drivers/soc/ti/wkup_m3_ipc.c

   1 /*
   2  * AMx3 Wkup M3 IPC driver
   3  *
   4  * Copyright (C) 2015 Texas Instruments, Inc.
   5  *
   6  * Dave Gerlach <d-gerlach@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kthread.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/irq.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/omap-mailbox.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/remoteproc.h>
  28 #include <linux/suspend.h>
  29 #include <linux/wkup_m3_ipc.h>
  30
  31 #define AM33XX_CTRL_IPC_REG_COUNT       0x8
  32 #define AM33XX_CTRL_IPC_REG_OFFSET(m)   (0x4 + 4 * (m))
  33
  34 /* AM33XX M3_TXEV_EOI register */
  35 #define AM33XX_CONTROL_M3_TXEV_EOI      0x00
  36
  37 #define AM33XX_M3_TXEV_ACK              (0x1 << 0)
  38 #define AM33XX_M3_TXEV_ENABLE           (0x0 << 0)
  39
  40 #define IPC_CMD_DS0                     0x4
  41 #define IPC_CMD_STANDBY                 0xc
  42 #define IPC_CMD_IDLE                    0x10
  43 #define IPC_CMD_RESET                   0xe
  44 #define DS_IPC_DEFAULT                  0xffffffff
  45 #define M3_VERSION_UNKNOWN              0x0000ffff
  46 #define M3_BASELINE_VERSION             0x191
  47 #define M3_STATUS_RESP_MASK             (0xffff << 16)
  48 #define M3_FW_VERSION_MASK              0xffff
  49
  50 #define M3_STATE_UNKNOWN                0
  51 #define M3_STATE_RESET                  1
  52 #define M3_STATE_INITED                 2
  53 #define M3_STATE_MSG_FOR_LP             3
  54 #define M3_STATE_MSG_FOR_RESET          4
  55
  56 static struct wkup_m3_ipc *m3_ipc_state;
  57
  58 static void am33xx_txev_eoi(struct wkup_m3_ipc *m3_ipc)
  59 {
  60         writel(AM33XX_M3_TXEV_ACK,
  61                m3_ipc->ipc_mem_base + AM33XX_CONTROL_M3_TXEV_EOI);
  62 }
  63
  64 static void am33xx_txev_enable(struct wkup_m3_ipc *m3_ipc)
  65 {
  66         writel(AM33XX_M3_TXEV_ENABLE,
  67                m3_ipc->ipc_mem_base + AM33XX_CONTROL_M3_TXEV_EOI);
  68 }
  69
  70 static void wkup_m3_ctrl_ipc_write(struct wkup_m3_ipc *m3_ipc,
  71                                    u32 val, int ipc_reg_num)
  72 {
  73         if (WARN(ipc_reg_num < 0 || ipc_reg_num > AM33XX_CTRL_IPC_REG_COUNT,
  74                  "ipc register operation out of range"))
  75                 return;
  76
  77         writel(val, m3_ipc->ipc_mem_base +
  78                AM33XX_CTRL_IPC_REG_OFFSET(ipc_reg_num));
  79 }
  80
  81 static unsigned int wkup_m3_ctrl_ipc_read(struct wkup_m3_ipc *m3_ipc,
  82                                           int ipc_reg_num)
  83 {
  84         if (WARN(ipc_reg_num < 0 || ipc_reg_num > AM33XX_CTRL_IPC_REG_COUNT,
  85                  "ipc register operation out of range"))
  86                 return 0;
  87
  88         return readl(m3_ipc->ipc_mem_base +
  89                      AM33XX_CTRL_IPC_REG_OFFSET(ipc_reg_num));
  90 }
  91
  92 static int wkup_m3_fw_version_read(struct wkup_m3_ipc *m3_ipc)
  93 {
  94         int val;
  95
  96         val = wkup_m3_ctrl_ipc_read(m3_ipc, 2);
  97
  98         return val & M3_FW_VERSION_MASK;
  99 }
 100
 101 static irqreturn_t wkup_m3_txev_handler(int irq, void *ipc_data)
 102 {
 103         struct wkup_m3_ipc *m3_ipc = ipc_data;
 104         struct device *dev = m3_ipc->dev;
 105         int ver = 0;
 106
 107         am33xx_txev_eoi(m3_ipc);
 108
 109         switch (m3_ipc->state) {
 110         case M3_STATE_RESET:
 111                 ver = wkup_m3_fw_version_read(m3_ipc);
 112
 113                 if (ver == M3_VERSION_UNKNOWN ||
 114                     ver < M3_BASELINE_VERSION) {
