linux/drivers/hsi/clients/ssi_protocol.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * ssi_protocol.c
   4 *
   5 * Implementation of the SSI McSAAB improved protocol.
   6 *
   7 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
   8 * Copyright (C) 2013 Sebastian Reichel <sre@kernel.org>
   9 *
  10 * Contact: Carlos Chinea <carlos.chinea@nokia.com>
  11 */
  12
  13#include <linux/atomic.h>
  14#include <linux/clk.h>
  15#include <linux/device.h>
  16#include <linux/err.h>
  17#include <linux/gpio.h>
  18#include <linux/if_ether.h>
  19#include <linux/if_arp.h>
  20#include <linux/if_phonet.h>
  21#include <linux/init.h>
  22#include <linux/irq.h>
  23#include <linux/list.h>
  24#include <linux/module.h>
  25#include <linux/netdevice.h>
  26#include <linux/notifier.h>
  27#include <linux/scatterlist.h>
  28#include <linux/skbuff.h>
  29#include <linux/slab.h>
  30#include <linux/spinlock.h>
  31#include <linux/timer.h>
  32#include <linux/hsi/hsi.h>
  33#include <linux/hsi/ssi_protocol.h>
  34
  35void ssi_waketest(struct hsi_client *cl, unsigned int enable);
  36
  37#define SSIP_TXQUEUE_LEN        100
  38#define SSIP_MAX_MTU            65535
  39#define SSIP_DEFAULT_MTU        4000
  40#define PN_MEDIA_SOS            21
  41#define SSIP_MIN_PN_HDR         6       /* FIXME: Revisit */
  42#define SSIP_WDTOUT             2000    /* FIXME: has to be 500 msecs */
  43#define SSIP_KATOUT             15      /* 15 msecs */
  44#define SSIP_MAX_CMDS           5 /* Number of pre-allocated commands buffers */
  45#define SSIP_BYTES_TO_FRAMES(x) ((((x) - 1) >> 2) + 1)
  46#define SSIP_CMT_LOADER_SYNC    0x11223344
  47/*
  48 * SSI protocol command definitions
  49 */
  50#define SSIP_COMMAND(data)      ((data) >> 28)
  51#define SSIP_PAYLOAD(data)      ((data) & 0xfffffff)
  52/* Commands */
  53#define SSIP_SW_BREAK           0
  54#define SSIP_BOOTINFO_REQ       1
  55#define SSIP_BOOTINFO_RESP      2
  56#define SSIP_WAKETEST_RESULT    3
  57#define SSIP_START_TRANS        4
  58#define SSIP_READY              5
  59/* Payloads */
  60#define SSIP_DATA_VERSION(data) ((data) & 0xff)
  61#define SSIP_LOCAL_VERID        1
  62#define SSIP_WAKETEST_OK        0
  63#define SSIP_WAKETEST_FAILED    1
  64#define SSIP_PDU_LENGTH(data)   (((data) >> 8) & 0xffff)
  65#define SSIP_MSG_ID(data)       ((data) & 0xff)
  66/* Generic Command */
  67#define SSIP_CMD(cmd, payload)  (((cmd) << 28) | ((payload) & 0xfffffff))
  68/* Commands for the control channel */
  69#define SSIP_BOOTINFO_REQ_CMD(ver) \
  70                SSIP_CMD(SSIP_BOOTINFO_REQ, SSIP_DATA_VERSION(ver))
  71#define SSIP_BOOTINFO_RESP_CMD(ver) \
  72                SSIP_CMD(SSIP_BOOTINFO_RESP, SSIP_DATA_VERSION(ver))
  73#define SSIP_START_TRANS_CMD(pdulen, id) \
  74                SSIP_CMD(SSIP_START_TRANS, (((pdulen) << 8) | SSIP_MSG_ID(id)))
  75#define SSIP_READY_CMD          SSIP_CMD(SSIP_READY, 0)
  76#define SSIP_SWBREAK_CMD        SSIP_CMD(SSIP_SW_BREAK, 0)
  77
  78#define SSIP_WAKETEST_FLAG 0
  79
  80/* Main state machine states */
  81enum {
  82        INIT,
  83        HANDSHAKE,
  84        ACTIVE,
  85};
  86
  87/* Send state machine states */
  88enum {
  89        SEND_IDLE,
  90        WAIT4READY,
  91        SEND_READY,
  92        SENDING,
  93        SENDING_SWBREAK,
  94};
  95
  96/* Receive state machine states */
  97enum {
  98        RECV_IDLE,
  99        RECV_READY,
 100        RECEIVING,
 101};
 102
 103/**
 104 * struct ssi_protocol - SSI protocol (McSAAB) data
 105 * @main_state: Main state machine
 106 * @send_state: TX state machine
 107 * @recv_state: RX state machine
 108 * @flags: Flags, currently only used to follow wake line test
 109 * @rxid: RX data id
 110 * @txid: TX data id
 111 * @txqueue_len: TX queue length
 112 * @tx_wd: TX watchdog
 113 * @rx_wd: RX watchdog
 114 * @keep_alive: Workaround for SSI HW bug
 115 * @lock: To serialize access to this struct
 116 * @netdev: Phonet network device
 117 * @txqueue: TX data queue
 118 * @cmdqueue: Queue of free commands
 119 * @cl: HSI client own reference
 120 * @link: Link for ssip_list
 121 * @tx_usecount: Refcount to keep track the slaves that use the wake line
 122 * @channel_id_cmd: HSI channel id for command stream
 123 * @channel_id_data: HSI channel id for data stream
 124 */
 125struct ssi_protocol {
 126        unsigned int            main_state;
 127        unsigned int            send_state;
 128        unsigned int            recv_state;
 129        unsigned long           flags;
 130        u8                      rxid;
 131        u8                      txid;
 132        unsigned int            txqueue_len;
 133        struct timer_list       tx_wd;
 134        struct timer_list       rx_wd;
 135        struct timer_list       keep_alive; /* wake-up workaround */
 136        spinlock_t              lock;
 137        struct net_device       *netdev;
 138        struct list_head        txqueue;
 139        struct list_head        cmdqueue;
