hw: Move i.MX watchdog driver to hw/watchdog

In preparation for a full implementation, move i.MX watchdog driver
from hw/misc to hw/watchdog. While at it, add the watchdog files
to MAINTAINERS.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Message-id: 20200517162135.110364-2-linux@roeck-us.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 94 insertions, 0 deletions

diff --git a/hw/watchdog/Kconfig b/hw/watchdog/Kconfig
index 2118d897c9..293209b291 100644
--- a/hw/watchdog/Kconfig
+++ b/hw/watchdog/Kconfig
@@ -14,3 +14,6 @@ config WDT_IB700
 
 config WDT_DIAG288
     bool
+
+config WDT_IMX2
+    bool
diff --git a/hw/watchdog/Makefile.objs b/hw/watchdog/Makefile.objs
index 3f536d1cad..631b711d86 100644
--- a/hw/watchdog/Makefile.objs
+++ b/hw/watchdog/Makefile.objs
@@ -4,3 +4,4 @@ common-obj-$(CONFIG_WDT_IB6300ESB) += wdt_i6300esb.o
 common-obj-$(CONFIG_WDT_IB700) += wdt_ib700.o
 common-obj-$(CONFIG_WDT_DIAG288) += wdt_diag288.o
 common-obj-$(CONFIG_ASPEED_SOC) += wdt_aspeed.o
+common-obj-$(CONFIG_WDT_IMX2) += wdt_imx2.o
diff --git a/hw/watchdog/wdt_imx2.c b/hw/watchdog/wdt_imx2.c
new file mode 100644
index 0000000000..ad1ef02e9e
--- /dev/null
+++ b/hw/watchdog/wdt_imx2.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2018, Impinj, Inc.
+ *
+ * i.MX2 Watchdog IP block
+ *
+ * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
+ *
+ * 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 "qemu/bitops.h"
+#include "qemu/module.h"
+#include "sysemu/watchdog.h"
+
+#include "hw/watchdog/wdt_imx2.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)
+{
+    return 0;
+}
+
+static void imx2_wdt_write(void *opaque, hwaddr addr,
+                           uint64_t value, unsigned int size)
+{
+    if (addr == IMX2_WDT_WCR &&
+        (~value & (IMX2_WDT_WCR_WDA | IMX2_WDT_WCR_SRS))) {
+        watchdog_perform_action();
+    }
+}
+
+static const MemoryRegionOps imx2_wdt_ops = {
+    .read  = imx2_wdt_read,
+    .write = imx2_wdt_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        /*
+         * 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",
+                          IMX2_WDT_REG_NUM * sizeof(uint16_t));
+    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)