add hard fault handler to bsp.c

rename class_install_subtask to class_open_subtask
add class_close for unmount
adding code for usbh_device_unplugged_isr & invoke it in hcd_isr

demos/bsp/boards/board.c

@@ -50,3 +50,89 @@ void check_failed(uint8_t *file, uint32_t line)
   (void) file;
   (void) line;
 }
+
+/**
+ * HardFault_HandlerAsm:
+ * Alternative Hard Fault handler to help debug the reason for a fault.
+ * To use, edit the vector table to reference this function in the HardFault vector
+ * This code is suitable for Cortex-M3 and Cortex-M0 cores
+ */
+
+// Use the 'naked' attribute so that C stacking is not used.
+__attribute__((naked))
+void HardFault_HandlerAsm(void){
+  /*
+   * Get the appropriate stack pointer, depending on our mode,
+   * and use it as the parameter to the C handler. This function
+   * will never return
+   */
+
+  __asm(  ".syntax unified\n"
+      "MOVS   R0, #4  \n"
+      "MOV    R1, LR  \n"
+      "TST    R0, R1  \n"
+      "BEQ    _MSP    \n"
+      "MRS    R0, PSP \n"
+      "B      HardFault_HandlerC      \n"
+      "_MSP:  \n"
+      "MRS    R0, MSP \n"
+      "B      HardFault_HandlerC      \n"
+      ".syntax divided\n") ;
+}
+
+/**
+ * HardFaultHandler_C:
+ * This is called from the HardFault_HandlerAsm with a pointer the Fault stack
+ * as the parameter. We can then read the values from the stack and place them
+ * into local variables for ease of reading.
+ * We then read the various Fault Status and Address Registers to help decode
+ * cause of the fault.
+ * The function ends with a BKPT instruction to force control back into the debugger
+ */
+void HardFault_HandlerC(unsigned long *hardfault_args){
+  volatile unsigned long stacked_r0 ;
+  volatile unsigned long stacked_r1 ;
+  volatile unsigned long stacked_r2 ;
+  volatile unsigned long stacked_r3 ;
+  volatile unsigned long stacked_r12 ;
+  volatile unsigned long stacked_lr ;
+  volatile unsigned long stacked_pc ;
+  volatile unsigned long stacked_psr ;
+  volatile unsigned long _CFSR ;
+  volatile unsigned long _HFSR ;
+  volatile unsigned long _DFSR ;
+  volatile unsigned long _AFSR ;
+  volatile unsigned long _BFAR ;
+  volatile unsigned long _MMAR ;
+
+  stacked_r0  = ((unsigned long)hardfault_args[0]) ;
+  stacked_r1  = ((unsigned long)hardfault_args[1]) ;
+  stacked_r2  = ((unsigned long)hardfault_args[2]) ;
+  stacked_r3  = ((unsigned long)hardfault_args[3]) ;
+  stacked_r12 = ((unsigned long)hardfault_args[4]) ;
+  stacked_lr  = ((unsigned long)hardfault_args[5]) ;
+  stacked_pc  = ((unsigned long)hardfault_args[6]) ;
+  stacked_psr = ((unsigned long)hardfault_args[7]) ;
+
+  // Configurable Fault Status Register
+  // Consists of MMSR, BFSR and UFSR
+  _CFSR = (*((volatile unsigned long *)(0xE000ED28))) ;
+
+  // Hard Fault Status Register
+  _HFSR = (*((volatile unsigned long *)(0xE000ED2C))) ;
+
+  // Debug Fault Status Register
+  _DFSR = (*((volatile unsigned long *)(0xE000ED30))) ;
+
+  // Auxiliary Fault Status Register
+  _AFSR = (*((volatile unsigned long *)(0xE000ED3C))) ;
+
+  // Read the Fault Address Registers. These may not contain valid values.
+  // Check BFARVALID/MMARVALID to see if they are valid values
+  // MemManage Fault Address Register
+  _MMAR = (*((volatile unsigned long *)(0xE000ED34))) ;
+  // Bus Fault Address Register
+  _BFAR = (*((volatile unsigned long *)(0xE000ED38))) ;
+
+  __asm("BKPT #0\n") ; // Break into the debugger
+}