1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _PAPR_SYSPARM_H_
3#define _PAPR_SYSPARM_H_
4
5#include <linux/types.h>
6#include <asm/ioctl.h>
7#include <asm/papr-miscdev.h>
8
9enum {
10 PAPR_SYSPARM_MAX_INPUT = 1024,
11 PAPR_SYSPARM_MAX_OUTPUT = 4000,
12};
13
14struct papr_sysparm_io_block {
15 __u32 parameter;
16 __u16 length;
17 __u8 data[PAPR_SYSPARM_MAX_OUTPUT];
18};
19
20/**
21 * PAPR_SYSPARM_IOC_GET - Retrieve the value of a PAPR system parameter.
22 *
23 * Uses _IOWR because of one corner case: Retrieving the value of the
24 * "OS Service Entitlement Status" parameter (60) requires the caller
25 * to supply input data (a date string) in the buffer passed to
26 * firmware. So the @length and @data of the incoming
27 * papr_sysparm_io_block are always used to initialize the work area
28 * supplied to ibm,get-system-parameter. No other parameters are known
29 * to parameterize the result this way, and callers are encouraged
30 * (but not required) to zero-initialize @length and @data in the
31 * common case.
32 *
33 * On error the contents of the ioblock are indeterminate.
34 *
35 * Return:
36 * 0: Success; @length is the length of valid data in @data, not to exceed @PAPR_SYSPARM_MAX_OUTPUT.
37 * -EIO: Platform error. (-1)
38 * -EINVAL: Incorrect data length or format. (-9999)
39 * -EPERM: The calling partition is not allowed to access this parameter. (-9002)
40 * -EOPNOTSUPP: Parameter not supported on this platform (-3)
41 */
42#define PAPR_SYSPARM_IOC_GET _IOWR(PAPR_MISCDEV_IOC_ID, 1, struct papr_sysparm_io_block)
43
44/**
45 * PAPR_SYSPARM_IOC_SET - Update the value of a PAPR system parameter.
46 *
47 * The contents of the ioblock are unchanged regardless of success.
48 *
49 * Return:
50 * 0: Success; the parameter has been updated.
51 * -EIO: Platform error. (-1)
52 * -EINVAL: Incorrect data length or format. (-9999)
53 * -EPERM: The calling partition is not allowed to access this parameter. (-9002)
54 * -EOPNOTSUPP: Parameter not supported on this platform (-3)
55 */
56#define PAPR_SYSPARM_IOC_SET _IOW(PAPR_MISCDEV_IOC_ID, 2, struct papr_sysparm_io_block)
57
58#endif /* _PAPR_SYSPARM_H_ */