arch/powerpc/platforms/powernv/opal-powercap.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * PowerNV OPAL Powercap interface
   4  *
   5  * Copyright 2017 IBM Corp.
   6  */
   7
   8 #define pr_fmt(fmt)     "opal-powercap: " fmt
   9
  10 #include <linux/of.h>
  11 #include <linux/kobject.h>
  12 #include <linux/slab.h>
  13
  14 #include <asm/opal.h>
  15
  16 static DEFINE_MUTEX(powercap_mutex);
  17
  18 static struct kobject *powercap_kobj;
  19
  20 struct powercap_attr {
  21         u32 handle;
  22         struct kobj_attribute attr;
  23 };
  24
  25 static struct pcap {
  26         struct attribute_group pg;
  27         struct powercap_attr *pattrs;
  28 } *pcaps;
  29
  30 static ssize_t powercap_show(struct kobject *kobj, struct kobj_attribute *attr,
  31                              char *buf)
  32 {
  33         struct powercap_attr *pcap_attr = container_of(attr,
  34                                                 struct powercap_attr, attr);
  35         struct opal_msg msg;
  36         u32 pcap;
  37         int ret, token;
  38
  39         token = opal_async_get_token_interruptible();
  40         if (token < 0) {
  41                 pr_devel("Failed to get token\n");
  42                 return token;
  43         }
  44
  45         ret = mutex_lock_interruptible(&powercap_mutex);
  46         if (ret)
  47                 goto out_token;
  48
  49         ret = opal_get_powercap(pcap_attr->handle, token, (u32 *)__pa(&pcap));
  50         switch (ret) {
  51         case OPAL_ASYNC_COMPLETION:
  52                 ret = opal_async_wait_response(token, &msg);
  53                 if (ret) {
  54                         pr_devel("Failed to wait for the async response\n");
  55                         ret = -EIO;
  56                         goto out;
  57                 }
  58                 ret = opal_error_code(opal_get_async_rc(msg));
  59                 if (!ret) {
  60                         ret = sprintf(buf, "%u\n", be32_to_cpu(pcap));
  61                         if (ret < 0)
  62                                 ret = -EIO;
  63                 }
  64                 break;
  65         case OPAL_SUCCESS:
  66                 ret = sprintf(buf, "%u\n", be32_to_cpu(pcap));
  67                 if (ret < 0)
  68                         ret = -EIO;
  69                 break;
  70         default:
  71                 ret = opal_error_code(ret);
  72         }
  73
  74 out:
  75         mutex_unlock(&powercap_mutex);
  76 out_token:
  77         opal_async_release_token(token);
  78         return ret;
  79 }
  80
  81 static ssize_t powercap_store(struct kobject *kobj,
  82                               struct kobj_attribute *attr, const char *buf,
  83                               size_t count)
  84 {
  85         struct powercap_attr *pcap_attr = container_of(attr,
  86                                                 struct powercap_attr, attr);
  87         struct opal_msg msg;
  88         u32 pcap;
  89         int ret, token;
  90
  91         ret = kstrtoint(buf, 0, &pcap);
  92         if (ret)
  93                 return ret;
  94
  95         token = opal_async_get_token_interruptible();
  96         if (token < 0) {
  97                 pr_devel("Failed to get token\n");
  98                 return token;
  99         }
 100
 101         ret = mutex_lock_interruptible(&powercap_mutex);
 102         if (ret)
 103                 goto out_token;
 104
 105         ret = opal_set_powercap(pcap_attr->handle, token, pcap);
 106         switch (ret) {
 107         case OPAL_ASYNC_COMPLETION:
 108                 ret = opal_async_wait_response(token, &msg);
 109                 if (ret) {
 110                         pr_devel("Failed to wait for the async response\n");
 111                         ret = -EIO;
 112                         goto out;
 113                 }
 114                 ret = opal_error_code(opal_get_async_rc(msg));
 115                 if (!ret)
 116                         ret = count;
 117                 break;
 118         case OPAL_SUCCESS:
 119                 ret = count;
 120                 break;
 121         default:
 122                 ret = opal_error_code(ret);
 123         }
 124
 125 out:
 126         mutex_unlock(&powercap_mutex);
 127 out_token:
 128         opal_async_release_token(token);
 129         return ret;
