LPC1768: flash erase/write require a critical section

From RM:

32.3.2.6 Interrupts during IAP
The on-chip flash memory is not accessible during erase/write operations. When the user
application code starts executing the interrupt vectors from the user flash area are active.
The user should either disable interrupts, or ensure that user interrupt vectors are active in
RAM and that the interrupt handlers reside in RAM, before making a flash erase/write IAP
call. The IAP code does not use or disable interrupts.

Author: 0xc0170

targets/TARGET_NXP/TARGET_LPC176X/device/flash_api.c

@@ -85,6 +85,7 @@ int32_t flash_erase_sector(flash_t *obj, uint32_t address)
 
     n = GetSecNum(address); // Get Sector Number
 
+    core_util_critical_section_enter();
     IAP.cmd = 50;// Prepare Sector for Erase
     IAP.par[0] = n;// Start Sector
     IAP.par[1] = n;// End Sector
@@ -98,6 +99,7 @@ int32_t flash_erase_sector(flash_t *obj, uint32_t address)
     IAP.par[1] = n;// End Sector
     IAP.par[2] = CCLK;// CCLK in kHz
     IAP_Call (&IAP.cmd, &IAP.stat);// Call IAP Command
+    core_util_critical_section_exit();
     if (IAP.stat) {
         return (1); // Command Failed
     }
@@ -114,10 +116,12 @@ int32_t flash_program_page(flash_t *obj, uint32_t address,
         const uint8_t *data, uint32_t size)
 {
     unsigned long n;
-    uint8_t *alignedData = 0;
+    // always malloc outside critical section
+    uint8_t *alignedData = malloc(size);
 
     n = GetSecNum(address); // Get Sector Number
 
+    core_util_critical_section_enter();
     IAP.cmd = 50;// Prepare Sector for Write
     IAP.par[0] = n;// Start Sector
     IAP.par[1] = n;// End Sector
@@ -132,14 +136,14 @@ int32_t flash_program_page(flash_t *obj, uint32_t address,
     if ((unsigned long)data%4==0) { // Word boundary
         IAP.par[1] = (unsigned long)data;// Source RAM Address
     } else {
-        alignedData = malloc(size);
         memcpy(alignedData,data,size);
         IAP.par[1] = (unsigned long)alignedData; // Source RAM Address
     }
 
     IAP.par[2] = 1024; // Fixed Page Size
     IAP.par[3] = CCLK;// CCLK in kHz
     IAP_Call (&IAP.cmd, &IAP.stat);// Call IAP Command
+    core_util_critical_section_exit();
 
     if(alignedData !=0) { // We allocated our own memory
         free(alignedData);