drivers/firmware/arm_scmi/driver.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
scmi_to_linux_errno
scmi_dump_header_dbg
scmi_fetch_response
pack_scmi_header
unpack_scmi_header
scmi_tx_prepare
scmi_xfer_get
__scmi_xfer_put
scmi_rx_callback
scmi_xfer_put
scmi_xfer_poll_done
scmi_xfer_done_no_timeout
scmi_do_xfer
scmi_do_xfer_with_response
scmi_xfer_get_init
scmi_version_get
scmi_setup_protocol_implemented
scmi_is_protocol_implemented
scmi_handle_get
scmi_handle_put
scmi_xfer_info_init
scmi_mailbox_check
scmi_mbox_chan_setup
scmi_mbox_txrx_setup
scmi_create_protocol_device
scmi_probe
scmi_mbox_free_channel
scmi_remove
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * System Control and Management Interface (SCMI) Message Protocol driver
   4  *
   5  * SCMI Message Protocol is used between the System Control Processor(SCP)
   6  * and the Application Processors(AP). The Message Handling Unit(MHU)
   7  * provides a mechanism for inter-processor communication between SCP's
   8  * Cortex M3 and AP.
   9  *
  10  * SCP offers control and management of the core/cluster power states,
  11  * various power domain DVFS including the core/cluster, certain system
  12  * clocks configuration, thermal sensors and many others.
  13  *
  14  * Copyright (C) 2018 ARM Ltd.
  15  */
  16 
  17 #include <linux/bitmap.h>
  18 #include <linux/export.h>
  19 #include <linux/io.h>
  20 #include <linux/kernel.h>
  21 #include <linux/ktime.h>
  22 #include <linux/mailbox_client.h>
  23 #include <linux/module.h>
  24 #include <linux/of_address.h>
  25 #include <linux/of_device.h>
  26 #include <linux/processor.h>
  27 #include <linux/semaphore.h>
  28 #include <linux/slab.h>
  29 
  30 #include "common.h"
  31 
  32 #define MSG_ID_MASK             GENMASK(7, 0)
  33 #define MSG_XTRACT_ID(hdr)      FIELD_GET(MSG_ID_MASK, (hdr))
  34 #define MSG_TYPE_MASK           GENMASK(9, 8)
  35 #define MSG_XTRACT_TYPE(hdr)    FIELD_GET(MSG_TYPE_MASK, (hdr))
  36 #define MSG_TYPE_COMMAND        0
  37 #define MSG_TYPE_DELAYED_RESP   2
  38 #define MSG_TYPE_NOTIFICATION   3
  39 #define MSG_PROTOCOL_ID_MASK    GENMASK(17, 10)
  40 #define MSG_XTRACT_PROT_ID(hdr) FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
  41 #define MSG_TOKEN_ID_MASK       GENMASK(27, 18)
  42 #define MSG_XTRACT_TOKEN(hdr)   FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
  43 #define MSG_TOKEN_MAX           (MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
  44 
  45 enum scmi_error_codes {
  46         SCMI_SUCCESS = 0,       /* Success */
  47         SCMI_ERR_SUPPORT = -1,  /* Not supported */
  48         SCMI_ERR_PARAMS = -2,   /* Invalid Parameters */
  49         SCMI_ERR_ACCESS = -3,   /* Invalid access/permission denied */
  50         SCMI_ERR_ENTRY = -4,    /* Not found */
  51         SCMI_ERR_RANGE = -5,    /* Value out of range */
  52         SCMI_ERR_BUSY = -6,     /* Device busy */
  53         SCMI_ERR_COMMS = -7,    /* Communication Error */
  54         SCMI_ERR_GENERIC = -8,  /* Generic Error */
  55         SCMI_ERR_HARDWARE = -9, /* Hardware Error */
  56         SCMI_ERR_PROTOCOL = -10,/* Protocol Error */
  57         SCMI_ERR_MAX
  58 };
  59 
  60 /* List of all SCMI devices active in system */
  61 static LIST_HEAD(scmi_list);
  62 /* Protection for the entire list */
  63 static DEFINE_MUTEX(scmi_list_mutex);
  64 
  65 /**
  66  * struct scmi_xfers_info - Structure to manage transfer information
  67  *
  68  * @xfer_block: Preallocated Message array
  69  * @xfer_alloc_table: Bitmap table for allocated messages.
  70  *      Index of this bitmap table is also used for message
  71  *      sequence identifier.
  72  * @xfer_lock: Protection for message allocation
  73  */
  74 struct scmi_xfers_info {
  75         struct scmi_xfer *xfer_block;
  76         unsigned long *xfer_alloc_table;
  77         spinlock_t xfer_lock;
  78 };
  79 
  80 /**
  81  * struct scmi_desc - Description of SoC integration
  82  *
  83  * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
  84  * @max_msg: Maximum number of messages that can be pending
  85  *      simultaneously in the system
  86  * @max_msg_size: Maximum size of data per message that can be handled.
