linux/drivers/bluetooth/hci_h5.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *
   4 *  Bluetooth HCI Three-wire UART driver
   5 *
   6 *  Copyright (C) 2012  Intel Corporation
   7 */
   8
   9#include <linux/acpi.h>
  10#include <linux/errno.h>
  11#include <linux/gpio/consumer.h>
  12#include <linux/kernel.h>
  13#include <linux/mod_devicetable.h>
  14#include <linux/serdev.h>
  15#include <linux/skbuff.h>
  16
  17#include <net/bluetooth/bluetooth.h>
  18#include <net/bluetooth/hci_core.h>
  19
  20#include "btrtl.h"
  21#include "hci_uart.h"
  22
  23#define HCI_3WIRE_ACK_PKT       0
  24#define HCI_3WIRE_LINK_PKT      15
  25
  26/* Sliding window size */
  27#define H5_TX_WIN_MAX           4
  28
  29#define H5_ACK_TIMEOUT  msecs_to_jiffies(250)
  30#define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
  31
  32/*
  33 * Maximum Three-wire packet:
  34 *     4 byte header + max value for 12-bit length + 2 bytes for CRC
  35 */
  36#define H5_MAX_LEN (4 + 0xfff + 2)
  37
  38/* Convenience macros for reading Three-wire header values */
  39#define H5_HDR_SEQ(hdr)         ((hdr)[0] & 0x07)
  40#define H5_HDR_ACK(hdr)         (((hdr)[0] >> 3) & 0x07)
  41#define H5_HDR_CRC(hdr)         (((hdr)[0] >> 6) & 0x01)
  42#define H5_HDR_RELIABLE(hdr)    (((hdr)[0] >> 7) & 0x01)
  43#define H5_HDR_PKT_TYPE(hdr)    ((hdr)[1] & 0x0f)
  44#define H5_HDR_LEN(hdr)         ((((hdr)[1] >> 4) & 0x0f) + ((hdr)[2] << 4))
  45
  46#define SLIP_DELIMITER  0xc0
  47#define SLIP_ESC        0xdb
  48#define SLIP_ESC_DELIM  0xdc
  49#define SLIP_ESC_ESC    0xdd
  50
  51/* H5 state flags */
  52enum {
  53        H5_RX_ESC,      /* SLIP escape mode */
  54        H5_TX_ACK_REQ,  /* Pending ack to send */
  55};
  56
  57struct h5 {
  58        /* Must be the first member, hci_serdev.c expects this. */
  59        struct hci_uart         serdev_hu;
  60
  61        struct sk_buff_head     unack;          /* Unack'ed packets queue */
  62        struct sk_buff_head     rel;            /* Reliable packets queue */
  63        struct sk_buff_head     unrel;          /* Unreliable packets queue */
  64
  65        unsigned long           flags;
  66
  67        struct sk_buff          *rx_skb;        /* Receive buffer */
  68        size_t                  rx_pending;     /* Expecting more bytes */
  69        u8                      rx_ack;         /* Last ack number received */
  70
  71        int                     (*rx_func)(struct hci_uart *hu, u8 c);
  72
  73        struct timer_list       timer;          /* Retransmission timer */
  74        struct hci_uart         *hu;            /* Parent HCI UART */
  75
  76        u8                      tx_seq;         /* Next seq number to send */
  77        u8                      tx_ack;         /* Next ack number to send */
  78        u8                      tx_win;         /* Sliding window size */
  79
  80        enum {
  81                H5_UNINITIALIZED,
  82                H5_INITIALIZED,
  83                H5_ACTIVE,
  84        } state;
  85
  86        enum {
  87                H5_AWAKE,
  88                H5_SLEEPING,
  89                H5_WAKING_UP,
  90        } sleep;
  91
  92        const struct h5_vnd *vnd;
  93        const char *id;
  94
  95        struct gpio_desc *enable_gpio;
  96        struct gpio_desc *device_wake_gpio;
  97};
  98
  99struct h5_vnd {
 100        int (*setup)(struct h5 *h5);
 101        void (*open)(struct h5 *h5);
 102        void (*close)(struct h5 *h5);
 103        int (*suspend)(struct h5 *h5);
 104        int (*resume)(struct h5 *h5);
 105        const struct acpi_gpio_mapping *acpi_gpio_map;
 106};
 107
 108static void h5_reset_rx(struct h5 *h5);
 109
 110static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)
 111{
 112        struct h5 *h5 = hu->priv;
 113        struct sk_buff *nskb;
 114
 115        nskb = alloc_skb(3, GFP_ATOMIC);
 116        if (!nskb)
 117                return;
 118
 119        hci_skb_pkt_type(nskb) = HCI_3WIRE_LINK_PKT;
 120
 121        skb_put_data(nskb, data, len);
 122
 123        skb_queue_tail(&h5->unrel, nskb);
 124}
 125
 126static u8 h5_cfg_field(struct h5 *h5)
 127{