 140        struct work_struct      work;
 141        struct hsi_client       *cl;
 142        struct list_head        link;
 143        atomic_t                tx_usecnt;
 144        int                     channel_id_cmd;
 145        int                     channel_id_data;
 146};
 147
 148/* List of ssi protocol instances */
 149static LIST_HEAD(ssip_list);
 150
 151static void ssip_rxcmd_complete(struct hsi_msg *msg);
 152
 153static inline void ssip_set_cmd(struct hsi_msg *msg, u32 cmd)
 154{
 155        u32 *data;
 156
 157        data = sg_virt(msg->sgt.sgl);
 158        *data = cmd;
 159}
 160
 161static inline u32 ssip_get_cmd(struct hsi_msg *msg)
 162{
 163        u32 *data;
 164
 165        data = sg_virt(msg->sgt.sgl);
 166
 167        return *data;
 168}
 169
 170static void ssip_skb_to_msg(struct sk_buff *skb, struct hsi_msg *msg)
 171{
 172        skb_frag_t *frag;
 173        struct scatterlist *sg;
 174        int i;
 175
 176        BUG_ON(msg->sgt.nents != (unsigned int)(skb_shinfo(skb)->nr_frags + 1));
 177
 178        sg = msg->sgt.sgl;
 179        sg_set_buf(sg, skb->data, skb_headlen(skb));
 180        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 181                sg = sg_next(sg);
 182                BUG_ON(!sg);
 183                frag = &skb_shinfo(skb)->frags[i];
 184                sg_set_page(sg, frag->page.p, frag->size, frag->page_offset);
 185        }
 186}
 187
 188static void ssip_free_data(struct hsi_msg *msg)
 189{
 190        struct sk_buff *skb;
 191
 192        skb = msg->context;
 193        pr_debug("free data: msg %p context %p skb %p\n", msg, msg->context,
 194                                                                skb);
 195        msg->destructor = NULL;
 196        dev_kfree_skb(skb);
 197        hsi_free_msg(msg);
 198}
 199
 200static struct hsi_msg *ssip_alloc_data(struct ssi_protocol *ssi,
 201                                        struct sk_buff *skb, gfp_t flags)
 202{
 203        struct hsi_msg *msg;
 204
 205        msg = hsi_alloc_msg(skb_shinfo(skb)->nr_frags + 1, flags);
 206        if (!msg)
 207                return NULL;
 208        ssip_skb_to_msg(skb, msg);
 209        msg->destructor = ssip_free_data;
 210        msg->channel = ssi->channel_id_data;
 211        msg->context = skb;
 212
 213        return msg;
 214}
 215
 216static inline void ssip_release_cmd(struct hsi_msg *msg)
 217{
 218        struct ssi_protocol *ssi = hsi_client_drvdata(msg->cl);
 219
 220        dev_dbg(&msg->cl->device, "Release cmd 0x%08x\n", ssip_get_cmd(msg));
 221        spin_lock_bh(&ssi->lock);
 222        list_add_tail(&msg->link, &ssi->cmdqueue);
 223        spin_unlock_bh(&ssi->lock);
 224}
 225
 226static struct hsi_msg *ssip_claim_cmd(struct ssi_protocol *ssi)
 227{
 228        struct hsi_msg *msg;
 229
 230        BUG_ON(list_empty(&ssi->cmdqueue));
 231
 232        spin_lock_bh(&ssi->lock);
 233        msg = list_first_entry(&ssi->cmdqueue, struct hsi_msg, link);
 234        list_del(&msg->link);
 235        spin_unlock_bh(&ssi->lock);
 236        msg->destructor = ssip_release_cmd;
 237
 238        return msg;
 239}
 240
 241static void ssip_free_cmds(struct ssi_protocol *ssi)
 242{
 243        struct hsi_msg *msg, *tmp;
 244
 245        list_for_each_entry_safe(msg, tmp, &ssi->cmdqueue, link) {
 246                list_del(&msg->link);
 247                msg->destructor = NULL;
 248                kfree(sg_virt(msg->sgt.sgl));
 249                hsi_free_msg(msg);
 250        }
 251}
 252
 253static int ssip_alloc_cmds(struct ssi_protocol *ssi)
 254{
 255        struct hsi_msg *msg;
 256        u32 *buf;
 257        unsigned int i;
 258
 259        for (i = 0; i < SSIP_MAX_CMDS; i++) {
 260                msg = hsi_alloc_msg(1, GFP_KERNEL);
 261                if (!msg)
 262                        goto out;
 263                buf = kmalloc(sizeof(*buf), GFP_KERNEL);
 264                if (!buf) {
 265                        hsi_free_msg(msg);
 266                        goto out;
 267                }
 268                sg_init_one(msg->sgt.sgl, buf, sizeof(*buf));
 269                msg->channel = ssi->channel_id_cmd;
 270                list_add_tail(&msg->link, &ssi->cmdqueue);
 271        }
 272
 273        return 0;
 274out:
 275        ssip_free_cmds(ssi);
 276
 277        return -ENOMEM;
 278}
 279
 280static void ssip_set_rxstate(struct ssi_protocol *ssi, unsigned int state)
 281{
 282        ssi->recv_state = state;
 283        switch (state) {
 284        case RECV_IDLE:
 285                del_timer(&ssi->rx_wd);
 286                if (ssi->send_state == SEND_IDLE)
 287                        del_timer(&ssi->keep_alive);
 288                break;
 289        case RECV_READY:
 290                /* CMT speech workaround */
 291                if (atomic_read(&ssi->tx_usecnt))
 292                        break;
 293                /* Otherwise fall through */
 294        case RECEIVING:
