Initial XSCOM delivery

Change-Id: I80278bf2e03b4e6403d9a36b8782b225dba29fe3
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/144
Tested-by: Jenkins Server
Reviewed-by: MIKE J. JONES <mjjones@us.ibm.com>
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>

15 files changed, 849 insertions, 3 deletions

diff --git a/src/include/usr/devicefw/driverif.H b/src/include/usr/devicefw/driverif.H
index a3c5b37b6..c7f094d8a 100644
--- a/src/include/usr/devicefw/driverif.H
+++ b/src/include/usr/devicefw/driverif.H
@@ -56,6 +56,13 @@ namespace DeviceFW
         WILDCARD = -1,
     };
     
+    /** Construct the device addressing parameters for XSCOM device ops.
+     *  @param[in] i_address - XSCom address to operate on.
+     */
+    #define DEVICE_XSCOM_ADDRESS(i_address) \
+        DeviceFW::XSCOM, static_cast<uint64_t>((i_address))
+
+
     /** @class InvalidParameterType 
      *  @brief Unused type to cause compiler fails for invalid template types.
      *
diff --git a/src/include/usr/hbotcompid.H b/src/include/usr/hbotcompid.H
index b99e91c35..e6be3adc8 100644
--- a/src/include/usr/hbotcompid.H
+++ b/src/include/usr/hbotcompid.H
@@ -46,5 +46,20 @@ const compId_t DEVFW_COMP_ID = 0x0200;
 const char DEVFW_COMP_NAME[] = "devfw";
 //@}
 
+/** @name SCOM
+ *  SCOM component
+ */
+//@{
+const compId_t SCOM_COMP_ID = 0x0300;
+const char SCOM_COMP_NAME[] = "scom";
+//@}
+
+/** @name XSCOM
+ *  XSCOM component
+ */
+//@{
+const compId_t XSCOM_COMP_ID = 0x0400;
+const char XSCOM_COMP_NAME[] = "xscom";
+//@}
 
 #endif
diff --git a/src/include/usr/xscom/xscomreasoncodes.H b/src/include/usr/xscom/xscomreasoncodes.H
new file mode 100644
index 000000000..552b517e9
--- /dev/null
+++ b/src/include/usr/xscom/xscomreasoncodes.H
@@ -0,0 +1,22 @@
+#ifndef __XSCOM_REASONCODES_H
+#define __XSCOM_REASONCODES_H
+
+#include <hbotcompid.H>
+
+namespace XSCOM
+{
+    enum xscomModuleId
+    {
+        XSCOM_PERFORM_OP      = 0x00,
+        XSCOM_SANITY_CHECK    = 0x01,
+    };
+
+    enum xscomReasonCode
+    {
+        XSCOM_STATUS_ERR           = XSCOM_COMP_ID | 0x01,
+        XSCOM_INVALID_DATA_BUFFER  = XSCOM_COMP_ID | 0x02,
+        XSCOM_INVALID_OP_TYPE      = XSCOM_COMP_ID | 0x03,
+    };
+};
+
+#endif
diff --git a/src/makefile b/src/makefile
index f3bb5dfe8..351caa289 100644
--- a/src/makefile
+++ b/src/makefile
@@ -15,10 +15,11 @@ DIRECT_BOOT_OBJECTS = start.o kernel.o taskmgr.o cpumgr.o syscall.o \
 
 RUNTIME_OBJECTS =
 
-BASE_MODULES = trace errl devicefw
+BASE_MODULES = trace errl devicefw scom xscom
 DIRECT_BOOT_MODULES = example
 RUNTIME_MODULES =
-TESTCASE_MODULES = cxxtest testerrl testdevicefw testsyslib
+TESTCASE_MODULES = cxxtest testerrl testdevicefw testsyslib \
+		   testscom testxscom
 
 RELOCATABLE_IMAGE_LDFLAGS = -pie --export-dynamic
 
diff --git a/src/usr/makefile b/src/usr/makefile
index 64c9dea42..c1a57cddb 100644
--- a/src/usr/makefile
+++ b/src/usr/makefile
@@ -1,6 +1,7 @@
 ROOTPATH = ../..