 115                         dev_warn(dev, "CM3 Firmware Version %x not supported\n",
 116                                  ver);
 117                 } else {
 118                         dev_info(dev, "CM3 Firmware Version = 0x%x\n", ver);
 119                 }
 120
 121                 m3_ipc->state = M3_STATE_INITED;
 122                 complete(&m3_ipc->sync_complete);
 123                 break;
 124         case M3_STATE_MSG_FOR_RESET:
 125                 m3_ipc->state = M3_STATE_INITED;
 126                 complete(&m3_ipc->sync_complete);
 127                 break;
 128         case M3_STATE_MSG_FOR_LP:
 129                 complete(&m3_ipc->sync_complete);
 130                 break;
 131         case M3_STATE_UNKNOWN:
 132                 dev_warn(dev, "Unknown CM3 State\n");
 133         }
 134
 135         am33xx_txev_enable(m3_ipc);
 136
 137         return IRQ_HANDLED;
 138 }
 139
 140 static int wkup_m3_ping(struct wkup_m3_ipc *m3_ipc)
 141 {
 142         struct device *dev = m3_ipc->dev;
 143         mbox_msg_t dummy_msg = 0;
 144         int ret;
 145
 146         if (!m3_ipc->mbox) {
 147                 dev_err(dev,
 148                         "No IPC channel to communicate with wkup_m3!\n");
 149                 return -EIO;
 150         }
 151
 152         /*
 153          * Write a dummy message to the mailbox in order to trigger the RX
 154          * interrupt to alert the M3 that data is available in the IPC
 155          * registers. We must enable the IRQ here and disable it after in
 156          * the RX callback to avoid multiple interrupts being received
 157          * by the CM3.
 158          */
 159         ret = mbox_send_message(m3_ipc->mbox, &dummy_msg);
 160         if (ret < 0) {
 161                 dev_err(dev, "%s: mbox_send_message() failed: %d\n",
 162                         __func__, ret);
 163                 return ret;
 164         }
 165
 166         ret = wait_for_completion_timeout(&m3_ipc->sync_complete,
 167                                           msecs_to_jiffies(500));
 168         if (!ret) {
 169                 dev_err(dev, "MPU<->CM3 sync failure\n");
 170                 m3_ipc->state = M3_STATE_UNKNOWN;
 171                 return -EIO;
 172         }
 173
 174         mbox_client_txdone(m3_ipc->mbox, 0);
 175         return 0;
 176 }
 177
 178 static int wkup_m3_ping_noirq(struct wkup_m3_ipc *m3_ipc)
 179 {
 180         struct device *dev = m3_ipc->dev;
 181         mbox_msg_t dummy_msg = 0;
 182         int ret;
 183
 184         if (!m3_ipc->mbox) {
 185                 dev_err(dev,
 186                         "No IPC channel to communicate with wkup_m3!\n");
 187                 return -EIO;
 188         }
 189
 190         ret = mbox_send_message(m3_ipc->mbox, &dummy_msg);
 191         if (ret < 0) {
 192                 dev_err(dev, "%s: mbox_send_message() failed: %d\n",
 193                         __func__, ret);
 194                 return ret;
 195         }
 196
 197         mbox_client_txdone(m3_ipc->mbox, 0);
 198         return 0;
 199 }
 200
 201 static int wkup_m3_is_available(struct wkup_m3_ipc *m3_ipc)
 202 {
 203         return ((m3_ipc->state != M3_STATE_RESET) &&
 204                 (m3_ipc->state != M3_STATE_UNKNOWN));
 205 }
 206
 207 /* Public functions */
 208 /**
 209  * wkup_m3_set_mem_type - Pass wkup_m3 which type of memory is in use
 210  * @mem_type: memory type value read directly from emif
 211  *
 212  * wkup_m3 must know what memory type is in use to properly suspend
 213  * and resume.
