[Qemu-devel] [PATCH 1/9] hw/mips: implement ITC Configuration Tags

[Leon Alrae]

Implement ITC as a single object consisting of two memory regions:

* tag_io: ITC Configuration Tags (i.e. ITCAddressMap{0,1} registers) which
  are accessible by the CPU via CACHE instruction. Also adding
  MemoryRegion *itc_tag to the CPUMIPSState so that CACHE instruction will
  dispatch reads/writes directly.

* storage_io: memory-mapped ITC Storage whose address space is
  configurable (i.e. enabled/remapped/resized) by writing to
  ITCAddressMap{0,1} registers.

Signed-off-by: Leon Alrae <address@hidden>
---
 default-configs/mips-softmmu.mak     |   1 +
 default-configs/mips64-softmmu.mak   |   1 +
 default-configs/mips64el-softmmu.mak |   1 +
 default-configs/mipsel-softmmu.mak   |   1 +
 hw/misc/Makefile.objs                |   1 +
 hw/misc/mips_itu.c                   | 186 +++++++++++++++++++++++++++++++++++
 include/hw/misc/mips_itu.h           |  47 +++++++++
 target-mips/cpu.h                    |   1 +
 8 files changed, 239 insertions(+)
 create mode 100644 hw/misc/mips_itu.c
 create mode 100644 include/hw/misc/mips_itu.h

diff --git a/default-configs/mips-softmmu.mak b/default-configs/mips-softmmu.mak
index 44467c3..9754371 100644
--- a/default-configs/mips-softmmu.mak
+++ b/default-configs/mips-softmmu.mak
@@ -30,3 +30,4 @@ CONFIG_I8259=y
 CONFIG_MC146818RTC=y
 CONFIG_ISA_TESTDEV=y
 CONFIG_EMPTY_SLOT=y
+CONFIG_MIPS_ITU=y
diff --git a/default-configs/mips64-softmmu.mak 
b/default-configs/mips64-softmmu.mak
index 66ed5f9..598d6b7 100644
--- a/default-configs/mips64-softmmu.mak
+++ b/default-configs/mips64-softmmu.mak
@@ -36,3 +36,4 @@ CONFIG_JAZZ_LED=y
 CONFIG_MC146818RTC=y
 CONFIG_ISA_TESTDEV=y
 CONFIG_EMPTY_SLOT=y
+CONFIG_MIPS_ITU=y
diff --git a/default-configs/mips64el-softmmu.mak 
b/default-configs/mips64el-softmmu.mak
index bfca2b2..3639f66 100644
--- a/default-configs/mips64el-softmmu.mak
+++ b/default-configs/mips64el-softmmu.mak
@@ -39,3 +39,4 @@ CONFIG_MC146818RTC=y
 CONFIG_VT82C686=y
 CONFIG_ISA_TESTDEV=y
 CONFIG_EMPTY_SLOT=y
+CONFIG_MIPS_ITU=y
diff --git a/default-configs/mipsel-softmmu.mak 
b/default-configs/mipsel-softmmu.mak
index 0162ef0..371aea8 100644
--- a/default-configs/mipsel-softmmu.mak
+++ b/default-configs/mipsel-softmmu.mak
@@ -30,3 +30,4 @@ CONFIG_I8259=y
 CONFIG_MC146818RTC=y
 CONFIG_ISA_TESTDEV=y
 CONFIG_EMPTY_SLOT=y
+CONFIG_MIPS_ITU=y
diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index d4765c2..2d95404 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -40,6 +40,7 @@ obj-$(CONFIG_SLAVIO) += slavio_misc.o
 obj-$(CONFIG_ZYNQ) += zynq_slcr.o
 obj-$(CONFIG_ZYNQ) += zynq-xadc.o
 obj-$(CONFIG_STM32F2XX_SYSCFG) += stm32f2xx_syscfg.o
+obj-$(CONFIG_MIPS_ITU) += mips_itu.o
 
