Correct gpe timebase

Change-Id: I47524f8400d1b5f2ed5423c2bea105a22a099205
CQ: SW402715
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/46917
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Christopher J. Cain <cjcain@us.ibm.com>
Reviewed-by: William A. Bryan <wilbryan@us.ibm.com>
Reviewed-by: Martha Broyles <mbroyles@us.ibm.com>

4 files changed, 21 insertions, 25 deletions

diff --git a/src/common/gpe_export.h b/src/common/gpe_export.h
index 2cc9191..0957175 100755
--- a/src/common/gpe_export.h
+++ b/src/common/gpe_export.h
@@ -58,7 +58,7 @@ typedef struct nop
 
 typedef struct gpe_shared_data
 {
-    uint32_t    nest_freq_div;  // Nest freq / 4
+    uint32_t    nest_freq_div;  // Nest freq / 64
     uint32_t    spipss_spec_p9; // Which APSS spec to use
     uint32_t    fir_heap_buffer_ptr;
     uint32_t    fir_params_buffer_ptr;
diff --git a/src/occ_405/main.c b/src/occ_405/main.c
index 35267b7..ad09280 100755
--- a/src/occ_405/main.c
+++ b/src/occ_405/main.c
@@ -2071,9 +2071,10 @@ int main(int argc, char **argv)
                    0,
                    l_tb_freq_hz);
 
-    // Store the nest / 4 frequency in shared SRAM so the GPEs
-    // can be initialized with the correct timebase as well.
-    G_shared_gpe_data.nest_freq_div = l_tb_freq_hz;
+    // The GPEs are configured to use the OCB_OTBR as a timebase.
+    // This counter runs at (nest freq)/64.  The 405 timebase frequency runs at
+    // (nest freq)/4, so divide this by 16 to get the gpe timebase frequency.
+    G_shared_gpe_data.nest_freq_div = l_tb_freq_hz/16;
 
     CHECKPOINT(SSX_INITIALIZED);
     // TRAC_XXX needs ssx services, traces can only be done after ssx_initialize
diff --git a/src/occ_gpe0/gpe_util.c b/src/occ_gpe0/gpe_util.c
index 59e44c1..2606a3d 100644
--- a/src/occ_gpe0/gpe_util.c
+++ b/src/occ_gpe0/gpe_util.c
@@ -159,29 +159,24 @@ int wait_spi_completion(GpeErrorStruct *error, uint32_t reg, uint32_t i_timeout)
  */
 void busy_wait(uint32_t i_microseconds)
 {
-    uint32_t start_decrementer_value;      // The decrementer register value at the beginning
-    uint32_t end_decrementer_value;        // The decrementer register value at the end
-    uint32_t current_decrementer_value;    // The current decrementer register value
-    uint32_t duration;
-    MFDEC(start_decrementer_value);        // get the decrementer register value at the beginning
-    current_decrementer_value = start_decrementer_value;
+    uint32_t current_count = pk_timebase32_get();
+    uint32_t end_count = current_count +
+        PK_INTERVAL_SCALE((uint32_t)PK_MICROSECONDS(i_microseconds));
 
-    // multiply the delay time by the external clock frequency (~37.5 MHz)
-    duration =  (i_microseconds * 37);
-    duration += (i_microseconds >> 1);
-
-    // Calculate the decrementer register value at the end of the busy wait period
-    end_decrementer_value = start_decrementer_value - duration;
-
-    if(start_decrementer_value < end_decrementer_value)           // decrementer overflows during the busy wait?
+    // Handle wrap case
+    if(current_count > end_count)
     {
-        MFDEC(current_decrementer_value);
-        while(current_decrementer_value < end_decrementer_value)  // Wait until Decrementer overflows
-            MFDEC(current_decrementer_value);
+        // let counter roll over
+        while(current_count > end_count)
+        {
+            current_count = pk_timebase32_get();
+        }
     }
 
-    while (current_decrementer_value > end_decrementer_value)     // Wait until end_decrementer_value is reached
-        MFDEC(current_decrementer_value);
+    while (current_count < end_count)
+    {
+        current_count = pk_timebase32_get();
+    }
 }
 
 /*
diff --git a/src/ppe/pk/ppe42/ppe42_core.c b/src/ppe/pk/ppe42/ppe42_core.c
index 36a153d..b659aa6 100644
--- a/src/ppe/pk/ppe42/ppe42_core.c
+++ b/src/ppe/pk/ppe42/ppe42_core.c
@@ -128,9 +128,9 @@ __pk_schedule_hardware_timeout(PkTimebase timeout)
         {
             diff = (timeout - now);
 
-            if (diff > 0xfffffffful)
+            if (diff > 0xffff0000ull)
             {
-                new_dec = 0xffffffff;
+                new_dec = 0xffff0000;
             }
             else
             {