Fix Andrew's PR comments

Author: guberti

apps/microtvm/arduino/example_project/project.ino

@@ -21,9 +21,10 @@
 
 void setup() {
   TVMInitialize();
-  //TVMExecute(input_data, output_data);
+  // If desired, initialize the RNG with random noise
+  // randomSeed(analogRead(0));
 }
 
 void loop() {
-  // put your main code here, to run repeatedly:
+  //TVMExecute(input_data, output_data);
 }

apps/microtvm/arduino/example_project/src/model.c

@@ -17,9 +17,6 @@
  * under the License.
  */
 
-#ifndef TVM_IMPLEMENTATION_ARDUINO
-#define TVM_IMPLEMENTATION_ARDUINO
-
 #include "model.h"
 
 #include "Arduino.h"
@@ -33,6 +30,7 @@ tvm_workspace_t app_workspace;
 
 // Blink code for debugging purposes
 void TVMPlatformAbort(tvm_crt_error_t error) {
+  TVMLogf("TVMPlatformAbort: %08x\n", error);
   for (;;) {
 #ifdef LED_BUILTIN
     digitalWrite(LED_BUILTIN, HIGH);
@@ -57,18 +55,15 @@ tvm_crt_error_t TVMPlatformMemoryFree(void* ptr, DLDevice dev) {
   return StackMemoryManager_Free(&app_workspace, ptr);
 }
 
-unsigned long g_utvm_start_time;
-
-#define MILLIS_TIL_EXPIRY 200
-
+unsigned long g_utvm_start_time_micros;
 int g_utvm_timer_running = 0;
 
 tvm_crt_error_t TVMPlatformTimerStart() {
   if (g_utvm_timer_running) {
     return kTvmErrorPlatformTimerBadState;
   }
   g_utvm_timer_running = 1;
-  g_utvm_start_time = micros();
+  g_utvm_start_time_micros = micros();
   return kTvmErrorNoError;
 }
 
@@ -77,7 +72,7 @@ tvm_crt_error_t TVMPlatformTimerStop(double* elapsed_time_seconds) {
     return kTvmErrorPlatformTimerBadState;
   }
   g_utvm_timer_running = 0;
-  unsigned long g_utvm_stop_time = micros() - g_utvm_start_time;
+  unsigned long g_utvm_stop_time = micros() - g_utvm_start_time_micros;
   *elapsed_time_seconds = ((double)g_utvm_stop_time) / 1e6;
   return kTvmErrorNoError;
 }
@@ -97,5 +92,3 @@ void TVMExecute(void* input_data, void* output_data) {
     TVMPlatformAbort(kTvmErrorPlatformCheckFailure);
   }
 }
-
-#endif

apps/microtvm/arduino/example_project/src/model.h

@@ -17,9 +17,6 @@
  * under the License.
  */
 
-#ifndef IMPLEMENTATION_H_
-#define IMPLEMENTATION_H_
-
 #define WORKSPACE_SIZE $workspace_size_bytes
 
 #ifdef __cplusplus
@@ -28,11 +25,16 @@ extern "C" {
 
 void TVMInitialize();
 
-// TODO template these void* values once MLF format has input and output data
+/* TODO template this function signature with the input and output
+ * data types and sizes. For example:
+ *
+ * void TVMExecute(uint8_t input_data[9216], uint8_t output_data[3]);
+ *
+ * Note this can only be done once MLF has JSON metadata describing
+ * inputs and outputs.
+ */
 void TVMExecute(void* input_data, void* output_data);
 
 #ifdef __cplusplus
 }  // extern "C"
 #endif
-
-#endif  // IMPLEMENTATION_H_

apps/microtvm/arduino/host_driven/project.ino

@@ -19,7 +19,6 @@
 
 #include "src/standalone_crt/include/tvm/runtime/crt/microtvm_rpc_server.h"
 #include "src/standalone_crt/include/tvm/runtime/crt/logging.h"
-#include "src/model.h"
 microtvm_rpc_server_t server;
 