  87  */
  88 struct scmi_desc {
  89         int max_rx_timeout_ms;
  90         int max_msg;
  91         int max_msg_size;
  92 };
  93 
  94 /**
  95  * struct scmi_chan_info - Structure representing a SCMI channel information
  96  *
  97  * @cl: Mailbox Client
  98  * @chan: Transmit/Receive mailbox channel
  99  * @payload: Transmit/Receive mailbox channel payload area
 100  * @dev: Reference to device in the SCMI hierarchy corresponding to this
 101  *       channel
 102  * @handle: Pointer to SCMI entity handle
 103  */
 104 struct scmi_chan_info {
 105         struct mbox_client cl;
 106         struct mbox_chan *chan;
 107         void __iomem *payload;
 108         struct device *dev;
 109         struct scmi_handle *handle;
 110 };
 111 
 112 /**
 113  * struct scmi_info - Structure representing a SCMI instance
 114  *
 115  * @dev: Device pointer
 116  * @desc: SoC description for this instance
 117  * @handle: Instance of SCMI handle to send to clients
 118  * @version: SCMI revision information containing protocol version,
 119  *      implementation version and (sub-)vendor identification.
 120  * @tx_minfo: Universal Transmit Message management info
 121  * @tx_idr: IDR object to map protocol id to Tx channel info pointer
 122  * @rx_idr: IDR object to map protocol id to Rx channel info pointer
 123  * @protocols_imp: List of protocols implemented, currently maximum of
 124  *      MAX_PROTOCOLS_IMP elements allocated by the base protocol
 125  * @node: List head
 126  * @users: Number of users of this instance
 127  */
 128 struct scmi_info {
 129         struct device *dev;
 130         const struct scmi_desc *desc;
 131         struct scmi_revision_info version;
 132         struct scmi_handle handle;
 133         struct scmi_xfers_info tx_minfo;
 134         struct idr tx_idr;
 135         struct idr rx_idr;
 136         u8 *protocols_imp;
 137         struct list_head node;
 138         int users;
 139 };
 140 
 141 #define client_to_scmi_chan_info(c) container_of(c, struct scmi_chan_info, cl)
 142 #define handle_to_scmi_info(h)  container_of(h, struct scmi_info, handle)
 143 
 144 /*
 145  * SCMI specification requires all parameters, message headers, return
 146  * arguments or any protocol data to be expressed in little endian
 147  * format only.
 148  */
 149 struct scmi_shared_mem {
 150         __le32 reserved;
 151         __le32 channel_status;
 152 #define SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR      BIT(1)
 153 #define SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE       BIT(0)
 154         __le32 reserved1[2];
 155         __le32 flags;
 156 #define SCMI_SHMEM_FLAG_INTR_ENABLED    BIT(0)
 157         __le32 length;
 158         __le32 msg_header;
 159         u8 msg_payload[0];
 160 };
 161 
 162 static const int scmi_linux_errmap[] = {
 163         /* better than switch case as long as return value is continuous */
 164         0,                      /* SCMI_SUCCESS */
 165         -EOPNOTSUPP,            /* SCMI_ERR_SUPPORT */
 166         -EINVAL,                /* SCMI_ERR_PARAM */
 167         -EACCES,                /* SCMI_ERR_ACCESS */
 168         -ENOENT,                /* SCMI_ERR_ENTRY */
 169         -ERANGE,                /* SCMI_ERR_RANGE */
 170         -EBUSY,                 /* SCMI_ERR_BUSY */
 171         -ECOMM,                 /* SCMI_ERR_COMMS */
 172         -EIO,                   /* SCMI_ERR_GENERIC */
 173         -EREMOTEIO,             /* SCMI_ERR_HARDWARE */
 174         -EPROTO,                /* SCMI_ERR_PROTOCOL */
 175 };
 176 
 177 static inline int scmi_to_linux_errno(int errno)
 178 {
 179         if (errno < SCMI_SUCCESS && errno > SCMI_ERR_MAX)
 180                 return scmi_linux_errmap[-errno];
 181         return -EIO;
 182 }
 183 
 184 /**
 185  * scmi_dump_header_dbg() - Helper to dump a message header.
 186  *
 187  * @dev: Device pointer corresponding to the SCMI entity
 188  * @hdr: pointer to header.
 189  */
 190 static inline void scmi_dump_header_dbg(struct device *dev,
 191                                         struct scmi_msg_hdr *hdr)
 192 {
 193         dev_dbg(dev, "Message ID: %x Sequence ID: %x Protocol: %x\n",
 194                 hdr->id, hdr->seq, hdr->protocol_id);
 195 }
 196 
 197 static void scmi_fetch_response(struct scmi_xfer *xfer,
 198                                 struct scmi_shared_mem __iomem *mem)
 199 {
 200         xfer->hdr.status = ioread32(mem->msg_payload);
 201         /* Skip the length of header and status in payload area i.e 8 bytes */
 202         xfer->rx.len = min_t(size_t, xfer->rx.len, ioread32(&mem->length) - 8);
 203 
 204         /* Take a copy to the rx buffer.. */
 205         memcpy_fromio(xfer->rx.buf, mem->msg_payload + 4, xfer->rx.len);
 206 }
 207 
 208 /**
 209  * pack_scmi_header() - packs and returns 32-bit header
 210  *
 211  * @hdr: pointer to header containing all the information on message id,
 212  *      protocol id and sequence id.