 214  */
 215 static void wkup_m3_set_mem_type(struct wkup_m3_ipc *m3_ipc, int mem_type)
 216 {
 217         m3_ipc->mem_type = mem_type;
 218 }
 219
 220 /**
 221  * wkup_m3_set_resume_address - Pass wkup_m3 resume address
 222  * @addr: Physical address from which resume code should execute
 223  */
 224 static void wkup_m3_set_resume_address(struct wkup_m3_ipc *m3_ipc, void *addr)
 225 {
 226         m3_ipc->resume_addr = (unsigned long)addr;
 227 }
 228
 229 /**
 230  * wkup_m3_request_pm_status - Retrieve wkup_m3 status code after suspend
 231  *
 232  * Returns code representing the status of a low power mode transition.
 233  *      0 - Successful transition
 234  *      1 - Failure to transition to low power state
 235  */
 236 static int wkup_m3_request_pm_status(struct wkup_m3_ipc *m3_ipc)
 237 {
 238         unsigned int i;
 239         int val;
 240
 241         val = wkup_m3_ctrl_ipc_read(m3_ipc, 1);
 242
 243         i = M3_STATUS_RESP_MASK & val;
 244         i >>= __ffs(M3_STATUS_RESP_MASK);
 245
 246         return i;
 247 }
 248
 249 /**
 250  * wkup_m3_prepare_low_power - Request preparation for transition to
 251  *                             low power state
 252  * @state: A kernel suspend state to enter, either MEM or STANDBY
 253  *
 254  * Returns 0 if preparation was successful, otherwise returns error code
 255  */
 256 static int wkup_m3_prepare_low_power(struct wkup_m3_ipc *m3_ipc, int state)
 257 {
 258         struct device *dev = m3_ipc->dev;
 259         int m3_power_state;
 260         int ret = 0;
 261
 262         if (!wkup_m3_is_available(m3_ipc))
 263                 return -ENODEV;
 264
 265         switch (state) {
 266         case WKUP_M3_DEEPSLEEP:
 267                 m3_power_state = IPC_CMD_DS0;
 268                 break;
 269         case WKUP_M3_STANDBY:
 270                 m3_power_state = IPC_CMD_STANDBY;
 271                 break;
 272         case WKUP_M3_IDLE:
 273                 m3_power_state = IPC_CMD_IDLE;
 274                 break;
 275         default:
 276                 return 1;
 277         }
 278
 279         /* Program each required IPC register then write defaults to others */
 280         wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->resume_addr, 0);
 281         wkup_m3_ctrl_ipc_write(m3_ipc, m3_power_state, 1);
 282         wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->mem_type, 4);
 283
 284         wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 2);
 285         wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 3);
 286         wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 5);
 287         wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 6);
 288         wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 7);
 289
 290         m3_ipc->state = M3_STATE_MSG_FOR_LP;
 291
 292         if (state == WKUP_M3_IDLE)
 293                 ret = wkup_m3_ping_noirq(m3_ipc);
 294         else
 295                 ret = wkup_m3_ping(m3_ipc);
 296
 297         if (ret) {
 298                 dev_err(dev, "Unable to ping CM3\n");
 299                 return ret;
 300         }
 301
 302         return 0;
 303 }
 304
 305 /**
 306  * wkup_m3_finish_low_power - Return m3 to reset state
 307  *
 308  * Returns 0 if reset was successful, otherwise returns error code