 obj-$(CONFIG_PVPANIC) += pvpanic.o
 obj-$(CONFIG_EDU) += edu.o
diff --git a/hw/misc/mips_itu.c b/hw/misc/mips_itu.c
new file mode 100644
index 0000000..cf79bc6
--- /dev/null
+++ b/hw/misc/mips_itu.c
@@ -0,0 +1,186 @@
+/*
+ * Inter-Thread Communication Unit emulation.
+ *
+ * Copyright (c) 2016 Imagination Technologies
+ *
+ * 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 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/>.
+ */
+
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "sysemu/sysemu.h"
+#include "hw/misc/mips_itu.h"
+
+#define ITC_TAG_ADDRSPACE_SZ (ITC_ADDRESSMAP_NUM * 8)
+/* Initialize as 4kB area to fit all 32 cells with default 128B grain.
+   Storage may be resized by the software. */
+#define ITC_STORAGE_ADDRSPACE_SZ 0x1000
+
+#define ITC_FIFO_NUM_MAX 16
+#define ITC_SEMAPH_NUM_MAX 16
+#define ITC_AM1_NUMENTRIES_OFS 20
+
+#define ITC_AM0_BASE_ADDRESS_MASK 0xFFFFFC00ULL
+#define ITC_AM0_EN_MASK 0x1
+
+#define ITC_AM1_ADDR_MASK_MASK 0x1FC00
+#define ITC_AM1_ENTRY_GRAIN_MASK 0x7
+
+MemoryRegion *mips_itu_get_tag_region(MIPSITUState *itu)
+{
+    return &itu->tag_io;
+}
+
+static uint64_t itc_tag_read(void *opaque, hwaddr addr, unsigned size)
+{
+    MIPSITUState *tag = (MIPSITUState *)opaque;
+    uint64_t index = addr >> 3;
+    uint64_t ret = 0;
+
+    switch (index) {
+    case 0 ... ITC_ADDRESSMAP_NUM:
+        ret = tag->ITCAddressMap[index];
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "Read 0x%" PRIx64 "\n", addr);
+        break;
+    }
+
+    return ret;
+}
+
+static void itc_tag_write(void *opaque, hwaddr addr,
+                          uint64_t data, unsigned size)
+{
+    MIPSITUState *tag = (MIPSITUState *)opaque;
+    uint64_t *am = &tag->ITCAddressMap[0];
+    uint64_t am_old, mask;
+    uint64_t index = addr >> 3;
+
+    switch (index) {
+    case 0:
+        mask = ITC_AM0_BASE_ADDRESS_MASK | ITC_AM0_EN_MASK;
+        break;
+    case 1:
+        mask = ITC_AM1_ADDR_MASK_MASK | ITC_AM1_ENTRY_GRAIN_MASK;
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "Bad write 0x%" PRIx64 "\n", addr);
+        return;
+    }
+
+    am_old = am[index];
+    am[index] = (data & mask) | (am_old & ~mask);
+
+    /* Reconfigure ITC block */
+    if (am_old != am[index]) {
+        MemoryRegion *mr = &tag->storage_io;
+        hwaddr address = am[0] & ITC_AM0_BASE_ADDRESS_MASK;
+        uint64_t size = (1 << 10) + (am[1] & ITC_AM1_ADDR_MASK_MASK);
+        bool is_enabled = (am[0] & ITC_AM0_EN_MASK) != 0;
+
+        if (!(size & (size - 1))) {
+            memory_region_set_size(mr, size);
+        }
+        memory_region_set_address(mr, address);
+        memory_region_set_enabled(mr, is_enabled);
+    }
+}
+
+static const MemoryRegionOps itc_tag_ops = {
+    .read = itc_tag_read,
+    .write = itc_tag_write,
+    .impl = {
+        .max_access_size = 8,
+    },
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static inline uint32_t get_num_cells(MIPSITUState *s)
+{
+    return s->num_fifo + s->num_semaphores;
+}
+
+static const MemoryRegionOps itc_storage_ops = {
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void mips_itu_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    MIPSITUState *s = MIPS_ITU(obj);
+