 295                mod_timer(&ssi->keep_alive, jiffies +
 296                                                msecs_to_jiffies(SSIP_KATOUT));
 297                mod_timer(&ssi->rx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
 298                break;
 299        default:
 300                break;
 301        }
 302}
 303
 304static void ssip_set_txstate(struct ssi_protocol *ssi, unsigned int state)
 305{
 306        ssi->send_state = state;
 307        switch (state) {
 308        case SEND_IDLE:
 309        case SEND_READY:
 310                del_timer(&ssi->tx_wd);
 311                if (ssi->recv_state == RECV_IDLE)
 312                        del_timer(&ssi->keep_alive);
 313                break;
 314        case WAIT4READY:
 315        case SENDING:
 316        case SENDING_SWBREAK:
 317                mod_timer(&ssi->keep_alive,
 318                                jiffies + msecs_to_jiffies(SSIP_KATOUT));
 319                mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
 320                break;
 321        default:
 322                break;
 323        }
 324}
 325
 326struct hsi_client *ssip_slave_get_master(struct hsi_client *slave)
 327{
 328        struct hsi_client *master = ERR_PTR(-ENODEV);
 329        struct ssi_protocol *ssi;
 330
 331        list_for_each_entry(ssi, &ssip_list, link)
 332                if (slave->device.parent == ssi->cl->device.parent) {
 333                        master = ssi->cl;
 334                        break;
 335                }
 336
 337        return master;
 338}
 339EXPORT_SYMBOL_GPL(ssip_slave_get_master);
 340
 341int ssip_slave_start_tx(struct hsi_client *master)
 342{
 343        struct ssi_protocol *ssi = hsi_client_drvdata(master);
 344
 345        dev_dbg(&master->device, "start TX %d\n", atomic_read(&ssi->tx_usecnt));
 346        spin_lock_bh(&ssi->lock);
 347        if (ssi->send_state == SEND_IDLE) {
 348                ssip_set_txstate(ssi, WAIT4READY);
 349                hsi_start_tx(master);
 350        }
 351        spin_unlock_bh(&ssi->lock);
 352        atomic_inc(&ssi->tx_usecnt);
 353
 354        return 0;
 355}
 356EXPORT_SYMBOL_GPL(ssip_slave_start_tx);
 357
 358int ssip_slave_stop_tx(struct hsi_client *master)
 359{
 360        struct ssi_protocol *ssi = hsi_client_drvdata(master);
 361
 362        WARN_ON_ONCE(atomic_read(&ssi->tx_usecnt) == 0);
 363
 364        if (atomic_dec_and_test(&ssi->tx_usecnt)) {
 365                spin_lock_bh(&ssi->lock);
 366                if ((ssi->send_state == SEND_READY) ||
 367                        (ssi->send_state == WAIT4READY)) {
 368                        ssip_set_txstate(ssi, SEND_IDLE);
 369                        hsi_stop_tx(master);
 370                }
 371                spin_unlock_bh(&ssi->lock);
 372        }
 373        dev_dbg(&master->device, "stop TX %d\n", atomic_read(&ssi->tx_usecnt));
 374
 375        return 0;
 376}
 377EXPORT_SYMBOL_GPL(ssip_slave_stop_tx);
 378
 379int ssip_slave_running(struct hsi_client *master)
 380{
 381        struct ssi_protocol *ssi = hsi_client_drvdata(master);
 382        return netif_running(ssi->netdev);
 383}
 384EXPORT_SYMBOL_GPL(ssip_slave_running);
 385
 386static void ssip_reset(struct hsi_client *cl)
 387{
 388        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 389        struct list_head *head, *tmp;
 390        struct hsi_msg *msg;
 391
 392        if (netif_running(ssi->netdev))
 393                netif_carrier_off(ssi->netdev);
 394        hsi_flush(cl);
 395        spin_lock_bh(&ssi->lock);
 396        if (ssi->send_state != SEND_IDLE)
 397                hsi_stop_tx(cl);
 398        spin_unlock_bh(&ssi->lock);
 399        if (test_and_clear_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
 400                ssi_waketest(cl, 0); /* FIXME: To be removed */
 401        spin_lock_bh(&ssi->lock);
 402        del_timer(&ssi->rx_wd);
 403        del_timer(&ssi->tx_wd);
 404        del_timer(&ssi->keep_alive);
 405        ssi->main_state = 0;
 406        ssi->send_state = 0;
 407        ssi->recv_state = 0;
 408        ssi->flags = 0;
 409        ssi->rxid = 0;
 410        ssi->txid = 0;
 411        list_for_each_safe(head, tmp, &ssi->txqueue) {
 412                msg = list_entry(head, struct hsi_msg, link);
 413                dev_dbg(&cl->device, "Pending TX data\n");
 414                list_del(head);
 415                ssip_free_data(msg);
 416        }
 417        ssi->txqueue_len = 0;
 418        spin_unlock_bh(&ssi->lock);
 419}
 420
 421static void ssip_dump_state(struct hsi_client *cl)
 422{
 423        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 424        struct hsi_msg *msg;
 425
 426        spin_lock_bh(&ssi->lock);
 427        dev_err(&cl->device, "Main state: %d\n", ssi->main_state);
 428        dev_err(&cl->device, "Recv state: %d\n", ssi->recv_state);
 429        dev_err(&cl->device, "Send state: %d\n", ssi->send_state);
 430        dev_err(&cl->device, "CMT %s\n", (ssi->main_state == ACTIVE) ?
