raspi: add BCM2835 SOC MPHI emulation

Add BCM2835 SOC MPHI (Message-based Parallel Host Interface)
emulation. It is very basic, only providing the FIQ interrupt
needed to allow the dwc-otg USB host controller driver in the
Raspbian kernel to function.

Signed-off-by: Paul Zimmerman <pauldzim@gmail.com>
Acked-by: Philippe Mathieu-Daude <f4bug@amsat.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20200520235349.21215-2-pauldzim@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 191 insertions, 0 deletions

diff --git a/hw/misc/bcm2835_mphi.c b/hw/misc/bcm2835_mphi.c
new file mode 100644
index 0000000..0428e10
--- /dev/null
+++ b/hw/misc/bcm2835_mphi.c
@@ -0,0 +1,191 @@
+/*
+ * BCM2835 SOC MPHI emulation
+ *
+ * Very basic emulation, only providing the FIQ interrupt needed to
+ * allow the dwc-otg USB host controller driver in the Raspbian kernel
+ * to function.
+ *
+ * Copyright (c) 2020 Paul Zimmerman <pauldzim@gmail.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.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/misc/bcm2835_mphi.h"
+#include "migration/vmstate.h"
+#include "qemu/error-report.h"
+#include "qemu/log.h"
+#include "qemu/main-loop.h"
+
+static inline void mphi_raise_irq(BCM2835MphiState *s)
+{
+    qemu_set_irq(s->irq, 1);
+}
+
+static inline void mphi_lower_irq(BCM2835MphiState *s)
+{
+    qemu_set_irq(s->irq, 0);
+}
+
+static uint64_t mphi_reg_read(void *ptr, hwaddr addr, unsigned size)
+{
+    BCM2835MphiState *s = ptr;
+    uint32_t val = 0;
+
+    switch (addr) {
+    case 0x28:  /* outdda */
+        val = s->outdda;
+        break;
+    case 0x2c:  /* outddb */
+        val = s->outddb;
+        break;
+    case 0x4c:  /* ctrl */
+        val = s->ctrl;
+        val |= 1 << 17;
+        break;
+    case 0x50:  /* intstat */
+        val = s->intstat;
+        break;
+    case 0x1f0: /* swirq_set */
+        val = s->swirq;
+        break;
+    case 0x1f4: /* swirq_clr */
+        val = s->swirq;
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "read from unknown register");
+        break;
+    }
+
+    return val;
+}
+
+static void mphi_reg_write(void *ptr, hwaddr addr, uint64_t val, unsigned size)
+{
+    BCM2835MphiState *s = ptr;
+    int do_irq = 0;
+
+    switch (addr) {
+    case 0x28:  /* outdda */
+        s->outdda = val;
+        break;
+    case 0x2c:  /* outddb */
+        s->outddb = val;
+        if (val & (1 << 29)) {
+            do_irq = 1;
+        }
+        break;
+    case 0x4c:  /* ctrl */
+        s->ctrl = val;
+        if (val & (1 << 16)) {
+            do_irq = -1;
+        }
+        break;
+    case 0x50:  /* intstat */
+        s->intstat = val;
+        if (val & ((1 << 16) | (1 << 29))) {
+            do_irq = -1;
+        }
+        break;
+    case 0x1f0: /* swirq_set */
+        s->swirq |= val;
+        do_irq = 1;
+        break;
+    case 0x1f4: /* swirq_clr */
+        s->swirq &= ~val;
+        do_irq = -1;
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "write to unknown register");
+        return;
+    }
+
+    if (do_irq > 0) {
+        mphi_raise_irq(s);
+    } else if (do_irq < 0) {
+        mphi_lower_irq(s);
+    }
+}
+
+static const MemoryRegionOps mphi_mmio_ops = {
+    .read = mphi_reg_read,
+    .write = mphi_reg_write,
+    .impl.min_access_size = 4,
+    .impl.max_access_size = 4,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void mphi_reset(DeviceState *dev)
+{
+    BCM2835MphiState *s = BCM2835_MPHI(dev);
+
+    s->outdda = 0;
+    s->outddb = 0;
+    s->ctrl = 0;
+    s->intstat = 0;
+    s->swirq = 0;
+}
+
+static void mphi_realize(DeviceState *dev, Error **errp)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    BCM2835MphiState *s = BCM2835_MPHI(dev);
+
+    sysbus_init_irq(sbd, &s->irq);
+}
+
+static void mphi_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    BCM2835MphiState *s = BCM2835_MPHI(obj);
+
+    memory_region_init_io(&s->iomem, obj, &mphi_mmio_ops, s, "mphi", MPHI_MMIO_SIZE);
+    sysbus_init_mmio(sbd, &s->iomem);
+}
+
+const VMStateDescription vmstate_mphi_state = {
+    .name = "mphi",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(outdda, BCM2835MphiState),
+        VMSTATE_UINT32(outddb, BCM2835MphiState),
+        VMSTATE_UINT32(ctrl, BCM2835MphiState),
+        VMSTATE_UINT32(intstat, BCM2835MphiState),
+        VMSTATE_UINT32(swirq, BCM2835MphiState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void mphi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = mphi_realize;
+    dc->reset = mphi_reset;
+    dc->vmsd = &vmstate_mphi_state;
+}
+
+static const TypeInfo bcm2835_mphi_type_info = {
+    .name          = TYPE_BCM2835_MPHI,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(BCM2835MphiState),
+    .instance_init = mphi_init,
+    .class_init    = mphi_class_init,
+};
+
+static void bcm2835_mphi_register_types(void)
+{
+    type_register_static(&bcm2835_mphi_type_info);
+}
+
+type_init(bcm2835_mphi_register_types)