mos6522: add "info via" HMP command for debugging

This displays detailed information about the device registers and timers to aid
debugging problems with timers and interrupts.

Currently the QAPI generators for HumanReadableText don't work correctly if
used in qapi/target-misc.json when a non-specified target is built, so for
now manually add a hmp_info_via() wrapper until direct support for per-device
HMP/QMP commands is implemented.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220305150957.5053-9-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

4 files changed, 121 insertions, 0 deletions

diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index e90f20a107..adfa085a9b 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -879,3 +879,18 @@ SRST
   ``info sgx``
     Show intel SGX information.
 ERST
+
+#if defined(TARGET_M68K) || defined(TARGET_PPC)
+    {
+        .name         = "via",
+        .args_type    = "",
+        .params       = "",
+        .help         = "show guest mos6522 VIA devices",
+        .cmd          = hmp_info_via,
+    },
+#endif
+
+SRST
+  ``info via``
+    Show guest mos6522 VIA devices.
+ERST
diff --git a/hw/misc/mos6522.c b/hw/misc/mos6522.c
index 9c8d4ca6ad..2c20decca1 100644
--- a/hw/misc/mos6522.c
+++ b/hw/misc/mos6522.c
@@ -30,6 +30,9 @@
 #include "hw/misc/mos6522.h"
 #include "hw/qdev-properties.h"
 #include "migration/vmstate.h"
+#include "monitor/monitor.h"
+#include "monitor/hmp.h"
+#include "qapi/type-helpers.h"
 #include "qemu/timer.h"
 #include "qemu/cutils.h"
 #include "qemu/log.h"
@@ -415,6 +418,106 @@ void mos6522_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
     }
 }
 
+static int qmp_x_query_via_foreach(Object *obj, void *opaque)
+{
+    GString *buf = opaque;
+
+    if (object_dynamic_cast(obj, TYPE_MOS6522)) {
+        MOS6522State *s = MOS6522(obj);
+        int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        uint16_t t1counter = get_counter(s, &s->timers[0]);
+        uint16_t t2counter = get_counter(s, &s->timers[1]);
+
+        g_string_append_printf(buf, "%s:\n", object_get_typename(obj));
+
+        g_string_append_printf(buf, "  Registers:\n");
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[0], s->b);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[1], s->a);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[2], s->dirb);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[3], s->dira);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[4], t1counter & 0xff);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[5], t1counter >> 8);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[6],
+                               s->timers[0].latch & 0xff);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[7],
+                               s->timers[0].latch >> 8);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[8], t2counter & 0xff);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[9], t2counter >> 8);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[10], s->sr);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[11], s->acr);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[12], s->pcr);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[13], s->ifr);
+        g_string_append_printf(buf, "    %-*s:    0x%x\n", 4,
+                               mos6522_reg_names[14], s->ier);
+
+        g_string_append_printf(buf, "  Timers:\n");
+        g_string_append_printf(buf, "    Using current time now(ns)=%"PRId64
+                                    "\n", now);
+        g_string_append_printf(buf, "    T1 freq(hz)=%"PRId64
+                               " mode=%s"
+                               " counter=0x%x"
+                               " latch=0x%x\n"
+                               "       load_time(ns)=%"PRId64
+                               " next_irq_time(ns)=%"PRId64 "\n",
+                               s->timers[0].frequency,
+                               ((s->acr & T1MODE) == T1MODE_CONT) ? "continuous"
+                                                                  : "one-shot",
+                               t1counter,
+                               s->timers[0].latch,
+                               s->timers[0].load_time,
+                               get_next_irq_time(s, &s->timers[0], now));
+        g_string_append_printf(buf, "    T2 freq(hz)=%"PRId64
+                               " mode=%s"
+                               " counter=0x%x"
+                               " latch=0x%x\n"
+                               "       load_time(ns)=%"PRId64
+                               " next_irq_time(ns)=%"PRId64 "\n",
+                               s->timers[1].frequency,
+                               "one-shot",
+                               t2counter,
+                               s->timers[1].latch,
+                               s->timers[1].load_time,
+                               get_next_irq_time(s, &s->timers[1], now));
+    }
+
+    return 0;
+}
+
+static HumanReadableText *qmp_x_query_via(Error **errp)
+{
+    g_autoptr(GString) buf = g_string_new("");
+
+    object_child_foreach_recursive(object_get_root(),
+                                   qmp_x_query_via_foreach, buf);
+
+    return human_readable_text_from_str(buf);
+}
+
+void hmp_info_via(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+    g_autoptr(HumanReadableText) info = qmp_x_query_via(&err);
+
+    if (hmp_handle_error(mon, err)) {
+        return;
+    }
+    monitor_printf(mon, "%s", info->human_readable_text);
+}
+
 static const MemoryRegionOps mos6522_ops = {
     .read = mos6522_read,
     .write = mos6522_write,
diff --git a/include/hw/misc/mos6522.h b/include/hw/misc/mos6522.h
index bbaec4ede2..193a3dc870 100644
--- a/include/hw/misc/mos6522.h
+++ b/include/hw/misc/mos6522.h
@@ -157,4 +157,6 @@ extern const VMStateDescription vmstate_mos6522;
 uint64_t mos6522_read(void *opaque, hwaddr addr, unsigned size);
 void mos6522_write(void *opaque, hwaddr addr, uint64_t val, unsigned size);
 
+void hmp_info_via(Monitor *mon, const QDict *qdict);
+
 #endif /* MOS6522_H */
diff --git a/include/monitor/hmp-target.h b/include/monitor/hmp-target.h
index ffdc15a34b..1891a19b21 100644
--- a/include/monitor/hmp-target.h
+++ b/include/monitor/hmp-target.h
@@ -50,5 +50,6 @@ void hmp_mce(Monitor *mon, const QDict *qdict);
 void hmp_info_local_apic(Monitor *mon, const QDict *qdict);
 void hmp_info_sev(Monitor *mon, const QDict *qdict);
 void hmp_info_sgx(Monitor *mon, const QDict *qdict);
+void hmp_info_via(Monitor *mon, const QDict *qdict);
 
 #endif /* MONITOR_HMP_TARGET_H */