 213  *
 214  * Return: 32-bit packed message header to be sent to the platform.
 215  */
 216 static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
 217 {
 218         return FIELD_PREP(MSG_ID_MASK, hdr->id) |
 219                 FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
 220                 FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
 221 }
 222 
 223 /**
 224  * unpack_scmi_header() - unpacks and records message and protocol id
 225  *
 226  * @msg_hdr: 32-bit packed message header sent from the platform
 227  * @hdr: pointer to header to fetch message and protocol id.
 228  */
 229 static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
 230 {
 231         hdr->id = MSG_XTRACT_ID(msg_hdr);
 232         hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
 233 }
 234 
 235 /**
 236  * scmi_tx_prepare() - mailbox client callback to prepare for the transfer
 237  *
 238  * @cl: client pointer
 239  * @m: mailbox message
 240  *
 241  * This function prepares the shared memory which contains the header and the
 242  * payload.
 243  */
 244 static void scmi_tx_prepare(struct mbox_client *cl, void *m)
 245 {
 246         struct scmi_xfer *t = m;
 247         struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
 248         struct scmi_shared_mem __iomem *mem = cinfo->payload;
 249 
 250         /*
 251          * Ideally channel must be free by now unless OS timeout last
 252          * request and platform continued to process the same, wait
 253          * until it releases the shared memory, otherwise we may endup
 254          * overwriting its response with new message payload or vice-versa
 255          */
 256         spin_until_cond(ioread32(&mem->channel_status) &
 257                         SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE);
 258         /* Mark channel busy + clear error */
 259         iowrite32(0x0, &mem->channel_status);
 260         iowrite32(t->hdr.poll_completion ? 0 : SCMI_SHMEM_FLAG_INTR_ENABLED,
 261                   &mem->flags);
 262         iowrite32(sizeof(mem->msg_header) + t->tx.len, &mem->length);
 263         iowrite32(pack_scmi_header(&t->hdr), &mem->msg_header);
 264         if (t->tx.buf)
 265                 memcpy_toio(mem->msg_payload, t->tx.buf, t->tx.len);
 266 }
 267 
 268 /**
 269  * scmi_xfer_get() - Allocate one message
 270  *
 271  * @handle: Pointer to SCMI entity handle
 272  * @minfo: Pointer to Tx/Rx Message management info based on channel type
 273  *
 274  * Helper function which is used by various message functions that are
 275  * exposed to clients of this driver for allocating a message traffic event.
 276  *
 277  * This function can sleep depending on pending requests already in the system
 278  * for the SCMI entity. Further, this also holds a spinlock to maintain
 279  * integrity of internal data structures.
 280  *
 281  * Return: 0 if all went fine, else corresponding error.
 282  */
 283 static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
 284                                        struct scmi_xfers_info *minfo)
 285 {
 286         u16 xfer_id;
 287         struct scmi_xfer *xfer;
 288         unsigned long flags, bit_pos;
 289         struct scmi_info *info = handle_to_scmi_info(handle);
 290 
 291         /* Keep the locked section as small as possible */
 292         spin_lock_irqsave(&minfo->xfer_lock, flags);
 293         bit_pos = find_first_zero_bit(minfo->xfer_alloc_table,
 294                                       info->desc->max_msg);
 295         if (bit_pos == info->desc->max_msg) {
 296                 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
 297                 return ERR_PTR(-ENOMEM);
 298         }
 299         set_bit(bit_pos, minfo->xfer_alloc_table);
 300         spin_unlock_irqrestore(&minfo->xfer_lock, flags);
 301 
 302         xfer_id = bit_pos;
 303 
 304         xfer = &minfo->xfer_block[xfer_id];
 305         xfer->hdr.seq = xfer_id;
 306         reinit_completion(&xfer->done);
 307 
 308         return xfer;
 309 }
 310 
 311 /**
 312  * __scmi_xfer_put() - Release a message
 313  *
 314  * @minfo: Pointer to Tx/Rx Message management info based on channel type
 315  * @xfer: message that was reserved by scmi_xfer_get
 316  *
 317  * This holds a spinlock to maintain integrity of internal data structures.
 318  */
 319 static void
 320 __scmi_xfer_put(struct scmi_xfers_info *minfo, struct scmi_xfer *xfer)
 321 {
 322         unsigned long flags;
 323 
 324         /*
 325          * Keep the locked section as small as possible
 326          * NOTE: we might escape with smp_mb and no lock here..