 
 OBJS = module_init.o
-SUBDIRS = example.d trace.d cxxtest.d testcore.d errl.d devicefw.d
+SUBDIRS = example.d trace.d cxxtest.d testcore.d errl.d devicefw.d \
+	  scom.d xscom.d
 
 include ${ROOTPATH}/config.mk
diff --git a/src/usr/scom/makefile b/src/usr/scom/makefile
new file mode 100644
index 000000000..777b4a2fd
--- /dev/null
+++ b/src/usr/scom/makefile
@@ -0,0 +1,8 @@
+ROOTPATH = ../../..
+MODULE = scom
+
+OBJS = scom.o
+
+SUBDIRS = test.d
+
+include ${ROOTPATH}/config.mk
diff --git a/src/usr/scom/scom.C b/src/usr/scom/scom.C
new file mode 100644
index 000000000..43357a85f
--- /dev/null
+++ b/src/usr/scom/scom.C
@@ -0,0 +1,46 @@
+/**
+ *  @file scom.C
+ *
+ *  @brief Implementation of SCOM operations
+ */
+
+/*****************************************************************************/
+// I n c l u d e s
+/*****************************************************************************/
+#include <devicefw/driverif.H>
+#include <trace/interface.H>
+#include <errl/errlentry.H>
+#include <errl/errlmanager.H>
+#include "scom.H"
+
+namespace SCOM
+{
+
+// Register SCom access functions to DD framework
+DEVICE_REGISTER_ROUTE(DeviceFW::WILDCARD,
+                      DeviceFW::SCOM,
+                      DeviceFW::PROCESSOR,
+                      scomPerformOp);
+
+///////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+errlHndl_t scomPerformOp(DeviceFW::OperationType i_opType,
+                         DeviceFW::TargetHandle_t i_target,
+                         void* io_buffer,
+                         size_t& io_buflen,
+                         int64_t i_accessType,
+                         va_list i_args)
+{
+    errlHndl_t l_err = NULL;
+
+    //@todo - For now, just call XSCOM
+    l_err = deviceOp(i_opType,
+                     i_target,
+                     io_buffer,
+                     io_buflen,
+                     DEVICE_XSCOM_ADDRESS(va_arg(i_args,uint64_t)));
+
+    return l_err;
+}
+
+} // end namespace
diff --git a/src/usr/scom/scom.H b/src/usr/scom/scom.H
new file mode 100644
index 000000000..332883d00
--- /dev/null
+++ b/src/usr/scom/scom.H
@@ -0,0 +1,41 @@
+#ifndef __SCOM_H
+#define __SCOM_H
+
+/** @file  scom.H
+ *  @brief Provides the interfaces to perform a SCom
+ */
+
+namespace SCOM
+{
+
+/**
+ * @brief Performs an SCom operation
+ * This function performs an SCom Read/Write operation. It follows a
+ * pre-defined prototype functions in order to be registered with the
+ * device-driver framework.
+ *
+ * @param[in]   i_opType        Operation type, see DeviceFW::OperationType
+ *                              in driverif.H
+ * @param[in]   i_target        SCom target
+ * @param[in/out] io_buffer     Read: pointer to output data storage
+ *                              Write: pointer to data to be written
+ * @param[in/out] io_buflen     Input: size of io_buffer (in bytes)
+ *                              Output: Read: size of output data
+ *                                      Write: size of data written
+ * @param[in]   i_accessType    Select from DeviceFW::AccessType enum
+ *                              (usrif.H)
+ * @param[in]   i_args          This is an argument list for DD framework.
+ *                              In this function, there's only one argument,
+ *                              which is the SCom address value.