 128        /* Sliding window size (first 3 bits) */
 129        return h5->tx_win & 0x07;
 130}
 131
 132static void h5_timed_event(struct timer_list *t)
 133{
 134        const unsigned char sync_req[] = { 0x01, 0x7e };
 135        unsigned char conf_req[3] = { 0x03, 0xfc };
 136        struct h5 *h5 = from_timer(h5, t, timer);
 137        struct hci_uart *hu = h5->hu;
 138        struct sk_buff *skb;
 139        unsigned long flags;
 140
 141        BT_DBG("%s", hu->hdev->name);
 142
 143        if (h5->state == H5_UNINITIALIZED)
 144                h5_link_control(hu, sync_req, sizeof(sync_req));
 145
 146        if (h5->state == H5_INITIALIZED) {
 147                conf_req[2] = h5_cfg_field(h5);
 148                h5_link_control(hu, conf_req, sizeof(conf_req));
 149        }
 150
 151        if (h5->state != H5_ACTIVE) {
 152                mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
 153                goto wakeup;
 154        }
 155
 156        if (h5->sleep != H5_AWAKE) {
 157                h5->sleep = H5_SLEEPING;
 158                goto wakeup;
 159        }
 160
 161        BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
 162
 163        spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
 164
 165        while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
 166                h5->tx_seq = (h5->tx_seq - 1) & 0x07;
 167                skb_queue_head(&h5->rel, skb);
 168        }
 169
 170        spin_unlock_irqrestore(&h5->unack.lock, flags);
 171
 172wakeup:
 173        hci_uart_tx_wakeup(hu);
 174}
 175
 176static void h5_peer_reset(struct hci_uart *hu)
 177{
 178        struct h5 *h5 = hu->priv;
 179
 180        BT_ERR("Peer device has reset");
 181
 182        h5->state = H5_UNINITIALIZED;
 183
 184        del_timer(&h5->timer);
 185
 186        skb_queue_purge(&h5->rel);
 187        skb_queue_purge(&h5->unrel);
 188        skb_queue_purge(&h5->unack);
 189
 190        h5->tx_seq = 0;
 191        h5->tx_ack = 0;
 192
 193        /* Send reset request to upper stack */
 194        hci_reset_dev(hu->hdev);
 195}
 196
 197static int h5_open(struct hci_uart *hu)
 198{
 199        struct h5 *h5;
 200        const unsigned char sync[] = { 0x01, 0x7e };
 201
 202        BT_DBG("hu %p", hu);
 203
 204        if (hu->serdev) {
 205                h5 = serdev_device_get_drvdata(hu->serdev);
 206        } else {
 207                h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
 208                if (!h5)
 209                        return -ENOMEM;
 210        }
 211
 212        hu->priv = h5;
 213        h5->hu = hu;
 214
 215        skb_queue_head_init(&h5->unack);
 216        skb_queue_head_init(&h5->rel);
 217        skb_queue_head_init(&h5->unrel);
 218
 219        h5_reset_rx(h5);
 220
 221        timer_setup(&h5->timer, h5_timed_event, 0);
 222
 223        h5->tx_win = H5_TX_WIN_MAX;
 224
 225        if (h5->vnd && h5->vnd->open)
 226                h5->vnd->open(h5);
 227
 228        set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
 229
 230        /* Send initial sync request */
 231        h5_link_control(hu, sync, sizeof(sync));
 232        mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
 233
 234        return 0;
 235}
 236
 237static int h5_close(struct hci_uart *hu)
 238{
 239        struct h5 *h5 = hu->priv;
 240
 241        del_timer_sync(&h5->timer);
 242
 243        skb_queue_purge(&h5->unack);
 244        skb_queue_purge(&h5->rel);
 245        skb_queue_purge(&h5->unrel);
 246
 247        if (h5->vnd && h5->vnd->close)
 248                h5->vnd->close(h5);
 249
 250        if (!hu->serdev)
 251                kfree(h5);
 252
 253        return 0;
 254}
 255
 256static int h5_setup(struct hci_uart *hu)
 257{
 258        struct h5 *h5 = hu->priv;
 259
 260        if (h5->vnd && h5->vnd->setup)
 261                return h5->vnd->setup(h5);
 262
 263        return 0;
 264}
 265
 266static void h5_pkt_cull(struct h5 *h5)
 267{
 268        struct sk_buff *skb, *tmp;
 269        unsigned long flags;
 270        int i, to_remove;
 271        u8 seq;
 272
 273        spin_lock_irqsave(&h5->unack.lock, flags);
 274
 275        to_remove = skb_queue_len(&h5->unack);
