Provide getSecureFlashData() APi for Portenta

Author: facchinm

cores/arduino/mbed/storage/blockdevice/COMPONENT_QSPIF/include/QSPIF/QSPIFBlockDevice.h

@@ -340,9 +340,11 @@ class QSPIFBlockDevice : public mbed::BlockDevice {
         QSPIF_BP_CLEAR_SR, // Clear protection bits in status register 1
     };
 
+protected:
     // QSPI Driver Object
     mbed::QSPI _qspi;
 
+private:
     // Static List of different QSPI based Flash devices csel that already exist
     // Each QSPI Flash device csel can have only 1 QSPIFBlockDevice instance
     // _devices_mutex is used to lock csel list - only one QSPIFBlockDevice instance per csel is allowed

libraries/STM32H747_System/src/Portenta_System.cpp

@@ -3,6 +3,7 @@
 #include "Portenta_System.h"
 #include "Wire.h"
 #include "mbed.h"
+#include "SecureQSPI.h"
 
 #define PMIC_ADDRESS 0x08
 
@@ -15,6 +16,14 @@ bool arduino::Portenta_System::enterLowPower() {
   /* TO DO */
 }
 
+// 8Kbit secure OTP area (on MX25L12833F)
+bool arduino::Portenta_System::getSecureFlashData(void* buf, size_t size) {
+    static SecureQSPIFBlockDevice root;
+    root.init();
+    auto ret = root.readSecure(buf, 0, size > 512 ? 512 : size);
+    return ret == 0;
+}
+
 arduino::Portenta_System Portenta;
 
 #endif

libraries/STM32H747_System/src/Portenta_System.h

@@ -12,6 +12,7 @@ class Portenta_System: public STM32H747
   Portenta_System() {};
   virtual bool begin();
   virtual bool enterLowPower();
+  bool getSecureFlashData(void* buf, size_t size);
 };
 
 }

libraries/STM32H747_System/src/SecureQSPI.h

@@ -0,0 +1,13 @@
+#include "Arduino.h"
+#include "QSPIFBlockDevice.h"
+
+class SecureQSPIFBlockDevice: public QSPIFBlockDevice {
+  public:
+    virtual int readSecure(void *buffer, mbed::bd_addr_t addr, mbed::bd_size_t size) {
+      int ret = 0;
+      ret &= _qspi.command_transfer(0xB1, -1, nullptr, 0, nullptr, 0);
+      ret &= read(buffer, addr, size);
+      ret &= _qspi.command_transfer(0xC1, -1, nullptr, 0, nullptr, 0);
+      return ret;
+    }
+};