linux/drivers/net/ethernet/qualcomm/qca_spi.c
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   1/*
   2 *   Copyright (c) 2011, 2012, Qualcomm Atheros Communications Inc.
   3 *   Copyright (c) 2014, I2SE GmbH
   4 *
   5 *   Permission to use, copy, modify, and/or distribute this software
   6 *   for any purpose with or without fee is hereby granted, provided
   7 *   that the above copyright notice and this permission notice appear
   8 *   in all copies.
   9 *
  10 *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  11 *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  12 *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  13 *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
  14 *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15 *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  16 *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  17 *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18 */
  19
  20/*   This module implements the Qualcomm Atheros SPI protocol for
  21 *   kernel-based SPI device; it is essentially an Ethernet-to-SPI
  22 *   serial converter;
  23 */
  24
  25#include <linux/errno.h>
  26#include <linux/etherdevice.h>
  27#include <linux/if_arp.h>
  28#include <linux/if_ether.h>
  29#include <linux/init.h>
  30#include <linux/interrupt.h>
  31#include <linux/jiffies.h>
  32#include <linux/kernel.h>
  33#include <linux/kthread.h>
  34#include <linux/module.h>
  35#include <linux/moduleparam.h>
  36#include <linux/netdevice.h>
  37#include <linux/of.h>
  38#include <linux/of_device.h>
  39#include <linux/of_net.h>
  40#include <linux/sched.h>
  41#include <linux/skbuff.h>
  42#include <linux/spi/spi.h>
  43#include <linux/types.h>
  44
  45#include "qca_7k.h"
  46#include "qca_7k_common.h"
  47#include "qca_debug.h"
  48#include "qca_spi.h"
  49
  50#define MAX_DMA_BURST_LEN 5000
  51
  52/*   Modules parameters     */
  53#define QCASPI_CLK_SPEED_MIN 1000000
  54#define QCASPI_CLK_SPEED_MAX 16000000
  55#define QCASPI_CLK_SPEED     8000000
  56static int qcaspi_clkspeed;
  57module_param(qcaspi_clkspeed, int, 0);
  58MODULE_PARM_DESC(qcaspi_clkspeed, "SPI bus clock speed (Hz). Use 1000000-16000000.");
  59
  60#define QCASPI_BURST_LEN_MIN 1
  61#define QCASPI_BURST_LEN_MAX MAX_DMA_BURST_LEN
  62static int qcaspi_burst_len = MAX_DMA_BURST_LEN;
  63module_param(qcaspi_burst_len, int, 0);
  64MODULE_PARM_DESC(qcaspi_burst_len, "Number of data bytes per burst. Use 1-5000.");
  65
  66#define QCASPI_PLUGGABLE_MIN 0
  67#define QCASPI_PLUGGABLE_MAX 1
  68static int qcaspi_pluggable = QCASPI_PLUGGABLE_MIN;
  69module_param(qcaspi_pluggable, int, 0);
  70MODULE_PARM_DESC(qcaspi_pluggable, "Pluggable SPI connection (yes/no).");
  71
  72#define QCASPI_WRITE_VERIFY_MIN 0
  73#define QCASPI_WRITE_VERIFY_MAX 3
  74static int wr_verify = QCASPI_WRITE_VERIFY_MIN;
  75module_param(wr_verify, int, 0);
  76MODULE_PARM_DESC(wr_verify, "SPI register write verify trails. Use 0-3.");
  77
  78#define QCASPI_TX_TIMEOUT (1 * HZ)
  79#define QCASPI_QCA7K_REBOOT_TIME_MS 1000
  80
  81static void
  82start_spi_intr_handling(struct qcaspi *qca, u16 *intr_cause)
  83{
  84        *intr_cause = 0;
  85
  86        qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0, wr_verify);
  87        qcaspi_read_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
  88        netdev_dbg(qca->net_dev, "interrupts: 0x%04x\n", *intr_cause);
  89}
  90
  91static void
  92end_spi_intr_handling(struct qcaspi *qca, u16 intr_cause)
  93{
  94        u16 intr_enable = (SPI_INT_CPU_ON |
  95                           SPI_INT_PKT_AVLBL |
  96                           SPI_INT_RDBUF_ERR |
  97                           SPI_INT_WRBUF_ERR);
  98
  99        qcaspi_write_register(qca, SPI_REG_INTR_CAUSE, intr_cause, 0);
 100        qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, intr_enable, wr_verify);
 101        netdev_dbg(qca->net_dev, "acking int: 0x%04x\n", intr_cause);
 102}
 103
 104static u32
 105qcaspi_write_burst(struct qcaspi *qca, u8 *src, u32 len)
 106{
 107        __be16 cmd;
 108        struct spi_message msg;
 109        struct spi_transfer transfer[2];
 110        int ret;
 111
 112        memset(&transfer, 0, sizeof(transfer));
 113        spi_message_init(&msg);
 114
 115        cmd = cpu_to_be16(QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
 116        transfer[0].tx_buf = &cmd;
 117        transfer[0].len = QCASPI_CMD_LEN;
 118        transfer[1].tx_buf = src;
 119        transfer[1].len = len;
 120
 121        spi_message_add_tail(&transfer[0], &msg);
 122        spi_message_add_tail(&transfer[1], &msg);
 123        ret = spi_sync(qca->spi_dev, &msg);
 124
 125        if (ret || (msg.actual_length != QCASPI_CMD_LEN + len)) {
 126                qcaspi_spi_error(qca);