 276        if (to_remove == 0)
 277                goto unlock;
 278
 279        seq = h5->tx_seq;
 280
 281        while (to_remove > 0) {
 282                if (h5->rx_ack == seq)
 283                        break;
 284
 285                to_remove--;
 286                seq = (seq - 1) & 0x07;
 287        }
 288
 289        if (seq != h5->rx_ack)
 290                BT_ERR("Controller acked invalid packet");
 291
 292        i = 0;
 293        skb_queue_walk_safe(&h5->unack, skb, tmp) {
 294                if (i++ >= to_remove)
 295                        break;
 296
 297                __skb_unlink(skb, &h5->unack);
 298                kfree_skb(skb);
 299        }
 300
 301        if (skb_queue_empty(&h5->unack))
 302                del_timer(&h5->timer);
 303
 304unlock:
 305        spin_unlock_irqrestore(&h5->unack.lock, flags);
 306}
 307
 308static void h5_handle_internal_rx(struct hci_uart *hu)
 309{
 310        struct h5 *h5 = hu->priv;
 311        const unsigned char sync_req[] = { 0x01, 0x7e };
 312        const unsigned char sync_rsp[] = { 0x02, 0x7d };
 313        unsigned char conf_req[3] = { 0x03, 0xfc };
 314        const unsigned char conf_rsp[] = { 0x04, 0x7b };
 315        const unsigned char wakeup_req[] = { 0x05, 0xfa };
 316        const unsigned char woken_req[] = { 0x06, 0xf9 };
 317        const unsigned char sleep_req[] = { 0x07, 0x78 };
 318        const unsigned char *hdr = h5->rx_skb->data;
 319        const unsigned char *data = &h5->rx_skb->data[4];
 320
 321        BT_DBG("%s", hu->hdev->name);
 322
 323        if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
 324                return;
 325
 326        if (H5_HDR_LEN(hdr) < 2)
 327                return;
 328
 329        conf_req[2] = h5_cfg_field(h5);
 330
 331        if (memcmp(data, sync_req, 2) == 0) {
 332                if (h5->state == H5_ACTIVE)
 333                        h5_peer_reset(hu);
 334                h5_link_control(hu, sync_rsp, 2);
 335        } else if (memcmp(data, sync_rsp, 2) == 0) {
 336                if (h5->state == H5_ACTIVE)
 337                        h5_peer_reset(hu);
 338                h5->state = H5_INITIALIZED;
 339                h5_link_control(hu, conf_req, 3);
 340        } else if (memcmp(data, conf_req, 2) == 0) {
 341                h5_link_control(hu, conf_rsp, 2);
 342                h5_link_control(hu, conf_req, 3);
 343        } else if (memcmp(data, conf_rsp, 2) == 0) {
 344                if (H5_HDR_LEN(hdr) > 2)
 345                        h5->tx_win = (data[2] & 0x07);
 346                BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
 347                h5->state = H5_ACTIVE;
 348                hci_uart_init_ready(hu);
 349                return;
 350        } else if (memcmp(data, sleep_req, 2) == 0) {
 351                BT_DBG("Peer went to sleep");
 352                h5->sleep = H5_SLEEPING;
 353                return;
 354        } else if (memcmp(data, woken_req, 2) == 0) {
 355                BT_DBG("Peer woke up");
 356                h5->sleep = H5_AWAKE;
 357        } else if (memcmp(data, wakeup_req, 2) == 0) {
 358                BT_DBG("Peer requested wakeup");
 359                h5_link_control(hu, woken_req, 2);
 360                h5->sleep = H5_AWAKE;
 361        } else {
 362                BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
 363                return;
 364        }
 365
 366        hci_uart_tx_wakeup(hu);
 367}
 368
 369static void h5_complete_rx_pkt(struct hci_uart *hu)
 370{
 371        struct h5 *h5 = hu->priv;
 372        const unsigned char *hdr = h5->rx_skb->data;
 373
 374        if (H5_HDR_RELIABLE(hdr)) {
 375                h5->tx_ack = (h5->tx_ack + 1) % 8;
 376                set_bit(H5_TX_ACK_REQ, &h5->flags);
 377                hci_uart_tx_wakeup(hu);
 378        }
 379
 380        h5->rx_ack = H5_HDR_ACK(hdr);
 381
 382        h5_pkt_cull(h5);
 383
 384        switch (H5_HDR_PKT_TYPE(hdr)) {
 385        case HCI_EVENT_PKT:
 386        case HCI_ACLDATA_PKT:
 387        case HCI_SCODATA_PKT:
 388                hci_skb_pkt_type(h5->rx_skb) = H5_HDR_PKT_TYPE(hdr);
 389
