LXR linux/drivers/misc/mei/init.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
   4 * Intel Management Engine Interface (Intel MEI) Linux driver
   5 */
   6
   7#include <linux/export.h>
   8#include <linux/sched.h>
   9#include <linux/wait.h>
  10#include <linux/delay.h>
  11
  12#include <linux/mei.h>
  13
  14#include "mei_dev.h"
  15#include "hbm.h"
  16#include "client.h"
  17
  18const char *mei_dev_state_str(int state)
  19{
  20#define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
  21        switch (state) {
  22        MEI_DEV_STATE(INITIALIZING);
  23        MEI_DEV_STATE(INIT_CLIENTS);
  24        MEI_DEV_STATE(ENABLED);
  25        MEI_DEV_STATE(RESETTING);
  26        MEI_DEV_STATE(DISABLED);
  27        MEI_DEV_STATE(POWER_DOWN);
  28        MEI_DEV_STATE(POWER_UP);
  29        default:
  30                return "unknown";
  31        }
  32#undef MEI_DEV_STATE
  33}
  34
  35const char *mei_pg_state_str(enum mei_pg_state state)
  36{
  37#define MEI_PG_STATE(state) case MEI_PG_##state: return #state
  38        switch (state) {
  39        MEI_PG_STATE(OFF);
  40        MEI_PG_STATE(ON);
  41        default:
  42                return "unknown";
  43        }
  44#undef MEI_PG_STATE
  45}
  46
  47/**
  48 * mei_fw_status2str - convert fw status registers to printable string
  49 *
  50 * @fw_status:  firmware status
  51 * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
  52 * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
  53 *
  54 * Return: number of bytes written or -EINVAL if buffer is to small
  55 */
  56ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
  57                          char *buf, size_t len)
  58{
  59        ssize_t cnt = 0;
  60        int i;
  61
  62        buf[0] = '\0';
  63
  64        if (len < MEI_FW_STATUS_STR_SZ)
  65                return -EINVAL;
  66
  67        for (i = 0; i < fw_status->count; i++)
  68                cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
  69                                fw_status->status[i]);
  70
  71        /* drop last space */
  72        buf[cnt] = '\0';
  73        return cnt;
  74}
  75EXPORT_SYMBOL_GPL(mei_fw_status2str);
  76
  77/**
  78 * mei_cancel_work - Cancel mei background jobs
  79 *
  80 * @dev: the device structure
  81 */
  82void mei_cancel_work(struct mei_device *dev)
  83{
  84        cancel_work_sync(&dev->reset_work);
  85        cancel_work_sync(&dev->bus_rescan_work);
  86
  87        cancel_delayed_work_sync(&dev->timer_work);
  88}
  89EXPORT_SYMBOL_GPL(mei_cancel_work);
  90
  91/**
  92 * mei_reset - resets host and fw.
  93 *
  94 * @dev: the device structure
  95 *
  96 * Return: 0 on success or < 0 if the reset hasn't succeeded
  97 */
  98int mei_reset(struct mei_device *dev)
  99{
 100        enum mei_dev_state state = dev->dev_state;
 101        bool interrupts_enabled;
 102        int ret;
 103
 104        if (state != MEI_DEV_INITIALIZING &&
 105            state != MEI_DEV_DISABLED &&
 106            state != MEI_DEV_POWER_DOWN &&
 107            state != MEI_DEV_POWER_UP) {
 108                char fw_sts_str[MEI_FW_STATUS_STR_SZ];
 109
 110                mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
 111                dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
 112                         mei_dev_state_str(state), fw_sts_str);
 113        }
 114
 115        mei_clear_interrupts(dev);
 116
 117        /* we're already in reset, cancel the init timer
 118         * if the reset was called due the hbm protocol error
 119         * we need to call it before hw start
 120         * so the hbm watchdog won't kick in
 121         */
 122        mei_hbm_idle(dev);
 123
 124        /* enter reset flow */
 125        interrupts_enabled = state != MEI_DEV_POWER_DOWN;
 126        mei_set_devstate(dev, MEI_DEV_RESETTING);
 127
 128        dev->reset_count++;
 129        if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
 130                dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
 131                mei_set_devstate(dev, MEI_DEV_DISABLED);
 132                return -ENODEV;
 133        }
 134
 135        ret = mei_hw_reset(dev, interrupts_enabled);
 136        /* fall through and remove the sw state even if hw reset has failed */
 137
 138        /* no need to clean up software state in case of power up */
 139        if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
 140                mei_cl_all_disconnect(dev);
 141
 142        mei_hbm_reset(dev);
 143
 144        memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
 145
 146        if (ret) {
 147                dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
 148                return ret;
 149        }
 150
 151        if (state == MEI_DEV_POWER_DOWN) {
 152                dev_dbg(dev->dev, "powering down: end of reset\n");
 153                mei_set_devstate(dev, MEI_DEV_DISABLED);
 154                return 0;
 155        }
 156
 157        ret = mei_hw_start(dev);
 158        if (ret) {
 159                dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
 160                return ret;
 161        }
 162
 163        dev_dbg(dev->dev, "link is established start sending messages.\n");
 164
 165        mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
 166        ret = mei_hbm_start_req(dev);
 167        if (ret) {
 168                dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
 169                mei_set_devstate(dev, MEI_DEV_RESETTING);
 170                return ret;
 171        }
 172
 173        return 0;
 174}
 175EXPORT_SYMBOL_GPL(mei_reset);
 176
 177/**
 178 * mei_start - initializes host and fw to start work.