+    memory_region_init_io(&s->storage_io, OBJECT(s), &itc_storage_ops, s,
+                          "mips-itc-storage", ITC_STORAGE_ADDRSPACE_SZ);
+    sysbus_init_mmio(sbd, &s->storage_io);
+
+    memory_region_init_io(&s->tag_io, OBJECT(s), &itc_tag_ops, s,
+                          "mips-itc-tag", ITC_TAG_ADDRSPACE_SZ);
+
+}
+
+static void mips_itu_realize(DeviceState *dev, Error **errp)
+{
+    MIPSITUState *s = MIPS_ITU(dev);
+
+    if (s->num_fifo > ITC_FIFO_NUM_MAX) {
+        error_setg(errp, "Exceed maximum number of FIFO cells: %d",
+                   s->num_fifo);
+        return;
+    }
+    if (s->num_semaphores > ITC_SEMAPH_NUM_MAX) {
+        error_setg(errp, "Exceed maximum number of Semaphore cells: %d",
+                   s->num_semaphores);
+        return;
+    }
+
+    s->ITCAddressMap[0] = 0;
+
+    s->ITCAddressMap[1] =
+        ((ITC_STORAGE_ADDRSPACE_SZ - 1) & ITC_AM1_ADDR_MASK_MASK) |
+        (get_num_cells(s) << ITC_AM1_NUMENTRIES_OFS);
+
+    memory_region_set_enabled(&s->storage_io, false);
+}
+
+static Property mips_itu_properties[] = {
+    DEFINE_PROP_INT32("num-fifo", MIPSITUState, num_fifo,
+                      ITC_FIFO_NUM_MAX),
+    DEFINE_PROP_INT32("num-semaphores", MIPSITUState, num_semaphores,
+                      ITC_SEMAPH_NUM_MAX),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void mips_itu_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->props = mips_itu_properties;
+    dc->realize = mips_itu_realize;
+}
+
+static const TypeInfo mips_itu_info = {
+    .name          = TYPE_MIPS_ITU,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(MIPSITUState),
+    .instance_init = mips_itu_init,
+    .class_init    = mips_itu_class_init,
+};
+
+static void mips_itu_register_types(void)
+{
+    type_register_static(&mips_itu_info);
+}
+
+type_init(mips_itu_register_types)
diff --git a/include/hw/misc/mips_itu.h b/include/hw/misc/mips_itu.h
new file mode 100644
index 0000000..9ddd8b4
--- /dev/null
+++ b/include/hw/misc/mips_itu.h
@@ -0,0 +1,47 @@
+/*
+ * Inter-Thread Communication Unit emulation.
+ *
+ * Copyright (c) 2016 Imagination Technologies
+ *
+ * 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 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/>.
+ */
+
+#ifndef MIPS_ITU_H
+#define MIPS_ITU_H
+
+#define TYPE_MIPS_ITU "mips-itu"
+#define MIPS_ITU(obj) OBJECT_CHECK(MIPSITUState, (obj), TYPE_MIPS_ITU)
+
+#define ITC_ADDRESSMAP_NUM 2
+
+typedef struct MIPSITUState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+    /*< public >*/
+
+    int32_t num_fifo;
+    int32_t num_semaphores;
+
+    /* ITC Storage */
+    MemoryRegion storage_io;
+
+    /* ITC Configuration Tags */
+    uint64_t ITCAddressMap[ITC_ADDRESSMAP_NUM];
+    MemoryRegion tag_io;
+} MIPSITUState;
+
+/* Get ITC Configuration Tag memory region. */
+MemoryRegion *mips_itu_get_tag_region(MIPSITUState *itu);
+
+#endif /* MIPS_ITU_H */
diff --git a/target-mips/cpu.h b/target-mips/cpu.h
index ae8c575..d947eae 100644
--- a/target-mips/cpu.h
+++ b/target-mips/cpu.h
@@ -600,6 +600,7 @@ struct CPUMIPSState {
     const mips_def_t *cpu_model;
     void *irq[8];
     QEMUTimer *timer; /* Internal timer */
+    MemoryRegion *itc_tag; /* ITC Configuration Tags */
 };
 
 #include "cpu-qom.h"
-- 
2.1.0