 390                /* Remove Three-wire header */
 391                skb_pull(h5->rx_skb, 4);
 392
 393                hci_recv_frame(hu->hdev, h5->rx_skb);
 394                h5->rx_skb = NULL;
 395
 396                break;
 397
 398        default:
 399                h5_handle_internal_rx(hu);
 400                break;
 401        }
 402
 403        h5_reset_rx(h5);
 404}
 405
 406static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
 407{
 408        h5_complete_rx_pkt(hu);
 409
 410        return 0;
 411}
 412
 413static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
 414{
 415        struct h5 *h5 = hu->priv;
 416        const unsigned char *hdr = h5->rx_skb->data;
 417
 418        if (H5_HDR_CRC(hdr)) {
 419                h5->rx_func = h5_rx_crc;
 420                h5->rx_pending = 2;
 421        } else {
 422                h5_complete_rx_pkt(hu);
 423        }
 424
 425        return 0;
 426}
 427
 428static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
 429{
 430        struct h5 *h5 = hu->priv;
 431        const unsigned char *hdr = h5->rx_skb->data;
 432
 433        BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
 434               hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
 435               H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
 436               H5_HDR_LEN(hdr));
 437
 438        if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
 439                BT_ERR("Invalid header checksum");
 440                h5_reset_rx(h5);
 441                return 0;
 442        }
 443
 444        if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
 445                BT_ERR("Out-of-order packet arrived (%u != %u)",
 446                       H5_HDR_SEQ(hdr), h5->tx_ack);
 447                h5_reset_rx(h5);
 448                return 0;
 449        }
 450
 451        if (h5->state != H5_ACTIVE &&
 452            H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
 453                BT_ERR("Non-link packet received in non-active state");
 454                h5_reset_rx(h5);
 455                return 0;
 456        }
 457
 458        h5->rx_func = h5_rx_payload;
 459        h5->rx_pending = H5_HDR_LEN(hdr);
 460
 461        return 0;
 462}
 463
 464static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
 465{
 466        struct h5 *h5 = hu->priv;
 467
 468        if (c == SLIP_DELIMITER)
 469                return 1;
 470
 471        h5->rx_func = h5_rx_3wire_hdr;
 472        h5->rx_pending = 4;
 473
 474        h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
 475        if (!h5->rx_skb) {
 476                BT_ERR("Can't allocate mem for new packet");
 477                h5_reset_rx(h5);
 478                return -ENOMEM;
 479        }
 480
 481        h5->rx_skb->dev = (void *)hu->hdev;
 482
 483        return 0;
 484}
 485
 486static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
 487{
 488        struct h5 *h5 = hu->priv;
 489
 490        if (c == SLIP_DELIMITER)
 491                h5->rx_func = h5_rx_pkt_start;
 492
 493        return 1;
 494}
 495
 496static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
 497{
 498        const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
 499        const u8 *byte = &c;
 500
 501        if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
 502                set_bit(H5_RX_ESC, &h5->flags);
 503                return;
 504        }
 505
 506        if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
 507                switch (c) {
 508                case SLIP_ESC_DELIM:
 509                        byte = &delim;
 510                        break;
 511                case SLIP_ESC_ESC:
 512                        byte = &esc;
 513                        break;
 514                default:
 515                        BT_ERR("Invalid esc byte 0x%02hhx", c);
 516                        h5_reset_rx(h5);
 517                        return;
 518                }
 519        }
 520
 521        skb_put_data(h5->rx_skb, byte, 1);
 522        h5->rx_pending--;
 523
 524        BT_DBG("unslipped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
 525}
 526
