pcan_isa.c

CAN 驱动编程

//****************************************************************************
// Copyright (C) 2001,2002,2003  PEAK System-Technik GmbH
//
// [e-mail]
// www.peak-system.com
//
// This program 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.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// Maintainer(s): Klaus Hitschler ([e-mail])
//****************************************************************************

//****************************************************************************
//
// all parts of the isa hardware for pcan-isa devices
//
// $Log: pcan_isa.c,v $
// Revision 1.23  2003/03/02 10:58:07  klaus
// merged USB thread into main path
//
// Revision 1.22  2003/03/02 10:58:07  klaus
// merged USB thread into main path
//
// Revision 1.21.2.5  2003/01/29 20:34:20  klaus
// release_20030129_a and release_20030129_u released
//
// Revision 1.21.2.4  2003/01/29 20:34:20  klaus
// release_20030129_a and release_20030129_u released
//
// Revision 1.21.2.3  2003/01/28 23:28:26  klaus
// reorderd pcan_usb.c and pcan_usb_kernel.c, tidied up
//
// Revision 1.21.2.2  2003/01/14 20:31:53  klaus
// read/write/minor assigment is working
//
//****************************************************************************

//****************************************************************************
// INCLUDES
#include <src/pcan_common.h>     // must always be the 1st include
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <asm/io.h>
#include <src/pcan_isa.h>
#include <src/pcan_sja1000.h>

//****************************************************************************
// DEFINES
#define PCAN_ISA_MINOR_BASE 8    // starting point of minors for ISA devices  
#define ISA_PORT_SIZE       0x20 // the address range of the isa-port
#define ISA_DEFAULT_COUNT   2    // count of defaults for init

//****************************************************************************
// GLOBALS

//****************************************************************************
// LOCALS
static u16 isa_ports[] = {0x300, 0x320};  // default values for pcan-isa
static u8  isa_irqs[]  = {10, 5};
static u16 isa_devices = 0;        // the number of accepted isa_devices

//****************************************************************************
// CODE  
static u8 pcan_isa_readreg(struct pcandev *dev, u8 port) // read a register
{
  return inb(dev->port.isa.dwPort + port);
}

static void pcan_isa_writereg(struct pcandev *dev, u8 port, u8 data) // write a register
{
  outb(data, dev->port.isa.dwPort + port);
}

static int pcan_isa_req_irq(struct pcandev *dev)
{
  int err;
  
  if (dev->wInitStep == 3)
  {
    if ((err = request_irq(dev->port.isa.wIrq, sja1000_irqhandler, SA_INTERRUPT | SA_SHIRQ, "pcan", dev)))
      return err;
  
    dev->wInitStep++;
  }
    
  return 0;
}

static void pcan_isa_free_irq(struct pcandev *dev)
{
  if (dev->wInitStep == 4)
  {
    free_irq(dev->port.isa.wIrq, dev); 
    dev->wInitStep--;
  }
}

// release and probe function
static int pcan_isa_cleanup(struct pcandev *dev)
{
  DPRINTK(KERN_DEBUG "%s: pcan_isa_cleanup()\n", DEVICE_NAME);

  switch(dev->wInitStep)
  {
    case 4: pcan_isa_free_irq(dev);
    case 3: isa_devices--;
    case 2:
    case 1: release_region(dev->port.isa.dwPort, ISA_PORT_SIZE);
    case 0: dev->wInitStep = 0;
  }
  
  return 0;
}

static int pcan_isa_probe(struct pcandev *dev) // probe for type
{
  return (check_region(dev->port.isa.dwPort, ISA_PORT_SIZE)) ? -EBUSY : 0;
}

// interface depended open and close
static int pcan_isa_open(struct pcandev *dev)
{
  return 0;
}

static int pcan_isa_release(struct pcandev *dev)
{
  return 0;
}

int  pcan_isa_init(struct pcandev *dev, u32 dwPort, u16 wIrq)
{
  int err;
  
  DPRINTK(KERN_DEBUG "%s: pcan_isa_init(), isa_devices = %d\n", DEVICE_NAME, isa_devices);

  // init process wait queues
  init_waitqueue_head(&dev->read_queue);
  init_waitqueue_head(&dev->write_queue);
  
  // set this before any instructions, fill struct pcandev, part 1  
	dev->wInitStep   = 0;           
  dev->readreg     = pcan_isa_readreg;
  dev->writereg    = pcan_isa_writereg;
  dev->cleanup     = pcan_isa_cleanup;
  dev->req_irq     = pcan_isa_req_irq;
  dev->free_irq    = pcan_isa_free_irq;
  dev->open        = pcan_isa_open;
  dev->release     = pcan_isa_release;

  // reject illegal combination
  if ((!dwPort && wIrq) || (dwPort && !wIrq))
    return -EINVAL;

  // a default is requested
  if (!dwPort)
  {
    // there's no default available
    if (isa_devices >= ISA_DEFAULT_COUNT)
      return -ENODEV;
    
    dev->port.isa.dwPort = isa_ports[isa_devices];
    dev->port.isa.wIrq   = isa_irqs[isa_devices];    
  }
  else
  {
    dev->port.isa.dwPort = dwPort;
    dev->port.isa.wIrq   = wIrq;    
  } 
   
	dev->nMinor      = PCAN_ISA_MINOR_BASE + isa_devices;
	 
	// is the device really available?	
  if ((err = pcan_isa_probe(dev)) < 0)
    return err;
    
  request_region(dev->port.isa.dwPort, ISA_PORT_SIZE, DEVICE_NAME);
  dev->wInitStep = 1;
  
  isa_devices++; 
  dev->wInitStep = 3;
  
  printk(KERN_INFO "%s: isa device minor %d found (io=0x%04x,irq=%d)\n", DEVICE_NAME, 
                               dev->nMinor, dev->port.isa.dwPort, dev->port.isa.wIrq);
    
  return 0;
}