 327          * but just be conservative and symmetric.
 328          */
 329         spin_lock_irqsave(&minfo->xfer_lock, flags);
 330         clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
 331         spin_unlock_irqrestore(&minfo->xfer_lock, flags);
 332 }
 333 
 334 /**
 335  * scmi_rx_callback() - mailbox client callback for receive messages
 336  *
 337  * @cl: client pointer
 338  * @m: mailbox message
 339  *
 340  * Processes one received message to appropriate transfer information and
 341  * signals completion of the transfer.
 342  *
 343  * NOTE: This function will be invoked in IRQ context, hence should be
 344  * as optimal as possible.
 345  */
 346 static void scmi_rx_callback(struct mbox_client *cl, void *m)
 347 {
 348         u8 msg_type;
 349         u32 msg_hdr;
 350         u16 xfer_id;
 351         struct scmi_xfer *xfer;
 352         struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
 353         struct device *dev = cinfo->dev;
 354         struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
 355         struct scmi_xfers_info *minfo = &info->tx_minfo;
 356         struct scmi_shared_mem __iomem *mem = cinfo->payload;
 357 
 358         msg_hdr = ioread32(&mem->msg_header);
 359         msg_type = MSG_XTRACT_TYPE(msg_hdr);
 360         xfer_id = MSG_XTRACT_TOKEN(msg_hdr);
 361 
 362         if (msg_type == MSG_TYPE_NOTIFICATION)
 363                 return; /* Notifications not yet supported */
 364 
 365         /* Are we even expecting this? */
 366         if (!test_bit(xfer_id, minfo->xfer_alloc_table)) {
 367                 dev_err(dev, "message for %d is not expected!\n", xfer_id);
 368                 return;
 369         }
 370 
 371         xfer = &minfo->xfer_block[xfer_id];
 372 
 373         scmi_dump_header_dbg(dev, &xfer->hdr);
 374 
 375         scmi_fetch_response(xfer, mem);
 376 
 377         if (msg_type == MSG_TYPE_DELAYED_RESP)
 378                 complete(xfer->async_done);
 379         else
 380                 complete(&xfer->done);
 381 }
 382 
 383 /**
 384  * scmi_xfer_put() - Release a transmit message
 385  *
 386  * @handle: Pointer to SCMI entity handle
 387  * @xfer: message that was reserved by scmi_xfer_get
 388  */
 389 void scmi_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
 390 {
 391         struct scmi_info *info = handle_to_scmi_info(handle);
 392 
 393         __scmi_xfer_put(&info->tx_minfo, xfer);
 394 }
 395 
 396 static bool
 397 scmi_xfer_poll_done(const struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
 398 {
 399         struct scmi_shared_mem __iomem *mem = cinfo->payload;
 400         u16 xfer_id = MSG_XTRACT_TOKEN(ioread32(&mem->msg_header));
 401 
 402         if (xfer->hdr.seq != xfer_id)
 403                 return false;
 404 
 405         return ioread32(&mem->channel_status) &
 406                 (SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR |
 407                 SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE);
 408 }
 409 
 410 #define SCMI_MAX_POLL_TO_NS     (100 * NSEC_PER_USEC)
 411 
 412 static bool scmi_xfer_done_no_timeout(const struct scmi_chan_info *cinfo,
 413                                       struct scmi_xfer *xfer, ktime_t stop)
 414 {
 415         ktime_t __cur = ktime_get();
 416 
 417         return scmi_xfer_poll_done(cinfo, xfer) || ktime_after(__cur, stop);
 418 }
 419 
 420 /**
 421  * scmi_do_xfer() - Do one transfer
 422  *
 423  * @handle: Pointer to SCMI entity handle
 424  * @xfer: Transfer to initiate and wait for response
 425  *
 426  * Return: -ETIMEDOUT in case of no response, if transmit error,
 427  *      return corresponding error, else if all goes well,
 428  *      return 0.