 527static void h5_reset_rx(struct h5 *h5)
 528{
 529        if (h5->rx_skb) {
 530                kfree_skb(h5->rx_skb);
 531                h5->rx_skb = NULL;
 532        }
 533
 534        h5->rx_func = h5_rx_delimiter;
 535        h5->rx_pending = 0;
 536        clear_bit(H5_RX_ESC, &h5->flags);
 537}
 538
 539static int h5_recv(struct hci_uart *hu, const void *data, int count)
 540{
 541        struct h5 *h5 = hu->priv;
 542        const unsigned char *ptr = data;
 543
 544        BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
 545               count);
 546
 547        while (count > 0) {
 548                int processed;
 549
 550                if (h5->rx_pending > 0) {
 551                        if (*ptr == SLIP_DELIMITER) {
 552                                BT_ERR("Too short H5 packet");
 553                                h5_reset_rx(h5);
 554                                continue;
 555                        }
 556
 557                        h5_unslip_one_byte(h5, *ptr);
 558
 559                        ptr++; count--;
 560                        continue;
 561                }
 562
 563                processed = h5->rx_func(hu, *ptr);
 564                if (processed < 0)
 565                        return processed;
 566
 567                ptr += processed;
 568                count -= processed;
 569        }
 570
 571        return 0;
 572}
 573
 574static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 575{
 576        struct h5 *h5 = hu->priv;
 577
 578        if (skb->len > 0xfff) {
 579                BT_ERR("Packet too long (%u bytes)", skb->len);
 580                kfree_skb(skb);
 581                return 0;
 582        }
 583
 584        if (h5->state != H5_ACTIVE) {
 585                BT_ERR("Ignoring HCI data in non-active state");
 586                kfree_skb(skb);
 587                return 0;
 588        }
 589
 590        switch (hci_skb_pkt_type(skb)) {
 591        case HCI_ACLDATA_PKT:
 592        case HCI_COMMAND_PKT:
 593                skb_queue_tail(&h5->rel, skb);
 594                break;
 595
 596        case HCI_SCODATA_PKT:
 597                skb_queue_tail(&h5->unrel, skb);
 598                break;
 599
 600        default:
 601                BT_ERR("Unknown packet type %u", hci_skb_pkt_type(skb));
 602                kfree_skb(skb);
 603                break;
 604        }
 605
 606        return 0;
 607}
 608
 609static void h5_slip_delim(struct sk_buff *skb)
 610{
 611        const char delim = SLIP_DELIMITER;
 612
 613        skb_put_data(skb, &delim, 1);
 614}
 615
 616static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
 617{
 618        const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
 619        const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
 620
 621        switch (c) {
 622        case SLIP_DELIMITER:
 623                skb_put_data(skb, &esc_delim, 2);
 624                break;
 625        case SLIP_ESC:
 626                skb_put_data(skb, &esc_esc, 2);
 627                break;
 628        default:
 629                skb_put_data(skb, &c, 1);
 630        }
 631}
 632
 633static bool valid_packet_type(u8 type)
 634{
 635        switch (type) {
 636        case HCI_ACLDATA_PKT:
 637        case HCI_COMMAND_PKT:
 638        case HCI_SCODATA_PKT:
 639        case HCI_3WIRE_LINK_PKT:
 640        case HCI_3WIRE_ACK_PKT:
 641                return true;
 642        default:
 643                return false;
 644        }
 645}
 646
 647static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
 648                                      const u8 *data, size_t len)
 649{
 650        struct h5 *h5 = hu->priv;
 651        struct sk_buff *nskb;
 652        u8 hdr[4];
 653        int i;
 654
 655        if (!valid_packet_type(pkt_type)) {
 656                BT_ERR("Unknown packet type %u", pkt_type);
 657                return NULL;
 658        }
 659
 660        /*
 661         * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
 662         * (because bytes 0xc0 and 0xdb are escaped, worst case is when
 663         * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
 664         * delimiters at start and end).
