[V3,4/8] introduce dpcd module.

diff --git a/default-configs/aarch64-softmmu.mak b/default-configs/aarch64-softmmu.mak
index d3a2665..87165b7 100644
--- a/default-configs/aarch64-softmmu.mak
+++ b/default-configs/aarch64-softmmu.mak
@@ -4,4 +4,5 @@ 
 include arm-softmmu.mak
 
 CONFIG_AUX=y
+CONFIG_DPCD=y
 CONFIG_XLNX_ZYNQMP=y
diff --git a/hw/display/Makefile.objs b/hw/display/Makefile.objs
index dd8ea76..6d7004a 100644
--- a/hw/display/Makefile.objs
+++ b/hw/display/Makefile.objs
@@ -38,3 +38,4 @@  common-obj-$(CONFIG_QXL) += qxl.o qxl-logger.o qxl-render.o
 obj-$(CONFIG_VIRTIO) += virtio-gpu.o
 obj-$(CONFIG_VIRTIO_PCI) += virtio-gpu-pci.o
 obj-$(CONFIG_VIRTIO_VGA) += virtio-vga.o
+obj-$(CONFIG_DPCD) += dpcd.o
diff --git a/hw/display/dpcd.c b/hw/display/dpcd.c
new file mode 100644
index 0000000..cf666f8
--- /dev/null
+++ b/hw/display/dpcd.c
@@ -0,0 +1,157 @@ 
+/*
+ * dpcd.c
+ *
+ *  Copyright (C) 2015 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Developed by :
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option)any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/*
+ * This is a simple AUX slave which emulates a connected screen.
+ */
+
+#include "hw/aux.h"
+#include "dpcd.h"
+
+#ifndef DEBUG_DPCD
+#define DEBUG_DPCD 0
+#endif
+
+#define DPRINTF(fmt, ...) do {                                                 \
+    if (DEBUG_DPCD) {                                                          \
+        qemu_log("dpcd: " fmt, ## __VA_ARGS__);                                \
+    }                                                                          \
+} while (0);
+
+#define DPCD_READABLE_AREA                      0x600
+
+struct DPCDState {
+    /*< private >*/
+    AUXSlave parent_obj;
+
+    /*< public >*/
+    /*
+     * The DCPD is 0x7FFFF length but read as 0 after offset 0x5FF.
+     */
+    uint8_t dpcd_info[DPCD_READABLE_AREA];
+
+    MemoryRegion iomem;
+};
+
+static uint64_t dpcd_read(void *opaque, hwaddr offset, unsigned size)
+{
+    uint8_t ret;
+    DPCDState *e = DPCD(opaque);
+
+    if (offset < DPCD_READABLE_AREA) {
+        ret = e->dpcd_info[offset];
+    } else {
+        ret = 0;
+    }
+
+    DPRINTF("read 0x%" PRIX8 " @0x%" HWADDR_PRIX "\n", ret, offset);
+    return ret;
+}
+
+static void dpcd_write(void *opaque, hwaddr offset, uint64_t value,
+                       unsigned size)
+{
+    DPCDState *e = DPCD(opaque);
+
+    DPRINTF("write 0x%" PRIX8 " @0x%" HWADDR_PRIX "\n", (uint8_t)value, offset);
+
+    if (offset < DPCD_READABLE_AREA) {
+        e->dpcd_info[offset] = value;
+    }
+}
+
+static const MemoryRegionOps aux_ops = {
+    .read = dpcd_read,
+    .write = dpcd_write,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+static void dpcd_reset(DeviceState *dev)
+{
+    DPCDState *s = DPCD(dev);
+
+    memset(&(s->dpcd_info), 0, sizeof(s->dpcd_info));
+
+    s->dpcd_info[DPCD_REVISION] = DPCD_REV_1_0;
+    s->dpcd_info[DPCD_MAX_LINK_RATE] = DPCD_5_4GBPS;
+    s->dpcd_info[DPCD_MAX_LANE_COUNT] = DPCD_ONE_LANE;
+    s->dpcd_info[DPCD_RECEIVE_PORT0_CAP_0] = DPCD_EDID_PRESENT;
+    /* buffer size */
+    s->dpcd_info[DPCD_RECEIVE_PORT0_CAP_1] = 0xFF;
+
+    s->dpcd_info[DPCD_LANE0_1_STATUS] = DPCD_LANE0_CR_DONE
+                                      | DPCD_LANE0_CHANNEL_EQ_DONE
+                                      | DPCD_LANE0_SYMBOL_LOCKED;
+
+    s->dpcd_info[DPCD_LANE_ALIGN_STATUS_UPDATED] = DPCD_INTERLANE_ALIGN_DONE;
+    s->dpcd_info[DPCD_SINK_STATUS] = DPCD_RECEIVE_PORT_0_STATUS;
+}
+
+static void dpcd_init(Object *obj)
+{
+    DPCDState *s = DPCD(obj);
+
+    memory_region_init_io(&s->iomem, obj, &aux_ops, s, TYPE_DPCD, 0x7FFFF);
+    aux_init_mmio(AUX_SLAVE(obj), &s->iomem);