 309  */
 310 static int wkup_m3_finish_low_power(struct wkup_m3_ipc *m3_ipc)
 311 {
 312         struct device *dev = m3_ipc->dev;
 313         int ret = 0;
 314
 315         if (!wkup_m3_is_available(m3_ipc))
 316                 return -ENODEV;
 317
 318         wkup_m3_ctrl_ipc_write(m3_ipc, IPC_CMD_RESET, 1);
 319         wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 2);
 320
 321         m3_ipc->state = M3_STATE_MSG_FOR_RESET;
 322
 323         ret = wkup_m3_ping(m3_ipc);
 324         if (ret) {
 325                 dev_err(dev, "Unable to ping CM3\n");
 326                 return ret;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static struct wkup_m3_ipc_ops ipc_ops = {
 333         .set_mem_type = wkup_m3_set_mem_type,
 334         .set_resume_address = wkup_m3_set_resume_address,
 335         .prepare_low_power = wkup_m3_prepare_low_power,
 336         .finish_low_power = wkup_m3_finish_low_power,
 337         .request_pm_status = wkup_m3_request_pm_status,
 338 };
 339
 340 /**
 341  * wkup_m3_ipc_get - Return handle to wkup_m3_ipc
 342  *
 343  * Returns NULL if the wkup_m3 is not yet available, otherwise returns
 344  * pointer to wkup_m3_ipc struct.
 345  */
 346 struct wkup_m3_ipc *wkup_m3_ipc_get(void)
 347 {
 348         if (m3_ipc_state)
 349                 get_device(m3_ipc_state->dev);
 350         else
 351                 return NULL;
 352
 353         return m3_ipc_state;
 354 }
 355 EXPORT_SYMBOL_GPL(wkup_m3_ipc_get);
 356
 357 /**
 358  * wkup_m3_ipc_put - Free handle to wkup_m3_ipc returned from wkup_m3_ipc_get
 359  * @m3_ipc: A pointer to wkup_m3_ipc struct returned by wkup_m3_ipc_get
 360  */
 361 void wkup_m3_ipc_put(struct wkup_m3_ipc *m3_ipc)
 362 {
 363         if (m3_ipc_state)
 364                 put_device(m3_ipc_state->dev);
 365 }
 366 EXPORT_SYMBOL_GPL(wkup_m3_ipc_put);
 367
 368 static void wkup_m3_rproc_boot_thread(struct wkup_m3_ipc *m3_ipc)
 369 {
 370         struct device *dev = m3_ipc->dev;
 371         int ret;
 372
 373         init_completion(&m3_ipc->sync_complete);
 374
 375         ret = rproc_boot(m3_ipc->rproc);
 376         if (ret)
 377                 dev_err(dev, "rproc_boot failed\n");
 378
 379         do_exit(0);
 380 }
 381
 382 static int wkup_m3_ipc_probe(struct platform_device *pdev)
 383 {
 384         struct device *dev = &pdev->dev;
 385         int irq, ret;
 386         phandle rproc_phandle;
 387         struct rproc *m3_rproc;
 388         struct resource *res;
 389         struct task_struct *task;
 390         struct wkup_m3_ipc *m3_ipc;
 391
 392         m3_ipc = devm_kzalloc(dev, sizeof(*m3_ipc), GFP_KERNEL);
 393         if (!m3_ipc)
 394                 return -ENOMEM;
 395
 396         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 397         m3_ipc->ipc_mem_base = devm_ioremap_resource(dev, res);
 398         if (IS_ERR(m3_ipc->ipc_mem_base)) {
 399                 dev_err(dev, "could not ioremap ipc_mem\n");
 400                 return PTR_ERR(m3_ipc->ipc_mem_base);
 401         }
 402
 403         irq = platform_get_irq(pdev, 0);
 404         if (!irq) {
 405                 dev_err(&pdev->dev, "no irq resource\n");
 406                 return -ENXIO;
 407         }
 408
 409         ret = devm_request_irq(dev, irq, wkup_m3_txev_handler,
 410                                0, "wkup_m3_txev", m3_ipc);
