1 #ifndef _UAPI_ASM_GENERIC_IOCTL_H 2 #define _UAPI_ASM_GENERIC_IOCTL_H 3 4 /* ioctl command encoding: 32 bits total, command in lower 16 bits, 5 * size of the parameter structure in the lower 14 bits of the 6 * upper 16 bits. 7 * Encoding the size of the parameter structure in the ioctl request 8 * is useful for catching programs compiled with old versions 9 * and to avoid overwriting user space outside the user buffer area. 10 * The highest 2 bits are reserved for indicating the ``access mode''. 11 * NOTE: This limits the max parameter size to 16kB -1 ! 12 */ 13 14 /* 15 * The following is for compatibility across the various Linux 16 * platforms. The generic ioctl numbering scheme doesn't really enforce 17 * a type field. De facto, however, the top 8 bits of the lower 16 18 * bits are indeed used as a type field, so we might just as well make 19 * this explicit here. Please be sure to use the decoding macros 20 * below from now on. 21 */ 22 #define _IOC_NRBITS 8 23 #define _IOC_TYPEBITS 8 24 25 /* 26 * Let any architecture override either of the following before 27 * including this file. 28 */ 29 30 #ifndef _IOC_SIZEBITS 31 # define _IOC_SIZEBITS 14 32 #endif 33 34 #ifndef _IOC_DIRBITS 35 # define _IOC_DIRBITS 2 36 #endif 37 38 #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1) 39 #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1) 40 #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1) 41 #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1) 42 43 #define _IOC_NRSHIFT 0 44 #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS) 45 #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS) 46 #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS) 47 48 /* 49 * Direction bits, which any architecture can choose to override 50 * before including this file. 51 * 52 * NOTE: _IOC_WRITE means userland is writing and kernel is 53 * reading. _IOC_READ means userland is reading and kernel is writing. 54 */ 55 56 #ifndef _IOC_NONE 57 # define _IOC_NONE 0U 58 #endif 59 60 #ifndef _IOC_WRITE 61 # define _IOC_WRITE 1U 62 #endif 63 64 #ifndef _IOC_READ 65 # define _IOC_READ 2U 66 #endif 67 68 #define _IOC(dir,type,nr,size) \ 69 (((dir) << _IOC_DIRSHIFT) | \ 70 ((type) << _IOC_TYPESHIFT) | \ 71 ((nr) << _IOC_NRSHIFT) | \ 72 ((size) << _IOC_SIZESHIFT)) 73 74 #ifndef __KERNEL__ 75 #define _IOC_TYPECHECK(t) (sizeof(t)) 76 #endif 77 78 /* 79 * Used to create numbers. 80 * 81 * NOTE: _IOW means userland is writing and kernel is reading. _IOR 82 * means userland is reading and kernel is writing. 83 */ 84 #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0) 85 #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size))) 86 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size))) 87 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size))) 88 #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size)) 89 #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size)) 90 #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size)) 91 92 /* used to decode ioctl numbers.. */ 93 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) 94 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK) 95 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK) 96 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK) 97 98 /* ...and for the drivers/sound files... */ 99 100 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT) 101 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT) 102 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT) 103 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT) 104 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT) 105 106 #endif /* _UAPI_ASM_GENERIC_IOCTL_H */ 107