 665         */
 666        nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
 667        if (!nskb)
 668                return NULL;
 669
 670        hci_skb_pkt_type(nskb) = pkt_type;
 671
 672        h5_slip_delim(nskb);
 673
 674        hdr[0] = h5->tx_ack << 3;
 675        clear_bit(H5_TX_ACK_REQ, &h5->flags);
 676
 677        /* Reliable packet? */
 678        if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) {
 679                hdr[0] |= 1 << 7;
 680                hdr[0] |= h5->tx_seq;
 681                h5->tx_seq = (h5->tx_seq + 1) % 8;
 682        }
 683
 684        hdr[1] = pkt_type | ((len & 0x0f) << 4);
 685        hdr[2] = len >> 4;
 686        hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
 687
 688        BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
 689               hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
 690               H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
 691               H5_HDR_LEN(hdr));
 692
 693        for (i = 0; i < 4; i++)
 694                h5_slip_one_byte(nskb, hdr[i]);
 695
 696        for (i = 0; i < len; i++)
 697                h5_slip_one_byte(nskb, data[i]);
 698
 699        h5_slip_delim(nskb);
 700
 701        return nskb;
 702}
 703
 704static struct sk_buff *h5_dequeue(struct hci_uart *hu)
 705{
 706        struct h5 *h5 = hu->priv;
 707        unsigned long flags;
 708        struct sk_buff *skb, *nskb;
 709
 710        if (h5->sleep != H5_AWAKE) {
 711                const unsigned char wakeup_req[] = { 0x05, 0xfa };
 712
 713                if (h5->sleep == H5_WAKING_UP)
 714                        return NULL;
 715
 716                h5->sleep = H5_WAKING_UP;
 717                BT_DBG("Sending wakeup request");
 718
 719                mod_timer(&h5->timer, jiffies + HZ / 100);
 720                return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
 721        }
 722
 723        skb = skb_dequeue(&h5->unrel);
 724        if (skb) {
 725                nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
 726                                      skb->data, skb->len);
 727                if (nskb) {
 728                        kfree_skb(skb);
 729                        return nskb;
 730                }
 731
 732                skb_queue_head(&h5->unrel, skb);
 733                BT_ERR("Could not dequeue pkt because alloc_skb failed");
 734        }
 735
 736        spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
 737
 738        if (h5->unack.qlen >= h5->tx_win)
 739                goto unlock;
 740
 741        skb = skb_dequeue(&h5->rel);
 742        if (skb) {
 743                nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
 744                                      skb->data, skb->len);
 745                if (nskb) {
 746                        __skb_queue_tail(&h5->unack, skb);
 747                        mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
 748                        spin_unlock_irqrestore(&h5->unack.lock, flags);
 749                        return nskb;
 750                }
 751
 752                skb_queue_head(&h5->rel, skb);
 753                BT_ERR("Could not dequeue pkt because alloc_skb failed");
 754        }
 755
 756unlock:
 757        spin_unlock_irqrestore(&h5->unack.lock, flags);
 758
 759        if (test_bit(H5_TX_ACK_REQ, &h5->flags))
 760                return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
 761
 762        return NULL;
 763}
 764
 765static int h5_flush(struct hci_uart *hu)
 766{
 767        BT_DBG("hu %p", hu);
 768        return 0;
 769}
 770
 771static const struct hci_uart_proto h5p = {
 772        .id             = HCI_UART_3WIRE,
 773        .name           = "Three-wire (H5)",
 774        .open           = h5_open,
 775        .close          = h5_close,
 776        .setup          = h5_setup,
 777        .recv           = h5_recv,
 778        .enqueue        = h5_enqueue,
 779        .dequeue        = h5_dequeue,
 780        .flush          = h5_flush,
 781};
 782
 783static int h5_serdev_probe(struct serdev_device *serdev)
 784{
 785        const struct acpi_device_id *match;
 786        struct device *dev = &serdev->dev;
 787        struct h5 *h5;
 788
 789        h5 = devm_kzalloc(dev, sizeof(*h5), GFP_KERNEL);
 790        if (!h5)
 791                return -ENOMEM;
 792
 793        set_bit(HCI_UART_RESET_ON_INIT, &h5->serdev_hu.flags);
 794
 795        h5->hu = &h5->serdev_hu;
 796        h5->serdev_hu.serdev = serdev;
 797        serdev_device_set_drvdata(serdev, h5);
 798
 799        if (has_acpi_companion(dev)) {
