[Xen-devel] [PATCH 09/32] piix4: add Reset Control Register

[Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>]

From: Hervé Poussineau <hpoussin@xxxxxxxxxxx>

The RCR I/O port (0xcf9) is used to generate a hard reset or a soft reset.

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Hervé Poussineau <hpoussin@xxxxxxxxxxx>
Message-Id: <20171216090228.28505-7-hpoussin@xxxxxxxxxxx>
[PMD: rebased, updated includes]
Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
---
 hw/isa/piix4.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
index 4202243e41..6e2d9b9774 100644
--- a/hw/isa/piix4.c
+++ b/hw/isa/piix4.c
@@ -2,6 +2,7 @@
  * QEMU PIIX4 PCI Bridge Emulation
  *
  * Copyright (c) 2006 Fabrice Bellard
+ * Copyright (c) 2018 Hervé Poussineau
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to 
deal
@@ -29,11 +30,16 @@
 #include "hw/sysbus.h"
 #include "migration/vmstate.h"
 #include "sysemu/reset.h"
+#include "sysemu/runstate.h"
 
 PCIDevice *piix4_dev;
 
 typedef struct PIIX4State {
     PCIDevice dev;
+
+    /* Reset Control Register */
+    MemoryRegion rcr_mem;
+    uint8_t rcr;
 } PIIX4State;
 
 #define TYPE_PIIX4_PCI_DEVICE "PIIX4"
@@ -88,6 +94,34 @@ static const VMStateDescription vmstate_piix4 = {
     }
 };
 
+static void piix4_rcr_write(void *opaque, hwaddr addr, uint64_t val,
+                            unsigned int len)
+{
+    PIIX4State *s = opaque;
+
+    if (val & 4) {
+        qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
+        return;
+    }
+    s->rcr = val & 2; /* keep System Reset type only */
+}
+
+static uint64_t piix4_rcr_read(void *opaque, hwaddr addr, unsigned int len)
+{
+    PIIX4State *s = opaque;
+    return s->rcr;
+}
+
+static const MemoryRegionOps piix4_rcr_ops = {
+    .read = piix4_rcr_read,
+    .write = piix4_rcr_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
 static void piix4_realize(PCIDevice *pci_dev, Error **errp)
 {
     DeviceState *dev = DEVICE(pci_dev);
@@ -97,6 +131,12 @@ static void piix4_realize(PCIDevice *pci_dev, Error **errp)
                      pci_address_space_io(pci_dev), errp)) {
         return;
     }
+
+    memory_region_init_io(&s->rcr_mem, OBJECT(dev), &piix4_rcr_ops, s,
+                          "reset-control", 1);
+    memory_region_add_subregion_overlap(pci_address_space_io(pci_dev), 0xcf9,
+                                        &s->rcr_mem, 1);
+
     piix4_dev = pci_dev;
     qemu_register_reset(piix4_reset, s);
 }
-- 
2.21.0


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