 127                return 0;
 128        }
 129
 130        return len;
 131}
 132
 133static u32
 134qcaspi_write_legacy(struct qcaspi *qca, u8 *src, u32 len)
 135{
 136        struct spi_message msg;
 137        struct spi_transfer transfer;
 138        int ret;
 139
 140        memset(&transfer, 0, sizeof(transfer));
 141        spi_message_init(&msg);
 142
 143        transfer.tx_buf = src;
 144        transfer.len = len;
 145
 146        spi_message_add_tail(&transfer, &msg);
 147        ret = spi_sync(qca->spi_dev, &msg);
 148
 149        if (ret || (msg.actual_length != len)) {
 150                qcaspi_spi_error(qca);
 151                return 0;
 152        }
 153
 154        return len;
 155}
 156
 157static u32
 158qcaspi_read_burst(struct qcaspi *qca, u8 *dst, u32 len)
 159{
 160        struct spi_message msg;
 161        __be16 cmd;
 162        struct spi_transfer transfer[2];
 163        int ret;
 164
 165        memset(&transfer, 0, sizeof(transfer));
 166        spi_message_init(&msg);
 167
 168        cmd = cpu_to_be16(QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
 169        transfer[0].tx_buf = &cmd;
 170        transfer[0].len = QCASPI_CMD_LEN;
 171        transfer[1].rx_buf = dst;
 172        transfer[1].len = len;
 173
 174        spi_message_add_tail(&transfer[0], &msg);
 175        spi_message_add_tail(&transfer[1], &msg);
 176        ret = spi_sync(qca->spi_dev, &msg);
 177
 178        if (ret || (msg.actual_length != QCASPI_CMD_LEN + len)) {
 179                qcaspi_spi_error(qca);
 180                return 0;
 181        }
 182
 183        return len;
 184}
 185
 186static u32
 187qcaspi_read_legacy(struct qcaspi *qca, u8 *dst, u32 len)
 188{
 189        struct spi_message msg;
 190        struct spi_transfer transfer;
 191        int ret;
 192
 193        memset(&transfer, 0, sizeof(transfer));
 194        spi_message_init(&msg);
 195
 196        transfer.rx_buf = dst;
 197        transfer.len = len;
 198
 199        spi_message_add_tail(&transfer, &msg);
 200        ret = spi_sync(qca->spi_dev, &msg);
 201
 202        if (ret || (msg.actual_length != len)) {
 203                qcaspi_spi_error(qca);
 204                return 0;
 205        }
 206
 207        return len;
 208}
 209
 210static int
 211qcaspi_tx_cmd(struct qcaspi *qca, u16 cmd)
 212{
 213        __be16 tx_data;
 214        struct spi_message msg;
 215        struct spi_transfer transfer;
 216        int ret;
 217
 218        memset(&transfer, 0, sizeof(transfer));
 219
 220        spi_message_init(&msg);
 221
 222        tx_data = cpu_to_be16(cmd);
 223        transfer.len = sizeof(cmd);
 224        transfer.tx_buf = &tx_data;
 225        spi_message_add_tail(&transfer, &msg);
 226
 227        ret = spi_sync(qca->spi_dev, &msg);
 228
 229        if (!ret)
 230                ret = msg.status;
 231
 232        if (ret)
 233                qcaspi_spi_error(qca);
 234
 235        return ret;
 236}
 237
 238static int
 239qcaspi_tx_frame(struct qcaspi *qca, struct sk_buff *skb)
 240{
 241        u32 count;
 242        u32 written;
 243        u32 offset;
 244        u32 len;
 245
 246        len = skb->len;
 247
 248        qcaspi_write_register(qca, SPI_REG_BFR_SIZE, len, wr_verify);
 249        if (qca->legacy_mode)
 250                qcaspi_tx_cmd(qca, QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
 251
 252        offset = 0;
 253        while (len) {
 254                count = len;
 255                if (count > qca->burst_len)
 256                        count = qca->burst_len;
 257
 258                if (qca->legacy_mode) {
 259                        written = qcaspi_write_legacy(qca,
 260                                                      skb->data + offset,
 261                                                      count);
 262                } else {
 263                        written = qcaspi_write_burst(qca,
 264                                                     skb->data + offset,
 265                                                     count);
 266                }
 267
 268                if (written != count)
 269                        return -1;
 270
 271                offset += count;
 272                len -= count;
 273        }
 274
 275        return 0;
 276}
 277
 278static int
 279qcaspi_transmit(struct qcaspi *qca)
 280{
 281        struct net_device_stats *n_stats = &qca->net_dev->stats;
 282        u16 available = 0;
 283        u32 pkt_len;
 284        u16 new_head;
 285        u16 packets = 0;
 286
 287        if (qca->txr.skb[qca->txr.head] == NULL)
 288                return 0;
 289
 290        qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA, &available);
 291
 292        if (available > QCASPI_HW_BUF_LEN) {
 293                /* This could only happen by interferences on the SPI line.
