1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI_PAPR_SYSPARM_H_
3 #define _UAPI_PAPR_SYSPARM_H_
4 
5 #include <linux/types.h>
6 #include <asm/ioctl.h>
7 #include <asm/papr-miscdev.h>
8 
9 enum {
10 	PAPR_SYSPARM_MAX_INPUT  = 1024,
11 	PAPR_SYSPARM_MAX_OUTPUT = 4000,
12 };
13 
14 struct 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 /* _UAPI_PAPR_SYSPARM_H_ */
59