ECC508: add support for reading and writing slots

Author: sandeepmistry

Diff for: src/utility/ECC508.cpp

@@ -173,6 +173,44 @@ int ECC508Class::ecSign(int slot, const byte message[], byte signature[])
   return 1;
 }
 
+int ECC508Class::readSlot(int slot, byte data[], int length)
+{
+  if (slot < 0 || slot > 15) {
+    return -1;
+  }
+
+  if (length % 4 != 0) {
+    return 0;
+  }
+
+  for (int i = 0; i < length; i += 4) {
+    if (!read(2, addressForSlotOffset(slot, i), &data[i], 4)) {
+      return 0;
+    }
+  }
+
+  return 1;
+}
+
+int ECC508Class::writeSlot(int slot, const byte data[], int length)
+{
+  if (slot < 0 || slot > 15) {
+    return -1;
+  }
+
+  if (length % 4 != 0) {
+    return 0;
+  }
+
+  for (int i = 0; i < length; i += 4) {
+    if (!write(2, addressForSlotOffset(slot, i), &data[i], 4)) {
+      return 0;
+    }
+  }
+
+  return 1;
+}
+
 int ECC508Class::locked()
 {
   byte config[4];
@@ -476,6 +514,14 @@ int ECC508Class::lock(int zone)
   return 1;
 }
 
+int ECC508Class::addressForSlotOffset(int slot, int offset)
+{
+  int block = offset / 32;
+  offset = (offset % 32) / 4;  
+
+  return (slot << 3) | (block << 8) | (offset);
+}
+
 int ECC508Class::sendCommand(uint8_t opcode, uint8_t param1, uint16_t param2, const byte data[], size_t dataLength)
 {
   int commandLength = 8 + dataLength; // 1 for type, 1 for length, 1 for opcode, 1 for param1, 2 for param2, 2 for crc
@@ -502,7 +548,7 @@ int ECC508Class::sendCommand(uint8_t opcode, uint8_t param1, uint16_t param2, co
 
 int ECC508Class::receiveResponse(void* response, size_t length)
 {
-  int retries = 20;
+  int retries = 25;
   int responseSize = length + 3; // 1 for length header, 2 for CRC
   byte responseBuffer[responseSize];
 

Diff for: src/utility/ECC508.h

@@ -23,6 +23,9 @@ class ECC508Class
   int ecdsaVerify(const byte message[], const byte signature[], const byte pubkey[]);
   int ecSign(int slot, const byte message[], byte signature[]);
 
+  int readSlot(int slot, byte data[], int length);
+  int writeSlot(int slot, const byte data[], int length);
+
   int locked();
   int writeConfiguration(const byte data[]);
   int readConfiguration(byte data[]);
@@ -42,6 +45,8 @@ class ECC508Class
   int write(int zone, int address, const byte buffer[], int length);
   int lock(int zone);
 
+  int addressForSlotOffset(int slot, int offset);
+
   int sendCommand(uint8_t opcode, uint8_t param1, uint16_t param2, const byte data[] = NULL, size_t dataLength = 0);
   int receiveResponse(void* response, size_t length);
   uint16_t crc16(const byte data[], size_t length);