+ *
+ * @return  errlHndl_t
+ */
+errlHndl_t scomPerformOp(DeviceFW::OperationType i_opType,
+                         DeviceFW::TargetHandle_t i_target,
+                         void* io_buffer,
+                         size_t& io_buflen,
+                         int64_t i_accessType,
+                         va_list i_args);
+}; // End namespace
+
+#endif
diff --git a/src/usr/scom/test/makefile b/src/usr/scom/test/makefile
new file mode 100644
index 000000000..298f91b6e
--- /dev/null
+++ b/src/usr/scom/test/makefile
@@ -0,0 +1,6 @@
+ROOTPATH = ../../../..
+
+MODULE = testscom
+TESTS = *.H
+
+include ${ROOTPATH}/config.mk
diff --git a/src/usr/scom/test/scomtest.H b/src/usr/scom/test/scomtest.H
new file mode 100644
index 000000000..6082db403
--- /dev/null
+++ b/src/usr/scom/test/scomtest.H
@@ -0,0 +1,30 @@
+#ifndef __SCOMTEST_H
+#define __SCOMTEST_H
+
+/**
+ *  @file scomtest.H
+ *
+ *  @brief Test case for SCOM code
+*/
+
+#include <cxxtest/TestSuite.H>
+#include <errl/errlmanager.H>
+#include <errl/errlentry.H>
+#include <errl/errltypes.H>
+#include <devicefw/userif.H>
+
+class ScomTest: public CxxTest::TestSuite
+{
+public:
+
+    /**
+     * @brief SCOM test #1
+     *        TBD
+     */
+    void testScom1(void)
+    {
+         return;
+    }
+};
+
+#endif
diff --git a/src/usr/xscom/makefile b/src/usr/xscom/makefile
new file mode 100644
index 000000000..557920fdc
--- /dev/null
+++ b/src/usr/xscom/makefile
@@ -0,0 +1,8 @@
+ROOTPATH = ../../..
+MODULE = xscom
+
+OBJS = xscom.o
+
+SUBDIRS = test.d
+
+include ${ROOTPATH}/config.mk
diff --git a/src/usr/xscom/test/makefile b/src/usr/xscom/test/makefile
new file mode 100644
index 000000000..57e9ca832
--- /dev/null
+++ b/src/usr/xscom/test/makefile
@@ -0,0 +1,6 @@
+ROOTPATH = ../../../..
+
+MODULE = testxscom
+TESTS = *.H
+
+include ${ROOTPATH}/config.mk
diff --git a/src/usr/xscom/test/xscomtest.H b/src/usr/xscom/test/xscomtest.H
new file mode 100644
index 000000000..4351487e9
--- /dev/null
+++ b/src/usr/xscom/test/xscomtest.H
@@ -0,0 +1,113 @@
+#ifndef __XCOMTEST_H
+#define __XCOMTEST_H
+
+/**
+ *  @file xscomtest.H
+ *
+ *  @brief Test case for XSCOM code
+*/
+
+#include <cxxtest/TestSuite.H>
+#include <errl/errlmanager.H>
+#include <errl/errlentry.H>
+#include <errl/errltypes.H>
+#include <devicefw/userif.H>
+
+// Address and data to read/write
+struct testXscomAddrData
+{
+    uint32_t addr;
+    uint64_t data;
+};
+
+// Test table values
+//@todo - Select scratch register so chip doesn't get messed-up
+const testXscomAddrData g_xscomAddrTable[] =
+{
+    {0x08030007, 0x8000000000000001},
+    {0x08010587, 0x9000000000000003},
+
+};
+const uint32_t g_xscomAddrTableSz =
+                    sizeof(g_xscomAddrTable)/sizeof(testXscomAddrData);
+
+
+class XscomTest: public CxxTest::TestSuite
+{
+public:
+
+    /**
+     * @brief XSCOM test #1
+     *        Write value and read back to verify
+     */
+    void testXscom1(void)
+    {
+
+        //@todo - Replace printk with traces
+
+        DeviceFW::TargetHandle_t l_testTarget = 0; //@todo - Fix this
+        size_t l_size = sizeof(uint64_t);
+
+        // Loop thru table
+        for( uint32_t l_num=0; l_num < g_xscomAddrTableSz; l_num++)
+        {
+             testXscomAddrData l_testEntry = g_xscomAddrTable[l_num];
+
+             // Perform XSComOM read
+             uint64_t l_data = 0;
