1 // SPDX-License-Identifier: GPL-2.0-only
2
3 #define pr_fmt(fmt) "papr-sysparm: " fmt
4
5 #include <linux/bug.h>
6 #include <linux/init.h>
7 #include <linux/kernel.h>
8 #include <linux/printk.h>
9 #include <linux/slab.h>
10 #include <asm/rtas.h>
11 #include <asm/papr-sysparm.h>
12 #include <asm/rtas-work-area.h>
13
papr_sysparm_buf_alloc(void)14 struct papr_sysparm_buf *papr_sysparm_buf_alloc(void)
15 {
16 struct papr_sysparm_buf *buf = kzalloc(sizeof(*buf), GFP_KERNEL);
17
18 return buf;
19 }
20
papr_sysparm_buf_free(struct papr_sysparm_buf * buf)21 void papr_sysparm_buf_free(struct papr_sysparm_buf *buf)
22 {
23 kfree(buf);
24 }
25
26 /**
27 * papr_sysparm_get() - Retrieve the value of a PAPR system parameter.
28 * @param: PAPR system parameter token as described in
29 * 7.3.16 "System Parameters Option".
30 * @buf: A &struct papr_sysparm_buf as returned from papr_sysparm_buf_alloc().
31 *
32 * Place the result of querying the specified parameter, if available,
33 * in @buf. The result includes a be16 length header followed by the
34 * value, which may be a string or binary data. See &struct papr_sysparm_buf.
35 *
36 * Since there is at least one parameter (60, OS Service Entitlement
37 * Status) where the results depend on the incoming contents of the
38 * work area, the caller-supplied buffer is copied unmodified into the
39 * work area before calling ibm,get-system-parameter.
40 *
41 * A defined parameter may not be implemented on a given system, and
42 * some implemented parameters may not be available to all partitions
43 * on a system. A parameter's disposition may change at any time due
44 * to system configuration changes or partition migration.
45 *
46 * Context: This function may sleep.
47 *
48 * Return: 0 on success, -errno otherwise. @buf is unmodified on error.
49 */
50
papr_sysparm_get(papr_sysparm_t param,struct papr_sysparm_buf * buf)51 int papr_sysparm_get(papr_sysparm_t param, struct papr_sysparm_buf *buf)
52 {
53 const s32 token = rtas_function_token(RTAS_FN_IBM_GET_SYSTEM_PARAMETER);
54 struct rtas_work_area *work_area;
55 s32 fwrc;
56 int ret;
57
58 might_sleep();
59
60 if (WARN_ON(!buf))
61 return -EFAULT;
62
63 if (token == RTAS_UNKNOWN_SERVICE)
64 return -ENOENT;
65
66 work_area = rtas_work_area_alloc(sizeof(*buf));
67
68 memcpy(rtas_work_area_raw_buf(work_area), buf, sizeof(*buf));
69
70 do {
71 fwrc = rtas_call(token, 3, 1, NULL, param.token,
72 rtas_work_area_phys(work_area),
73 rtas_work_area_size(work_area));
74 } while (rtas_busy_delay(fwrc));
75
76 switch (fwrc) {
77 case 0:
78 ret = 0;
79 memcpy(buf, rtas_work_area_raw_buf(work_area), sizeof(*buf));
80 break;
81 case -3: /* parameter not implemented */
82 ret = -EOPNOTSUPP;
83 break;
84 case -9002: /* this partition not authorized to retrieve this parameter */
85 ret = -EPERM;
86 break;
87 case -9999: /* "parameter error" e.g. the buffer is too small */
88 ret = -EINVAL;
89 break;
90 default:
91 pr_err("unexpected ibm,get-system-parameter result %d\n", fwrc);
92 fallthrough;
93 case -1: /* Hardware/platform error */
94 ret = -EIO;
95 break;
96 }
97
98 rtas_work_area_free(work_area);
99
100 return ret;
101 }
102
papr_sysparm_set(papr_sysparm_t param,const struct papr_sysparm_buf * buf)103 int papr_sysparm_set(papr_sysparm_t param, const struct papr_sysparm_buf *buf)
104 {
105 const s32 token = rtas_function_token(RTAS_FN_IBM_SET_SYSTEM_PARAMETER);
106 struct rtas_work_area *work_area;
107 s32 fwrc;
108 int ret;
109
110 might_sleep();
111
112 if (WARN_ON(!buf))
113 return -EFAULT;
114
115 if (token == RTAS_UNKNOWN_SERVICE)
116 return -ENOENT;
117
118 work_area = rtas_work_area_alloc(sizeof(*buf));
119
120 memcpy(rtas_work_area_raw_buf(work_area), buf, sizeof(*buf));
121
122 do {
123 fwrc = rtas_call(token, 2, 1, NULL, param.token,
124 rtas_work_area_phys(work_area));
125 } while (rtas_busy_delay(fwrc));
126
127 switch (fwrc) {
128 case 0:
129 ret = 0;
130 break;
131 case -3: /* parameter not supported */
132 ret = -EOPNOTSUPP;
133 break;
134 case -9002: /* this partition not authorized to modify this parameter */
135 ret = -EPERM;
136 break;
137 case -9999: /* "parameter error" e.g. invalid input data */
138 ret = -EINVAL;
139 break;
140 default:
141 pr_err("unexpected ibm,set-system-parameter result %d\n", fwrc);
142 fallthrough;
143 case -1: /* Hardware/platform error */
144 ret = -EIO;
145 break;
146 }
147
148 rtas_work_area_free(work_area);
149
150 return ret;
151 }
152