 411         if (ret) {
 412                 dev_err(dev, "request_irq failed\n");
 413                 return ret;
 414         }
 415
 416         m3_ipc->mbox_client.dev = dev;
 417         m3_ipc->mbox_client.tx_done = NULL;
 418         m3_ipc->mbox_client.tx_prepare = NULL;
 419         m3_ipc->mbox_client.rx_callback = NULL;
 420         m3_ipc->mbox_client.tx_block = false;
 421         m3_ipc->mbox_client.knows_txdone = false;
 422
 423         m3_ipc->mbox = mbox_request_channel(&m3_ipc->mbox_client, 0);
 424
 425         if (IS_ERR(m3_ipc->mbox)) {
 426                 dev_err(dev, "IPC Request for A8->M3 Channel failed! %ld\n",
 427                         PTR_ERR(m3_ipc->mbox));
 428                 return PTR_ERR(m3_ipc->mbox);
 429         }
 430
 431         if (of_property_read_u32(dev->of_node, "ti,rproc", &rproc_phandle)) {
 432                 dev_err(&pdev->dev, "could not get rproc phandle\n");
 433                 ret = -ENODEV;
 434                 goto err_free_mbox;
 435         }
 436
 437         m3_rproc = rproc_get_by_phandle(rproc_phandle);
 438         if (!m3_rproc) {
 439                 dev_err(&pdev->dev, "could not get rproc handle\n");
 440                 ret = -EPROBE_DEFER;
 441                 goto err_free_mbox;
 442         }
 443
 444         m3_ipc->rproc = m3_rproc;
 445         m3_ipc->dev = dev;
 446         m3_ipc->state = M3_STATE_RESET;
 447
 448         m3_ipc->ops = &ipc_ops;
 449
 450         /*
 451          * Wait for firmware loading completion in a thread so we
 452          * can boot the wkup_m3 as soon as it's ready without holding
 453          * up kernel boot
 454          */
 455         task = kthread_run((void *)wkup_m3_rproc_boot_thread, m3_ipc,
 456                            "wkup_m3_rproc_loader");
 457
 458         if (IS_ERR(task)) {
 459                 dev_err(dev, "can't create rproc_boot thread\n");
 460                 ret = PTR_ERR(task);
 461                 goto err_put_rproc;
 462         }
 463
 464         m3_ipc_state = m3_ipc;
 465
 466         return 0;
 467
 468 err_put_rproc:
 469         rproc_put(m3_rproc);
 470 err_free_mbox:
 471         mbox_free_channel(m3_ipc->mbox);
 472         return ret;
 473 }
 474
 475 static int wkup_m3_ipc_remove(struct platform_device *pdev)
 476 {
 477         mbox_free_channel(m3_ipc_state->mbox);
 478
 479         rproc_shutdown(m3_ipc_state->rproc);
 480         rproc_put(m3_ipc_state->rproc);
 481
 482         m3_ipc_state = NULL;
 483
 484         return 0;
 485 }
 486
 487 static const struct of_device_id wkup_m3_ipc_of_match[] = {
 488         { .compatible = "ti,am3352-wkup-m3-ipc", },
 489         { .compatible = "ti,am4372-wkup-m3-ipc", },
 490         {},
 491 };
 492 MODULE_DEVICE_TABLE(of, wkup_m3_ipc_of_match);
 493
 494 static struct platform_driver wkup_m3_ipc_driver = {
 495         .probe = wkup_m3_ipc_probe,
 496         .remove = wkup_m3_ipc_remove,
 497         .driver = {
 498                 .name = "wkup_m3_ipc",
 499                 .of_match_table = wkup_m3_ipc_of_match,
 500         },
 501 };
 502
 503 module_platform_driver(wkup_m3_ipc_driver);
 504
 505 MODULE_LICENSE("GPL v2");
 506 MODULE_DESCRIPTION("wkup m3 remote processor ipc driver");
 507 MODULE_AUTHOR("Dave Gerlach <d-gerlach@ti.com>");