+             errlHndl_t l_err = deviceRead(l_testTarget,
+                                &l_data,
+                                l_size,
+                                DEVICE_SCOM_ADDRESS(l_testEntry.addr));
+             if (l_err)
+             {
+                 printk("\ntestXscom1: XSCom read: deviceRead() fails (1) !\n");
+             }
+             else
+             {
+                 printk("\ntestXscom1: XSCom read (1) Address 0x%.8X, Data %llx\n\n\n",
+                          l_testEntry.addr,
+                          (long long unsigned)l_data);
+             }
+
+             // Perform an XSCom write
+             l_err = deviceWrite(l_testTarget,
+                     &l_testEntry.data,
+                     l_size,
+                     DeviceFW::SCOM,
+                     l_testEntry.addr);
+
+             if (l_err)
+             {
+                 printk("\ntestXscom1: XSCom write: deviceWrite() fails!\n");
+                 break;
+             }
+             else
+             {
+                 printk("\ntestXscom1: XSCom write Address 0x%.8X, Data %llx\n",
+                         l_testEntry.addr,
+                         (long long unsigned)l_testEntry.data);
+             }
+
+             // Read back
+             l_data = 0;
+             l_err = deviceRead(l_testTarget,
+                                &l_data,
+                                l_size,
+                                DEVICE_SCOM_ADDRESS(l_testEntry.addr));
+             if (l_err)
+             {
+                 printk("\ntestXscom1: XSCom read: deviceRead() fails (2) !\n");
+             }
+             else
+             {
+                 printk("\ntestXscom1: XSCom read (2) Address 0x%.8X, Data %llx\n\n\n",
+                          l_testEntry.addr,
+                          (long long unsigned)l_data);
+             }
+         }
+         return;
+    }
+};
+
+#endif
diff --git a/src/usr/xscom/xscom.C b/src/usr/xscom/xscom.C
new file mode 100644
index 000000000..b07eb5747
--- /dev/null
+++ b/src/usr/xscom/xscom.C
@@ -0,0 +1,309 @@
+/**
+ *  @file xscom.C
+ *
+ *  @brief Implementation of SCOM operations
+ */
+
+/*****************************************************************************/
+// I n c l u d e s
+/*****************************************************************************/
+#include <sys/mmio.h>
+#include <sys/task.h>
+#include <sys/sync.h>
+#include <string.h>
+#include <devicefw/driverif.H>
+#include <trace/interface.H>
+#include <errl/errlentry.H>
+#include <errl/errlmanager.H>
+#include <xscom/xscomreasoncodes.H>
+#include "xscom.H"
+
+// Trace definition
+trace_desc_t* g_trac_xscom = NULL;
+TRAC_INIT(&g_trac_xscom, "XSCOM", 4096);
+
+namespace XSCOM
+{
+
+// Register XSCcom access functions to DD framework
+DEVICE_REGISTER_ROUTE(DeviceFW::WILDCARD,
+                      DeviceFW::XSCOM,
+                      DeviceFW::PROCESSOR,
+                      xscomPerformOp);
+
+/**
+ * @brief Internal routine that reset XSCOM status bits
+ *        of HMER register before an XSCOM operation
+ *
+ * @return  None
+ */
+void resetHMERStatus()
+{
+
+    // mtspr on the HMER is an AND write.
+    // This is not set the bits value to 1s, it's clearing
+    // the xscom status bits while leaving the rest of the bits
+    // in the register alone.