 800                match = acpi_match_device(dev->driver->acpi_match_table, dev);
 801                if (!match)
 802                        return -ENODEV;
 803
 804                h5->vnd = (const struct h5_vnd *)match->driver_data;
 805                h5->id  = (char *)match->id;
 806
 807                if (h5->vnd->acpi_gpio_map)
 808                        devm_acpi_dev_add_driver_gpios(dev,
 809                                                       h5->vnd->acpi_gpio_map);
 810        }
 811
 812        h5->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
 813        if (IS_ERR(h5->enable_gpio))
 814                return PTR_ERR(h5->enable_gpio);
 815
 816        h5->device_wake_gpio = devm_gpiod_get_optional(dev, "device-wake",
 817                                                       GPIOD_OUT_LOW);
 818        if (IS_ERR(h5->device_wake_gpio))
 819                return PTR_ERR(h5->device_wake_gpio);
 820
 821        return hci_uart_register_device(&h5->serdev_hu, &h5p);
 822}
 823
 824static void h5_serdev_remove(struct serdev_device *serdev)
 825{
 826        struct h5 *h5 = serdev_device_get_drvdata(serdev);
 827
 828        hci_uart_unregister_device(&h5->serdev_hu);
 829}
 830
 831static int __maybe_unused h5_serdev_suspend(struct device *dev)
 832{
 833        struct h5 *h5 = dev_get_drvdata(dev);
 834        int ret = 0;
 835
 836        if (h5->vnd && h5->vnd->suspend)
 837                ret = h5->vnd->suspend(h5);
 838
 839        return ret;
 840}
 841
 842static int __maybe_unused h5_serdev_resume(struct device *dev)
 843{
 844        struct h5 *h5 = dev_get_drvdata(dev);
 845        int ret = 0;
 846
 847        if (h5->vnd && h5->vnd->resume)
 848                ret = h5->vnd->resume(h5);
 849
 850        return ret;
 851}
 852
 853#ifdef CONFIG_BT_HCIUART_RTL
 854static int h5_btrtl_setup(struct h5 *h5)
 855{
 856        struct btrtl_device_info *btrtl_dev;
 857        struct sk_buff *skb;
 858        __le32 baudrate_data;
 859        u32 device_baudrate;
 860        unsigned int controller_baudrate;
 861        bool flow_control;
 862        int err;
 863
 864        btrtl_dev = btrtl_initialize(h5->hu->hdev, h5->id);
 865        if (IS_ERR(btrtl_dev))
 866                return PTR_ERR(btrtl_dev);
 867
 868        err = btrtl_get_uart_settings(h5->hu->hdev, btrtl_dev,
 869                                      &controller_baudrate, &device_baudrate,
 870                                      &flow_control);
 871        if (err)
 872                goto out_free;
 873
 874        baudrate_data = cpu_to_le32(device_baudrate);
 875        skb = __hci_cmd_sync(h5->hu->hdev, 0xfc17, sizeof(baudrate_data),
 876                             &baudrate_data, HCI_INIT_TIMEOUT);
 877        if (IS_ERR(skb)) {
 878                rtl_dev_err(h5->hu->hdev, "set baud rate command failed\n");
 879                err = PTR_ERR(skb);
 880                goto out_free;
 881        } else {
 882                kfree_skb(skb);
 883        }
 884        /* Give the device some time to set up the new baudrate. */
 885        usleep_range(10000, 20000);
 886
 887        serdev_device_set_baudrate(h5->hu->serdev, controller_baudrate);
 888        serdev_device_set_flow_control(h5->hu->serdev, flow_control);
 889
 890        err = btrtl_download_firmware(h5->hu->hdev, btrtl_dev);
 891        /* Give the device some time before the hci-core sends it a reset */
 892        usleep_range(10000, 20000);
 893
 894out_free:
 895        btrtl_free(btrtl_dev);
 896
 897        return err;
 898}
 899
 900static void h5_btrtl_open(struct h5 *h5)
 901{
 902        /* Devices always start with these fixed parameters */
 903        serdev_device_set_flow_control(h5->hu->serdev, false);
 904        serdev_device_set_parity(h5->hu->serdev, SERDEV_PARITY_EVEN);
 905        serdev_device_set_baudrate(h5->hu->serdev, 115200);
 906
 907        /* The controller needs up to 500ms to wakeup */
 908        gpiod_set_value_cansleep(h5->enable_gpio, 1);
 909        gpiod_set_value_cansleep(h5->device_wake_gpio, 1);
 910        msleep(500);
 911}
 912
 913static void h5_btrtl_close(struct h5 *h5)
 914{
 915        gpiod_set_value_cansleep(h5->device_wake_gpio, 0);
 916        gpiod_set_value_cansleep(h5->enable_gpio, 0);
 917}
 918
 919/* Suspend/resume support. On many devices the RTL BT device loses power during
 920 * suspend/resume, causing it to lose its firmware and all state. So we simply
 921 * turn it off on suspend and reprobe on resume.  This mirrors how RTL devices
 922 * are handled in the USB driver, where the USB_QUIRK_RESET_RESUME is used which
 923 * also causes a reprobe on resume.
