drivers/firmware/arm_scmi/clock.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * System Control and Management Interface (SCMI) Clock Protocol
   4  *
   5  * Copyright (C) 2018 ARM Ltd.
   6  */
   7
   8 #include "common.h"
   9
  10 enum scmi_clock_protocol_cmd {
  11         CLOCK_ATTRIBUTES = 0x3,
  12         CLOCK_DESCRIBE_RATES = 0x4,
  13         CLOCK_RATE_SET = 0x5,
  14         CLOCK_RATE_GET = 0x6,
  15         CLOCK_CONFIG_SET = 0x7,
  16 };
  17
  18 struct scmi_msg_resp_clock_protocol_attributes {
  19         __le16 num_clocks;
  20         u8 max_async_req;
  21         u8 reserved;
  22 };
  23
  24 struct scmi_msg_resp_clock_attributes {
  25         __le32 attributes;
  26 #define CLOCK_ENABLE    BIT(0)
  27             u8 name[SCMI_MAX_STR_SIZE];
  28 };
  29
  30 struct scmi_clock_set_config {
  31         __le32 id;
  32         __le32 attributes;
  33 };
  34
  35 struct scmi_msg_clock_describe_rates {
  36         __le32 id;
  37         __le32 rate_index;
  38 };
  39
  40 struct scmi_msg_resp_clock_describe_rates {
  41         __le32 num_rates_flags;
  42 #define NUM_RETURNED(x)         ((x) & 0xfff)
  43 #define RATE_DISCRETE(x)        !((x) & BIT(12))
  44 #define NUM_REMAINING(x)        ((x) >> 16)
  45         struct {
  46                 __le32 value_low;
  47                 __le32 value_high;
  48         } rate[0];
  49 #define RATE_TO_U64(X)          \
  50 ({                              \
  51         typeof(X) x = (X);      \
  52         le32_to_cpu((x).value_low) | (u64)le32_to_cpu((x).value_high) << 32; \
  53 })
  54 };
  55
  56 struct scmi_clock_set_rate {
  57         __le32 flags;
  58 #define CLOCK_SET_ASYNC         BIT(0)
  59 #define CLOCK_SET_IGNORE_RESP   BIT(1)
  60 #define CLOCK_SET_ROUND_UP      BIT(2)
  61 #define CLOCK_SET_ROUND_AUTO    BIT(3)
  62         __le32 id;
  63         __le32 value_low;
  64         __le32 value_high;
  65 };
  66
  67 struct clock_info {
  68         u32 version;
  69         int num_clocks;
  70         int max_async_req;
  71         atomic_t cur_async_req;
  72         struct scmi_clock_info *clk;
  73 };
  74
  75 static int scmi_clock_protocol_attributes_get(const struct scmi_handle *handle,
  76                                               struct clock_info *ci)
  77 {
  78         int ret;
  79         struct scmi_xfer *t;
  80         struct scmi_msg_resp_clock_protocol_attributes *attr;
  81
  82         ret = scmi_xfer_get_init(handle, PROTOCOL_ATTRIBUTES,
  83                                  SCMI_PROTOCOL_CLOCK, 0, sizeof(*attr), &t);
  84         if (ret)
  85                 return ret;
  86
  87         attr = t->rx.buf;
  88
  89         ret = scmi_do_xfer(handle, t);
  90         if (!ret) {
  91                 ci->num_clocks = le16_to_cpu(attr->num_clocks);
  92                 ci->max_async_req = attr->max_async_req;
  93         }
  94
  95         scmi_xfer_put(handle, t);
  96         return ret;
  97 }
  98
  99 static int scmi_clock_attributes_get(const struct scmi_handle *handle,
 100                                      u32 clk_id, struct scmi_clock_info *clk)
 101 {
 102         int ret;
 103         struct scmi_xfer *t;
 104         struct scmi_msg_resp_clock_attributes *attr;
 105
 106         ret = scmi_xfer_get_init(handle, CLOCK_ATTRIBUTES, SCMI_PROTOCOL_CLOCK,
 107                                  sizeof(clk_id), sizeof(*attr), &t);
 108         if (ret)
 109                 return ret;
 110
 111         put_unaligned_le32(clk_id, t->tx.buf);
 112         attr = t->rx.buf;
 113
 114         ret = scmi_do_xfer(handle, t);
 115         if (!ret)
 116                 strlcpy(clk->name, attr->name, SCMI_MAX_STR_SIZE);
 117         else
 118                 clk->name[0] = '\0';
 119
 120         scmi_xfer_put(handle, t);
 121         return ret;
 122 }
 123
 124 static int
 125 scmi_clock_describe_rates_get(const struct scmi_handle *handle, u32 clk_id,
 126                               struct scmi_clock_info *clk)
 127 {
 128         u64 *rate;
 129         int ret, cnt;