+    HMER hmer(-1);
+
+    hmer.mXSComDone = 0;
+    hmer.mXSComFail = 0;
+    hmer.mXSComStatus = 0;
+    // This call always returns 0, no checking needed
+    mmio_hmer_write(hmer);
+    return;
+}
+
+/**
+ * @brief Internal routine that monitor XSCOM Fail and XSCOM Done
+ *        status bits of HMER register
+ *
+ * @return  None
+ */
+HMER waitForHMERStatus()
+{
+    HMER hmer;
+
+    do
+    {
+        hmer = mmio_hmer_read();
+    }
+    while(!hmer.mXSComFail && !hmer.mXSComDone);
+    return hmer;
+}
+
+
+/**
+ * @brief Internal routine that checks to see if retry is
+ *        possible on an XSCOM error
+ *
+ * @return  true if retry is possible; false otherwise.
+ */
+bool XSComRetry(const HMER i_hmer)
+{
+    bool l_retry = false;
+    switch (i_hmer.mXSComStatus)
+    {
+        // Should retry if parity or timeout error.
+        case HMER::XSCOM_PARITY_ERROR:
+        case HMER::XSCOM_TIMEOUT:
+             l_retry = true;
+             break;
+        default:
+             break;
+    }
+    return l_retry;
+}
+
+/**
+ * @brief Internal routine that verifies the validity of input parameters
+ * for an XSCOM access.
+ *
+ * @param[in]   i_opType       Operation type, see DeviceFW::OperationType
+ *                             in driverif.H
+ * @param[in]   i_target       XSCom target
+ * @param[in/out] i_buffer     Read: Pointer to output data storage
+ *                             Write: Pointer to input data storage
+ * @param[in/out] i_buflen     Input: size of io_buffer (in bytes)
+ *                              Output:
+ *                                  Read: Size of output data
+ *                                  Write: Size of data written
+ * @param[in]   i_args         This is an argument list for DD framework.
+ *                             In this function, there's only one argument,
+ *                             which is the MMIO XSCom address
+ * @return  errlHndl_t
+ */
+errlHndl_t xscomOpSanityCheck(const DeviceFW::OperationType i_opType,
+                              const DeviceFW::TargetHandle_t i_target,
+                              const void* i_buffer,
+                              const size_t& i_buflen,
+                              const va_list i_args)
+{
+    errlHndl_t l_err = NULL;
+
+    do
+    {
+        // Verify data buffer
+        if ( (i_buflen < XSCOM_BUFFER_SIZE) ||
+             (i_buffer == NULL) )
+        {
+            /*@
+             * @errortype
+             * @moduleid     XSCOM_SANITY_CHECK
+             * @reasoncode   XSCOM_INVALID_DATA_BUFFER
+             * @userdata1    Buffer size
+             * @userdata2    XSCom address
+             * @devdesc      XSCOM buffer size < 8 bytes or NULL data buffer
+             */
+            l_err = new ERRORLOG::ErrlEntry(ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                            XSCOM_SANITY_CHECK,
+                                            XSCOM_INVALID_DATA_BUFFER,
+                                            i_buflen,
+                                            va_arg(i_args,uint64_t));
+            break;
+        }
+
+        // Verify OP type
+        if ( (i_opType != DeviceFW::READ) &&
+             (i_opType != DeviceFW::WRITE) )
+        {
+            /*@
+             * @errortype
+             * @moduleid     XSCOM_SANITY_CHECK
+             * @reasoncode   XSCOM_INVALID_OP_TYPE
+             * @userdata1    Operation type
+             * @userdata2    XSCom address
+             * @devdesc      XSCOM invalid operation type
+             */
+            l_err = new ERRORLOG::ErrlEntry(ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                            XSCOM_SANITY_CHECK,
+                                            XSCOM_INVALID_OP_TYPE,
+                                            i_opType,
+                                            va_arg(i_args,uint64_t));
+            break;
+        }
+
+
+    } while(0);
+
