PM: p9_setup_evid steps voltage to avoid Fleetwood VRM limitations

- use the present value of ATTR_EXT_VRM_STEPSIZE (used by PGPE for Pstate
  movement) to step the the boot voltage setup during istep 8.  This attribute
  defaults to 50mV.
- Done only for rails attached via AVSBus

Key_Cronus_Test=PM_REGRESS

Change-Id: I63feb361323246c8b92f1e96dc41f8fc19bd0912
CQ: SW420343
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/55386
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: HWSV CI <hwsv-ci+hostboot@us.ibm.com>
Tested-by: PPE CI <ppe-ci+hostboot@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Hostboot CI <hostboot-ci+hostboot@us.ibm.com>
Tested-by: Cronus HW CI <cronushw-ci+hostboot@us.ibm.com>
Reviewed-by: RANGANATHPRASAD G. BRAHMASAMUDRA <prasadbgr@in.ibm.com>
Reviewed-by: Brian T. Vanderpool <vanderp@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <stofer@us.ibm.com>
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/55395
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

4 files changed, 142 insertions, 26 deletions

diff --git a/src/import/chips/p9/procedures/hwp/lib/p9_avsbus_lib.C b/src/import/chips/p9/procedures/hwp/lib/p9_avsbus_lib.C
index 3875806ce..e177c8940 100644
--- a/src/import/chips/p9/procedures/hwp/lib/p9_avsbus_lib.C
+++ b/src/import/chips/p9/procedures/hwp/lib/p9_avsbus_lib.C
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2016,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2016,2018                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -71,7 +71,7 @@ uint32_t avsCRCcalc(const uint32_t i_avs_cmd)
         l_msb = l_msb >> 1;
     }
 
-    FAPI_INF("The computed CRC Value is %d", o_crc_value)
+    FAPI_DBG("Computed CRC Value = %d", o_crc_value)
     return o_crc_value;
 }
 
diff --git a/src/import/chips/p9/procedures/hwp/pm/p9_pm_reset.C b/src/import/chips/p9/procedures/hwp/pm/p9_pm_reset.C
index c0a443399..c2a6d8593 100644
--- a/src/import/chips/p9/procedures/hwp/pm/p9_pm_reset.C
+++ b/src/import/chips/p9/procedures/hwp/pm/p9_pm_reset.C
@@ -438,6 +438,7 @@ p9_pm_reset_psafe_update(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_ta
     fapi2::ATTR_FREQ_PROC_REFCLOCK_KHZ_Type l_freq_proc_refclock_khz;
     fapi2::ATTR_PROC_DPLL_DIVIDER_Type      l_proc_dpll_divider;
     fapi2::ATTR_SAFE_MODE_NOVDM_UPLIFT_MV_Type l_uplift_mv;
+    fapi2::ATTR_EXTERNAL_VRM_STEPSIZE_Type l_ext_vrm_step_size_mv;
 
     FAPI_TRY(FAPI_ATTR_GET(fapi2::ATTR_SAFE_MODE_FREQUENCY_MHZ, i_target, l_attr_safe_mode_freq_mhz));
     FAPI_TRY(FAPI_ATTR_GET(fapi2::ATTR_SAFE_MODE_VOLTAGE_MV, i_target, l_attr_safe_mode_mv));
@@ -447,6 +448,7 @@ p9_pm_reset_psafe_update(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_ta
     FAPI_TRY(FAPI_ATTR_GET(fapi2::ATTR_PROC_DPLL_DIVIDER, i_target, l_proc_dpll_divider));
     FAPI_TRY(FAPI_ATTR_GET(fapi2::ATTR_FREQ_PROC_REFCLOCK_KHZ, FAPI_SYSTEM, l_freq_proc_refclock_khz));
     FAPI_TRY(FAPI_ATTR_GET(fapi2::ATTR_SAFE_MODE_NOVDM_UPLIFT_MV, i_target, l_uplift_mv));
+    FAPI_TRY(FAPI_ATTR_GET(fapi2::ATTR_EXTERNAL_VRM_STEPSIZE, FAPI_SYSTEM, l_ext_vrm_step_size_mv));
     l_attr_safe_mode_mv += l_uplift_mv;
 
     do
@@ -556,6 +558,7 @@ p9_pm_reset_psafe_update(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_ta
                                                 l_vdd_bus_num,
                                                 l_vdd_bus_rail,
                                                 l_vdd_voltage_mv,
+                                                l_ext_vrm_step_size_mv,
                                                 VDD_SETUP),
                      "Error from VDD setup function");
         }
diff --git a/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.C b/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.C
index 42bf05e86..15af9ab31 100644
--- a/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.C
+++ b/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.C
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2016,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2016,2018                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -261,6 +261,7 @@ compute_boot_safe(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_target,
                     uint32_t l_ext_vcs_mv = sysparm_uplift(l_int_vcs_mv,
                                                            l_ics_ma,
                                                            attrs->r_loadline_vcs_uohm,
+
                                                            attrs->r_distloss_vcs_uohm,
                                                            attrs->vrm_voffset_vcs_uv);
 