 179 *
 180 * @dev: the device structure
 181 *
 182 * Return: 0 on success, <0 on failure.
 183 */
 184int mei_start(struct mei_device *dev)
 185{
 186        int ret;
 187
 188        mutex_lock(&dev->device_lock);
 189
 190        /* acknowledge interrupt and stop interrupts */
 191        mei_clear_interrupts(dev);
 192
 193        ret = mei_hw_config(dev);
 194        if (ret)
 195                goto err;
 196
 197        dev_dbg(dev->dev, "reset in start the mei device.\n");
 198
 199        dev->reset_count = 0;
 200        do {
 201                mei_set_devstate(dev, MEI_DEV_INITIALIZING);
 202                ret = mei_reset(dev);
 203
 204                if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 205                        dev_err(dev->dev, "reset failed ret = %d", ret);
 206                        goto err;
 207                }
 208        } while (ret);
 209
 210        if (mei_hbm_start_wait(dev)) {
 211                dev_err(dev->dev, "HBM haven't started");
 212                goto err;
 213        }
 214
 215        if (!mei_host_is_ready(dev)) {
 216                dev_err(dev->dev, "host is not ready.\n");
 217                goto err;
 218        }
 219
 220        if (!mei_hw_is_ready(dev)) {
 221                dev_err(dev->dev, "ME is not ready.\n");
 222                goto err;
 223        }
 224
 225        if (!mei_hbm_version_is_supported(dev)) {
 226                dev_dbg(dev->dev, "MEI start failed.\n");
 227                goto err;
 228        }
 229
 230        dev_dbg(dev->dev, "link layer has been established.\n");
 231
 232        mutex_unlock(&dev->device_lock);
 233        return 0;
 234err:
 235        dev_err(dev->dev, "link layer initialization failed.\n");
 236        mei_set_devstate(dev, MEI_DEV_DISABLED);
 237        mutex_unlock(&dev->device_lock);
 238        return -ENODEV;
 239}
 240EXPORT_SYMBOL_GPL(mei_start);
 241
 242/**
 243 * mei_restart - restart device after suspend
 244 *
 245 * @dev: the device structure
 246 *
 247 * Return: 0 on success or -ENODEV if the restart hasn't succeeded
 248 */
 249int mei_restart(struct mei_device *dev)
 250{
 251        int err;
 252
 253        mutex_lock(&dev->device_lock);
 254
 255        mei_set_devstate(dev, MEI_DEV_POWER_UP);
 256        dev->reset_count = 0;
 257
 258        err = mei_reset(dev);
 259
 260        mutex_unlock(&dev->device_lock);
 261
 262        if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
 263                dev_err(dev->dev, "device disabled = %d\n", err);
 264                return -ENODEV;
 265        }
 266
 267        /* try to start again */
 268        if (err)
 269                schedule_work(&dev->reset_work);
 270
 271
 272        return 0;
 273}
 274EXPORT_SYMBOL_GPL(mei_restart);
 275
 276static void mei_reset_work(struct work_struct *work)
 277{
 278        struct mei_device *dev =
 279                container_of(work, struct mei_device,  reset_work);
 280        int ret;
 281
 282        mei_clear_interrupts(dev);
 283        mei_synchronize_irq(dev);
 284
 285        mutex_lock(&dev->device_lock);
 286
 287        ret = mei_reset(dev);
 288
 289        mutex_unlock(&dev->device_lock);
 290
 291        if (dev->dev_state == MEI_DEV_DISABLED) {
 292                dev_err(dev->dev, "device disabled = %d\n", ret);
 293                return;
 294        }
 295
 296        /* retry reset in case of failure */
 297        if (ret)
 298                schedule_work(&dev->reset_work);
 299}
 300
 301void mei_stop(struct mei_device *dev)