+    return l_err;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+///////////////////////////////////////////////////////////////////////////////
+errlHndl_t xscomPerformOp(DeviceFW::OperationType i_opType,
+                          DeviceFW::TargetHandle_t i_target,
+                          void* io_buffer,
+                          size_t& io_buflen,
+                          int64_t i_accessType,
+                          va_list i_args)
+{
+    errlHndl_t l_err = NULL;
+    HMER l_hmer;
+    mutex_t* l_XSComMutex;
+
+    // Retry loop
+    bool l_retry = false;
+    uint8_t l_retryCtr = 0;
+    do
+    {
+        // XSCOM operation sanity check
+        l_err = xscomOpSanityCheck(i_opType, i_target, io_buffer,
+                io_buflen, i_args);
+        if (l_err)
+        {
+            break;
+        }
+
+        // Set to buffer len to 0 until successfully access
+        io_buflen = 0;
+
+        // Setup the address
+        // @todo: Hard code chipId and Base address for now
+        XSComChipId_t l_chipId = 0;
+        XSComBase_t l_XSComBaseAddr = 0x300000000000; // Node0,chip0, Simics map
+        XSComP8Address l_mmioAddr(va_arg(i_args,uint64_t), l_chipId,
+                                 l_XSComBaseAddr);
+
+        // Re-init l_retry for loop
+        l_retry = false;
+
+        // Pin this thread to current CPU
+        task_affinity_pin();
+
+        // Lock other XSCom in this same thread from running
+        l_XSComMutex = mmio_xscom_mutex();
+        mutex_lock(l_XSComMutex);
+
+        // Single XSCom read
+        // Keep MMIO reading until XSCOM successfully done or error
+        do
+        {
+            // Reset status
+            resetHMERStatus();
+
+            // Calculate MMIO addr
+            uint64_t l_page = l_mmioAddr.page();
+            uint64_t l_offset_64 = (l_mmioAddr.offset()/sizeof(uint64_t));
+            uint64_t* l_virtAddr = static_cast<uint64_t*>
+                    (mmio_map(reinterpret_cast<void*>(l_page), 1));
+
+            // The dereferencing should handle Cache inhibited internally
+            // Use local variable and memcpy to avoid unaligned memory access
+            uint64_t l_data = 0;
+            if (i_opType == DeviceFW::READ)
+            {
+                 l_data = *(l_virtAddr + l_offset_64);
+                 memcpy(io_buffer, &l_data, sizeof(l_data));
+            }
+            else
+            {
+                memcpy(&l_data, io_buffer, sizeof(l_data));
+                *(l_virtAddr + l_offset_64) = l_data;
+            }
+
+            // @todo - Need to un-map for now
+            mmio_unmap(l_virtAddr, 1);
+
+            TRACFCOMP(g_trac_xscom, "xscomPerformOp: OpType 0x%.8X, Address %llx, Page %llx; Offset %llx; VirtAddr %llx; l_virtAddr+l_offset %llx",
+                    i_opType, static_cast<uint64_t>(l_mmioAddr), l_page,
+                    l_offset_64, l_virtAddr, l_virtAddr + l_offset_64);
+
+             // Check for error or done
+            l_hmer = waitForHMERStatus();
+
+        } while (l_hmer.mXSComStatus == HMER::XSCOM_BLOCKED); // Single read
+
+        // Unlock
+        mutex_unlock(l_XSComMutex);
+
+        // Done, un-pin
+        task_affinity_unpin();
+
+        // Handle error
+        if (l_hmer.mXSComStatus != HMER::XSCOM_GOOD)
+        {
+            /*@
+             * @errortype
+             * @moduleid     XSCOM_PERFORM_OP
+             * @reasoncode   XSCOM_STATUS_ERR
+             * @userdata1    HMER value
+             * @userdata2    XSCom address
+             * @devdesc      XSCom access error
+             */
+            l_err = new ERRORLOG::ErrlEntry(ERRORLOG::ERRL_SEV_UNRECOVERABLE,
+                                            XSCOM_PERFORM_OP,
+                                            XSCOM_STATUS_ERR,
+                                            l_hmer,
+                                            l_mmioAddr);
+
+            // @todo - Collect more FFDC: HMER value, target ID, other registers?