 130 }
 131
 132 static void powercap_add_attr(int handle, const char *name,
 133                               struct powercap_attr *attr)
 134 {
 135         attr->handle = handle;
 136         sysfs_attr_init(&attr->attr.attr);
 137         attr->attr.attr.name = name;
 138         attr->attr.attr.mode = 0444;
 139         attr->attr.show = powercap_show;
 140 }
 141
 142 void __init opal_powercap_init(void)
 143 {
 144         struct device_node *powercap, *node;
 145         int i = 0;
 146
 147         powercap = of_find_compatible_node(NULL, NULL, "ibm,opal-powercap");
 148         if (!powercap) {
 149                 pr_devel("Powercap node not found\n");
 150                 return;
 151         }
 152
 153         pcaps = kcalloc(of_get_child_count(powercap), sizeof(*pcaps),
 154                         GFP_KERNEL);
 155         if (!pcaps)
 156                 return;
 157
 158         powercap_kobj = kobject_create_and_add("powercap", opal_kobj);
 159         if (!powercap_kobj) {
 160                 pr_warn("Failed to create powercap kobject\n");
 161                 goto out_pcaps;
 162         }
 163
 164         i = 0;
 165         for_each_child_of_node(powercap, node) {
 166                 u32 cur, min, max;
 167                 int j = 0;
 168                 bool has_cur = false, has_min = false, has_max = false;
 169
 170                 if (!of_property_read_u32(node, "powercap-min", &min)) {
 171                         j++;
 172                         has_min = true;
 173                 }
 174
 175                 if (!of_property_read_u32(node, "powercap-max", &max)) {
 176                         j++;
 177                         has_max = true;
 178                 }
 179
 180                 if (!of_property_read_u32(node, "powercap-current", &cur)) {
 181                         j++;
 182                         has_cur = true;
 183                 }
 184
 185                 pcaps[i].pattrs = kcalloc(j, sizeof(struct powercap_attr),
 186                                           GFP_KERNEL);
 187                 if (!pcaps[i].pattrs)
 188                         goto out_pcaps_pattrs;
 189
 190                 pcaps[i].pg.attrs = kcalloc(j + 1, sizeof(struct attribute *),
 191                                             GFP_KERNEL);
 192                 if (!pcaps[i].pg.attrs) {
 193                         kfree(pcaps[i].pattrs);
 194                         goto out_pcaps_pattrs;
 195                 }
 196
 197                 j = 0;
 198                 pcaps[i].pg.name = kasprintf(GFP_KERNEL, "%pOFn", node);
 199                 if (has_min) {
 200                         powercap_add_attr(min, "powercap-min",
 201                                           &pcaps[i].pattrs[j]);
 202                         pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
 203                         j++;
 204                 }
 205
 206                 if (has_max) {
 207                         powercap_add_attr(max, "powercap-max",
 208                                           &pcaps[i].pattrs[j]);
 209                         pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
 210                         j++;
 211                 }
 212
 213                 if (has_cur) {
 214                         powercap_add_attr(cur, "powercap-current",
 215                                           &pcaps[i].pattrs[j]);
 216                         pcaps[i].pattrs[j].attr.attr.mode |= 0220;
 217                         pcaps[i].pattrs[j].attr.store = powercap_store;
 218                         pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
 219                         j++;
 220                 }
 221
 222                 if (sysfs_create_group(powercap_kobj, &pcaps[i].pg)) {
 223                         pr_warn("Failed to create powercap attribute group %s\n",
 224                                 pcaps[i].pg.name);
 225                         goto out_pcaps_pattrs;
 226                 }
 227                 i++;
 228         }
 229
 230         return;
 231
 232 out_pcaps_pattrs:
 233         while (--i >= 0) {
 234                 kfree(pcaps[i].pattrs);
 235                 kfree(pcaps[i].pg.attrs);
 236                 kfree(pcaps[i].pg.name);
 237         }
 238         kobject_put(powercap_kobj);
 239 out_pcaps:
 240         kfree(pcaps);
 241 }