+}
+
+static const VMStateDescription vmstate_dpcd = {
+    .name = TYPE_DPCD,
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8_ARRAY_V(dpcd_info, DPCDState, DPCD_READABLE_AREA, 0),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void dpcd_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->reset = dpcd_reset;
+    dc->vmsd = &vmstate_dpcd;
+}
+
+static const TypeInfo dpcd_info = {
+    .name          = TYPE_DPCD,
+    .parent        = TYPE_AUX_SLAVE,
+    .instance_size = sizeof(DPCDState),
+    .class_init    = dpcd_class_init,
+    .instance_init = dpcd_init,
+};
+
+static void dpcd_register_types(void)
+{
+    type_register_static(&dpcd_info);
+}
+
+type_init(dpcd_register_types)
diff --git a/hw/display/dpcd.h b/hw/display/dpcd.h
new file mode 100644
index 0000000..8951557
--- /dev/null
+++ b/hw/display/dpcd.h
@@ -0,0 +1,94 @@ 
+/*
+ * dpcd.h
+ *
+ *  Copyright (C)2015 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Developed by :
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option)any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef DPCD_H
+#define DPCD_H
+
+typedef struct DPCDState DPCDState;
+
+#define TYPE_DPCD "dpcd"
+#define DPCD(obj) OBJECT_CHECK(DPCDState, (obj), TYPE_DPCD)
+
+/* DCPD Revision. */
+#define DPCD_REVISION                           0x00
+#define DPCD_REV_1_0                            0x10
+#define DPCD_REV_1_1                            0x11
+
+/* DCPD Max Link Rate. */
+#define DPCD_MAX_LINK_RATE                      0x01
+#define DPCD_1_62GBPS                           0x06
+#define DPCD_2_7GBPS                            0x0A
+#define DPCD_5_4GBPS                            0x14
+
+#define DPCD_MAX_LANE_COUNT                     0x02
+#define DPCD_ONE_LANE                           0x01
+#define DPCD_TWO_LANES                          0x02
+#define DPCD_FOUR_LANES                         0x04
+
+/* DCPD Max down spread. */
+#define DPCD_UP_TO_0_5                          0x01
+#define DPCD_NO_AUX_HANDSHAKE_LINK_TRAINING     0x40
+
+/* DCPD Downstream port type. */
+#define DPCD_DISPLAY_PORT                       0x00
+#define DPCD_ANALOG                             0x02
+#define DPCD_DVI_HDMI                           0x04
+#define DPCD_OTHER                              0x06
+
+/* DPCD Format conversion. */
+#define DPCD_FORMAT_CONVERSION                  0x08
+
+/* Main link channel coding. */
+#define DPCD_ANSI_8B_10B                        0x01
+
+/* Down stream port count. */
+#define DPCD_OUI_SUPPORTED                      0x80
+
+/* Receiver port capability. */
+#define DPCD_RECEIVE_PORT0_CAP_0                0x08
+#define DPCD_RECEIVE_PORT0_CAP_1                0x09
+#define DPCD_EDID_PRESENT                       0x02
+#define DPCD_ASSOCIATED_TO_PRECEDING_PORT       0x04
+
+/* Down stream port capability. */
+#define DPCD_CAP_DISPLAY_PORT                   0x000
+#define DPCD_CAP_ANALOG_VGA                     0x001
+#define DPCD_CAP_DVI                            0x002
+#define DPCD_CAP_HDMI                           0x003
+#define DPCD_CAP_OTHER                          0x100
+
+#define DPCD_LANE0_1_STATUS                     0x202
+#define DPCD_LANE0_CR_DONE                      0x01
+#define DPCD_LANE0_CHANNEL_EQ_DONE              0x02
+#define DPCD_LANE0_SYMBOL_LOCKED                0x04
+
+#define DPCD_LANE_ALIGN_STATUS_UPDATED          0x204
+#define DPCD_INTERLANE_ALIGN_DONE               0x01
+#define DPCD_DOWNSTREAM_PORT_STATUS_CHANGED     0x40
+#define DPCD_LINK_STATUS_UPDATED                0x80
+
+#define DPCD_SINK_STATUS                        0x205
+#define DPCD_RECEIVE_PORT_0_STATUS              0x01
+
+#endif /* !DPCD_H */