 431                                                        "Online" : "Offline");
 432        dev_err(&cl->device, "Wake test %d\n",
 433                                test_bit(SSIP_WAKETEST_FLAG, &ssi->flags));
 434        dev_err(&cl->device, "Data RX id: %d\n", ssi->rxid);
 435        dev_err(&cl->device, "Data TX id: %d\n", ssi->txid);
 436
 437        list_for_each_entry(msg, &ssi->txqueue, link)
 438                dev_err(&cl->device, "pending TX data (%p)\n", msg);
 439        spin_unlock_bh(&ssi->lock);
 440}
 441
 442static void ssip_error(struct hsi_client *cl)
 443{
 444        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 445        struct hsi_msg *msg;
 446
 447        ssip_dump_state(cl);
 448        ssip_reset(cl);
 449        msg = ssip_claim_cmd(ssi);
 450        msg->complete = ssip_rxcmd_complete;
 451        hsi_async_read(cl, msg);
 452}
 453
 454static void ssip_keep_alive(struct timer_list *t)
 455{
 456        struct ssi_protocol *ssi = from_timer(ssi, t, keep_alive);
 457        struct hsi_client *cl = ssi->cl;
 458
 459        dev_dbg(&cl->device, "Keep alive kick in: m(%d) r(%d) s(%d)\n",
 460                ssi->main_state, ssi->recv_state, ssi->send_state);
 461
 462        spin_lock(&ssi->lock);
 463        if (ssi->recv_state == RECV_IDLE)
 464                switch (ssi->send_state) {
 465                case SEND_READY:
 466                        if (atomic_read(&ssi->tx_usecnt) == 0)
 467                                break;
 468                        /*
 469                         * Fall through. Workaround for cmt-speech
 470                         * in that case we relay on audio timers.
 471                         */
 472                case SEND_IDLE:
 473                        spin_unlock(&ssi->lock);
 474                        return;
 475                }
 476        mod_timer(&ssi->keep_alive, jiffies + msecs_to_jiffies(SSIP_KATOUT));
 477        spin_unlock(&ssi->lock);
 478}
 479
 480static void ssip_rx_wd(struct timer_list *t)
 481{
 482        struct ssi_protocol *ssi = from_timer(ssi, t, rx_wd);
 483        struct hsi_client *cl = ssi->cl;
 484
 485        dev_err(&cl->device, "Watchdog triggered\n");
 486        ssip_error(cl);
 487}
 488
 489static void ssip_tx_wd(struct timer_list *t)
 490{
 491        struct ssi_protocol *ssi = from_timer(ssi, t, tx_wd);
 492        struct hsi_client *cl = ssi->cl;
 493
 494        dev_err(&cl->device, "Watchdog triggered\n");
 495        ssip_error(cl);
 496}
 497
 498static void ssip_send_bootinfo_req_cmd(struct hsi_client *cl)
 499{
 500        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 501        struct hsi_msg *msg;
 502
 503        dev_dbg(&cl->device, "Issuing BOOT INFO REQ command\n");
 504        msg = ssip_claim_cmd(ssi);
 505        ssip_set_cmd(msg, SSIP_BOOTINFO_REQ_CMD(SSIP_LOCAL_VERID));
 506        msg->complete = ssip_release_cmd;
 507        hsi_async_write(cl, msg);
 508        dev_dbg(&cl->device, "Issuing RX command\n");
 509        msg = ssip_claim_cmd(ssi);
 510        msg->complete = ssip_rxcmd_complete;
 511        hsi_async_read(cl, msg);
 512}
 513
 514static void ssip_start_rx(struct hsi_client *cl)
 515{
 516        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 517        struct hsi_msg *msg;
 518
 519        dev_dbg(&cl->device, "RX start M(%d) R(%d)\n", ssi->main_state,
 520                                                ssi->recv_state);
 521        spin_lock_bh(&ssi->lock);
 522        /*
 523         * We can have two UP events in a row due to a short low
 524         * high transition. Therefore we need to ignore the sencond UP event.
 525         */
 526        if ((ssi->main_state != ACTIVE) || (ssi->recv_state == RECV_READY)) {
 527                spin_unlock_bh(&ssi->lock);
 528                return;
 529        }
 530        ssip_set_rxstate(ssi, RECV_READY);
 531        spin_unlock_bh(&ssi->lock);
 532
 533        msg = ssip_claim_cmd(ssi);
 534        ssip_set_cmd(msg, SSIP_READY_CMD);
 535        msg->complete = ssip_release_cmd;
 536        dev_dbg(&cl->device, "Send READY\n");
 537        hsi_async_write(cl, msg);
 538}
 539
 540static void ssip_stop_rx(struct hsi_client *cl)
 541{
 542        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 543
 544        dev_dbg(&cl->device, "RX stop M(%d)\n", ssi->main_state);
 545        spin_lock_bh(&ssi->lock);
 546        if (likely(ssi->main_state == ACTIVE))
 547                ssip_set_rxstate(ssi, RECV_IDLE);
 548        spin_unlock_bh(&ssi->lock);
 549}
 550
 551static void ssip_free_strans(struct hsi_msg *msg)
 552{
 553        ssip_free_data(msg->context);
 554        ssip_release_cmd(msg);
 555}
 556
 557static void ssip_strans_complete(struct hsi_msg *msg)
 558{
 559        struct hsi_client *cl = msg->cl;
 560        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 561        struct hsi_msg *data;
 562
 563        data = msg->context;
 564        ssip_release_cmd(msg);
 565        spin_lock_bh(&ssi->lock);
 566        ssip_set_txstate(ssi, SENDING);
 567        spin_unlock_bh(&ssi->lock);
 568        hsi_async_write(cl, data);
 569}
 570
 571static int ssip_xmit(struct hsi_client *cl)
 572{
 573        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 574        struct hsi_msg *msg, *dmsg;
 575        struct sk_buff *skb;
 576
 577        spin_lock_bh(&ssi->lock);
 578        if (list_empty(&ssi->txqueue)) {
 579                spin_unlock_bh(&ssi->lock);
 580                return 0;
 581        }
 582        dmsg = list_first_entry(&ssi->txqueue, struct hsi_msg, link);
