pm: support for tracing using GPIOs

components/esp32/pm_trace.c

@@ -0,0 +1,51 @@
+// Copyright 2016-2017 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+
+
+#include "pm_trace.h"
+#include "driver/gpio.h"
+#include "soc/gpio_reg.h"
+
+/* GPIOs to use for tracing of esp_pm events.
+ * Two entries in the array for each type, one for each CPU.
+ * Feel free to change when debugging.
+ */
+static const int DRAM_ATTR s_trace_io[] = {
+        BIT(4),  BIT(5),  // ESP_PM_TRACE_IDLE
+        BIT(16), BIT(17), // ESP_PM_TRACE_TICK
+        BIT(18), BIT(18), // ESP_PM_TRACE_FREQ_SWITCH
+        BIT(19), BIT(19), // ESP_PM_TRACE_CCOMPARE_UPDATE
+        BIT(25), BIT(26), // ESP_PM_TRACE_ISR_HOOK
+};
+
+void esp_pm_trace_init()
+{
+    for (size_t i = 0; i < sizeof(s_trace_io)/sizeof(s_trace_io[0]); ++i) {
+        int io = __builtin_ffs(s_trace_io[i]);
+        if (io == 0) {
+            continue;
+        }
+        gpio_set_direction(io - 1, GPIO_MODE_OUTPUT);
+    }
+}
+
+void IRAM_ATTR esp_pm_trace_enter(esp_pm_trace_event_t event, int core_id)
+{
+    REG_WRITE(GPIO_OUT_W1TS_REG, s_trace_io[2 * event + core_id]);
+}
+
+void IRAM_ATTR esp_pm_trace_exit(esp_pm_trace_event_t event, int core_id)
+{
+    REG_WRITE(GPIO_OUT_W1TC_REG, s_trace_io[2 * event + core_id]);
+}

components/esp32/pm_trace.h

@@ -0,0 +1,44 @@
+// Copyright 2016-2017 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+
+#pragma once
+
+#include "sdkconfig.h"
+
+typedef enum {
+    ESP_PM_TRACE_IDLE,
+    ESP_PM_TRACE_TICK,
+    ESP_PM_TRACE_FREQ_SWITCH,
+    ESP_PM_TRACE_CCOMPARE_UPDATE,
+    ESP_PM_TRACE_ISR_HOOK,
+    ESP_PM_TRACE_TYPE_MAX
+} esp_pm_trace_event_t;
+
+void esp_pm_trace_init();
+void esp_pm_trace_enter(esp_pm_trace_event_t event, int core_id);
+void esp_pm_trace_exit(esp_pm_trace_event_t event, int core_id);
+
+#ifdef CONFIG_PM_TRACE
+
+#define ESP_PM_TRACE_ENTER(event, core_id)   \
+            esp_pm_trace_enter(ESP_PM_TRACE_ ## event, core_id)
+#define ESP_PM_TRACE_EXIT(event, core_id)    \
+            esp_pm_trace_exit(ESP_PM_TRACE_ ## event, core_id)
+
+#else // CONFIG_PM_TRACE
+
+#define ESP_PM_TRACE_ENTER(type, core_id) do { (void) core_id; } while(0);
+#define ESP_PM_TRACE_EXIT(type, core_id)  do { (void) core_id; } while(0);
+
+#endif // CONFIG_PM_TRACE

components/freertos/portasm.S

@@ -24,6 +24,7 @@
 */
 
 #include "xtensa_rtos.h"
+#include "sdkconfig.h"
 
 #define TOPOFSTACK_OFFS                 0x00    /* StackType_t *pxTopOfStack */
 #define CP_TOPOFSTACK_OFFS              0x04    /* xMPU_SETTINGS.coproc_area */
@@ -269,6 +270,12 @@ _frxt_timer_int:
 
     ENTRY(16)
 
+    #ifdef CONFIG_PM_TRACE
+    movi a6, 1 /* = ESP_PM_TRACE_TICK */
+    getcoreid a7
+    call4 esp_pm_trace_enter
+    #endif // CONFIG_PM_TRACE
+
 .L_xt_timer_int_catchup:
 
     /* Update the timer comparator for the next tick. */
@@ -308,6 +315,12 @@ _frxt_timer_int:
     sub     a4, a4, a3                  /* diff = ccount - old comparator     */
     blt     a2, a4, .L_xt_timer_int_catchup  /* repeat while diff > divisor */
 
+#ifdef CONFIG_PM_TRACE
+    movi a6, 1 /* = ESP_PM_TRACE_TICK */
+    getcoreid a7
+    call4 esp_pm_trace_exit
+#endif // CONFIG_PM_TRACE
+
     RET(16)
 
     /*

components/freertos/xtensa_vectors.S

@@ -175,7 +175,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
   NOTE: For CALL0 ABI, a12-a15 have not yet been saved.
 
-  NOTE: This macro will use registers a0 and a2-a6. The arguments are:
+  NOTE: This macro will use registers a0 and a2-a7. The arguments are:
     level -- interrupt level
     mask  -- interrupt bitmask for this level
 --------------------------------------------------------------------------------
@@ -183,6 +183,12 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
     .macro  dispatch_c_isr    level  mask
 
+    #ifdef CONFIG_PM_TRACE
+    movi a6, 0 /* = ESP_PM_TRACE_IDLE */
+    getcoreid a7
+    call4 esp_pm_trace_exit
+    #endif // CONFIG_PM_TRACE
+
     /* Get mask of pending, enabled interrupts at this level into a2. */
 
 .L_xt_user_int_&level&: