[PATCH V6 2/4] hw/intc: Add Loongson liointc support

[Huacai Chen]

Loongson-3 has an integrated liointc (Local I/O interrupt controller).
It is similar to goldfish interrupt controller, but more powerful (e.g.,
it can route external interrupt to multi-cores).

Documents about Loongson-3's liointc:
1, https://wiki.godson.ac.cn/ip_block:liointc;
2, The "I/O中断" section of Loongson-3's user mannual, part 1.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 hw/intc/Kconfig            |   3 +
 hw/intc/Makefile.objs      |   1 +
 hw/intc/loongson_liointc.c | 241 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 245 insertions(+)
 create mode 100644 hw/intc/loongson_liointc.c

diff --git a/hw/intc/Kconfig b/hw/intc/Kconfig
index f562342..2ae1e89 100644
--- a/hw/intc/Kconfig
+++ b/hw/intc/Kconfig
@@ -64,3 +64,6 @@ config OMPIC
 
 config RX_ICU
     bool
+
+config LOONGSON_LIOINTC
+    bool
diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
index a420263..3ac2b40 100644
--- a/hw/intc/Makefile.objs
+++ b/hw/intc/Makefile.objs
@@ -51,3 +51,4 @@ obj-$(CONFIG_MIPS_CPS) += mips_gic.o
 obj-$(CONFIG_NIOS2) += nios2_iic.o
 obj-$(CONFIG_OMPIC) += ompic.o
 obj-$(CONFIG_IBEX) += ibex_plic.o
+obj-$(CONFIG_LOONGSON_LIOINTC) += loongson_liointc.o
diff --git a/hw/intc/loongson_liointc.c b/hw/intc/loongson_liointc.c
new file mode 100644
index 0000000..e39e39e
--- /dev/null
+++ b/hw/intc/loongson_liointc.c
@@ -0,0 +1,241 @@
+/*
+ * QEMU Loongson Local I/O interrupt controler.
+ *
+ * Copyright (c) 2020 Jiaxun Yang <jiaxun.yang@flygoat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/sysbus.h"
+#include "qemu/module.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+
+#define D(x)
+
+#define NUM_IRQS    32
+
+#define NUM_CORES   4
+#define NUM_IPS     4
+#define NUM_PARENTS (NUM_CORES * NUM_IPS)
+#define PARENT_COREx_IPy(x, y)    (NUM_IPS * x + y)
+
+#define R_MAPPER_START    0x0
+#define R_MAPPER_END      0x20
+#define R_ISR           R_MAPPER_END
+#define R_IEN           0x24
+#define R_IEN_SET       0x28
+#define R_IEN_CLR       0x2c
+#define R_PERCORE_ISR(x) (0x40 + 0x8 * x)
+#define R_END           0x64
+
+#define TYPE_LOONGSON_LIOINTC "loongson.liointc"
+#define LOONGSON_LIOINTC(obj) \
+        OBJECT_CHECK(struct loongson_liointc, (obj), TYPE_LOONGSON_LIOINTC)
+
+struct loongson_liointc {
+    SysBusDevice parent_obj;
+
+    MemoryRegion mmio;
+    qemu_irq parent_irq[NUM_PARENTS];
+
+    uint8_t mapper[NUM_IRQS]; /* 0:3 for core, 4:7 for IP */
+    uint32_t isr;
+    uint32_t ien;
+    uint32_t per_core_isr[NUM_CORES];
+
+    /* state of the interrupt input pins */
+    uint32_t pin_state;
+    bool parent_state[NUM_PARENTS];
+};
+
+static void update_irq(struct loongson_liointc *p)
+{
+    uint32_t irq, core, ip;
+    uint32_t per_ip_isr[NUM_IPS] = {0};
+
+    /* level triggered interrupt */
+    p->isr = p->pin_state;
+
+    /* Clear disabled IRQs */
+    p->isr &= p->ien;
+
+    /* Clear per_core_isr */
+    for (core = 0; core < NUM_CORES; core++) {
+        p->per_core_isr[core] = 0;
+    }
+
+    /* Update per_core_isr and per_ip_isr */
+    for (irq = 0; irq < NUM_IRQS; irq++) {
+        if (!(p->isr & (1 << irq))) {
+            continue;
+        }
+
+        for (core = 0; core < NUM_CORES; core++) {
+            if ((p->mapper[irq] & (1 << core))) {
+                p->per_core_isr[core] |= (1 << irq);
+            }
+        }
+
+        for (ip = 0; ip < NUM_IPS; ip++) {
+            if ((p->mapper[irq] & (1 << (ip + 4)))) {