+
+            // Retry
+            if (l_retryCtr <= MAX_XSCOM_RETRY)
+            {
+                l_retryCtr++;
+                // If retry is possible, commit error as informational.
+                l_retry = XSComRetry(l_hmer);
+                if (l_retry == true)
+                {
+                    l_err->setSev(ERRORLOG::ERRL_SEV_INFORMATIONAL);
+                    // Commit/delete error
+                    errlCommit(l_err);
+                }
+            }
+        }
+        else
+        {
+            // No error, set output buffer size.
+            // Always 8 bytes for XSCOM, but we want to make it consistent
+            // with all other device drivers
+            io_buflen = XSCOM_BUFFER_SIZE;
+        }
+
+    } while (l_retry == true); // End retry loop
+
+    return l_err;
+}
+
+} // end namespace
diff --git a/src/usr/xscom/xscom.H b/src/usr/xscom/xscom.H
new file mode 100644
index 000000000..613ab2d01
--- /dev/null
+++ b/src/usr/xscom/xscom.H
@@ -0,0 +1,233 @@
+#ifndef __XSCOM_H
+#define __XSCOM_H
+
+/** @file xscom.H
+ *  @brief Provides the interfaces to perform XSCom
+ */
+
+#include <stdint.h>
+#include <limits.h>
+
+/**
+ *  @brief  Max number of retries if XSCOM fails with certain errors
+ */
+#define     MAX_XSCOM_RETRY     1
+
+/**
+ *  @brief  Type definition for XSCom address and Chip ID
+ */
+typedef uint32_t XSComAddress_t;
+typedef uint16_t XSComChipId_t;
+typedef uint64_t XSComBase_t;
+
+namespace XSCOM
+{
+
+#define     XSCOM_BUFFER_SIZE   8   // 8 bytes
+
+/**
+ * @brief Performs an XSCom access operation
+ * This function performs an XSCom access operation. It follows a pre-defined
+ * prototype functions in order to be registered with the device-driver
+ * framework.
+ *
+ * @param[in]   i_opType        Operation type, see DeviceFW::OperationType
+ *                              in driverif.H
+ * @param[in]   i_target        XSCom target
+ * @param[in/out] io_buffer      Read: Pointer to output data storage
+ *                              Write: Pointer to input data storage
+ * @param[in/out] io_buflen     Input: size of io_buffer (in bytes)
+ *                              Output:
+ *                                  Read: Size of output data
+ *                                  Write: Size of data written
+ * @param[in]   i_accessType    DeviceFW::AccessType enum (usrif.H)
+ * @param[in]   i_args          This is an argument list for DD framework.
+ *                              In this function, there's only one argument,
+ *                              which is the MMIO XSCom address
+ * @return  errlHndl_t
+ */
+errlHndl_t xscomPerformOp(DeviceFW::OperationType i_opType,
+                          DeviceFW::TargetHandle_t i_target,
+                          void* io_buffer,
+                          size_t& io_buflen,
+                          int64_t i_accessType,
+                          va_list i_args);
+
+/**
+ *  @brief  Abstracts HMER register of a P8/Salerno chip
+ */
+class HMER
+{
+
+public:
+
+    /**
+     * @brief Constructor
+     */
+    ALWAYS_INLINE inline HMER()
+    {
+        mRegister = 0;
+    }
+
+    /**
+     * @brief Constructor that takes in a value
+     */
+    explicit ALWAYS_INLINE inline HMER(uint64_t val)
+    {
+        mRegister = val;
+    }
+
+    /**
+     * @brief Conversion operator
+     */
+    ALWAYS_INLINE inline operator uint64_t() const
+    {
+        return mRegister;
+    }
+
+    /**
+     * @brief Operator=
+     */
+    ALWAYS_INLINE inline uint64_t operator = (uint64_t val)
+    {
+        return mRegister = val;
+    }
+
+    /**
+     * @brief XSCom status values
+     */
+    enum XSComStatus
+    {
+        XSCOM_GOOD = 0,
+        XSCOM_BLOCKED = 1,
+        XSCOM_OFFLINE = 2,
+        XSCOM_PARTIAL = 3,
+        XSCOM_BAD_ADDRESS = 4,
+        XSCOM_CLOCK_ERROR = 5,
+        XSCOM_PARITY_ERROR = 6,
+        XSCOM_TIMEOUT= 7,
+    };
+
+    // Layout of HMER register parts
+    union
+    {
+        uint64_t mRegister;
+        struct
+        {
+            uint64_t :8;
+            uint64_t mXSComFail:1;
+            uint64_t mXSComDone:1;
+            uint64_t :11;
+            uint64_t mXSComStatus:3;
+            uint64_t :40;
+        };
+    };
+};
+
+/**
+ *  @brief  This class contains necessary information to build an XSCOM
+ *  address for a P8/Salerno chip.