 294                 * So retry later ...
 295                 */
 296                qca->stats.buf_avail_err++;
 297                return -1;
 298        }
 299
 300        while (qca->txr.skb[qca->txr.head]) {
 301                pkt_len = qca->txr.skb[qca->txr.head]->len + QCASPI_HW_PKT_LEN;
 302
 303                if (available < pkt_len) {
 304                        if (packets == 0)
 305                                qca->stats.write_buf_miss++;
 306                        break;
 307                }
 308
 309                if (qcaspi_tx_frame(qca, qca->txr.skb[qca->txr.head]) == -1) {
 310                        qca->stats.write_err++;
 311                        return -1;
 312                }
 313
 314                packets++;
 315                n_stats->tx_packets++;
 316                n_stats->tx_bytes += qca->txr.skb[qca->txr.head]->len;
 317                available -= pkt_len;
 318
 319                /* remove the skb from the queue */
 320                /* XXX After inconsistent lock states netif_tx_lock()
 321                 * has been replaced by netif_tx_lock_bh() and so on.
 322                 */
 323                netif_tx_lock_bh(qca->net_dev);
 324                dev_kfree_skb(qca->txr.skb[qca->txr.head]);
 325                qca->txr.skb[qca->txr.head] = NULL;
 326                qca->txr.size -= pkt_len;
 327                new_head = qca->txr.head + 1;
 328                if (new_head >= qca->txr.count)
 329                        new_head = 0;
 330                qca->txr.head = new_head;
 331                if (netif_queue_stopped(qca->net_dev))
 332                        netif_wake_queue(qca->net_dev);
 333                netif_tx_unlock_bh(qca->net_dev);
 334        }
 335
 336        return 0;
 337}
 338
 339static int
 340qcaspi_receive(struct qcaspi *qca)
 341{
 342        struct net_device *net_dev = qca->net_dev;
 343        struct net_device_stats *n_stats = &net_dev->stats;
 344        u16 available = 0;
 345        u32 bytes_read;
 346        u8 *cp;
 347
 348        /* Allocate rx SKB if we don't have one available. */
 349        if (!qca->rx_skb) {
 350                qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
 351                                                        net_dev->mtu +
 352                                                        VLAN_ETH_HLEN);
 353                if (!qca->rx_skb) {
 354                        netdev_dbg(net_dev, "out of RX resources\n");
 355                        qca->stats.out_of_mem++;
 356                        return -1;
 357                }
 358        }
 359
 360        /* Read the packet size. */
 361        qcaspi_read_register(qca, SPI_REG_RDBUF_BYTE_AVA, &available);
 362
 363        netdev_dbg(net_dev, "qcaspi_receive: SPI_REG_RDBUF_BYTE_AVA: Value: %08x\n",
 364                   available);
 365
 366        if (available > QCASPI_HW_BUF_LEN + QCASPI_HW_PKT_LEN) {
 367                /* This could only happen by interferences on the SPI line.
 368                 * So retry later ...
 369                 */
 370                qca->stats.buf_avail_err++;
 371                return -1;
 372        } else if (available == 0) {
 373                netdev_dbg(net_dev, "qcaspi_receive called without any data being available!\n");
 374                return -1;
 375        }
 376
 377        qcaspi_write_register(qca, SPI_REG_BFR_SIZE, available, wr_verify);
 378
 379        if (qca->legacy_mode)
 380                qcaspi_tx_cmd(qca, QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
 381
 382        while (available) {
 383                u32 count = available;
 384
 385                if (count > qca->burst_len)
 386                        count = qca->burst_len;
 387
 388                if (qca->legacy_mode) {
 389                        bytes_read = qcaspi_read_legacy(qca, qca->rx_buffer,
 390                                                        count);
 391                } else {
 392                        bytes_read = qcaspi_read_burst(qca, qca->rx_buffer,
 393                                                       count);
 394                }
 395
 396                netdev_dbg(net_dev, "available: %d, byte read: %d\n",
 397                           available, bytes_read);
 398
 399                if (bytes_read) {
 400                        available -= bytes_read;
 401                } else {
 402                        qca->stats.read_err++;
 403                        return -1;
 404                }
 405
 406                cp = qca->rx_buffer;
 407
 408                while ((bytes_read--) && (qca->rx_skb)) {
 409                        s32 retcode;
 410
 411                        retcode = qcafrm_fsm_decode(&qca->frm_handle,