+                per_ip_isr[ip] |= (1 << irq);
+            }
+        }
+    }
+
+    /* Emit IRQ to parent! */
+    for (core = 0; core < NUM_CORES; core++) {
+        for (ip = 0; ip < NUM_IPS; ip++) {
+            int parent = PARENT_COREx_IPy(core, ip);
+            if (p->parent_state[parent] !=
+                (!!p->per_core_isr[core] && !!per_ip_isr[ip])) {
+                p->parent_state[parent] = !p->parent_state[parent];
+                qemu_set_irq(p->parent_irq[parent], p->parent_state[parent]);
+            }
+        }
+    }
+}
+
+static uint64_t
+liointc_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    struct loongson_liointc *p = opaque;
+    uint32_t r = 0;
+
+    /* Mapper is 1 byte */
+    if (size == 1 && addr < R_MAPPER_END) {
+        r = p->mapper[addr];
+        goto out;
+    }
+
+    /* Rest is 4 byte */
+    if (size != 4 || (addr % 4)) {
+        goto out;
+    }
+
+    if (addr >= R_PERCORE_ISR(0) &&
+        addr < R_PERCORE_ISR(NUM_CORES)) {
+        int core = (addr - R_PERCORE_ISR(0)) / 4;
+        r = p->per_core_isr[core];
+        goto out;
+    }
+
+    switch (addr) {
+    case R_ISR:
+        r = p->isr;
+        break;
+    case R_IEN:
+        r = p->ien;
+        break;
+    default:
+        break;
+    }
+
+out:
+    D(qemu_log("%s: size=%d addr=%lx val=%x\n", __func__, size, addr, r));
+    return r;
+}
+
+static void
+liointc_write(void *opaque, hwaddr addr,
+          uint64_t val64, unsigned int size)
+{
+    struct loongson_liointc *p = opaque;
+    uint32_t value = val64;
+
+    D(qemu_log("%s: size=%d, addr=%lx val=%x\n", __func__, size, addr, value));
+
+    /* Mapper is 1 byte */
+    if (size == 1 && addr < R_MAPPER_END) {
+        p->mapper[addr] = value;
+        goto out;
+    }
+
+    /* Rest is 4 byte */
+    if (size != 4 || (addr % 4)) {
+        goto out;
+    }
+
+    if (addr >= R_PERCORE_ISR(0) &&
+        addr < R_PERCORE_ISR(NUM_CORES)) {
+        int core = (addr - R_PERCORE_ISR(0)) / 4;
+        p->per_core_isr[core] = value;
+        goto out;
+    }
+
+    switch (addr) {
+    case R_IEN_SET:
+        p->ien |= value;
+        break;
+    case R_IEN_CLR:
+        p->ien &= ~value;
+        break;
+    default:
+        break;
+    }
+
+out:
+    update_irq(p);
+}
+
+static const MemoryRegionOps pic_ops = {
+    .read = liointc_read,
+    .write = liointc_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 4
+    }
+};
+
+static void irq_handler(void *opaque, int irq, int level)
+{
+    struct loongson_liointc *p = opaque;
+
+    p->pin_state &= ~(1 << irq);
+    p->pin_state |= level << irq;
+    update_irq(p);
+}
+
+static void loongson_liointc_init(Object *obj)
+{
+    struct loongson_liointc *p = LOONGSON_LIOINTC(obj);
+    int i;
+
+    qdev_init_gpio_in(DEVICE(obj), irq_handler, 32);
+
+    for (i = 0; i < NUM_PARENTS; i++) {
+        sysbus_init_irq(SYS_BUS_DEVICE(obj), &p->parent_irq[i]);
+    }
+
+    memory_region_init_io(&p->mmio, obj, &pic_ops, p,
+                         "loongson.liointc", R_END);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &p->mmio);
+}
+
+static const TypeInfo loongson_liointc_info = {
+    .name          = TYPE_LOONGSON_LIOINTC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(struct loongson_liointc),
+    .instance_init = loongson_liointc_init,
+};
+
+static void loongson_liointc_register_types(void)
+{
+    type_register_static(&loongson_liointc_info);
+}
+
+type_init(loongson_liointc_register_types)
-- 
2.7.0