 924 */
 925static int h5_btrtl_suspend(struct h5 *h5)
 926{
 927        serdev_device_set_flow_control(h5->hu->serdev, false);
 928        gpiod_set_value_cansleep(h5->device_wake_gpio, 0);
 929        gpiod_set_value_cansleep(h5->enable_gpio, 0);
 930        return 0;
 931}
 932
 933struct h5_btrtl_reprobe {
 934        struct device *dev;
 935        struct work_struct work;
 936};
 937
 938static void h5_btrtl_reprobe_worker(struct work_struct *work)
 939{
 940        struct h5_btrtl_reprobe *reprobe =
 941                container_of(work, struct h5_btrtl_reprobe, work);
 942        int ret;
 943
 944        ret = device_reprobe(reprobe->dev);
 945        if (ret && ret != -EPROBE_DEFER)
 946                dev_err(reprobe->dev, "Reprobe error %d\n", ret);
 947
 948        put_device(reprobe->dev);
 949        kfree(reprobe);
 950        module_put(THIS_MODULE);
 951}
 952
 953static int h5_btrtl_resume(struct h5 *h5)
 954{
 955        struct h5_btrtl_reprobe *reprobe;
 956
 957        reprobe = kzalloc(sizeof(*reprobe), GFP_KERNEL);
 958        if (!reprobe)
 959                return -ENOMEM;
 960
 961        __module_get(THIS_MODULE);
 962
 963        INIT_WORK(&reprobe->work, h5_btrtl_reprobe_worker);
 964        reprobe->dev = get_device(&h5->hu->serdev->dev);
 965        queue_work(system_long_wq, &reprobe->work);
 966        return 0;
 967}
 968
 969static const struct acpi_gpio_params btrtl_device_wake_gpios = { 0, 0, false };
 970static const struct acpi_gpio_params btrtl_enable_gpios = { 1, 0, false };
 971static const struct acpi_gpio_params btrtl_host_wake_gpios = { 2, 0, false };
 972static const struct acpi_gpio_mapping acpi_btrtl_gpios[] = {
 973        { "device-wake-gpios", &btrtl_device_wake_gpios, 1 },
 974        { "enable-gpios", &btrtl_enable_gpios, 1 },
 975        { "host-wake-gpios", &btrtl_host_wake_gpios, 1 },
 976        {},
 977};
 978
 979static struct h5_vnd rtl_vnd = {
 980        .setup          = h5_btrtl_setup,
 981        .open           = h5_btrtl_open,
 982        .close          = h5_btrtl_close,
 983        .suspend        = h5_btrtl_suspend,
 984        .resume         = h5_btrtl_resume,
 985        .acpi_gpio_map  = acpi_btrtl_gpios,
 986};
 987#endif
 988
 989#ifdef CONFIG_ACPI
 990static const struct acpi_device_id h5_acpi_match[] = {
 991#ifdef CONFIG_BT_HCIUART_RTL
 992        { "OBDA8723", (kernel_ulong_t)&rtl_vnd },
 993#endif
 994        { },
 995};
 996MODULE_DEVICE_TABLE(acpi, h5_acpi_match);
 997#endif
 998
 999static const struct dev_pm_ops h5_serdev_pm_ops = {
1000        SET_SYSTEM_SLEEP_PM_OPS(h5_serdev_suspend, h5_serdev_resume)
1001};
1002
1003static struct serdev_device_driver h5_serdev_driver = {
1004        .probe = h5_serdev_probe,
1005        .remove = h5_serdev_remove,
1006        .driver = {
1007                .name = "hci_uart_h5",
1008                .acpi_match_table = ACPI_PTR(h5_acpi_match),
1009                .pm = &h5_serdev_pm_ops,
1010        },
1011};
1012
1013int __init h5_init(void)
1014{
1015        serdev_device_driver_register(&h5_serdev_driver);
1016        return hci_uart_register_proto(&h5p);
1017}
1018
1019int __exit h5_deinit(void)
1020{
1021        serdev_device_driver_unregister(&h5_serdev_driver);
1022        return hci_uart_unregister_proto(&h5p);
1023}
1024