 // Called by TVM to write serial data to the UART.
@@ -32,22 +31,23 @@ void setup() {
   server = MicroTVMRpcServerInit(write_serial, NULL);
   TVMLogf("microTVM Arduino runtime - running");
   Serial.begin(115200);
+
+  // If desired, initialize the RNG with random noise
+  // randomSeed(analogRead(0));
 }
 
 void loop() {
-  int to_read = Serial.available();
+  // Read at most 128 bytes at a time to prevent stack blowup
+  int to_read = min(Serial.available(), 128);
+
   uint8_t data[to_read];
-  size_t bytes_read = Serial.readBytes(data, to_read);
+  size_t bytes_remaining = Serial.readBytes(data, to_read);
   uint8_t* arr_ptr = data;
-  uint8_t** data_ptr = &arr_ptr;
-  if (bytes_read > 0) {
-    size_t bytes_remaining = bytes_read;
-    while (bytes_remaining > 0) {
-      // Pass the received bytes to the RPC server.
-      tvm_crt_error_t err = MicroTVMRpcServerLoop(server, data_ptr, &bytes_remaining);
-      if (err != kTvmErrorNoError && err != kTvmErrorFramingShortPacket) {
-        TVMPlatformAbort(err);
-      }
+  while (bytes_remaining > 0) {
+    // Pass the received bytes to the RPC server.
+    tvm_crt_error_t err = MicroTVMRpcServerLoop(server, &arr_ptr, &bytes_remaining);
+    if (err != kTvmErrorNoError && err != kTvmErrorFramingShortPacket) {
+      TVMPlatformAbort(err);
     }
   }
 }

apps/microtvm/arduino/host_driven/src/model.h

@@ -17,29 +17,13 @@
  * under the License.
  */
 
-#ifndef TVM_IMPLEMENTATION_ARDUINO
-#define TVM_IMPLEMENTATION_ARDUINO
-
-#include "model.h"
-
-#include "Arduino.h"
-#include "standalone_crt/include/tvm/runtime/crt/internal/aot_executor/aot_executor.h"
 #include "stdarg.h"
+#include "standalone_crt/include/tvm/runtime/crt/internal/aot_executor/aot_executor.h"
 
 // Blink code for debugging purposes
 void TVMPlatformAbort(tvm_crt_error_t error) {
-  for (;;) {
-#ifdef LED_BUILTIN
-    digitalWrite(LED_BUILTIN, HIGH);
-    delay(250);
-    digitalWrite(LED_BUILTIN, LOW);
-    delay(250);
-    digitalWrite(LED_BUILTIN, HIGH);
-    delay(250);
-    digitalWrite(LED_BUILTIN, LOW);
-    delay(750);
-#endif
-  }
+  TVMLogf("TVMPlatformAbort: %08x\n", error);
+  for (;;);
 }
 
 size_t TVMPlatformFormatMessage(char* out_buf, size_t out_buf_size_bytes, const char* fmt,
@@ -60,18 +44,15 @@ tvm_crt_error_t TVMPlatformMemoryFree(void* ptr, DLDevice dev) {
   return kTvmErrorNoError;
 }
 
-unsigned long g_utvm_start_time;
-
-#define MILLIS_TIL_EXPIRY 200
-
+unsigned long g_utvm_start_time_micros;
 int g_utvm_timer_running = 0;
 
 tvm_crt_error_t TVMPlatformTimerStart() {
   if (g_utvm_timer_running) {
     return kTvmErrorPlatformTimerBadState;
   }
   g_utvm_timer_running = 1;
-  g_utvm_start_time = micros();
+  g_utvm_start_time_micros = micros();
   return kTvmErrorNoError;
 }
 
@@ -80,7 +61,7 @@ tvm_crt_error_t TVMPlatformTimerStop(double* elapsed_time_seconds) {
     return kTvmErrorPlatformTimerBadState;
   }
   g_utvm_timer_running = 0;
-  unsigned long g_utvm_stop_time = micros() - g_utvm_start_time;
+  unsigned long g_utvm_stop_time = micros() - g_utvm_start_time_micros;
   *elapsed_time_seconds = ((double)g_utvm_stop_time) / 1e6;
   return kTvmErrorNoError;
 }
@@ -91,5 +72,3 @@ tvm_crt_error_t TVMPlatformGenerateRandom(uint8_t* buffer, size_t num_bytes) {
   }
   return kTvmErrorNoError;
 }
-
-#endif