FreeBSD/Linux Kernel Cross Reference
sys/include/minix/devio.h

     /* This file provides basic types and some constants for the 
      * SYS_DEVIO and SYS_VDEVIO system calls, which allow user-level 
      * processes to perform device I/O. 
      *
      * Created: 
      *      Apr 08, 2004 by Jorrit N. Herder
      */
     
     #ifndef _DEVIO_H
    #define _DEVIO_H
    
    #include <minix/sys_config.h>     /* needed to include <minix/type.h> */
    #include <sys/types.h>        /* u8_t, u16_t, u32_t needed */
    
    typedef u16_t port_t;
    typedef U16_t Port_t;
    
    /* We have different granularities of port I/O: 8, 16, 32 bits.
     * Also see <ibm/portio.h>, which has functions for bytes, words,  
     * and longs. Hence, we need different (port,value)-pair types. 
     */
    typedef struct { u16_t port;  u8_t value; } pvb_pair_t;
    typedef struct { u16_t port; u16_t value; } pvw_pair_t;
    typedef struct { u16_t port; u32_t value; } pvl_pair_t;
    
    /* Macro shorthand to set (port,value)-pair. */
    #define pv_set(pv, p, v) ((pv).port = (p), (pv).value = (v))
    #define pv_ptr_set(pv_ptr, p, v) ((pv_ptr)->port = (p), (pv_ptr)->value = (v))
    
    #if 0   /* no longer in use !!! */
    /* Define a number of flags to indicate granularity we are using. */
    #define MASK_GRANULARITY 0x000F  /* not in use! does not match flags */
    #define PVB_FLAG 'b'
    #define PVW_FLAG 'w'
    #define PVL_FLAG 'l'
    
    /* Flags indicating whether request wants to do input or output. */
    #define MASK_IN_OR_OUT 0x00F0
    #define DEVIO_INPUT 0x0010
    #define DEVIO_OUTPUT 0x0020
    #endif  /* 0 */
    
    #if 0   /* no longer used !!! */
    /* Define how large the (port,value)-pair buffer in the kernel is. 
     * This buffer is used to copy the (port,value)-pairs in kernel space.
     */
    #define PV_BUF_SIZE  64      /* creates char pv_buf[PV_BUF_SIZE] */
    
    /* Note that SYS_VDEVIO sends a pointer to a vector of (port,value)-pairs, 
     * whereas SYS_DEVIO includes a single (port,value)-pair in the messages.
     * Calculate maximum number of (port,value)-pairs that can be handled 
     * in a single SYS_VDEVIO system call with above struct definitions. 
     */
    #define MAX_PVB_PAIRS ((PV_BUF_SIZE * sizeof(char)) / sizeof(pvb_pair_t))
    #define MAX_PVW_PAIRS ((PV_BUF_SIZE * sizeof(char)) / sizeof(pvw_pair_t))
    #define MAX_PVL_PAIRS ((PV_BUF_SIZE * sizeof(char)) / sizeof(pvl_pair_t))
    #endif /* 0 */
            
    
    #endif  /* _DEVIO_H */

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