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 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 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 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 } 102 103 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