 429  */
 430 int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer)
 431 {
 432         int ret;
 433         int timeout;
 434         struct scmi_info *info = handle_to_scmi_info(handle);
 435         struct device *dev = info->dev;
 436         struct scmi_chan_info *cinfo;
 437 
 438         cinfo = idr_find(&info->tx_idr, xfer->hdr.protocol_id);
 439         if (unlikely(!cinfo))
 440                 return -EINVAL;
 441 
 442         ret = mbox_send_message(cinfo->chan, xfer);
 443         if (ret < 0) {
 444                 dev_dbg(dev, "mbox send fail %d\n", ret);
 445                 return ret;
 446         }
 447 
 448         /* mbox_send_message returns non-negative value on success, so reset */
 449         ret = 0;
 450 
 451         if (xfer->hdr.poll_completion) {
 452                 ktime_t stop = ktime_add_ns(ktime_get(), SCMI_MAX_POLL_TO_NS);
 453 
 454                 spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer, stop));
 455 
 456                 if (ktime_before(ktime_get(), stop))
 457                         scmi_fetch_response(xfer, cinfo->payload);
 458                 else
 459                         ret = -ETIMEDOUT;
 460         } else {
 461                 /* And we wait for the response. */
 462                 timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms);
 463                 if (!wait_for_completion_timeout(&xfer->done, timeout)) {
 464                         dev_err(dev, "mbox timed out in resp(caller: %pS)\n",
 465                                 (void *)_RET_IP_);
 466                         ret = -ETIMEDOUT;
 467                 }
 468         }
 469 
 470         if (!ret && xfer->hdr.status)
 471                 ret = scmi_to_linux_errno(xfer->hdr.status);
 472 
 473         /*
 474          * NOTE: we might prefer not to need the mailbox ticker to manage the
 475          * transfer queueing since the protocol layer queues things by itself.
 476          * Unfortunately, we have to kick the mailbox framework after we have
 477          * received our message.
 478          */
 479         mbox_client_txdone(cinfo->chan, ret);
 480 
 481         return ret;
 482 }
 483 
 484 #define SCMI_MAX_RESPONSE_TIMEOUT       (2 * MSEC_PER_SEC)
 485 
 486 /**
 487  * scmi_do_xfer_with_response() - Do one transfer and wait until the delayed
 488  *      response is received
 489  *
 490  * @handle: Pointer to SCMI entity handle
 491  * @xfer: Transfer to initiate and wait for response
 492  *
 493  * Return: -ETIMEDOUT in case of no delayed response, if transmit error,
 494  *      return corresponding error, else if all goes well, return 0.
 495  */
 496 int scmi_do_xfer_with_response(const struct scmi_handle *handle,
 497                                struct scmi_xfer *xfer)
 498 {
 499         int ret, timeout = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT);
 500         DECLARE_COMPLETION_ONSTACK(async_response);
 501 
 502         xfer->async_done = &async_response;
 503 
 504         ret = scmi_do_xfer(handle, xfer);
 505         if (!ret && !wait_for_completion_timeout(xfer->async_done, timeout))
 506                 ret = -ETIMEDOUT;
 507 
 508         xfer->async_done = NULL;
 509         return ret;
 510 }
 511 
 512 /**
 513  * scmi_xfer_get_init() - Allocate and initialise one message for transmit
 514  *
 515  * @handle: Pointer to SCMI entity handle
 516  * @msg_id: Message identifier
 517  * @prot_id: Protocol identifier for the message
 518  * @tx_size: transmit message size
 519  * @rx_size: receive message size
 520  * @p: pointer to the allocated and initialised message
 521  *
 522  * This function allocates the message using @scmi_xfer_get and
 523  * initialise the header.
 524  *
 525  * Return: 0 if all went fine with @p pointing to message, else
 526  *      corresponding error.
 527  */
 528 int scmi_xfer_get_init(const struct scmi_handle *handle, u8 msg_id, u8 prot_id,
 529                        size_t tx_size, size_t rx_size, struct scmi_xfer **p)
 530 {
 531         int ret;
 532         struct scmi_xfer *xfer;
 533         struct scmi_info *info = handle_to_scmi_info(handle);
 534         struct scmi_xfers_info *minfo = &info->tx_minfo;
 535         struct device *dev = info->dev;
 536 
 537         /* Ensure we have sane transfer sizes */
 538         if (rx_size > info->desc->max_msg_size ||
 539             tx_size > info->desc->max_msg_size)
 540                 return -ERANGE;
 541 
 542         xfer = scmi_xfer_get(handle, minfo);
 543         if (IS_ERR(xfer)) {
 544                 ret = PTR_ERR(xfer);
 545                 dev_err(dev, "failed to get free message slot(%d)\n", ret);
 546                 return ret;
 547         }
 548 
 549         xfer->tx.len = tx_size;
 550         xfer->rx.len = rx_size ? : info->desc->max_msg_size;
 551         xfer->hdr.id = msg_id;
 552         xfer->hdr.protocol_id = prot_id;
 553         xfer->hdr.poll_completion = false;
 554 
 555         *p = xfer;
 556 
 557         return 0;
 558 }
 559 
 560 /**
 561  * scmi_version_get() - command to get the revision of the SCMI entity
 562  *
 563  * @handle: Pointer to SCMI entity handle
 564  * @protocol: Protocol identifier for the message
 565  * @version: Holds returned version of protocol.
 566  *
 567  * Updates the SCMI information in the internal data structure.
 568  *
 569  * Return: 0 if all went fine, else return appropriate error.
