target/nios2: Move IIC code into CPU object proper

The Nios2 architecture supports two different interrupt controller
options:

 * The IIC (Internal Interrupt Controller) is part of the CPU itself;
   it has 32 IRQ input lines and no NMI support.  Interrupt status is
   queried and controlled via the CPU's ipending and istatus
   registers.

 * The EIC (External Interrupt Controller) interface allows the CPU
   to connect to an external interrupt controller.  The interface
   allows the interrupt controller to present a packet of information
   containing:
    - handler address
    - interrupt level
    - register set
    - NMI mode

QEMU does not model an EIC currently.  We do model the IIC, but its
implementation is split across code in hw/nios2/cpu_pic.c and
hw/intc/nios2_iic.c.  The code in those two files has no state of its
own -- the IIC state is in the Nios2CPU state struct.

Because CPU objects now inherit (indirectly) from TYPE_DEVICE, they
can have GPIO input lines themselves, so we can implement the IIC
directly in the CPU object the same way that real hardware does.

Create named "IRQ" GPIO inputs to the Nios2 CPU object, and make the
only user of the IIC wire up directly to those instead.

Note that the old code had an "NMI" concept which was entirely unused
and also as far as I can see not architecturally correct, since only
the EIC has a concept of an NMI.

This fixes a Coverity-reported trivial memory leak of the IRQ array
allocated in nios2_cpu_pic_init().

Fixes: Coverity CID 1421916
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20201129174022.26530-2-peter.maydell@linaro.org
Reviewed-by: Wentong Wu <wentong.wu@intel.com>
Tested-by: Wentong Wu <wentong.wu@intel.com>

7 files changed, 32 insertions, 140 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 062074e..99293a5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -259,7 +259,6 @@ M: Marek Vasut <marex@denx.de>
 S: Maintained
 F: target/nios2/
 F: hw/nios2/
-F: hw/intc/nios2_iic.c
 F: disas/nios2.c
 F: default-configs/nios2-softmmu.mak
 