 412                                                    qca->rx_skb->data,
 413                                                    skb_tailroom(qca->rx_skb),
 414                                                    *cp);
 415                        cp++;
 416                        switch (retcode) {
 417                        case QCAFRM_GATHER:
 418                        case QCAFRM_NOHEAD:
 419                                break;
 420                        case QCAFRM_NOTAIL:
 421                                netdev_dbg(net_dev, "no RX tail\n");
 422                                n_stats->rx_errors++;
 423                                n_stats->rx_dropped++;
 424                                break;
 425                        case QCAFRM_INVLEN:
 426                                netdev_dbg(net_dev, "invalid RX length\n");
 427                                n_stats->rx_errors++;
 428                                n_stats->rx_dropped++;
 429                                break;
 430                        default:
 431                                qca->rx_skb->dev = qca->net_dev;
 432                                n_stats->rx_packets++;
 433                                n_stats->rx_bytes += retcode;
 434                                skb_put(qca->rx_skb, retcode);
 435                                qca->rx_skb->protocol = eth_type_trans(
 436                                        qca->rx_skb, qca->rx_skb->dev);
 437                                qca->rx_skb->ip_summed = CHECKSUM_UNNECESSARY;
 438                                netif_rx_ni(qca->rx_skb);
 439                                qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
 440                                        net_dev->mtu + VLAN_ETH_HLEN);
 441                                if (!qca->rx_skb) {
 442                                        netdev_dbg(net_dev, "out of RX resources\n");
 443                                        n_stats->rx_errors++;
 444                                        qca->stats.out_of_mem++;
 445                                        break;
 446                                }
 447                        }
 448                }
 449        }
 450
 451        return 0;
 452}
 453
 454/*   Check that tx ring stores only so much bytes
 455 *   that fit into the internal QCA buffer.
 456 */
 457
 458static int
 459qcaspi_tx_ring_has_space(struct tx_ring *txr)
 460{
 461        if (txr->skb[txr->tail])
 462                return 0;
 463
 464        return (txr->size + QCAFRM_MAX_LEN < QCASPI_HW_BUF_LEN) ? 1 : 0;
 465}
 466
 467/*   Flush the tx ring. This function is only safe to
 468 *   call from the qcaspi_spi_thread.
 469 */
 470
 471static void
 472qcaspi_flush_tx_ring(struct qcaspi *qca)
 473{
 474        int i;
 475
 476        /* XXX After inconsistent lock states netif_tx_lock()
 477         * has been replaced by netif_tx_lock_bh() and so on.
 478         */
 479        netif_tx_lock_bh(qca->net_dev);
 480        for (i = 0; i < TX_RING_MAX_LEN; i++) {
 481                if (qca->txr.skb[i]) {
 482                        dev_kfree_skb(qca->txr.skb[i]);
 483                        qca->txr.skb[i] = NULL;
 484                        qca->net_dev->stats.tx_dropped++;
 485                }
 486        }
 487        qca->txr.tail = 0;
 488        qca->txr.head = 0;
 489        qca->txr.size = 0;
 490        netif_tx_unlock_bh(qca->net_dev);
 491}
 492
 493static void
 494qcaspi_qca7k_sync(struct qcaspi *qca, int event)
 495{
 496        u16 signature = 0;
 497        u16 spi_config;
 498        u16 wrbuf_space = 0;
 499
 500        if (event == QCASPI_EVENT_CPUON) {
 501                /* Read signature twice, if not valid
 502                 * go back to unknown state.
 503                 */
 504                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 505                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 506                if (signature != QCASPI_GOOD_SIGNATURE) {
 507                        qca->sync = QCASPI_SYNC_UNKNOWN;
 508                        netdev_dbg(qca->net_dev, "sync: got CPU on, but signature was invalid, restart\n");
 509                } else {
 510                        /* ensure that the WRBUF is empty */
 511                        qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA,
 512                                             &wrbuf_space);
 513                        if (wrbuf_space != QCASPI_HW_BUF_LEN) {
 514                                netdev_dbg(qca->net_dev, "sync: got CPU on, but wrbuf not empty. reset!\n");
 515                                qca->sync = QCASPI_SYNC_UNKNOWN;
 516                        } else {
 517                                netdev_dbg(qca->net_dev, "sync: got CPU on, now in sync\n");
