vt82c686: Make vt82c686-pm an I/O tracing region

Previously just an empty RAM region was mapped on realize, now we add
an empty io range logging access instead. I think the pm timer should
be hooked up here but not sure guests need it. PMON on fuloong2e sets
a base address but does not seem to enable region; the pegasos2
firmware pokes some regs but continues anyway so don't know if
anything would make use of these facilities. Therefore this is just a
clean up of previous state for now and not intending to fully
implement missing functionality which could be done later if some
guests need it.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <cff9b2442d3e2e1cfbdcbc2dfbb559031b4b1cc1.1610223397.git.balaton@eik.bme.hu>
[PMD: Split original patch, this is part 1/4
      (make 'vt82c686-pm' an I/O tracing region)]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

hw/isa/trace-events

@@ -17,5 +17,7 @@ apm_io_write(uint8_t addr, uint8_t val) "write addr=0x%x val=0x%02x"
 # vt82c686.c
 via_isa_write(uint32_t addr, uint32_t val, int len) "addr 0x%x val 0x%x len 0x%x"
 via_pm_write(uint32_t addr, uint32_t val, int len) "addr 0x%x val 0x%x len 0x%x"
+via_pm_io_read(uint32_t addr, uint32_t val, int len) "addr 0x%x val 0x%x len 0x%x"
+via_pm_io_write(uint32_t addr, uint32_t val, int len) "addr 0x%x val 0x%x len 0x%x"
 via_superio_read(uint8_t addr, uint8_t val) "addr 0x%x val 0x%x"
 via_superio_write(uint8_t addr, uint32_t val) "addr 0x%x val 0x%x"

hw/isa/vt82c686.c

@@ -102,6 +102,27 @@ static void pm_write_config(PCIDevice *d, uint32_t addr, uint32_t val, int len)
     }
 }
 
+static void pm_io_write(void *op, hwaddr addr, uint64_t data, unsigned size)
+{
+    trace_via_pm_io_write(addr, data, size);
+}
+
+static uint64_t pm_io_read(void *op, hwaddr addr, unsigned size)
+{
+    trace_via_pm_io_read(addr, 0, size);
+    return 0;
+}
+
+static const MemoryRegionOps pm_io_ops = {
+    .read = pm_io_read,
+    .write = pm_io_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
 static void pm_update_sci(VT686PMState *s)
 {
     int sci_level, pmsts;
@@ -154,9 +175,10 @@ static void vt82c686b_pm_realize(PCIDevice *dev, Error **errp)
 
     apm_init(dev, &s->apm, NULL, s);
 
-    memory_region_init(&s->io, OBJECT(dev), "vt82c686-pm", 64);
+    memory_region_init_io(&s->io, OBJECT(dev), &pm_io_ops, s,
+                          "vt82c686-pm", 64);
+    memory_region_add_subregion(pci_address_space_io(dev), 0, &s->io);
     memory_region_set_enabled(&s->io, false);
-    memory_region_add_subregion(get_system_io(), 0, &s->io);
 
     acpi_pm_tmr_init(&s->ar, pm_tmr_timer, &s->io);
     acpi_pm1_evt_init(&s->ar, pm_tmr_timer, &s->io);