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| -rw-r--r-- | drivers/staging/memrar/memrar-abi | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/staging/memrar/memrar-abi b/drivers/staging/memrar/memrar-abi new file mode 100644 index 000000000000..98a6bb158baf --- /dev/null +++ b/drivers/staging/memrar/memrar-abi @@ -0,0 +1,89 @@ +What: /dev/memrar +Date: March 2010 +KernelVersion: Kernel version this feature first showed up in. +Contact: Ossama Othman <ossama.othman@intel.com> +Description: The Intel Moorestown Restricted Access Region (RAR) + Handler driver exposes an ioctl() based interface that + allows a user to reserve and release blocks of RAR + memory. + + Note: A sysfs based one was not appropriate for the + RAR handler's usage model. + + ========================================================= + ioctl() Requests + ========================================================= + RAR_HANDLER_RESERVE + ------------------- + Description: Reserve RAR block. + Type: struct RAR_block_info + Direction: in/out + Errors: EINVAL (invalid RAR type or size) + ENOMEM (not enough RAR memory) + + RAR_HANDLER_STAT + ---------------- + Description: Get RAR statistics. + Type: struct RAR_stat + Direction: in/out + Errors: EINVAL (invalid RAR type) + + RAR_HANDLER_RELEASE + ------------------- + Description: Release previously reserved RAR block. + Type: 32 bit unsigned integer + (e.g. uint32_t), i.e the RAR "handle". + Direction: in + Errors: EINVAL (invalid RAR handle) + + + ========================================================= + ioctl() Request Parameter Types + ========================================================= + The structures referred to above are defined as + follows: + + /** + * struct RAR_block_info - user space struct that + * describes RAR buffer + * @type: Type of RAR memory (e.g., + * RAR_TYPE_VIDEO or RAR_TYPE_AUDIO) [in] + * @size: Requested size of a block in bytes to + * be reserved in RAR. [in] + * @handle: Handle that can be used to refer to + * reserved block. [out] + * + * This is the basic structure exposed to the user + * space that describes a given RAR buffer. It used + * as the parameter for the RAR_HANDLER_RESERVE ioctl. + * The buffer's underlying bus address is not exposed + * to the user. User space code refers to the buffer + * entirely by "handle". + */ + struct RAR_block_info { + __u32 type; + __u32 size; + __u32 handle; + }; + + /** + * struct RAR_stat - RAR statistics structure + * @type: Type of RAR memory (e.g., + * RAR_TYPE_VIDEO or + * RAR_TYPE_AUDIO) [in] + * @capacity: Total size of RAR memory + * region. [out] + * @largest_block_size: Size of the largest reservable + * block. [out] + * + * This structure is used for RAR_HANDLER_STAT ioctl. + */ + struct RAR_stat { + __u32 type; + __u32 capacity; + __u32 largest_block_size; + }; + + Lastly, the RAR_HANDLER_RELEASE ioctl expects a + "handle" to the RAR block of memory. It is a 32 bit + unsigned integer. |