[Qemu-devel] [PATCH 13/17] i.MX: Add code to emulate i.MX2 watchdog IP block

[Andrey Smirnov]

Add enough code to emulate i.MX2 watchdog IP block so it would be
possible to reboot the machine running Linux Guest.

Cc: Peter Maydell <address@hidden>
Cc: address@hidden
Cc: address@hidden
Cc: address@hidden
Signed-off-by: Andrey Smirnov <address@hidden>
---
 hw/misc/Makefile.objs      |   1 +
 hw/misc/imx2_wdt.c         | 117 +++++++++++++++++++++++++++++++++++++++++++++
 include/hw/misc/imx2_wdt.h |  36 ++++++++++++++
 3 files changed, 154 insertions(+)
 create mode 100644 hw/misc/imx2_wdt.c
 create mode 100644 include/hw/misc/imx2_wdt.h

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index ac1be05a03..c393a93456 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -35,6 +35,7 @@ obj-$(CONFIG_IMX) += imx25_ccm.o
 obj-$(CONFIG_IMX) += imx6_ccm.o
 obj-$(CONFIG_IMX) += imx6_src.o
 obj-$(CONFIG_IMX) += imx7_ccm.o
+obj-$(CONFIG_IMX) += imx2_wdt.o
 obj-$(CONFIG_MILKYMIST) += milkymist-hpdmc.o
 obj-$(CONFIG_MILKYMIST) += milkymist-pfpu.o
 obj-$(CONFIG_MAINSTONE) += mst_fpga.o
diff --git a/hw/misc/imx2_wdt.c b/hw/misc/imx2_wdt.c
new file mode 100644
index 0000000000..9d97a19511
--- /dev/null
+++ b/hw/misc/imx2_wdt.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2017, Impinj, Inc.
+ *
+ * i.MX2 Watchdog IP block
+ *
+ * Author: Andrey Smirnov <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "hw/hw.h"
+#include "exec/memory.h"
+#include "exec/address-spaces.h"
+#include "hw/sysbus.h"
+#include "qemu/log.h"
+#include "qemu/timer.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/watchdog.h"
+#include "qemu/error-report.h"
+#include "qemu/sizes.h"
+
+#include "hw/misc/imx2_wdt.h"
+
+
+#define IMX2_WDT_WCR_WDA       BIT(5)          /* -> External Reset WDOG_B */
+#define IMX2_WDT_WCR_SRS       BIT(4)          /* -> Software Reset Signal */
+
+static uint64_t imx2_wdt_read(void *opaque, hwaddr addr,
+                              unsigned int size)
+{
+    IMX2WdtState *s = opaque;
+    const size_t index = addr / sizeof(s->reg[0]);
+
+    if (index < ARRAY_SIZE(s->reg))
+        return s->reg[index];
+    else
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
+
+    return 0xDEADBEEF;
+}
+
+static void imx2_wdt_write(void *opaque, hwaddr addr,
+                           uint64_t val64, unsigned int size)
+{
+    uint16_t value  = val64;
+    IMX2WdtState *s = opaque;
+    const size_t index = addr / sizeof(s->reg[0]);
+
+    switch (index) {
+    case IMX2_WDT_WCR:
+        if (value & (IMX2_WDT_WCR_WDA | IMX2_WDT_WCR_SRS))
+            watchdog_perform_action();
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
+    }
+}
+
+static const MemoryRegionOps imx2_wdt_ops = {
+    .read  = imx2_wdt_read,
+    .write = imx2_wdt_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        /*
+         * Our device would not work correctly if the guest was doing
+         * unaligned access. This might not be a limitation on the real
+         * device but in practice there is no reason for a guest to access
+         * this device unaligned.
+         */
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+};
+
+static void imx2_wdt_realize(DeviceState *dev, Error **errp)
+{
+    IMX2WdtState *s = IMX2_WDT(dev);
+
+    memory_region_init_io(&s->mmio, OBJECT(dev),
+                          &imx2_wdt_ops, s,
+                          TYPE_IMX2_WDT".mmio", SZ_64K);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
+}
+
+static void imx2_wdt_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = imx2_wdt_realize;
+
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static const TypeInfo imx2_wdt_info = {
+    .name          = TYPE_IMX2_WDT,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IMX2WdtState),
+    .class_init    = imx2_wdt_class_init,
+};
+
+static WatchdogTimerModel model = {
+    .wdt_name = "imx2-watchdog",
+    .wdt_description = "i.MX2 Watchdog",
+};
+
+static void imx2_wdt_register_type(void)
+{
+    watchdog_add_model(&model);
+    type_register_static(&imx2_wdt_info);
+}
+type_init(imx2_wdt_register_type)
diff --git a/include/hw/misc/imx2_wdt.h b/include/hw/misc/imx2_wdt.h
new file mode 100644
index 0000000000..3a30ed1ef8
--- /dev/null
+++ b/include/hw/misc/imx2_wdt.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2017, Impinj, Inc.
+ *
+ * i.MX2 Watchdog IP block
+ *
+ * Author: Andrey Smirnov <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef IMX2_WDT_H
+#define IMX2_WDT_H
+
+#include "qemu/bitops.h"
+#include "hw/sysbus.h"
+
+#define TYPE_IMX2_WDT "imx2.wdt"
+#define IMX2_WDT(obj) OBJECT_CHECK(IMX2WdtState, (obj), TYPE_IMX2_WDT)
+
+enum IMX2WdtRegisters {
+    IMX2_WDT_WCR,
+    IMX2_WDT_REG_NUM
+};
+
+
+typedef struct IMX2WdtState {
+    /* <private> */
+    SysBusDevice parent_obj;
+
+    MemoryRegion mmio;
+
+    uint16_t reg[IMX2_WDT_REG_NUM];
+} IMX2WdtState;
+
+#endif /* IMX7_SNVS_H */
-- 
2.13.5