 302{
 303        dev_dbg(dev->dev, "stopping the device.\n");
 304
 305        mutex_lock(&dev->device_lock);
 306        mei_set_devstate(dev, MEI_DEV_POWERING_DOWN);
 307        mutex_unlock(&dev->device_lock);
 308        mei_cl_bus_remove_devices(dev);
 309        mutex_lock(&dev->device_lock);
 310        mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
 311        mutex_unlock(&dev->device_lock);
 312
 313        mei_cancel_work(dev);
 314
 315        mei_clear_interrupts(dev);
 316        mei_synchronize_irq(dev);
 317
 318        mutex_lock(&dev->device_lock);
 319
 320        mei_reset(dev);
 321        /* move device to disabled state unconditionally */
 322        mei_set_devstate(dev, MEI_DEV_DISABLED);
 323
 324        mutex_unlock(&dev->device_lock);
 325}
 326EXPORT_SYMBOL_GPL(mei_stop);
 327
 328/**
 329 * mei_write_is_idle - check if the write queues are idle
 330 *
 331 * @dev: the device structure
 332 *
 333 * Return: true of there is no pending write
 334 */
 335bool mei_write_is_idle(struct mei_device *dev)
 336{
 337        bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
 338                list_empty(&dev->ctrl_wr_list) &&
 339                list_empty(&dev->write_list)   &&
 340                list_empty(&dev->write_waiting_list));
 341
 342        dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
 343                idle,
 344                mei_dev_state_str(dev->dev_state),
 345                list_empty(&dev->ctrl_wr_list),
 346                list_empty(&dev->write_list),
 347                list_empty(&dev->write_waiting_list));
 348
 349        return idle;
 350}
 351EXPORT_SYMBOL_GPL(mei_write_is_idle);
 352
 353/**
 354 * mei_device_init  -- initialize mei_device structure
 355 *
 356 * @dev: the mei device
 357 * @device: the device structure
 358 * @hw_ops: hw operations
 359 */
 360void mei_device_init(struct mei_device *dev,
 361                     struct device *device,
 362                     const struct mei_hw_ops *hw_ops)
 363{
 364        /* setup our list array */
 365        INIT_LIST_HEAD(&dev->file_list);
 366        INIT_LIST_HEAD(&dev->device_list);
 367        INIT_LIST_HEAD(&dev->me_clients);
 368        mutex_init(&dev->device_lock);
 369        init_rwsem(&dev->me_clients_rwsem);
 370        mutex_init(&dev->cl_bus_lock);
 371        init_waitqueue_head(&dev->wait_hw_ready);
 372        init_waitqueue_head(&dev->wait_pg);
 373        init_waitqueue_head(&dev->wait_hbm_start);
 374        dev->dev_state = MEI_DEV_INITIALIZING;
 375        dev->reset_count = 0;
 376
 377        INIT_LIST_HEAD(&dev->write_list);
 378        INIT_LIST_HEAD(&dev->write_waiting_list);
 379        INIT_LIST_HEAD(&dev->ctrl_wr_list);
 380        INIT_LIST_HEAD(&dev->ctrl_rd_list);
 381        dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;
 382
 383        INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
 384        INIT_WORK(&dev->reset_work, mei_reset_work);
 385        INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
 386
 387        bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
 388        dev->open_handle_count = 0;
 389
 390        /*
 391         * Reserving the first client ID
 392         * 0: Reserved for MEI Bus Message communications
 393         */
 394        bitmap_set(dev->host_clients_map, 0, 1);
 395
 396        dev->pg_event = MEI_PG_EVENT_IDLE;
 397        dev->ops      = hw_ops;
 398        dev->dev      = device;
 399}
 400EXPORT_SYMBOL_GPL(mei_device_init);
 401
 402