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devops.c

/*
 * devops.c:  Device operations using the PROM.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>

#include <asm/openprom.h>
#include <asm/oplib.h>

extern void restore_current(void);

/* Open the device described by the string 'dstr'.  Returns the handle
 * to that device used for subsequent operations on that device.
 * Returns -1 on failure.
 */
int
prom_devopen(char *dstr)
{
      int handle;
      unsigned long flags;
      spin_lock_irqsave(&prom_lock, flags);
      switch(prom_vers) {
      case PROM_V0:
            handle = (*(romvec->pv_v0devops.v0_devopen))(dstr);
            if(handle == 0) handle = -1;
            break;
      case PROM_V2:
      case PROM_V3:
            handle = (*(romvec->pv_v2devops.v2_dev_open))(dstr);
            break;
      default:
            handle = -1;
            break;
      };
      restore_current();
      spin_unlock_irqrestore(&prom_lock, flags);

      return handle;
}

/* Close the device described by device handle 'dhandle'. */
int
prom_devclose(int dhandle)
{
      unsigned long flags;
      spin_lock_irqsave(&prom_lock, flags);
      switch(prom_vers) {
      case PROM_V0:
            (*(romvec->pv_v0devops.v0_devclose))(dhandle);
            break;
      case PROM_V2:
      case PROM_V3:
            (*(romvec->pv_v2devops.v2_dev_close))(dhandle);
            break;
      default:
            break;
      };
      restore_current();
      spin_unlock_irqrestore(&prom_lock, flags);
      return 0;
}

/* Seek to specified location described by 'seekhi' and 'seeklo'
 * for device 'dhandle'.
 */
void
prom_seek(int dhandle, unsigned int seekhi, unsigned int seeklo)
{
      unsigned long flags;
      spin_lock_irqsave(&prom_lock, flags);
      switch(prom_vers) {
      case PROM_V0:
            (*(romvec->pv_v0devops.v0_seekdev))(dhandle, seekhi, seeklo);
            break;
      case PROM_V2:
      case PROM_V3:
            (*(romvec->pv_v2devops.v2_dev_seek))(dhandle, seekhi, seeklo);
            break;
      default:
            break;
      };
      restore_current();
      spin_unlock_irqrestore(&prom_lock, flags);

      return;
}

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