 570  */
 571 int scmi_version_get(const struct scmi_handle *handle, u8 protocol,
 572                      u32 *version)
 573 {
 574         int ret;
 575         __le32 *rev_info;
 576         struct scmi_xfer *t;
 577 
 578         ret = scmi_xfer_get_init(handle, PROTOCOL_VERSION, protocol, 0,
 579                                  sizeof(*version), &t);
 580         if (ret)
 581                 return ret;
 582 
 583         ret = scmi_do_xfer(handle, t);
 584         if (!ret) {
 585                 rev_info = t->rx.buf;
 586                 *version = le32_to_cpu(*rev_info);
 587         }
 588 
 589         scmi_xfer_put(handle, t);
 590         return ret;
 591 }
 592 
 593 void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
 594                                      u8 *prot_imp)
 595 {
 596         struct scmi_info *info = handle_to_scmi_info(handle);
 597 
 598         info->protocols_imp = prot_imp;
 599 }
 600 
 601 static bool
 602 scmi_is_protocol_implemented(const struct scmi_handle *handle, u8 prot_id)
 603 {
 604         int i;
 605         struct scmi_info *info = handle_to_scmi_info(handle);
 606 
 607         if (!info->protocols_imp)
 608                 return false;
 609 
 610         for (i = 0; i < MAX_PROTOCOLS_IMP; i++)
 611                 if (info->protocols_imp[i] == prot_id)
 612                         return true;
 613         return false;
 614 }
 615 
 616 /**
 617  * scmi_handle_get() - Get the SCMI handle for a device
 618  *
 619  * @dev: pointer to device for which we want SCMI handle
 620  *
 621  * NOTE: The function does not track individual clients of the framework
 622  * and is expected to be maintained by caller of SCMI protocol library.
 623  * scmi_handle_put must be balanced with successful scmi_handle_get
 624  *
 625  * Return: pointer to handle if successful, NULL on error
 626  */
 627 struct scmi_handle *scmi_handle_get(struct device *dev)
 628 {
 629         struct list_head *p;
 630         struct scmi_info *info;
 631         struct scmi_handle *handle = NULL;
 632 
 633         mutex_lock(&scmi_list_mutex);
 634         list_for_each(p, &scmi_list) {
 635                 info = list_entry(p, struct scmi_info, node);
 636                 if (dev->parent == info->dev) {
 637                         handle = &info->handle;
 638                         info->users++;
 639                         break;
 640                 }
 641         }
 642         mutex_unlock(&scmi_list_mutex);
 643 
 644         return handle;
 645 }
 646 
 647 /**
 648  * scmi_handle_put() - Release the handle acquired by scmi_handle_get
 649  *
 650  * @handle: handle acquired by scmi_handle_get
 651  *
 652  * NOTE: The function does not track individual clients of the framework
 653  * and is expected to be maintained by caller of SCMI protocol library.
 654  * scmi_handle_put must be balanced with successful scmi_handle_get
 655  *
 656  * Return: 0 is successfully released
 657  *      if null was passed, it returns -EINVAL;
 658  */
 659 int scmi_handle_put(const struct scmi_handle *handle)
 660 {
 661         struct scmi_info *info;
 662 
 663         if (!handle)
 664                 return -EINVAL;
 665 
 666         info = handle_to_scmi_info(handle);
 667         mutex_lock(&scmi_list_mutex);
 668         if (!WARN_ON(!info->users))
 669                 info->users--;
 670         mutex_unlock(&scmi_list_mutex);
 671 
 672         return 0;
 673 }
 674 
 675 static int scmi_xfer_info_init(struct scmi_info *sinfo)
 676 {
 677         int i;
 678         struct scmi_xfer *xfer;
 679         struct device *dev = sinfo->dev;
 680         const struct scmi_desc *desc = sinfo->desc;
 681         struct scmi_xfers_info *info = &sinfo->tx_minfo;
 682 
 683         /* Pre-allocated messages, no more than what hdr.seq can support */
 684         if (WARN_ON(desc->max_msg >= MSG_TOKEN_MAX)) {
 685                 dev_err(dev, "Maximum message of %d exceeds supported %ld\n",
 686                         desc->max_msg, MSG_TOKEN_MAX);
 687                 return -EINVAL;
 688         }
 689 
 690         info->xfer_block = devm_kcalloc(dev, desc->max_msg,
 691                                         sizeof(*info->xfer_block), GFP_KERNEL);
 692         if (!info->xfer_block)
 693                 return -ENOMEM;
 694 
 695         info->xfer_alloc_table = devm_kcalloc(dev, BITS_TO_LONGS(desc->max_msg),
 696                                               sizeof(long), GFP_KERNEL);
 697         if (!info->xfer_alloc_table)
 698                 return -ENOMEM;
 699 
 700         /* Pre-initialize the buffer pointer to pre-allocated buffers */
 701         for (i = 0, xfer = info->xfer_block; i < desc->max_msg; i++, xfer++) {