 130         bool rate_discrete = false;
 131         u32 tot_rate_cnt = 0, rates_flag;
 132         u16 num_returned, num_remaining;
 133         struct scmi_xfer *t;
 134         struct scmi_msg_clock_describe_rates *clk_desc;
 135         struct scmi_msg_resp_clock_describe_rates *rlist;
 136
 137         ret = scmi_xfer_get_init(handle, CLOCK_DESCRIBE_RATES,
 138                                  SCMI_PROTOCOL_CLOCK, sizeof(*clk_desc), 0, &t);
 139         if (ret)
 140                 return ret;
 141
 142         clk_desc = t->tx.buf;
 143         rlist = t->rx.buf;
 144
 145         do {
 146                 clk_desc->id = cpu_to_le32(clk_id);
 147                 /* Set the number of rates to be skipped/already read */
 148                 clk_desc->rate_index = cpu_to_le32(tot_rate_cnt);
 149
 150                 ret = scmi_do_xfer(handle, t);
 151                 if (ret)
 152                         goto err;
 153
 154                 rates_flag = le32_to_cpu(rlist->num_rates_flags);
 155                 num_remaining = NUM_REMAINING(rates_flag);
 156                 rate_discrete = RATE_DISCRETE(rates_flag);
 157                 num_returned = NUM_RETURNED(rates_flag);
 158
 159                 if (tot_rate_cnt + num_returned > SCMI_MAX_NUM_RATES) {
 160                         dev_err(handle->dev, "No. of rates > MAX_NUM_RATES");
 161                         break;
 162                 }
 163
 164                 if (!rate_discrete) {
 165                         clk->range.min_rate = RATE_TO_U64(rlist->rate[0]);
 166                         clk->range.max_rate = RATE_TO_U64(rlist->rate[1]);
 167                         clk->range.step_size = RATE_TO_U64(rlist->rate[2]);
 168                         dev_dbg(handle->dev, "Min %llu Max %llu Step %llu Hz\n",
 169                                 clk->range.min_rate, clk->range.max_rate,
 170                                 clk->range.step_size);
 171                         break;
 172                 }
 173
 174                 rate = &clk->list.rates[tot_rate_cnt];
 175                 for (cnt = 0; cnt < num_returned; cnt++, rate++) {
 176                         *rate = RATE_TO_U64(rlist->rate[cnt]);
 177                         dev_dbg(handle->dev, "Rate %llu Hz\n", *rate);
 178                 }
 179
 180                 tot_rate_cnt += num_returned;
 181                 /*
 182                  * check for both returned and remaining to avoid infinite
 183                  * loop due to buggy firmware
 184                  */
 185         } while (num_returned && num_remaining);
 186
 187         if (rate_discrete)
 188                 clk->list.num_rates = tot_rate_cnt;
 189
 190         clk->rate_discrete = rate_discrete;
 191
 192 err:
 193         scmi_xfer_put(handle, t);
 194         return ret;
 195 }
 196
 197 static int
 198 scmi_clock_rate_get(const struct scmi_handle *handle, u32 clk_id, u64 *value)
 199 {
 200         int ret;
 201         struct scmi_xfer *t;
 202
 203         ret = scmi_xfer_get_init(handle, CLOCK_RATE_GET, SCMI_PROTOCOL_CLOCK,
 204                                  sizeof(__le32), sizeof(u64), &t);
 205         if (ret)
 206                 return ret;
 207
 208         put_unaligned_le32(clk_id, t->tx.buf);
 209
 210         ret = scmi_do_xfer(handle, t);
 211         if (!ret)
 212                 *value = get_unaligned_le64(t->rx.buf);
 213
 214         scmi_xfer_put(handle, t);
 215         return ret;
 216 }
 217
 218 static int scmi_clock_rate_set(const struct scmi_handle *handle, u32 clk_id,
 219                                u64 rate)
 220 {
 221         int ret;
 222         u32 flags = 0;
 223         struct scmi_xfer *t;
 224         struct scmi_clock_set_rate *cfg;
 225         struct clock_info *ci = handle->clk_priv;
 226
 227         ret = scmi_xfer_get_init(handle, CLOCK_RATE_SET, SCMI_PROTOCOL_CLOCK,
 228                                  sizeof(*cfg), 0, &t);
 229         if (ret)
 230                 return ret;
 231
 232         if (ci->max_async_req &&
 233             atomic_inc_return(&ci->cur_async_req) < ci->max_async_req)
