Doorbell Interrupt Base Support for Core/Thread Wakeup

This change includes:
    - Implementation of a generic KernelWorkItem Class
    - Kernel functionality for doorbell send to specific PIRs
    - Kernel changes to send core/thread Wakeup doorbells using
      doorbell_send() + placing KernelWorkItems on a cpu stack obj
      to be executed during doorbell wakeup
    - Kernel Interrupt Message handler changes to send wakeup msgs
    - Interrupt Resource Provider (INTRRP) Changes to handle
      wakeup msgs and monitor for timeouts
    - Changes to the IPL flow to invoke proper Core/Thread Wakeup
    - A basic outline (commented out) for how IPC messages can be
      implemented in the future

Change-Id: I547fb8719bac657def561565ae11ab18cde72096
CMVC-Prereq: 992722
RTC:137564
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/22815
Tested-by: Jenkins Server
Tested-by: FSP CI Jenkins
Reviewed-by: Andrew J. Geissler <andrewg@us.ibm.com>
Reviewed-by: Prachi Gupta <pragupta@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

4 files changed, 105 insertions, 7 deletions

diff --git a/src/include/kernel/cpu.H b/src/include/kernel/cpu.H
index 963063b34..b967c1319 100644
--- a/src/include/kernel/cpu.H
+++ b/src/include/kernel/cpu.H
@@ -5,7 +5,9 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* COPYRIGHT International Business Machines Corp. 2010,2014              */
+/* Contributors Listed Below - COPYRIGHT 2010,2016                        */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
 /*                                                                        */
 /* Licensed under the Apache License, Version 2.0 (the "License");        */
 /* you may not use this file except in compliance with the License.       */
@@ -29,9 +31,11 @@
 #define __KERNEL_CPU_H
 
 #include <kernel/types.h>
+#include <kernel/workitem.H>
 #include <arch/ppc.H>
 #include <builtins.h>
 #include <sys/sync.h>
+#include <util/lockfree/stack.H>
 
 // See BookIV PIR definition.
 #define KERNEL_MAX_SUPPORTED_NODES 8
@@ -97,6 +101,8 @@ struct cpu_t
     /** Sequence ID of CPU initialization. */
     uint64_t cpu_start_seqid;
 
+    /** Stack of WorkItems to be executed during doorbell wakeup */
+    Util::Lockfree::Stack<KernelWorkItem> doorbell_actions;
 };
 
 /** @fn getCpuId
diff --git a/src/include/kernel/doorbell.H b/src/include/kernel/doorbell.H
index d0c65be2c..8275c4fc7 100644
--- a/src/include/kernel/doorbell.H
+++ b/src/include/kernel/doorbell.H
@@ -38,4 +38,27 @@ void doorbell_broadcast();
  */
 void doorbell_clear();
 
+/** Send a doorbell exception to the given pir
+ *
+ *  @param i_pir - PIR to send doorbell exception to
+ */
+void doorbell_send(uint64_t i_pir);
+
+/** Initiate a thread/core wakeup using a doorbell
+ *
+ *  @param i_pir - PIR to send doorbell to wakeup
+ */
+void send_doorbell_wakeup(uint64_t i_pir);
+
+/* TODO RTC 150861
+ * send_doorbell_ipc
+ *
+ * void send_doorbell_ipc(cpu_t *i_cpu, uint64_t pir);
+**/
+
+enum
+{
+    _DOORBELL_MSG_TYPE = 0x0000000028000000, /// Comes from the ISA.
+};
+
 #endif
diff --git a/src/include/kernel/intmsghandler.H b/src/include/kernel/intmsghandler.H
index 8fd4e34b6..8f7c08559 100644
--- a/src/include/kernel/intmsghandler.H
+++ b/src/include/kernel/intmsghandler.H
@@ -145,14 +145,15 @@ class InterruptMsgHdlr : public MessageHandler
         static void addCpuCore(uint64_t i_pir);
 
         /**
-         * Issue an IPI to the core.
+         * Send message to interrupt resource provider (intrrp) in userspace to
+         * indicate a wakeup occurred for core/thread indicated by given pir.
+         * The intrrp monitors the expected cores/threads wakeup and will issue
+         * a timeout/error in the event that not all expected cores/threads
+         * send this message
          *
-         * @param[in] i_pir - The PIR of the CPU to send IPI at.
-         * @param[in] i_favor - How favored the interrupt is; 0 = most favored
-         *                      254 = least favored, 255 = no interrupt
-         *                      Default 0x1 - IPI from kernel side (wakeup)
+         * @param[in] i_pir - The PIR of the CPU to send doorbell to.
          */
-        static void sendIPI(uint64_t i_pir, uint8_t i_favor = 0x1);
+        static void sendThreadWakeupMsg(uint64_t i_pir);
 
         /**
          * Issue the sbe/mailbox workaround (issue a mbox EOI to mailbox)
diff --git a/src/include/kernel/workitem.H b/src/include/kernel/workitem.H
new file mode 100644
index 000000000..3a41cc526
--- /dev/null
+++ b/src/include/kernel/workitem.H
@@ -0,0 +1,68 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/include/kernel/workitem.H $                               */
+/*                                                                        */
+/* OpenPOWER HostBoot Project                                             */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2016                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+
+#ifndef __KERNEL_WORKITEM_H
+#define __KERNEL_WORKITEM_H
+
+//The WorkItem class is a generic base class for a work item.
+class KernelWorkItem
+{
+    public:
+        //Virtual operator to be defined by child classes to define proper
+        // behavior in that situation
+        virtual void operator() (void);
+
+        /** Default destructor */
+        virtual ~KernelWorkItem() = default;
+
+        //Next Pointer is needed to be used with the lockfree::Stack container
+        KernelWorkItem* next;
+};
+
+//A work item to be created/executed during a CPU core/thread
+// wakeup scenario
+class CpuWakeupDoorbellWorkItem : public KernelWorkItem
+{
+    public:
+        //Implement operator() function
+        void operator() (void);
+
+        //No data to clean up, use default destructor
+        ~CpuWakeupDoorbellWorkItem() = default;
+};
+
+
+/* TODO RTC 150861
+
+//A work item to be created/executed during an IPC scenario
+class IPCDoorbellWorkItem : public KernelWorkItem
+{
+    public:
+        //Implement operator() function
+        void operator() (void);
+};
+**/
+#endif
+