diff --git a/hw/intc/meson.build b/hw/intc/meson.build
index 3f82cc2..7c3e9da 100644
--- a/hw/intc/meson.build
+++ b/hw/intc/meson.build
@@ -37,7 +37,6 @@ specific_ss.add(when: 'CONFIG_IBEX', if_true: files('ibex_plic.c'))
 specific_ss.add(when: 'CONFIG_IOAPIC', if_true: files('ioapic.c'))
 specific_ss.add(when: 'CONFIG_LOONGSON_LIOINTC', if_true: files('loongson_liointc.c'))
 specific_ss.add(when: 'CONFIG_MIPS_CPS', if_true: files('mips_gic.c'))
-specific_ss.add(when: 'CONFIG_NIOS2', if_true: files('nios2_iic.c'))
 specific_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_intc.c'))
 specific_ss.add(when: 'CONFIG_OMPIC', if_true: files('ompic.c'))
 specific_ss.add(when: 'CONFIG_OPENPIC_KVM', if_true: files('openpic_kvm.c'))
diff --git a/hw/intc/nios2_iic.c b/hw/intc/nios2_iic.c
deleted file mode 100644
index 216db670..0000000
--- a/hw/intc/nios2_iic.c
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * QEMU Altera Internal Interrupt Controller.
- *
- * Copyright (c) 2012 Chris Wulff <crwulff@gmail.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, see
- * <http://www.gnu.org/licenses/lgpl-2.1.html>
- */
-
-#include "qemu/osdep.h"
-#include "qemu/module.h"
-#include "qapi/error.h"
-
-#include "hw/irq.h"
-#include "hw/sysbus.h"
-#include "cpu.h"
-#include "qom/object.h"
-
-#define TYPE_ALTERA_IIC "altera,iic"
-OBJECT_DECLARE_SIMPLE_TYPE(AlteraIIC, ALTERA_IIC)
-
-struct AlteraIIC {
-    SysBusDevice  parent_obj;
-    void         *cpu;
-    qemu_irq      parent_irq;
-};
-
-static void update_irq(AlteraIIC *pv)
-{
-    CPUNios2State *env = &((Nios2CPU *)(pv->cpu))->env;
-
-    qemu_set_irq(pv->parent_irq,
-                 env->regs[CR_IPENDING] & env->regs[CR_IENABLE]);
-}
-
-static void irq_handler(void *opaque, int irq, int level)
-{
-    AlteraIIC *pv = opaque;
-    CPUNios2State *env = &((Nios2CPU *)(pv->cpu))->env;
-
-    env->regs[CR_IPENDING] &= ~(1 << irq);
-    env->regs[CR_IPENDING] |= !!level << irq;
-
-    update_irq(pv);
-}
-
-static void altera_iic_init(Object *obj)
-{
-    AlteraIIC *pv = ALTERA_IIC(obj);
-
-    qdev_init_gpio_in(DEVICE(pv), irq_handler, 32);
-    sysbus_init_irq(SYS_BUS_DEVICE(obj), &pv->parent_irq);
-}
-
-static void altera_iic_realize(DeviceState *dev, Error **errp)
-{
-    struct AlteraIIC *pv = ALTERA_IIC(dev);
-
-    pv->cpu = object_property_get_link(OBJECT(dev), "cpu", &error_abort);
-}
-
-static void altera_iic_class_init(ObjectClass *klass, void *data)
-{
-    DeviceClass *dc = DEVICE_CLASS(klass);
-
-    /* Reason: needs to be wired up, e.g. by nios2_10m50_ghrd_init() */
-    dc->user_creatable = false;
-    dc->realize = altera_iic_realize;
-}
-
-static TypeInfo altera_iic_info = {
-    .name          = TYPE_ALTERA_IIC,
-    .parent        = TYPE_SYS_BUS_DEVICE,
-    .instance_size = sizeof(AlteraIIC),
-    .instance_init = altera_iic_init,
-    .class_init    = altera_iic_class_init,
-};
-
-static void altera_iic_register(void)
-{
-    type_register_static(&altera_iic_info);
-}
-
-type_init(altera_iic_register)
diff --git a/hw/nios2/10m50_devboard.c b/hw/nios2/10m50_devboard.c
index 5c13b74..a14fc31 100644
--- a/hw/nios2/10m50_devboard.c
+++ b/hw/nios2/10m50_devboard.c
@@ -52,7 +52,7 @@ static void nios2_10m50_ghrd_init(MachineState *machine)
     ram_addr_t tcm_size = 0x1000;    /* 1 kiB, but QEMU limit is 4 kiB */
     ram_addr_t ram_base = 0x08000000;
     ram_addr_t ram_size = 0x08000000;
-    qemu_irq *cpu_irq, irq[32];
+    qemu_irq irq[32];
     int i;
 
     /* Physical TCM (tb_ram_1k) with alias at 0xc0000000 */
@@ -75,17 +75,8 @@ static void nios2_10m50_ghrd_init(MachineState *machine)
 
     /* Create CPU -- FIXME */
     cpu = NIOS2_CPU(cpu_create(TYPE_NIOS2_CPU));
-
-    /* Register: CPU interrupt controller (PIC) */
-    cpu_irq = nios2_cpu_pic_init(cpu);
-
-    /* Register: Internal Interrupt Controller (IIC) */
-    dev = qdev_new("altera,iic");
-    object_property_add_const_link(OBJECT(dev), "cpu", OBJECT(cpu));
-    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
-    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, cpu_irq[0]);
     for (i = 0; i < 32; i++) {
-        irq[i] = qdev_get_gpio_in(dev, i);
+        irq[i] = qdev_get_gpio_in_named(DEVICE(cpu), "IRQ", i);
     }
 
     /* Register: Altera 16550 UART */
diff --git a/hw/nios2/cpu_pic.c b/hw/nios2/cpu_pic.c
index 5ea7e52..3fb621c 100644
--- a/hw/nios2/cpu_pic.c
+++ b/hw/nios2/cpu_pic.c
@@ -26,32 +26,6 @@
 