 518                                qca->sync = QCASPI_SYNC_READY;
 519                                return;
 520                        }
 521                }
 522        }
 523
 524        switch (qca->sync) {
 525        case QCASPI_SYNC_READY:
 526                /* Read signature, if not valid go to unknown state. */
 527                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 528                if (signature != QCASPI_GOOD_SIGNATURE) {
 529                        qca->sync = QCASPI_SYNC_UNKNOWN;
 530                        netdev_dbg(qca->net_dev, "sync: bad signature, restart\n");
 531                        /* don't reset right away */
 532                        return;
 533                }
 534                break;
 535        case QCASPI_SYNC_UNKNOWN:
 536                /* Read signature, if not valid stay in unknown state */
 537                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 538                if (signature != QCASPI_GOOD_SIGNATURE) {
 539                        netdev_dbg(qca->net_dev, "sync: could not read signature to reset device, retry.\n");
 540                        return;
 541                }
 542
 543                /* TODO: use GPIO to reset QCA7000 in legacy mode*/
 544                netdev_dbg(qca->net_dev, "sync: resetting device.\n");
 545                qcaspi_read_register(qca, SPI_REG_SPI_CONFIG, &spi_config);
 546                spi_config |= QCASPI_SLAVE_RESET_BIT;
 547                qcaspi_write_register(qca, SPI_REG_SPI_CONFIG, spi_config, 0);
 548
 549                qca->sync = QCASPI_SYNC_RESET;
 550                qca->stats.trig_reset++;
 551                qca->reset_count = 0;
 552                break;
 553        case QCASPI_SYNC_RESET:
 554                qca->reset_count++;
 555                netdev_dbg(qca->net_dev, "sync: waiting for CPU on, count %u.\n",
 556                           qca->reset_count);
 557                if (qca->reset_count >= QCASPI_RESET_TIMEOUT) {
 558                        /* reset did not seem to take place, try again */
 559                        qca->sync = QCASPI_SYNC_UNKNOWN;
 560                        qca->stats.reset_timeout++;
 561                        netdev_dbg(qca->net_dev, "sync: reset timeout, restarting process.\n");
 562                }
 563                break;
 564        }
 565}
 566
 567static int
 568qcaspi_spi_thread(void *data)
 569{
 570        struct qcaspi *qca = data;
 571        u16 intr_cause = 0;
 572
 573        netdev_info(qca->net_dev, "SPI thread created\n");
 574        while (!kthread_should_stop()) {
 575                set_current_state(TASK_INTERRUPTIBLE);
 576                if ((qca->intr_req == qca->intr_svc) &&
 577                    (qca->txr.skb[qca->txr.head] == NULL) &&
 578                    (qca->sync == QCASPI_SYNC_READY))
 579                        schedule();
 580
 581                set_current_state(TASK_RUNNING);
 582
 583                netdev_dbg(qca->net_dev, "have work to do. int: %d, tx_skb: %p\n",
 584                           qca->intr_req - qca->intr_svc,
 585                           qca->txr.skb[qca->txr.head]);
 586
 587                qcaspi_qca7k_sync(qca, QCASPI_EVENT_UPDATE);
 588
 589                if (qca->sync != QCASPI_SYNC_READY) {
 590                        netdev_dbg(qca->net_dev, "sync: not ready %u, turn off carrier and flush\n",
 591                                   (unsigned int)qca->sync);
 592                        netif_stop_queue(qca->net_dev);
 593                        netif_carrier_off(qca->net_dev);
 594                        qcaspi_flush_tx_ring(qca);
 595                        msleep(QCASPI_QCA7K_REBOOT_TIME_MS);
 596                }
 597
 598                if (qca->intr_svc != qca->intr_req) {
 599                        qca->intr_svc = qca->intr_req;
 600                        start_spi_intr_handling(qca, &intr_cause);
 601
 602                        if (intr_cause & SPI_INT_CPU_ON) {
 603                                qcaspi_qca7k_sync(qca, QCASPI_EVENT_CPUON);
 604
 605                                /* not synced. */
 606                                if (qca->sync != QCASPI_SYNC_READY)
 607                                        continue;
 608
 609                                qca->stats.device_reset++;
 610                                netif_wake_queue(qca->net_dev);
 611                                netif_carrier_on(qca->net_dev);
 612                        }
 613
 614                        if (intr_cause & SPI_INT_RDBUF_ERR) {
 615                                /* restart sync */
 616                                netdev_dbg(qca->net_dev, "===> rdbuf error!\n");
 617                                qca->stats.read_buf_err++;
 618                                qca->sync = QCASPI_SYNC_UNKNOWN;