 583        list_del(&dmsg->link);
 584        ssi->txqueue_len--;
 585        spin_unlock_bh(&ssi->lock);
 586
 587        msg = ssip_claim_cmd(ssi);
 588        skb = dmsg->context;
 589        msg->context = dmsg;
 590        msg->complete = ssip_strans_complete;
 591        msg->destructor = ssip_free_strans;
 592
 593        spin_lock_bh(&ssi->lock);
 594        ssip_set_cmd(msg, SSIP_START_TRANS_CMD(SSIP_BYTES_TO_FRAMES(skb->len),
 595                                                                ssi->txid));
 596        ssi->txid++;
 597        ssip_set_txstate(ssi, SENDING);
 598        spin_unlock_bh(&ssi->lock);
 599
 600        dev_dbg(&cl->device, "Send STRANS (%d frames)\n",
 601                                                SSIP_BYTES_TO_FRAMES(skb->len));
 602
 603        return hsi_async_write(cl, msg);
 604}
 605
 606/* In soft IRQ context */
 607static void ssip_pn_rx(struct sk_buff *skb)
 608{
 609        struct net_device *dev = skb->dev;
 610
 611        if (unlikely(!netif_running(dev))) {
 612                dev_dbg(&dev->dev, "Drop RX packet\n");
 613                dev->stats.rx_dropped++;
 614                dev_kfree_skb(skb);
 615                return;
 616        }
 617        if (unlikely(!pskb_may_pull(skb, SSIP_MIN_PN_HDR))) {
 618                dev_dbg(&dev->dev, "Error drop RX packet\n");
 619                dev->stats.rx_errors++;
 620                dev->stats.rx_length_errors++;
 621                dev_kfree_skb(skb);
 622                return;
 623        }
 624        dev->stats.rx_packets++;
 625        dev->stats.rx_bytes += skb->len;
 626
 627        /* length field is exchanged in network byte order */
 628        ((u16 *)skb->data)[2] = ntohs(((u16 *)skb->data)[2]);
 629        dev_dbg(&dev->dev, "RX length fixed (%04x -> %u)\n",
 630                        ((u16 *)skb->data)[2], ntohs(((u16 *)skb->data)[2]));
 631
 632        skb->protocol = htons(ETH_P_PHONET);
 633        skb_reset_mac_header(skb);
 634        __skb_pull(skb, 1);
 635        netif_rx(skb);
 636}
 637
 638static void ssip_rx_data_complete(struct hsi_msg *msg)
 639{
 640        struct hsi_client *cl = msg->cl;
 641        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 642        struct sk_buff *skb;
 643
 644        if (msg->status == HSI_STATUS_ERROR) {
 645                dev_err(&cl->device, "RX data error\n");
 646                ssip_free_data(msg);
 647                ssip_error(cl);
 648                return;
 649        }
 650        del_timer(&ssi->rx_wd); /* FIXME: Revisit */
 651        skb = msg->context;
 652        ssip_pn_rx(skb);
 653        hsi_free_msg(msg);
 654}
 655
 656static void ssip_rx_bootinforeq(struct hsi_client *cl, u32 cmd)
 657{
 658        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 659        struct hsi_msg *msg;
 660
 661        /* Workaroud: Ignore CMT Loader message leftover */
 662        if (cmd == SSIP_CMT_LOADER_SYNC)
 663                return;
 664
 665        switch (ssi->main_state) {
 666        case ACTIVE:
 667                dev_err(&cl->device, "Boot info req on active state\n");
 668                ssip_error(cl);
 669                /* Fall through */
 670        case INIT:
 671        case HANDSHAKE:
 672                spin_lock_bh(&ssi->lock);
 673                ssi->main_state = HANDSHAKE;
 674                spin_unlock_bh(&ssi->lock);
 675
 676                if (!test_and_set_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
 677                        ssi_waketest(cl, 1); /* FIXME: To be removed */
 678
 679                spin_lock_bh(&ssi->lock);
 680                /* Start boot handshake watchdog */
 681                mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
 682                spin_unlock_bh(&ssi->lock);
 683                dev_dbg(&cl->device, "Send BOOTINFO_RESP\n");
 684                if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
 685                        dev_warn(&cl->device, "boot info req verid mismatch\n");
 686                msg = ssip_claim_cmd(ssi);
 687                ssip_set_cmd(msg, SSIP_BOOTINFO_RESP_CMD(SSIP_LOCAL_VERID));
 688                msg->complete = ssip_release_cmd;
 689                hsi_async_write(cl, msg);
 690                break;
 691        default:
 692                dev_dbg(&cl->device, "Wrong state M(%d)\n", ssi->main_state);
 693                break;
 694        }
 695}
 696
 697static void ssip_rx_bootinforesp(struct hsi_client *cl, u32 cmd)
 698{
 699        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 700
 701        if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
 702                dev_warn(&cl->device, "boot info resp verid mismatch\n");
 703
 704        spin_lock_bh(&ssi->lock);
 705        if (ssi->main_state != ACTIVE)
 706                /* Use tx_wd as a boot watchdog in non ACTIVE state */
 707                mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
 708        else
 709                dev_dbg(&cl->device, "boot info resp ignored M(%d)\n",
 710                                                        ssi->main_state);
 711        spin_unlock_bh(&ssi->lock);
 712}
 713
 714static void ssip_rx_waketest(struct hsi_client *cl, u32 cmd)
 715{
 716        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 717        unsigned int wkres = SSIP_PAYLOAD(cmd);
 718
 719        spin_lock_bh(&ssi->lock);
 720        if (ssi->main_state != HANDSHAKE) {
 721                dev_dbg(&cl->device, "wake lines test ignored M(%d)\n",
