ppc/pnv: add XSCOM infrastructure

On a real POWER8 system, the Pervasive Interconnect Bus (PIB) serves
as a backbone to connect different units of the system. The host
firmware connects to the PIB through a bridge unit, the
Alter-Display-Unit (ADU), which gives him access to all the chiplets
on the PCB network (Pervasive Connect Bus), the PIB acting as the root
of this network.

XSCOM (serial communication) is the interface to the sideband bus
provided by the POWER8 pervasive unit to read and write to chiplets
resources. This is needed by the host firmware, OPAL and to a lesser
extent, Linux. This is among others how the PCI Host bridges get
configured at boot or how the LPC bus is accessed.

To represent the ADU of a real system, we introduce a specific
AddressSpace to dispatch XSCOM accesses to the targeted chiplets. The
translation of an XSCOM address into a PCB register address is
slightly different between the P9 and the P8. This is handled before
the dispatch using a 8byte alignment for all.

To customize the device tree, a QOM InterfaceClass, PnvXScomInterface,
is provided with a populate() handler. The chip populates the device
tree by simply looping on its children. Therefore, each model needing
custom nodes should not forget to declare itself as a child at
instantiation time.

Based on previous work done by :
      Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
[dwg: Added cpu parameter to xscom_complete()]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

2 files changed, 71 insertions, 0 deletions

diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
index cec869ce6b..7db922e285 100644
--- a/include/hw/ppc/pnv.h
+++ b/include/hw/ppc/pnv.h
@@ -21,6 +21,7 @@
 
 #include "hw/boards.h"
 #include "hw/sysbus.h"
+#include "hw/ppc/pnv_xscom.h"
 
 #define TYPE_PNV_CHIP "powernv-chip"
 #define PNV_CHIP(obj) OBJECT_CHECK(PnvChip, (obj), TYPE_PNV_CHIP)
@@ -48,6 +49,11 @@ typedef struct PnvChip {
     uint32_t     nr_cores;
     uint64_t     cores_mask;
     void         *cores;
+
+    hwaddr       xscom_base;
+    MemoryRegion xscom_mmio;
+    MemoryRegion xscom;
+    AddressSpace xscom_as;
 } PnvChip;
 
 typedef struct PnvChipClass {
@@ -60,6 +66,8 @@ typedef struct PnvChipClass {
     uint64_t     chip_cfam_id;
     uint64_t     cores_mask;
 
+    hwaddr       xscom_base;
+
     uint32_t (*core_pir)(PnvChip *chip, uint32_t core_id);
 } PnvChipClass;
 
@@ -106,4 +114,11 @@ typedef struct PnvMachineState {
 #define PNV_FDT_ADDR          0x01000000
 #define PNV_TIMEBASE_FREQ     512000000ULL
 
+/*
+ * POWER8 MMIO base addresses
+ */
+#define PNV_XSCOM_SIZE        0x800000000ull
+#define PNV_XSCOM_BASE(chip)                                            \
+    (chip->xscom_base + ((uint64_t)(chip)->chip_id) * PNV_XSCOM_SIZE)
+
 #endif /* _PPC_PNV_H */
diff --git a/include/hw/ppc/pnv_xscom.h b/include/hw/ppc/pnv_xscom.h
new file mode 100644
index 0000000000..ee25ec455e
--- /dev/null
+++ b/include/hw/ppc/pnv_xscom.h
@@ -0,0 +1,56 @@
+/*
+ * QEMU PowerPC PowerNV XSCOM bus definitions
+ *
+ * Copyright (c) 2016, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _PPC_PNV_XSCOM_H
+#define _PPC_PNV_XSCOM_H
+
+#include "qom/object.h"
+
+typedef struct PnvChip PnvChip;
+
+typedef struct PnvXScomInterface {
+    Object parent;
+} PnvXScomInterface;
+
+#define TYPE_PNV_XSCOM_INTERFACE "pnv-xscom-interface"
+#define PNV_XSCOM_INTERFACE(obj) \
+     OBJECT_CHECK(PnvXScomInterface, (obj), TYPE_PNV_XSCOM_INTERFACE)
+#define PNV_XSCOM_INTERFACE_CLASS(klass)                \
+    OBJECT_CLASS_CHECK(PnvXScomInterfaceClass, (klass), \
+                       TYPE_PNV_XSCOM_INTERFACE)
+#define PNV_XSCOM_INTERFACE_GET_CLASS(obj) \
+     OBJECT_GET_CLASS(PnvXScomInterfaceClass, (obj), TYPE_PNV_XSCOM_INTERFACE)
+
+typedef struct PnvXScomInterfaceClass {
+    InterfaceClass parent;
+    int (*populate)(PnvXScomInterface *dev, void *fdt, int offset);
+} PnvXScomInterfaceClass;
+
+extern void pnv_xscom_realize(PnvChip *chip, Error **errp);
+extern int pnv_xscom_populate(PnvChip *chip, void *fdt, int offset);
+
+extern void pnv_xscom_add_subregion(PnvChip *chip, hwaddr offset,
+                                    MemoryRegion *mr);
+extern void pnv_xscom_region_init(MemoryRegion *mr,
+                                  struct Object *owner,
+                                  const MemoryRegionOps *ops,
+                                  void *opaque,
+                                  const char *name,
+                                  uint64_t size);
+
+#endif /* _PPC_PNV_XSCOM_H */