 619                                continue;
 620                        }
 621
 622                        if (intr_cause & SPI_INT_WRBUF_ERR) {
 623                                /* restart sync */
 624                                netdev_dbg(qca->net_dev, "===> wrbuf error!\n");
 625                                qca->stats.write_buf_err++;
 626                                qca->sync = QCASPI_SYNC_UNKNOWN;
 627                                continue;
 628                        }
 629
 630                        /* can only handle other interrupts
 631                         * if sync has occurred
 632                         */
 633                        if (qca->sync == QCASPI_SYNC_READY) {
 634                                if (intr_cause & SPI_INT_PKT_AVLBL)
 635                                        qcaspi_receive(qca);
 636                        }
 637
 638                        end_spi_intr_handling(qca, intr_cause);
 639                }
 640
 641                if (qca->sync == QCASPI_SYNC_READY)
 642                        qcaspi_transmit(qca);
 643        }
 644        set_current_state(TASK_RUNNING);
 645        netdev_info(qca->net_dev, "SPI thread exit\n");
 646
 647        return 0;
 648}
 649
 650static irqreturn_t
 651qcaspi_intr_handler(int irq, void *data)
 652{
 653        struct qcaspi *qca = data;
 654
 655        qca->intr_req++;
 656        if (qca->spi_thread &&
 657            qca->spi_thread->state != TASK_RUNNING)
 658                wake_up_process(qca->spi_thread);
 659
 660        return IRQ_HANDLED;
 661}
 662
 663static int
 664qcaspi_netdev_open(struct net_device *dev)
 665{
 666        struct qcaspi *qca = netdev_priv(dev);
 667        int ret = 0;
 668
 669        if (!qca)
 670                return -EINVAL;
 671
 672        qca->intr_req = 1;
 673        qca->intr_svc = 0;
 674        qca->sync = QCASPI_SYNC_UNKNOWN;
 675        qcafrm_fsm_init_spi(&qca->frm_handle);
 676
 677        qca->spi_thread = kthread_run((void *)qcaspi_spi_thread,
 678                                      qca, "%s", dev->name);
 679
 680        if (IS_ERR(qca->spi_thread)) {
 681                netdev_err(dev, "%s: unable to start kernel thread.\n",
 682                           QCASPI_DRV_NAME);
 683                return PTR_ERR(qca->spi_thread);
 684        }
 685
 686        ret = request_irq(qca->spi_dev->irq, qcaspi_intr_handler, 0,
 687                          dev->name, qca);
 688        if (ret) {
 689                netdev_err(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
 690                           QCASPI_DRV_NAME, qca->spi_dev->irq, ret);
 691                kthread_stop(qca->spi_thread);
 692                return ret;
 693        }
 694
 695        /* SPI thread takes care of TX queue */
 696
 697        return 0;
 698}
 699
 700static int
 701qcaspi_netdev_close(struct net_device *dev)
 702{
 703        struct qcaspi *qca = netdev_priv(dev);
 704
 705        netif_stop_queue(dev);
 706
 707        qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0, wr_verify);
 708        free_irq(qca->spi_dev->irq, qca);
 709
 710        kthread_stop(qca->spi_thread);
 711        qca->spi_thread = NULL;
 712        qcaspi_flush_tx_ring(qca);
 713
 714        return 0;
 715}
 716
 717static netdev_tx_t
 718qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
 719{
 720        u32 frame_len;
 721        u8 *ptmp;
 722        struct qcaspi *qca = netdev_priv(dev);
 723        u16 new_tail;
 724        struct sk_buff *tskb;
 725        u8 pad_len = 0;
 726
 727        if (skb->len < QCAFRM_MIN_LEN)
 728                pad_len = QCAFRM_MIN_LEN - skb->len;
 729
 730        if (qca->txr.skb[qca->txr.tail]) {
 731                netdev_warn(qca->net_dev, "queue was unexpectedly full!\n");
 732                netif_stop_queue(qca->net_dev);
 733                qca->stats.ring_full++;
 734                return NETDEV_TX_BUSY;
 735        }
 736
 737        if ((skb_headroom(skb) < QCAFRM_HEADER_LEN) ||
 738            (skb_tailroom(skb) < QCAFRM_FOOTER_LEN + pad_len)) {
 739                tskb = skb_copy_expand(skb, QCAFRM_HEADER_LEN,
 740                                       QCAFRM_FOOTER_LEN + pad_len, GFP_ATOMIC);
 741                if (!tskb) {
 742                        qca->stats.out_of_mem++;
 743                        return NETDEV_TX_BUSY;
 744                }
 745                dev_kfree_skb(skb);
 746                skb = tskb;
 747        }
 748
 749        frame_len = skb->len + pad_len;
 750
 751        ptmp = skb_push(skb, QCAFRM_HEADER_LEN);
 752        qcafrm_create_header(ptmp, frame_len);
 753
 754        if (pad_len) {
 755                ptmp = skb_put_zero(skb, pad_len);
 756        }
 757