 #include "boot.h"
 
-static void nios2_pic_cpu_handler(void *opaque, int irq, int level)
-{
-    Nios2CPU *cpu = opaque;
-    CPUNios2State *env = &cpu->env;
-    CPUState *cs = CPU(cpu);
-    int type = irq ? CPU_INTERRUPT_NMI : CPU_INTERRUPT_HARD;
-
-    if (type == CPU_INTERRUPT_HARD) {
-        env->irq_pending = level;
-
-        if (level && (env->regs[CR_STATUS] & CR_STATUS_PIE)) {
-            env->irq_pending = 0;
-            cpu_interrupt(cs, type);
-        } else if (!level) {
-            env->irq_pending = 0;
-            cpu_reset_interrupt(cs, type);
-        }
-    } else {
-        if (level) {
-            cpu_interrupt(cs, type);
-        } else {
-            cpu_reset_interrupt(cs, type);
-        }
-    }
-}
-
 void nios2_check_interrupts(CPUNios2State *env)
 {
     if (env->irq_pending &&
@@ -60,8 +34,3 @@ void nios2_check_interrupts(CPUNios2State *env)
         cpu_interrupt(env_cpu(env), CPU_INTERRUPT_HARD);
     }
 }
-
-qemu_irq *nios2_cpu_pic_init(Nios2CPU *cpu)
-{
-    return qemu_allocate_irqs(nios2_pic_cpu_handler, cpu, 2);
-}
diff --git a/target/nios2/cpu.c b/target/nios2/cpu.c
index 8f7011f..52ebda8 100644
--- a/target/nios2/cpu.c
+++ b/target/nios2/cpu.c
@@ -64,6 +64,27 @@ static void nios2_cpu_reset(DeviceState *dev)
 #endif
 }
 
+#ifndef CONFIG_USER_ONLY
+static void nios2_cpu_set_irq(void *opaque, int irq, int level)
+{
+    Nios2CPU *cpu = opaque;
+    CPUNios2State *env = &cpu->env;
+    CPUState *cs = CPU(cpu);
+
+    env->regs[CR_IPENDING] &= ~(1 << irq);
+    env->regs[CR_IPENDING] |= !!level << irq;
+
+    env->irq_pending = env->regs[CR_IPENDING] & env->regs[CR_IENABLE];
+
+    if (env->irq_pending && (env->regs[CR_STATUS] & CR_STATUS_PIE)) {
+        env->irq_pending = 0;
+        cpu_interrupt(cs, CPU_INTERRUPT_HARD);
+    } else if (!env->irq_pending) {
+        cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
+    }
+}
+#endif
+
 static void nios2_cpu_initfn(Object *obj)
 {
     Nios2CPU *cpu = NIOS2_CPU(obj);
@@ -72,6 +93,15 @@ static void nios2_cpu_initfn(Object *obj)
 
 #if !defined(CONFIG_USER_ONLY)
     mmu_init(&cpu->env);
+
+    /*
+     * These interrupt lines model the IIC (internal interrupt
+     * controller). QEMU does not currently support the EIC
+     * (external interrupt controller) -- if we did it would be
+     * a separate device in hw/intc with a custom interface to
+     * the CPU, and boards using it would not wire up these IRQ lines.
+     */
+    qdev_init_gpio_in_named(DEVICE(cpu), nios2_cpu_set_irq, "IRQ", 32);
 #endif
 }
 
diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h
index 86bbe1d..b7efb54 100644
--- a/target/nios2/cpu.h
+++ b/target/nios2/cpu.h
@@ -201,7 +201,6 @@ void nios2_cpu_do_unaligned_access(CPUState *cpu, vaddr addr,
                                    MMUAccessType access_type,
                                    int mmu_idx, uintptr_t retaddr);
 
-qemu_irq *nios2_cpu_pic_init(Nios2CPU *cpu);
 void nios2_check_interrupts(CPUNios2State *env);
 
 void do_nios2_semihosting(CPUNios2State *env);