 702                 xfer->rx.buf = devm_kcalloc(dev, sizeof(u8), desc->max_msg_size,
 703                                             GFP_KERNEL);
 704                 if (!xfer->rx.buf)
 705                         return -ENOMEM;
 706 
 707                 xfer->tx.buf = xfer->rx.buf;
 708                 init_completion(&xfer->done);
 709         }
 710 
 711         spin_lock_init(&info->xfer_lock);
 712 
 713         return 0;
 714 }
 715 
 716 static int scmi_mailbox_check(struct device_node *np, int idx)
 717 {
 718         return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells",
 719                                           idx, NULL);
 720 }
 721 
 722 static int scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev,
 723                                 int prot_id, bool tx)
 724 {
 725         int ret, idx;
 726         struct resource res;
 727         resource_size_t size;
 728         struct device_node *shmem, *np = dev->of_node;
 729         struct scmi_chan_info *cinfo;
 730         struct mbox_client *cl;
 731         struct idr *idr;
 732         const char *desc = tx ? "Tx" : "Rx";
 733 
 734         /* Transmit channel is first entry i.e. index 0 */
 735         idx = tx ? 0 : 1;
 736         idr = tx ? &info->tx_idr : &info->rx_idr;
 737 
 738         if (scmi_mailbox_check(np, idx)) {
 739                 cinfo = idr_find(idr, SCMI_PROTOCOL_BASE);
 740                 if (unlikely(!cinfo)) /* Possible only if platform has no Rx */
 741                         return -EINVAL;
 742                 goto idr_alloc;
 743         }
 744 
 745         cinfo = devm_kzalloc(info->dev, sizeof(*cinfo), GFP_KERNEL);
 746         if (!cinfo)
 747                 return -ENOMEM;
 748 
 749         cinfo->dev = dev;
 750 
 751         cl = &cinfo->cl;
 752         cl->dev = dev;
 753         cl->rx_callback = scmi_rx_callback;
 754         cl->tx_prepare = tx ? scmi_tx_prepare : NULL;
 755         cl->tx_block = false;
 756         cl->knows_txdone = tx;
 757 
 758         shmem = of_parse_phandle(np, "shmem", idx);
 759         ret = of_address_to_resource(shmem, 0, &res);
 760         of_node_put(shmem);
 761         if (ret) {
 762                 dev_err(dev, "failed to get SCMI %s payload memory\n", desc);
 763                 return ret;
 764         }
 765 
 766         size = resource_size(&res);
 767         cinfo->payload = devm_ioremap(info->dev, res.start, size);
 768         if (!cinfo->payload) {
 769                 dev_err(dev, "failed to ioremap SCMI %s payload\n", desc);
 770                 return -EADDRNOTAVAIL;
 771         }
 772 
 773         cinfo->chan = mbox_request_channel(cl, idx);
 774         if (IS_ERR(cinfo->chan)) {
 775                 ret = PTR_ERR(cinfo->chan);
 776                 if (ret != -EPROBE_DEFER)
 777                         dev_err(dev, "failed to request SCMI %s mailbox\n",
 778                                 desc);
 779                 return ret;
 780         }
 781 
 782 idr_alloc:
 783         ret = idr_alloc(idr, cinfo, prot_id, prot_id + 1, GFP_KERNEL);
 784         if (ret != prot_id) {
 785                 dev_err(dev, "unable to allocate SCMI idr slot err %d\n", ret);
 786                 return ret;
 787         }
 788 
 789         cinfo->handle = &info->handle;
 790         return 0;
 791 }
 792 
 793 static inline int
 794 scmi_mbox_txrx_setup(struct scmi_info *info, struct device *dev, int prot_id)
 795 {
 796         int ret = scmi_mbox_chan_setup(info, dev, prot_id, true);
 797 
 798         if (!ret) /* Rx is optional, hence no error check */
 799                 scmi_mbox_chan_setup(info, dev, prot_id, false);
 800 
 801         return ret;
 802 }
 803 
 804 static inline void
 805 scmi_create_protocol_device(struct device_node *np, struct scmi_info *info,
 806                             int prot_id)
 807 {
 808         struct scmi_device *sdev;
 809 
 810         sdev = scmi_device_create(np, info->dev, prot_id);
 811         if (!sdev) {
 812                 dev_err(info->dev, "failed to create %d protocol device\n",
 813                         prot_id);
 814                 return;
 815         }
 816 
 817         if (scmi_mbox_txrx_setup(info, &sdev->dev, prot_id)) {
 818                 dev_err(&sdev->dev, "failed to setup transport\n");
 819                 scmi_device_destroy(sdev);
 820                 return;
 821         }
 822 
 823         /* setup handle now as the transport is ready */
 824         scmi_set_handle(sdev);
 825 }
 826 
 827 static int scmi_probe(struct platform_device *pdev)
 828 {
 829         int ret;
 830         struct scmi_handle *handle;
 831         const struct scmi_desc *desc;
 832         struct scmi_info *info;
 833         struct device *dev = &pdev->dev;