 758        ptmp = skb_put(skb, QCAFRM_FOOTER_LEN);
 759        qcafrm_create_footer(ptmp);
 760
 761        netdev_dbg(qca->net_dev, "Tx-ing packet: Size: 0x%08x\n",
 762                   skb->len);
 763
 764        qca->txr.size += skb->len + QCASPI_HW_PKT_LEN;
 765
 766        new_tail = qca->txr.tail + 1;
 767        if (new_tail >= qca->txr.count)
 768                new_tail = 0;
 769
 770        qca->txr.skb[qca->txr.tail] = skb;
 771        qca->txr.tail = new_tail;
 772
 773        if (!qcaspi_tx_ring_has_space(&qca->txr)) {
 774                netif_stop_queue(qca->net_dev);
 775                qca->stats.ring_full++;
 776        }
 777
 778        netif_trans_update(dev);
 779
 780        if (qca->spi_thread &&
 781            qca->spi_thread->state != TASK_RUNNING)
 782                wake_up_process(qca->spi_thread);
 783
 784        return NETDEV_TX_OK;
 785}
 786
 787static void
 788qcaspi_netdev_tx_timeout(struct net_device *dev, unsigned int txqueue)
 789{
 790        struct qcaspi *qca = netdev_priv(dev);
 791
 792        netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
 793                    jiffies, jiffies - dev_trans_start(dev));
 794        qca->net_dev->stats.tx_errors++;
 795        /* Trigger tx queue flush and QCA7000 reset */
 796        qca->sync = QCASPI_SYNC_UNKNOWN;
 797
 798        if (qca->spi_thread)
 799                wake_up_process(qca->spi_thread);
 800}
 801
 802static int
 803qcaspi_netdev_init(struct net_device *dev)
 804{
 805        struct qcaspi *qca = netdev_priv(dev);
 806
 807        dev->mtu = QCAFRM_MAX_MTU;
 808        dev->type = ARPHRD_ETHER;
 809        qca->clkspeed = qcaspi_clkspeed;
 810        qca->burst_len = qcaspi_burst_len;
 811        qca->spi_thread = NULL;
 812        qca->buffer_size = (dev->mtu + VLAN_ETH_HLEN + QCAFRM_HEADER_LEN +
 813                QCAFRM_FOOTER_LEN + 4) * 4;
 814
 815        memset(&qca->stats, 0, sizeof(struct qcaspi_stats));
 816
 817        qca->rx_buffer = kmalloc(qca->buffer_size, GFP_KERNEL);
 818        if (!qca->rx_buffer)
 819                return -ENOBUFS;
 820
 821        qca->rx_skb = netdev_alloc_skb_ip_align(dev, qca->net_dev->mtu +
 822                                                VLAN_ETH_HLEN);
 823        if (!qca->rx_skb) {
 824                kfree(qca->rx_buffer);
 825                netdev_info(qca->net_dev, "Failed to allocate RX sk_buff.\n");
 826                return -ENOBUFS;
 827        }
 828
 829        return 0;
 830}
 831
 832static void
 833qcaspi_netdev_uninit(struct net_device *dev)
 834{
 835        struct qcaspi *qca = netdev_priv(dev);
 836
 837        kfree(qca->rx_buffer);
 838        qca->buffer_size = 0;
 839        dev_kfree_skb(qca->rx_skb);
 840}
 841
 842static const struct net_device_ops qcaspi_netdev_ops = {
 843        .ndo_init = qcaspi_netdev_init,
 844        .ndo_uninit = qcaspi_netdev_uninit,
 845        .ndo_open = qcaspi_netdev_open,
 846        .ndo_stop = qcaspi_netdev_close,
 847        .ndo_start_xmit = qcaspi_netdev_xmit,
 848        .ndo_set_mac_address = eth_mac_addr,
 849        .ndo_tx_timeout = qcaspi_netdev_tx_timeout,
 850        .ndo_validate_addr = eth_validate_addr,
 851};
 852
 853static void
 854qcaspi_netdev_setup(struct net_device *dev)
 855{
 856        struct qcaspi *qca = NULL;
 857
 858        dev->netdev_ops = &qcaspi_netdev_ops;
 859        qcaspi_set_ethtool_ops(dev);
 860        dev->watchdog_timeo = QCASPI_TX_TIMEOUT;
 861        dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 862        dev->tx_queue_len = 100;
 863
 864        /* MTU range: 46 - 1500 */
 865        dev->min_mtu = QCAFRM_MIN_MTU;
 866        dev->max_mtu = QCAFRM_MAX_MTU;
 867
 868        qca = netdev_priv(dev);
 869        memset(qca, 0, sizeof(struct qcaspi));
 870
 871        memset(&qca->txr, 0, sizeof(qca->txr));
 872        qca->txr.count = TX_RING_MAX_LEN;
 873}
 874
 875static const struct of_device_id qca_spi_of_match[] = {
 876        { .compatible = "qca,qca7000" },
 877        { /* sentinel */ }
 878};
 879MODULE_DEVICE_TABLE(of, qca_spi_of_match);
 880
 881static int
 882qca_spi_probe(struct spi_device *spi)
 883{
 884        struct qcaspi *qca = NULL;
 885        struct net_device *qcaspi_devs = NULL;
 886        u8 legacy_mode = 0;
 887        u16 signature;
 888        int ret;
 889
 890        if (!spi->dev.of_node) {
 891                dev_err(&spi->dev, "Missing device tree\n");
 892                return -EINVAL;
 893        }
 894
 895        legacy_mode = of_property_read_bool(spi->dev.of_node,
 896                                            "qca,legacy-mode");
 897
 898        if (qcaspi_clkspeed == 0) {
 899                if (spi->max_speed_hz)
 900                        qcaspi_clkspeed = spi->max_speed_hz;