@@ -392,6 +393,7 @@ p9_setup_evid(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_target, const
                                                 attrs.vdd_bus_num,
                                                 attrs.vdd_rail_select,
                                                 attrs.vdd_voltage_mv,
+                                                attrs.attr_ext_vrm_step_size_mv,
                                                 VDD_SETUP),
                      "Error from VDD setup function");
         }
@@ -402,6 +404,7 @@ p9_setup_evid(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_target, const
                                                 attrs.vdn_bus_num,
                                                 attrs.vdn_rail_select,
                                                 attrs.vdn_voltage_mv,
+                                                attrs.attr_ext_vrm_step_size_mv,
                                                 VDN_SETUP),
                      "error from VDN setup function");
         }
@@ -420,6 +423,7 @@ p9_setup_evid(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_target, const
                                                     attrs.vcs_bus_num,
                                                     attrs.vcs_rail_select,
                                                     attrs.vcs_voltage_mv,
+                                                    attrs.attr_ext_vrm_step_size_mv,
                                                     VCS_SETUP),
                          "error from VCS setup function");
             }
@@ -436,12 +440,36 @@ p9_setup_evid_voltageWrite(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_
                            const uint8_t i_bus_num,
                            const uint8_t i_rail_select,
                            const uint32_t i_voltage_mv,
+                           const uint32_t i_ext_vrm_step_size_mv,
                            const P9_SETUP_EVID_CONSTANTS i_evid_value)
 
 {
-    uint8_t l_count = 1;
-    uint8_t l_goodResponse = 0;
-    uint8_t l_throwAssert = 0;
+
+    uint8_t     l_goodResponse = 0;
+    uint8_t     l_throwAssert = true;
+    uint32_t    l_present_voltage_mv;
+    uint32_t    l_target_mv;
+    uint32_t    l_count;
+    int32_t     l_delta_mv = 0;
+    char        rail_str[8];
+
+    switch (i_evid_value)
+    {
+        case VCS_SETUP:
+            strcpy(rail_str, "VCS");
+            break;
+
+        case VDD_SETUP:
+            strcpy(rail_str, "VDD");
+            break;
+
+        case VDN_SETUP:
+            strcpy(rail_str, "VDN");
+            break;
+
+        default:
+            ;
+    }
 
     if (i_evid_value != VCS_SETUP)
     {
@@ -451,31 +479,115 @@ p9_setup_evid_voltageWrite(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_
                  "Initializing avsBus VDD/VDN, bridge %d", BRIDGE_NUMBER);
     }
 
+    FAPI_INF("Setting voltage for %s to %d mV", rail_str, i_voltage_mv);
+
+    // Drive AVS Bus with a frame value 0xFFFFFFFF (idle frame) to
+    // initialize the AVS slave
+    FAPI_TRY(avsIdleFrame(i_target, i_bus_num, BRIDGE_NUMBER));
+
+    // Read the present voltage
+
+    // This loop is to ensrue AVSBus Master and Slave are in sync
+    l_count = 0;
+
     do
     {
-        FAPI_INF("Sending an Idle frame before Voltage writes");
-
-        // Drive AVS Bus with a frame value 0xFFFFFFFF (idle frame) to
-        // initialize the AVS slave
-        FAPI_TRY(avsIdleFrame(i_target, i_bus_num, BRIDGE_NUMBER));
-
-        // Set Boot voltage
-        FAPI_TRY(avsVoltageWrite(i_target,
-                                 i_bus_num,
-                                 BRIDGE_NUMBER,
-                                 i_rail_select,
-                                 i_voltage_mv),
-                 "Setting voltage via AVSBus %d, Bridge %d",
+
+        FAPI_TRY(avsVoltageRead(i_target, i_bus_num, BRIDGE_NUMBER,
+                                i_rail_select, l_present_voltage_mv),
+                 "AVS Voltage read transaction failed to %d, Bridge %d",
                  i_bus_num,
                  BRIDGE_NUMBER);
-
         // Throw an assertion if we don't get a good response.
-        l_throwAssert =  l_count >= AVSBUS_VOLTAGE_WRITE_RETRY_COUNT;
-        FAPI_TRY(avsValidateResponse(i_target,  i_bus_num, BRIDGE_NUMBER, l_throwAssert, l_goodResponse));
+        l_throwAssert =  (l_count >= AVSBUS_RETRY_COUNT);
+        FAPI_TRY(avsValidateResponse(i_target,  i_bus_num, BRIDGE_NUMBER,
+                                     l_throwAssert, l_goodResponse));
+
+        if (!l_goodResponse)
+        {
+            FAPI_TRY(avsIdleFrame(i_target, i_bus_num, BRIDGE_NUMBER));
+        }
 