 722                                                        ssi->main_state);
 723                spin_unlock_bh(&ssi->lock);
 724                return;
 725        }
 726        spin_unlock_bh(&ssi->lock);
 727
 728        if (test_and_clear_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
 729                ssi_waketest(cl, 0); /* FIXME: To be removed */
 730
 731        spin_lock_bh(&ssi->lock);
 732        ssi->main_state = ACTIVE;
 733        del_timer(&ssi->tx_wd); /* Stop boot handshake timer */
 734        spin_unlock_bh(&ssi->lock);
 735
 736        dev_notice(&cl->device, "WAKELINES TEST %s\n",
 737                                wkres & SSIP_WAKETEST_FAILED ? "FAILED" : "OK");
 738        if (wkres & SSIP_WAKETEST_FAILED) {
 739                ssip_error(cl);
 740                return;
 741        }
 742        dev_dbg(&cl->device, "CMT is ONLINE\n");
 743        netif_wake_queue(ssi->netdev);
 744        netif_carrier_on(ssi->netdev);
 745}
 746
 747static void ssip_rx_ready(struct hsi_client *cl)
 748{
 749        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 750
 751        spin_lock_bh(&ssi->lock);
 752        if (unlikely(ssi->main_state != ACTIVE)) {
 753                dev_dbg(&cl->device, "READY on wrong state: S(%d) M(%d)\n",
 754                                        ssi->send_state, ssi->main_state);
 755                spin_unlock_bh(&ssi->lock);
 756                return;
 757        }
 758        if (ssi->send_state != WAIT4READY) {
 759                dev_dbg(&cl->device, "Ignore spurious READY command\n");
 760                spin_unlock_bh(&ssi->lock);
 761                return;
 762        }
 763        ssip_set_txstate(ssi, SEND_READY);
 764        spin_unlock_bh(&ssi->lock);
 765        ssip_xmit(cl);
 766}
 767
 768static void ssip_rx_strans(struct hsi_client *cl, u32 cmd)
 769{
 770        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 771        struct sk_buff *skb;
 772        struct hsi_msg *msg;
 773        int len = SSIP_PDU_LENGTH(cmd);
 774
 775        dev_dbg(&cl->device, "RX strans: %d frames\n", len);
 776        spin_lock_bh(&ssi->lock);
 777        if (unlikely(ssi->main_state != ACTIVE)) {
 778                dev_err(&cl->device, "START TRANS wrong state: S(%d) M(%d)\n",
 779                                        ssi->send_state, ssi->main_state);
 780                spin_unlock_bh(&ssi->lock);
 781                return;
 782        }
 783        ssip_set_rxstate(ssi, RECEIVING);
 784        if (unlikely(SSIP_MSG_ID(cmd) != ssi->rxid)) {
 785                dev_err(&cl->device, "START TRANS id %d expected %d\n",
 786                                        SSIP_MSG_ID(cmd), ssi->rxid);
 787                spin_unlock_bh(&ssi->lock);
 788                goto out1;
 789        }
 790        ssi->rxid++;
 791        spin_unlock_bh(&ssi->lock);
 792        skb = netdev_alloc_skb(ssi->netdev, len * 4);
 793        if (unlikely(!skb)) {
 794                dev_err(&cl->device, "No memory for rx skb\n");
 795                goto out1;
 796        }
 797        skb->dev = ssi->netdev;
 798        skb_put(skb, len * 4);
 799        msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
 800        if (unlikely(!msg)) {
 801                dev_err(&cl->device, "No memory for RX data msg\n");
 802                goto out2;
 803        }
 804        msg->complete = ssip_rx_data_complete;
 805        hsi_async_read(cl, msg);
 806
 807        return;
 808out2:
 809        dev_kfree_skb(skb);
 810out1:
 811        ssip_error(cl);
 812}
 813
 814static void ssip_rxcmd_complete(struct hsi_msg *msg)
 815{
 816        struct hsi_client *cl = msg->cl;
 817        u32 cmd = ssip_get_cmd(msg);
 818        unsigned int cmdid = SSIP_COMMAND(cmd);
 819
 820        if (msg->status == HSI_STATUS_ERROR) {
 821                dev_err(&cl->device, "RX error detected\n");
 822                ssip_release_cmd(msg);
 823                ssip_error(cl);
 824                return;
 825        }
 826        hsi_async_read(cl, msg);
 827        dev_dbg(&cl->device, "RX cmd: 0x%08x\n", cmd);
 828        switch (cmdid) {
 829        case SSIP_SW_BREAK:
 830                /* Ignored */
 831                break;
 832        case SSIP_BOOTINFO_REQ:
 833                ssip_rx_bootinforeq(cl, cmd);
 834                break;
 835        case SSIP_BOOTINFO_RESP:
 836                ssip_rx_bootinforesp(cl, cmd);
 837                break;
 838        case SSIP_WAKETEST_RESULT:
 839                ssip_rx_waketest(cl, cmd);
 840                break;
 841        case SSIP_START_TRANS:
 842                ssip_rx_strans(cl, cmd);
 843                break;
 844        case SSIP_READY:
 845                ssip_rx_ready(cl);
 846                break;
 847        default:
 848                dev_warn(&cl->device, "command 0x%08x not supported\n", cmd);
 849                break;
 850        }
 851}
 852
 853static void ssip_swbreak_complete(struct hsi_msg *msg)
 854{
 855        struct hsi_client *cl = msg->cl;
 856        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 857
 858        ssip_release_cmd(msg);
 859        spin_lock_bh(&ssi->lock);
 860        if (list_empty(&ssi->txqueue)) {
 861                if (atomic_read(&ssi->tx_usecnt)) {
 862                        ssip_set_txstate(ssi, SEND_READY);
 863                } else {
 864                        ssip_set_txstate(ssi, SEND_IDLE);
 865                        hsi_stop_tx(cl);
 866                }
 867                spin_unlock_bh(&ssi->lock);
 868        } else {
 869                spin_unlock_bh(&ssi->lock);
