projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 933025b6 OO |
1 | What: /dev/memrar |
| 2 | Date: March 2010 | |
| d7a75e19 OO |
3 | KernelVersion: 2.6.34 |
| 4 | Contact: Eugene Epshteyn <eugene.epshteyn@intel.com> | |
| 933025b6 OO |
5 | Description: The Intel Moorestown Restricted Access Region (RAR) |
| 6 | Handler driver exposes an ioctl() based interface that | |
| 7 | allows a user to reserve and release blocks of RAR | |
| 8 | memory. | |
| 9 | ||
| 10 | Note: A sysfs based one was not appropriate for the | |
| 11 | RAR handler's usage model. | |
| 12 | ||
| 13 | ========================================================= | |
| 14 | ioctl() Requests | |
| 15 | ========================================================= | |
| 16 | RAR_HANDLER_RESERVE | |
| 17 | ------------------- | |
| 18 | Description: Reserve RAR block. | |
| 19 | Type: struct RAR_block_info | |
| 20 | Direction: in/out | |
| 21 | Errors: EINVAL (invalid RAR type or size) | |
| 22 | ENOMEM (not enough RAR memory) | |
| 23 | ||
| 24 | RAR_HANDLER_STAT | |
| 25 | ---------------- | |
| 26 | Description: Get RAR statistics. | |
| 27 | Type: struct RAR_stat | |
| 28 | Direction: in/out | |
| 29 | Errors: EINVAL (invalid RAR type) | |
| 30 | ||
| 31 | RAR_HANDLER_RELEASE | |
| 32 | ------------------- | |
| 33 | Description: Release previously reserved RAR block. | |
| 34 | Type: 32 bit unsigned integer | |
| 35 | (e.g. uint32_t), i.e the RAR "handle". | |
| 36 | Direction: in | |
| 37 | Errors: EINVAL (invalid RAR handle) | |
| 38 | ||
| 39 | ||
| 40 | ========================================================= | |
| 41 | ioctl() Request Parameter Types | |
| 42 | ========================================================= | |
| 43 | The structures referred to above are defined as | |
| 44 | follows: | |
| 45 | ||
| 46 | /** | |
| 47 | * struct RAR_block_info - user space struct that | |
| 48 | * describes RAR buffer | |
| 49 | * @type: Type of RAR memory (e.g., | |
| 50 | * RAR_TYPE_VIDEO or RAR_TYPE_AUDIO) [in] | |
| 51 | * @size: Requested size of a block in bytes to | |
| 52 | * be reserved in RAR. [in] | |
| 53 | * @handle: Handle that can be used to refer to | |
| 54 | * reserved block. [out] | |
| 55 | * | |
| 56 | * This is the basic structure exposed to the user | |
| 57 | * space that describes a given RAR buffer. It used | |
| 58 | * as the parameter for the RAR_HANDLER_RESERVE ioctl. | |
| 59 | * The buffer's underlying bus address is not exposed | |
| 60 | * to the user. User space code refers to the buffer | |
| 61 | * entirely by "handle". | |
| 62 | */ | |
| 63 | struct RAR_block_info { | |
| 64 | __u32 type; | |
| 65 | __u32 size; | |
| 66 | __u32 handle; | |
| 67 | }; | |
| 68 | ||
| 69 | /** | |
| 70 | * struct RAR_stat - RAR statistics structure | |
| 71 | * @type: Type of RAR memory (e.g., | |
| 72 | * RAR_TYPE_VIDEO or | |
| 73 | * RAR_TYPE_AUDIO) [in] | |
| 74 | * @capacity: Total size of RAR memory | |
| 75 | * region. [out] | |
| 76 | * @largest_block_size: Size of the largest reservable | |
| 77 | * block. [out] | |
| 78 | * | |
| 79 | * This structure is used for RAR_HANDLER_STAT ioctl. | |
| 80 | */ | |
| 81 | struct RAR_stat { | |
| 82 | __u32 type; | |
| 83 | __u32 capacity; | |
| 84 | __u32 largest_block_size; | |
| 85 | }; | |
| 86 | ||
| 87 | Lastly, the RAR_HANDLER_RELEASE ioctl expects a | |
| 88 | "handle" to the RAR block of memory. It is a 32 bit | |
| 89 | unsigned integer. |