 901                else
 902                        qcaspi_clkspeed = QCASPI_CLK_SPEED;
 903        }
 904
 905        if ((qcaspi_clkspeed < QCASPI_CLK_SPEED_MIN) ||
 906            (qcaspi_clkspeed > QCASPI_CLK_SPEED_MAX)) {
 907                dev_err(&spi->dev, "Invalid clkspeed: %d\n",
 908                        qcaspi_clkspeed);
 909                return -EINVAL;
 910        }
 911
 912        if ((qcaspi_burst_len < QCASPI_BURST_LEN_MIN) ||
 913            (qcaspi_burst_len > QCASPI_BURST_LEN_MAX)) {
 914                dev_err(&spi->dev, "Invalid burst len: %d\n",
 915                        qcaspi_burst_len);
 916                return -EINVAL;
 917        }
 918
 919        if ((qcaspi_pluggable < QCASPI_PLUGGABLE_MIN) ||
 920            (qcaspi_pluggable > QCASPI_PLUGGABLE_MAX)) {
 921                dev_err(&spi->dev, "Invalid pluggable: %d\n",
 922                        qcaspi_pluggable);
 923                return -EINVAL;
 924        }
 925
 926        if (wr_verify < QCASPI_WRITE_VERIFY_MIN ||
 927            wr_verify > QCASPI_WRITE_VERIFY_MAX) {
 928                dev_err(&spi->dev, "Invalid write verify: %d\n",
 929                        wr_verify);
 930                return -EINVAL;
 931        }
 932
 933        dev_info(&spi->dev, "ver=%s, clkspeed=%d, burst_len=%d, pluggable=%d\n",
 934                 QCASPI_DRV_VERSION,
 935                 qcaspi_clkspeed,
 936                 qcaspi_burst_len,
 937                 qcaspi_pluggable);
 938
 939        spi->mode = SPI_MODE_3;
 940        spi->max_speed_hz = qcaspi_clkspeed;
 941        if (spi_setup(spi) < 0) {
 942                dev_err(&spi->dev, "Unable to setup SPI device\n");
 943                return -EFAULT;
 944        }
 945
 946        qcaspi_devs = alloc_etherdev(sizeof(struct qcaspi));
 947        if (!qcaspi_devs)
 948                return -ENOMEM;
 949
 950        qcaspi_netdev_setup(qcaspi_devs);
 951        SET_NETDEV_DEV(qcaspi_devs, &spi->dev);
 952
 953        qca = netdev_priv(qcaspi_devs);
 954        if (!qca) {
 955                free_netdev(qcaspi_devs);
 956                dev_err(&spi->dev, "Fail to retrieve private structure\n");
 957                return -ENOMEM;
 958        }
 959        qca->net_dev = qcaspi_devs;
 960        qca->spi_dev = spi;
 961        qca->legacy_mode = legacy_mode;
 962
 963        spi_set_drvdata(spi, qcaspi_devs);
 964
 965        ret = of_get_mac_address(spi->dev.of_node, qca->net_dev->dev_addr);
 966        if (ret) {
 967                eth_hw_addr_random(qca->net_dev);
 968                dev_info(&spi->dev, "Using random MAC address: %pM\n",
 969                         qca->net_dev->dev_addr);
 970        }
 971
 972        netif_carrier_off(qca->net_dev);
 973
 974        if (!qcaspi_pluggable) {
 975                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 976                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 977
 978                if (signature != QCASPI_GOOD_SIGNATURE) {
 979                        dev_err(&spi->dev, "Invalid signature (0x%04X)\n",
 980                                signature);
 981                        free_netdev(qcaspi_devs);
 982                        return -EFAULT;
 983                }
 984        }
 985
 986        if (register_netdev(qcaspi_devs)) {
 987                dev_err(&spi->dev, "Unable to register net device %s\n",
 988                        qcaspi_devs->name);
 989                free_netdev(qcaspi_devs);
 990                return -EFAULT;
 991        }
 992
 993        qcaspi_init_device_debugfs(qca);
 994
 995        return 0;
 996}
 997
 998static int
 999qca_spi_remove(struct spi_device *spi)
1000{
1001        struct net_device *qcaspi_devs = spi_get_drvdata(spi);
1002        struct qcaspi *qca = netdev_priv(qcaspi_devs);
1003
1004        qcaspi_remove_device_debugfs(qca);
1005
1006        unregister_netdev(qcaspi_devs);
1007        free_netdev(qcaspi_devs);
1008
1009        return 0;
1010}
1011
1012static const struct spi_device_id qca_spi_id[] = {
1013        { "qca7000", 0 },
1014        { /* sentinel */ }
1015};
1016MODULE_DEVICE_TABLE(spi, qca_spi_id);
1017
1018static struct spi_driver qca_spi_driver = {
1019        .driver = {
1020                .name   = QCASPI_DRV_NAME,
1021                .of_match_table = qca_spi_of_match,
1022        },
1023        .id_table = qca_spi_id,
1024        .probe    = qca_spi_probe,
1025        .remove   = qca_spi_remove,
1026};
1027module_spi_driver(qca_spi_driver);
1028
1029MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 SPI Driver");
1030MODULE_AUTHOR("Qualcomm Atheros Communications");
1031MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
1032MODULE_LICENSE("Dual BSD/GPL");
1033MODULE_VERSION(QCASPI_DRV_VERSION);
1034