1 #ifndef _ASM_GENERIC_IOCTL_H 2 #define _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 53 #ifndef _IOC_NONE 54 # define _IOC_NONE 0U 55 #endif 56 57 #ifndef _IOC_WRITE 58 # define _IOC_WRITE 1U 59 #endif 60 61 #ifndef _IOC_READ 62 # define _IOC_READ 2U 63 #endif 64 65 #define _IOC(dir,type,nr,size) \ 66 (((dir) << _IOC_DIRSHIFT) | \ 67 ((type) << _IOC_TYPESHIFT) | \ 68 ((nr) << _IOC_NRSHIFT) | \ 69 ((size) << _IOC_SIZESHIFT)) 70 71 #ifdef __KERNEL__ 72 /* provoke compile error for invalid uses of size argument */ 73 extern unsigned int __invalid_size_argument_for_IOC; 74 #define _IOC_TYPECHECK(t) \ 75 ((sizeof(t) == sizeof(t[1]) && \ 76 sizeof(t) < (1 << _IOC_SIZEBITS)) ? \ 77 sizeof(t) : __invalid_size_argument_for_IOC) 78 #else 79 #define _IOC_TYPECHECK(t) (sizeof(t)) 80 #endif 81 82 /* used to create numbers */ 83 #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0) 84 #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size))) 85 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size))) 86 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size))) 87 #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size)) 88 #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size)) 89 #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size)) 90 91 /* used to decode ioctl numbers.. */ 92 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) 93 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK) 94 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK) 95 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK) 96 97 /* ...and for the drivers/sound files... */ 98 99 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT) 100 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT) 101 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT) 102 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT) 103 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT) 104 105 #endif /* _ASM_GENERIC_IOCTL_H */ 106