 870                ssip_xmit(cl);
 871        }
 872        netif_wake_queue(ssi->netdev);
 873}
 874
 875static void ssip_tx_data_complete(struct hsi_msg *msg)
 876{
 877        struct hsi_client *cl = msg->cl;
 878        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 879        struct hsi_msg *cmsg;
 880
 881        if (msg->status == HSI_STATUS_ERROR) {
 882                dev_err(&cl->device, "TX data error\n");
 883                ssip_error(cl);
 884                goto out;
 885        }
 886        spin_lock_bh(&ssi->lock);
 887        if (list_empty(&ssi->txqueue)) {
 888                ssip_set_txstate(ssi, SENDING_SWBREAK);
 889                spin_unlock_bh(&ssi->lock);
 890                cmsg = ssip_claim_cmd(ssi);
 891                ssip_set_cmd(cmsg, SSIP_SWBREAK_CMD);
 892                cmsg->complete = ssip_swbreak_complete;
 893                dev_dbg(&cl->device, "Send SWBREAK\n");
 894                hsi_async_write(cl, cmsg);
 895        } else {
 896                spin_unlock_bh(&ssi->lock);
 897                ssip_xmit(cl);
 898        }
 899out:
 900        ssip_free_data(msg);
 901}
 902
 903static void ssip_port_event(struct hsi_client *cl, unsigned long event)
 904{
 905        switch (event) {
 906        case HSI_EVENT_START_RX:
 907                ssip_start_rx(cl);
 908                break;
 909        case HSI_EVENT_STOP_RX:
 910                ssip_stop_rx(cl);
 911                break;
 912        default:
 913                return;
 914        }
 915}
 916
 917static int ssip_pn_open(struct net_device *dev)
 918{
 919        struct hsi_client *cl = to_hsi_client(dev->dev.parent);
 920        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 921        int err;
 922
 923        err = hsi_claim_port(cl, 1);
 924        if (err < 0) {
 925                dev_err(&cl->device, "SSI port already claimed\n");
 926                return err;
 927        }
 928        err = hsi_register_port_event(cl, ssip_port_event);
 929        if (err < 0) {
 930                dev_err(&cl->device, "Register HSI port event failed (%d)\n",
 931                        err);
 932                return err;
 933        }
 934        dev_dbg(&cl->device, "Configuring SSI port\n");
 935        hsi_setup(cl);
 936
 937        if (!test_and_set_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
 938                ssi_waketest(cl, 1); /* FIXME: To be removed */
 939
 940        spin_lock_bh(&ssi->lock);
 941        ssi->main_state = HANDSHAKE;
 942        spin_unlock_bh(&ssi->lock);
 943
 944        ssip_send_bootinfo_req_cmd(cl);
 945
 946        return 0;
 947}
 948
 949static int ssip_pn_stop(struct net_device *dev)
 950{
 951        struct hsi_client *cl = to_hsi_client(dev->dev.parent);
 952
 953        ssip_reset(cl);
 954        hsi_unregister_port_event(cl);
 955        hsi_release_port(cl);
 956
 957        return 0;
 958}
 959
 960static void ssip_xmit_work(struct work_struct *work)
 961{
 962        struct ssi_protocol *ssi =
 963                                container_of(work, struct ssi_protocol, work);
 964        struct hsi_client *cl = ssi->cl;
 965
 966        ssip_xmit(cl);
 967}
 968
 969static int ssip_pn_xmit(struct sk_buff *skb, struct net_device *dev)
 970{
 971        struct hsi_client *cl = to_hsi_client(dev->dev.parent);
 972        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
 973        struct hsi_msg *msg;
 974
 975        if ((skb->protocol != htons(ETH_P_PHONET)) ||
 976                                        (skb->len < SSIP_MIN_PN_HDR))
 977                goto drop;
 978        /* Pad to 32-bits - FIXME: Revisit*/
 979        if ((skb->len & 3) && skb_pad(skb, 4 - (skb->len & 3)))
 980                goto inc_dropped;
 981
 982        /*
 983         * Modem sends Phonet messages over SSI with its own endianness.
 984         * Assume that modem has the same endianness as we do.
 985         */
 986        if (skb_cow_head(skb, 0))
 987                goto drop;
 988
 989        /* length field is exchanged in network byte order */
 990        ((u16 *)skb->data)[2] = htons(((u16 *)skb->data)[2]);
 991
 992        msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
 993        if (!msg) {
 994                dev_dbg(&cl->device, "Dropping tx data: No memory\n");
 995                goto drop;
 996        }
 997        msg->complete = ssip_tx_data_complete;
 998
 999        spin_lock_bh(&ssi->lock);
1000        if (unlikely(ssi->main_state != ACTIVE)) {
1001                spin_unlock_bh(&ssi->lock);
1002                dev_dbg(&cl->device, "Dropping tx data: CMT is OFFLINE\n");
1003                goto drop2;
1004        }
1005        list_add_tail(&msg->link, &ssi->txqueue);
1006        ssi->txqueue_len++;
1007        if (dev->tx_queue_len < ssi->txqueue_len) {
1008                dev_info(&cl->device, "TX queue full %d\n", ssi->txqueue_len);
1009                netif_stop_queue(dev);
1010        }
1011        if (ssi->send_state == SEND_IDLE) {
1012                ssip_set_txstate(ssi, WAIT4READY);
1013                spin_unlock_bh(&ssi->lock);
1014                dev_dbg(&cl->device, "Start TX qlen %d\n", ssi->txqueue_len);
1015                hsi_start_tx(cl);
1016        } else if (ssi->send_state == SEND_READY) {
1017                /* Needed for cmt-speech workaround */
1018                dev_dbg(&cl->device, "Start TX on SEND READY qlen %d\n",
1019                                                        ssi->txqueue_len);
1020                spin_unlock_bh(&ssi->lock);
1021                schedule_work(&ssi->work);
