USBIsr.c

/*
  FreeRTOS.org V4.6.0 - Copyright (C) 2003-2007 Richard Barry.

  This file is part of the FreeRTOS.org distribution.

  FreeRTOS.org is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  FreeRTOS.org is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with FreeRTOS.org; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  A special exception to the GPL can be applied should you wish to distribute
  a combined work that includes FreeRTOS.org, without being obliged to provide
  the source code for any proprietary components.  See the licensing section 
  of http://www.FreeRTOS.org for full details of how and when the exception
  can be applied.

  ***************************************************************************
  See http://www.FreeRTOS.org for documentation, latest information, license 
  and contact details.  Please ensure to read the configuration and relevant 
  port sections of the online documentation.
  ***************************************************************************
*/


/* 
  BASIC INTERRUPT DRIVEN DRIVER FOR USB. 

  This file contains all the usb components that must be compiled
  to ARM mode.  The components that can be compiled to either ARM or THUMB
  mode are contained in USB-CDC.c.

*/

/* MakingThings */
#include "config.h"
#ifdef MAKE_CTRL_USB

#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "Board.h"
// MakingThings: renamed
#include "usb_internal.h"
#include "USB-CDC.h"

#define usbINT_CLEAR_MASK (AT91C_UDP_TXCOMP | AT91C_UDP_STALLSENT | AT91C_UDP_RXSETUP | AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RX_DATA_BK1 )
/*-----------------------------------------------------------*/

/* Messages and queue used to communicate between the ISR and the USB task. */
static xISRStatus xISRMessages[ usbQUEUE_LENGTH + 1 ];
extern xQueueHandle xUSBInterruptQueue;
/*-----------------------------------------------------------*/

/* The ISR can cause a context switch so is declared naked. */
void vUSB_ISR_Wrapper( void ) __attribute__ ((naked));

/* The function that actually performs the ISR work.  This must be separate
from the wrapper function to ensure the correct stack frame gets set up. */
void vUSB_ISR_Handler( void );
/*-----------------------------------------------------------*/

void vUSB_ISR_Handler( void )
{
portCHAR cTaskWokenByPost = pdFALSE;
static volatile unsigned portLONG ulNextMessage = 0;
xISRStatus *pxMessage;
unsigned portLONG ulRxBytes;
unsigned portCHAR ucFifoIndex;

    /* Use the next message from the array. */
  pxMessage = &( xISRMessages[ ( ulNextMessage & usbQUEUE_LENGTH ) ] );
  ulNextMessage++;

    /* Save UDP ISR state for task-level processing. */
  pxMessage->ulISR = AT91C_BASE_UDP->UDP_ISR;
  pxMessage->ulCSR0 = AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ];

    /* Clear interrupts from ICR. */
  AT91C_BASE_UDP->UDP_ICR = AT91C_BASE_UDP->UDP_IMR | AT91C_UDP_ENDBUSRES;
  
    
  /* Process incoming FIFO data.  Must set DIR (if needed) and clear RXSETUP 
  before exit. */

    /* Read CSR and get incoming byte count. */
  ulRxBytes = ( pxMessage->ulCSR0 >> 16 ) & usbRX_COUNT_MASK;
  
  /* Receive control transfers on endpoint 0. */
  if( pxMessage->ulCSR0 & ( AT91C_UDP_RXSETUP | AT91C_UDP_RX_DATA_BK0 ) )
  {
    /* Save FIFO data buffer for either a SETUP or DATA stage */
    for( ucFifoIndex = 0; ucFifoIndex < ulRxBytes; ucFifoIndex++ )
    {
      pxMessage->ucFifoData[ ucFifoIndex ] = AT91C_BASE_UDP->UDP_FDR[ usbEND_POINT_0 ];
    }

    /* Set direction for data stage.  Must be done before RXSETUP is 
    cleared. */
    if( ( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_RXSETUP ) )
    {
      if( ulRxBytes && ( pxMessage->ucFifoData[ usbREQUEST_TYPE_INDEX ] & 0x80 ) )
      {
        AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] |= AT91C_UDP_DIR;

        /* Might not be wise in an ISR! */
        while( !(AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_DIR) );
      }

      /* Clear RXSETUP */
      AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] &= ~AT91C_UDP_RXSETUP;

      /* Might not be wise in an ISR! */
      while ( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_RXSETUP );
    }
    else
    {
       /* Clear RX_DATA_BK0 */
       AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] &= ~AT91C_UDP_RX_DATA_BK0;

       /* Might not be wise in an ISR! */
       while ( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] & AT91C_UDP_RX_DATA_BK0 );
    }
  }
  
  /* If we received data on endpoint 1, disable its interrupts until it is 
  processed in the main loop */
  if( AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] & ( AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RX_DATA_BK1 ) )
  {
    AT91C_BASE_UDP->UDP_IDR = AT91C_UDP_EPINT1;
  }
  
  AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_0 ] &= ~( AT91C_UDP_TXCOMP | AT91C_UDP_STALLSENT );
     
  /* Clear interrupts for the other endpoints, retain data flags for endpoint 
  1. */
  AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_1 ] &= ~( AT91C_UDP_TXCOMP | AT91C_UDP_STALLSENT | AT91C_UDP_RXSETUP );
  AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_2 ] &= ~usbINT_CLEAR_MASK;
  AT91C_BASE_UDP->UDP_CSR[ usbEND_POINT_3 ] &= ~usbINT_CLEAR_MASK;

  /* Post ISR data to queue for task-level processing */
  cTaskWokenByPost = xQueueSendFromISR( xUSBInterruptQueue, &pxMessage, cTaskWokenByPost );

  /* Clear AIC to complete ISR processing */
  AT91C_BASE_AIC->AIC_EOICR = 0;

  /* Do a task switch if needed */
  if( cTaskWokenByPost )
  {
    /* This call will ensure that the unblocked task will be executed
    immediately upon completion of the ISR if it has a priority higher
    than the interrupted task. */
    portYIELD_FROM_ISR();
  }
}
/*-----------------------------------------------------------*/

void vUSB_ISR_Wrapper( void )
{
  /* Save the context of the interrupted task. */
  portSAVE_CONTEXT();

  /* Call the handler to do the work.  This must be a separate
  function to ensure the stack frame is set up correctly. */
  vUSB_ISR_Handler();

  /* Restore the context of whichever task will execute next. */
  portRESTORE_CONTEXT();
}

#endif // MAKE_CTRL_USB

---

The Make Controller Kit is an open source project maintained by MakingThings.
MakingThings code is released under the Apache 2.0 license.
Bug tracker, development wiki and status can be found at http://dev.makingthings.com.
This document was last updated on 18 May 2009.