static(&loongarch_ipi_info);
+}
+
+type_init(loongarch_ipi_register_types)
-- 
2.34.1