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CAN: Add infrastructure to assure that all CAN IOCTL commands are uniquely numbered.

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This commit is contained in:
Gregory Nutt 2017-02-25 15:28:27 -06:00
parent b0efacebe1
commit eb984e08d9
1 changed files with 27 additions and 4 deletions
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31
include/nuttx/drivers/can.h
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@ -197,11 +197,34 @@
#define CANIOC_GET_CONNMODES _CANIOC(8)
#define CANIOC_SET_CONNMODES _CANIOC(9)
/* CANIOC_USER: Device specific ioctl calls can be supported with cmds greater
* than this value
*/
#define CAN_FIRST 0x0001 /* First required command */
#define CAN_NCMDS 9 /* Two required commands */
#define CANIOC_USER _CANIOC(10)
/* User defined ioctl commands are also supported. These will be forwarded
* by the upper-half CAN driver to the lower-half CAN driver via the co_ioctl()
* method fo the CAN lower-half interface. However, the lower-half driver
* must reserve a block of commands as follows in order prevent IOCTL
* command numbers from overlapping.
*
* This is generally done as follows. The first reservation for CAN driver A would
* look like:
*
* CAN_A_FIRST (CAN_FIRST + CAN_NCMDS) <- First command
* CAN_A_NCMDS 42 <- Number of commands
*
* IOCTL commands for CAN driver A would then be defined in a CAN A header file like:
*
* CANIOC_A_CMD1 _CANIOC(CAN_A_FIRST+0)
* CANIOC_A_CMD2 _CANIOC(CAN_A_FIRST+1)
* CANIOC_A_CMD3 _CANIOC(CAN_A_FIRST+2)
* ...
* CANIOC_A_CMD42 _CANIOC(CAN_A_FIRST+41)
*
* The next reservation would look like:
*
* CAN_B_FIRST (CAN_A_FIRST + CAN_A_NCMDS) <- Next command
* CAN_B_NCMDS 77 <- Number of commands
*/
/* Convenience macros ***************************************************************/