 234                 flags |= CLOCK_SET_ASYNC;
 235
 236         cfg = t->tx.buf;
 237         cfg->flags = cpu_to_le32(flags);
 238         cfg->id = cpu_to_le32(clk_id);
 239         cfg->value_low = cpu_to_le32(rate & 0xffffffff);
 240         cfg->value_high = cpu_to_le32(rate >> 32);
 241
 242         if (flags & CLOCK_SET_ASYNC)
 243                 ret = scmi_do_xfer_with_response(handle, t);
 244         else
 245                 ret = scmi_do_xfer(handle, t);
 246
 247         if (ci->max_async_req)
 248                 atomic_dec(&ci->cur_async_req);
 249
 250         scmi_xfer_put(handle, t);
 251         return ret;
 252 }
 253
 254 static int
 255 scmi_clock_config_set(const struct scmi_handle *handle, u32 clk_id, u32 config)
 256 {
 257         int ret;
 258         struct scmi_xfer *t;
 259         struct scmi_clock_set_config *cfg;
 260
 261         ret = scmi_xfer_get_init(handle, CLOCK_CONFIG_SET, SCMI_PROTOCOL_CLOCK,
 262                                  sizeof(*cfg), 0, &t);
 263         if (ret)
 264                 return ret;
 265
 266         cfg = t->tx.buf;
 267         cfg->id = cpu_to_le32(clk_id);
 268         cfg->attributes = cpu_to_le32(config);
 269
 270         ret = scmi_do_xfer(handle, t);
 271
 272         scmi_xfer_put(handle, t);
 273         return ret;
 274 }
 275
 276 static int scmi_clock_enable(const struct scmi_handle *handle, u32 clk_id)
 277 {
 278         return scmi_clock_config_set(handle, clk_id, CLOCK_ENABLE);
 279 }
 280
 281 static int scmi_clock_disable(const struct scmi_handle *handle, u32 clk_id)
 282 {
 283         return scmi_clock_config_set(handle, clk_id, 0);
 284 }
 285
 286 static int scmi_clock_count_get(const struct scmi_handle *handle)
 287 {
 288         struct clock_info *ci = handle->clk_priv;
 289
 290         return ci->num_clocks;
 291 }
 292
 293 static const struct scmi_clock_info *
 294 scmi_clock_info_get(const struct scmi_handle *handle, u32 clk_id)
 295 {
 296         struct clock_info *ci = handle->clk_priv;
 297         struct scmi_clock_info *clk = ci->clk + clk_id;
 298
 299         if (!clk->name[0])
 300                 return NULL;
 301
 302         return clk;
 303 }
 304
 305 static struct scmi_clk_ops clk_ops = {
 306         .count_get = scmi_clock_count_get,
 307         .info_get = scmi_clock_info_get,
 308         .rate_get = scmi_clock_rate_get,
 309         .rate_set = scmi_clock_rate_set,
 310         .enable = scmi_clock_enable,
 311         .disable = scmi_clock_disable,
 312 };
 313
 314 static int scmi_clock_protocol_init(struct scmi_handle *handle)
 315 {
 316         u32 version;
 317         int clkid, ret;
 318         struct clock_info *cinfo;
 319
 320         scmi_version_get(handle, SCMI_PROTOCOL_CLOCK, &version);
 321
 322         dev_dbg(handle->dev, "Clock Version %d.%d\n",
 323                 PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
 324
 325         cinfo = devm_kzalloc(handle->dev, sizeof(*cinfo), GFP_KERNEL);
 326         if (!cinfo)
 327                 return -ENOMEM;
 328
 329         scmi_clock_protocol_attributes_get(handle, cinfo);
 330
 331         cinfo->clk = devm_kcalloc(handle->dev, cinfo->num_clocks,
 332                                   sizeof(*cinfo->clk), GFP_KERNEL);
 333         if (!cinfo->clk)
 334                 return -ENOMEM;
 335
 336         for (clkid = 0; clkid < cinfo->num_clocks; clkid++) {
 337                 struct scmi_clock_info *clk = cinfo->clk + clkid;
 338
 339                 ret = scmi_clock_attributes_get(handle, clkid, clk);
 340                 if (!ret)
 341                         scmi_clock_describe_rates_get(handle, clkid, clk);
 342         }
 343
 344         cinfo->version = version;
 345         handle->clk_ops = &clk_ops;
 346         handle->clk_priv = cinfo;
 347
 348         return 0;
 349 }
 350
 351 static int __init scmi_clock_init(void)
 352 {
 353         return scmi_protocol_register(SCMI_PROTOCOL_CLOCK,
 354                                       &scmi_clock_protocol_init);
 355 }
 356 subsys_initcall(scmi_clock_init);