+ */
+class XSComP8Address
+{
+  public:
+    /**
+     * @brief Constructor of XSComP8Address class
+     *
+     * @param[in]   i_addr          PCB address of the register being accessed
+     *
+     * @param[in]   i_chipId        Chip number of the processor chip that
+     *                              holds the register being accessed.
+     *
+     * @param[in]   i_mXSComBase    Base address of XSCom address range.
+     *
+     * @return  None
+     */
+     ALWAYS_INLINE inline XSComP8Address(const XSComAddress_t i_addr,
+                                         const XSComChipId_t i_chipId,
+                                         const XSComBase_t i_mXSComBase);
+
+    /**
+      * @brief Conversion operator
+      */
+      ALWAYS_INLINE inline operator uint64_t() const;
+
+    /**
+      * @brief Return the page-aligned value of the address
+      *
+      * @return  uint64_t
+      */
+      ALWAYS_INLINE inline uint64_t page() const;
+
+     /**
+       * @brief Return the address' byte offset from the aligned page
+       *
+       * @return  uint64_t
+       */
+     ALWAYS_INLINE inline uint64_t offset() const;
+
+  private:
+    /**
+      * @brief   Disabled copy constructor and assignment operator
+      */
+    XSComP8Address(const XSComP8Address& i_right);
+    XSComP8Address& operator=(const XSComP8Address& right);
+
+    // Layout of XSCOM address parts
+    union
+    {
+        uint64_t mMmioAddress;          // mMmio address
+        struct
+        {
+            uint64_t mReserved1:18;     // Not currently used (0:17)
+            uint64_t mBaseAddress:5;    // Base address (18:22)
+            uint64_t mChipId:6;         // Targeted chip ID (23:28)
+            uint64_t mSComAddrHi:27;    // PCB Address High (29:55)
+            uint64_t mCacheLine:1;      // Cached line (56)
+            uint64_t mSComAddrLo:4;     // PCB Address low (57:60)
+            uint64_t mAlign:3;          // Align (61:63)
+        } mAddressParts;
+    };
+
+}; // End XSComP8Address class
+
+//-----------------------------------------------------------------------
+// In-line functions
+//-----------------------------------------------------------------------
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+XSComP8Address::XSComP8Address(const XSComAddress_t i_addr,
+                               const XSComChipId_t i_chipId,
+                               const XSComBase_t i_mXSComBase)
+:mMmioAddress(i_mXSComBase)
+{
+    mAddressParts.mChipId = i_chipId;
+    mAddressParts.mSComAddrHi = i_addr >> 4; // Get 27-bits
+    mAddressParts.mSComAddrLo = i_addr;      // Get 4 bits
+}
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+XSComP8Address::operator uint64_t() const
+{
+    return mMmioAddress;
+}
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+uint64_t XSComP8Address::page() const
+{
+    return ((mMmioAddress/PAGE_SIZE) *  PAGE_SIZE);
+}
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+uint64_t XSComP8Address::offset() const
+{
+    return (mMmioAddress % PAGE_SIZE);
+}
+
+};
+
+#endif