         l_count++;
     }
-    while (l_goodResponse == 0);
+    while (!l_goodResponse);
+
+    // Compute the delta
+    l_delta_mv = l_present_voltage_mv - i_voltage_mv;
+
+    if (l_delta_mv > 0)
+    {
+        FAPI_DBG("Decreasing voltage - delta = %d", l_delta_mv );
+    }
+    else if (l_delta_mv < 0)
+    {
+        FAPI_DBG("Increasing voltage - delta = %d", l_delta_mv );
+    }
+    else
+    {
+        FAPI_DBG("Voltage to be set equals the initial voltage");
+    }
+
+    // Break into steps limited by attr.attr_ext_vrm_step_size_mv
+    while (l_delta_mv)
+    {
+        // Hostboot doesn't support abs()
+        uint32_t l_abs_delta_mv = l_delta_mv < 0 ? -l_delta_mv : l_delta_mv;
+
+        if (l_abs_delta_mv > i_ext_vrm_step_size_mv)
+        {
+            if (l_delta_mv > 0)  // Decreasing
+            {
+                l_target_mv = l_present_voltage_mv - i_ext_vrm_step_size_mv;
+            }
+            else
+            {
+                l_target_mv = l_present_voltage_mv + i_ext_vrm_step_size_mv;
+            }
+        }
+        else
+        {
+            l_target_mv = i_voltage_mv;
+        }
+
+        FAPI_INF("Target voltage = %d; Present voltage = %d",
+                 l_target_mv, l_present_voltage_mv);
+
+        l_count = 0;
+
+        do
+        {
+            FAPI_INF("Moving voltage to %d; retry count = %d", l_target_mv, l_count);
+            // Set Boot voltage
+            FAPI_TRY(avsVoltageWrite(i_target,
+                                     i_bus_num,
+                                     BRIDGE_NUMBER,
+                                     i_rail_select,
+                                     l_target_mv),
+                     "Setting voltage via AVSBus %d, Bridge %d",
+                     i_bus_num,
+                     BRIDGE_NUMBER);
+
+            // Throw an assertion if we don't get a good response.
+            l_throwAssert =  l_count >= AVSBUS_RETRY_COUNT;
+            FAPI_TRY(avsValidateResponse(i_target,
+                                         i_bus_num,
+                                         BRIDGE_NUMBER,
+                                         l_throwAssert,
+                                         l_goodResponse));
+
+            if (!l_goodResponse)
+            {
+                FAPI_TRY(avsIdleFrame(i_target, i_bus_num, BRIDGE_NUMBER));
+            }
+
+            l_count++;
+        }
+        while (!l_goodResponse);
+
+        l_present_voltage_mv = l_target_mv;
+        l_delta_mv = l_present_voltage_mv - i_voltage_mv;
+    }
 
 fapi_try_exit:
     return fapi2::current_err;
diff --git a/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.H b/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.H
index a73f44aab..838783a23 100644
--- a/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.H
+++ b/src/import/chips/p9/procedures/hwp/pm/p9_setup_evid.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2016,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2016,2018                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -47,7 +47,7 @@ enum P9_SETUP_EVID_CONSTANTS
     BRIDGE_NUMBER = 1,
 
 // Default voltages if mailbox -> attributes are not setup
-    AVSBUS_VOLTAGE_WRITE_RETRY_COUNT = 5,
+    AVSBUS_RETRY_COUNT = 5,
     VDD_SETUP = 6,
     VDN_SETUP = 7,
     VCS_SETUP = 8,
@@ -114,6 +114,7 @@ extern "C"
 /// @param [in]  i_rail_select AVS bus rail select
 /// @param [in]  i_voltage_mv voltage value in mv
 /// @param [in]  i_evid_value EVID setup mode
+/// @param [in]  i_ext_vrm_step_size_mv Maximum VRM step size in mv
 //@return fapi::ReturnCode. FAPI2_RC_SUCCESS if success, else error code.
     fapi2::ReturnCode
     p9_setup_evid_voltageWrite(
@@ -121,9 +122,9 @@ extern "C"
         const uint8_t i_bus_num,
         const uint8_t i_rail_select,
         const uint32_t i_voltage_mv,
+        const uint32_t i_ext_vrm_step_size_mv,
         const P9_SETUP_EVID_CONSTANTS i_evid_value);
 
-
 } // extern C
 
 #endif  // __P9_SETUP_EVID_H__