 834         struct device_node *child, *np = dev->of_node;
 835 
 836         /* Only mailbox method supported, check for the presence of one */
 837         if (scmi_mailbox_check(np, 0)) {
 838                 dev_err(dev, "no mailbox found in %pOF\n", np);
 839                 return -EINVAL;
 840         }
 841 
 842         desc = of_device_get_match_data(dev);
 843         if (!desc)
 844                 return -EINVAL;
 845 
 846         info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
 847         if (!info)
 848                 return -ENOMEM;
 849 
 850         info->dev = dev;
 851         info->desc = desc;
 852         INIT_LIST_HEAD(&info->node);
 853 
 854         ret = scmi_xfer_info_init(info);
 855         if (ret)
 856                 return ret;
 857 
 858         platform_set_drvdata(pdev, info);
 859         idr_init(&info->tx_idr);
 860         idr_init(&info->rx_idr);
 861 
 862         handle = &info->handle;
 863         handle->dev = info->dev;
 864         handle->version = &info->version;
 865 
 866         ret = scmi_mbox_txrx_setup(info, dev, SCMI_PROTOCOL_BASE);
 867         if (ret)
 868                 return ret;
 869 
 870         ret = scmi_base_protocol_init(handle);
 871         if (ret) {
 872                 dev_err(dev, "unable to communicate with SCMI(%d)\n", ret);
 873                 return ret;
 874         }
 875 
 876         mutex_lock(&scmi_list_mutex);
 877         list_add_tail(&info->node, &scmi_list);
 878         mutex_unlock(&scmi_list_mutex);
 879 
 880         for_each_available_child_of_node(np, child) {
 881                 u32 prot_id;
 882 
 883                 if (of_property_read_u32(child, "reg", &prot_id))
 884                         continue;
 885 
 886                 if (!FIELD_FIT(MSG_PROTOCOL_ID_MASK, prot_id))
 887                         dev_err(dev, "Out of range protocol %d\n", prot_id);
 888 
 889                 if (!scmi_is_protocol_implemented(handle, prot_id)) {
 890                         dev_err(dev, "SCMI protocol %d not implemented\n",
 891                                 prot_id);
 892                         continue;
 893                 }
 894 
 895                 scmi_create_protocol_device(child, info, prot_id);
 896         }
 897 
 898         return 0;
 899 }
 900 
 901 static int scmi_mbox_free_channel(int id, void *p, void *data)
 902 {
 903         struct scmi_chan_info *cinfo = p;
 904         struct idr *idr = data;
 905 
 906         if (!IS_ERR_OR_NULL(cinfo->chan)) {
 907                 mbox_free_channel(cinfo->chan);
 908                 cinfo->chan = NULL;
 909         }
 910 
 911         idr_remove(idr, id);
 912 
 913         return 0;
 914 }
 915 
 916 static int scmi_remove(struct platform_device *pdev)
 917 {
 918         int ret = 0;
 919         struct scmi_info *info = platform_get_drvdata(pdev);
 920         struct idr *idr = &info->tx_idr;
 921 
 922         mutex_lock(&scmi_list_mutex);
 923         if (info->users)
 924                 ret = -EBUSY;
 925         else
 926                 list_del(&info->node);
 927         mutex_unlock(&scmi_list_mutex);
 928 
 929         if (ret)
 930                 return ret;
 931 
 932         /* Safe to free channels since no more users */
 933         ret = idr_for_each(idr, scmi_mbox_free_channel, idr);
 934         idr_destroy(&info->tx_idr);
 935 
 936         idr = &info->rx_idr;
 937         ret = idr_for_each(idr, scmi_mbox_free_channel, idr);
 938         idr_destroy(&info->rx_idr);
 939 
 940         return ret;
 941 }
 942 
 943 static const struct scmi_desc scmi_generic_desc = {
 944         .max_rx_timeout_ms = 30,        /* We may increase this if required */
 945         .max_msg = 20,          /* Limited by MBOX_TX_QUEUE_LEN */
 946         .max_msg_size = 128,
 947 };
 948 
 949 /* Each compatible listed below must have descriptor associated with it */
 950 static const struct of_device_id scmi_of_match[] = {
 951         { .compatible = "arm,scmi", .data = &scmi_generic_desc },
 952         { /* Sentinel */ },
 953 };
 954 
 955 MODULE_DEVICE_TABLE(of, scmi_of_match);
 956 
 957 static struct platform_driver scmi_driver = {
 958         .driver = {
 959                    .name = "arm-scmi",
 960                    .of_match_table = scmi_of_match,
 961                    },
 962         .probe = scmi_probe,
 963         .remove = scmi_remove,
 964 };
 965 
 966 module_platform_driver(scmi_driver);
 967 
 968 MODULE_ALIAS("platform: arm-scmi");
 969 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 970 MODULE_DESCRIPTION("ARM SCMI protocol driver");
 971 MODULE_LICENSE("GPL v2");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/firmware/arm_scmi/driver.c

DEFINITIONS
