projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * linux/ioctl.h for Linux by H.H. Bergman. | |
| 3 | */ | |
| 4 | ||
| 5 | #ifndef _ASM_IOCTL_H | |
| 6 | #define _ASM_IOCTL_H | |
| 7 | ||
| 8 | /* ioctl command encoding: 32 bits total, command in lower 16 bits, | |
| 9 | * size of the parameter structure in the lower 14 bits of the | |
| 10 | * upper 16 bits. | |
| 11 | * Encoding the size of the parameter structure in the ioctl request | |
| 12 | * is useful for catching programs compiled with old versions | |
| 13 | * and to avoid overwriting user space outside the user buffer area. | |
| 14 | * The highest 2 bits are reserved for indicating the ``access mode''. | |
| 15 | * NOTE: This limits the max parameter size to 16kB -1 ! | |
| 16 | */ | |
| 17 | ||
| 18 | /* | |
| 19 | * I don't really have any idea about what this should look like, so | |
| 20 | * for the time being, this is heavily based on the PC definitions. | |
| 21 | */ | |
| 22 | ||
| 23 | /* | |
| 24 | * The following is for compatibility across the various Linux | |
| 25 | * platforms. The i386 ioctl numbering scheme doesn't really enforce | |
| 26 | * a type field. De facto, however, the top 8 bits of the lower 16 | |
| 27 | * bits are indeed used as a type field, so we might just as well make | |
| 28 | * this explicit here. Please be sure to use the decoding macros | |
| 29 | * below from now on. | |
| 30 | */ | |
| 31 | #define _IOC_NRBITS 8 | |
| 32 | #define _IOC_TYPEBITS 8 | |
| 33 | #define _IOC_SIZEBITS 14 | |
| 34 | #define _IOC_DIRBITS 2 | |
| 35 | ||
| 36 | #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1) | |
| 37 | #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1) | |
| 38 | #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1) | |
| 39 | #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1) | |
| 40 | ||
| 41 | #define _IOC_NRSHIFT 0 | |
| 42 | #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS) | |
| 43 | #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS) | |
| 44 | #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS) | |
| 45 | ||
| 46 | /* | |
| 47 | * Direction bits. | |
| 48 | */ | |
| 49 | #define _IOC_NONE 0U | |
| 50 | #define _IOC_WRITE 1U | |
| 51 | #define _IOC_READ 2U | |
| 52 | ||
| 53 | #define _IOC(dir,type,nr,size) \ | |
| 54 | (((dir) << _IOC_DIRSHIFT) | \ | |
| 55 | ((type) << _IOC_TYPESHIFT) | \ | |
| 56 | ((nr) << _IOC_NRSHIFT) | \ | |
| 57 | ((size) << _IOC_SIZESHIFT)) | |
| 58 | ||
| 59 | /* used to create numbers */ | |
| 60 | #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0) | |
| 61 | #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size)) | |
| 62 | #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size)) | |
| 63 | #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size)) | |
| 64 | ||
| 65 | /* used to decode ioctl numbers.. */ | |
| 66 | #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) | |
| 67 | #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK) | |
| 68 | #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK) | |
| 69 | #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK) | |
| 70 | ||
| 71 | /* ...and for the drivers/sound files... */ | |
| 72 | ||
| 73 | #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT) | |
| 74 | #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT) | |
| 75 | #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT) | |
| 76 | #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT) | |
| 77 | #define IOCSIZE_SHIFT (_IOC_SIZESHIFT) | |
| 78 | ||
| 79 | #endif /* _ASM_IOCTL_H */ | |
| 80 |