1022        } else {
1023                spin_unlock_bh(&ssi->lock);
1024        }
1025        dev->stats.tx_packets++;
1026        dev->stats.tx_bytes += skb->len;
1027
1028        return 0;
1029drop2:
1030        hsi_free_msg(msg);
1031drop:
1032        dev_kfree_skb(skb);
1033inc_dropped:
1034        dev->stats.tx_dropped++;
1035
1036        return 0;
1037}
1038
1039/* CMT reset event handler */
1040void ssip_reset_event(struct hsi_client *master)
1041{
1042        struct ssi_protocol *ssi = hsi_client_drvdata(master);
1043        dev_err(&ssi->cl->device, "CMT reset detected!\n");
1044        ssip_error(ssi->cl);
1045}
1046EXPORT_SYMBOL_GPL(ssip_reset_event);
1047
1048static const struct net_device_ops ssip_pn_ops = {
1049        .ndo_open       = ssip_pn_open,
1050        .ndo_stop       = ssip_pn_stop,
1051        .ndo_start_xmit = ssip_pn_xmit,
1052};
1053
1054static void ssip_pn_setup(struct net_device *dev)
1055{
1056        dev->features           = 0;
1057        dev->netdev_ops         = &ssip_pn_ops;
1058        dev->type               = ARPHRD_PHONET;
1059        dev->flags              = IFF_POINTOPOINT | IFF_NOARP;
1060        dev->mtu                = SSIP_DEFAULT_MTU;
1061        dev->hard_header_len    = 1;
1062        dev->dev_addr[0]        = PN_MEDIA_SOS;
1063        dev->addr_len           = 1;
1064        dev->tx_queue_len       = SSIP_TXQUEUE_LEN;
1065
1066        dev->needs_free_netdev  = true;
1067        dev->header_ops         = &phonet_header_ops;
1068}
1069
1070static int ssi_protocol_probe(struct device *dev)
1071{
1072        static const char ifname[] = "phonet%d";
1073        struct hsi_client *cl = to_hsi_client(dev);
1074        struct ssi_protocol *ssi;
1075        int err;
1076
1077        ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
1078        if (!ssi)
1079                return -ENOMEM;
1080
1081        spin_lock_init(&ssi->lock);
1082        timer_setup(&ssi->rx_wd, ssip_rx_wd, TIMER_DEFERRABLE);
1083        timer_setup(&ssi->tx_wd, ssip_tx_wd, TIMER_DEFERRABLE);
1084        timer_setup(&ssi->keep_alive, ssip_keep_alive, 0);
1085        INIT_LIST_HEAD(&ssi->txqueue);
1086        INIT_LIST_HEAD(&ssi->cmdqueue);
1087        atomic_set(&ssi->tx_usecnt, 0);
1088        hsi_client_set_drvdata(cl, ssi);
1089        ssi->cl = cl;
1090        INIT_WORK(&ssi->work, ssip_xmit_work);
1091
1092        ssi->channel_id_cmd = hsi_get_channel_id_by_name(cl, "mcsaab-control");
1093        if (ssi->channel_id_cmd < 0) {
1094                err = ssi->channel_id_cmd;
1095                dev_err(dev, "Could not get cmd channel (%d)\n", err);
1096                goto out;
1097        }
1098
1099        ssi->channel_id_data = hsi_get_channel_id_by_name(cl, "mcsaab-data");
1100        if (ssi->channel_id_data < 0) {
1101                err = ssi->channel_id_data;
1102                dev_err(dev, "Could not get data channel (%d)\n", err);
1103                goto out;
1104        }
1105
1106        err = ssip_alloc_cmds(ssi);
1107        if (err < 0) {
1108                dev_err(dev, "No memory for commands\n");
1109                goto out;
1110        }
1111
1112        ssi->netdev = alloc_netdev(0, ifname, NET_NAME_UNKNOWN, ssip_pn_setup);
1113        if (!ssi->netdev) {
1114                dev_err(dev, "No memory for netdev\n");
1115                err = -ENOMEM;
1116                goto out1;
1117        }
1118
1119        /* MTU range: 6 - 65535 */
1120        ssi->netdev->min_mtu = PHONET_MIN_MTU;
1121        ssi->netdev->max_mtu = SSIP_MAX_MTU;
1122
1123        SET_NETDEV_DEV(ssi->netdev, dev);
1124        netif_carrier_off(ssi->netdev);
1125        err = register_netdev(ssi->netdev);
1126        if (err < 0) {
1127                dev_err(dev, "Register netdev failed (%d)\n", err);
1128                goto out2;
1129        }
1130
1131        list_add(&ssi->link, &ssip_list);
1132
1133        dev_dbg(dev, "channel configuration: cmd=%d, data=%d\n",
1134                ssi->channel_id_cmd, ssi->channel_id_data);
1135
1136        return 0;
1137out2:
1138        free_netdev(ssi->netdev);
1139out1:
1140        ssip_free_cmds(ssi);
1141out:
1142        kfree(ssi);
1143
1144        return err;
1145}
1146
1147static int ssi_protocol_remove(struct device *dev)
1148{
1149        struct hsi_client *cl = to_hsi_client(dev);
1150        struct ssi_protocol *ssi = hsi_client_drvdata(cl);
1151
1152        list_del(&ssi->link);
1153        unregister_netdev(ssi->netdev);
1154        ssip_free_cmds(ssi);
1155        hsi_client_set_drvdata(cl, NULL);
1156        kfree(ssi);
1157
1158        return 0;
1159}
1160
1161static struct hsi_client_driver ssip_driver = {
1162        .driver = {
1163                .name   = "ssi-protocol",
1164                .owner  = THIS_MODULE,
1165                .probe  = ssi_protocol_probe,
1166                .remove = ssi_protocol_remove,
1167        },
1168};
1169
1170static int __init ssip_init(void)
1171{
1172        pr_info("SSI protocol aka McSAAB added\n");
1173
1174        return hsi_register_client_driver(&ssip_driver);
1175}
1176module_init(ssip_init);
1177
1178static void __exit ssip_exit(void)
1179{
1180        hsi_unregister_client_driver(&ssip_driver);
1181        pr_info("SSI protocol driver removed\n");
1182}
1183module_exit(ssip_exit);
1184
1185MODULE_ALIAS("hsi:ssi-protocol");
1186MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
1187MODULE_AUTHOR("Remi Denis-Courmont <remi.denis-courmont@nokia.com>");
1188MODULE_DESCRIPTION("SSI protocol improved aka McSAAB");
1189MODULE_LICENSE("GPL");
1190