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) {
 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        static u16 reset_count;
 500
 501        if (event == QCASPI_EVENT_CPUON) {
 502                /* Read signature twice, if not valid
 503                 * go back to unknown state.
 504                 */
 505                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 506                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 507                if (signature != QCASPI_GOOD_SIGNATURE) {
 508                        qca->sync = QCASPI_SYNC_UNKNOWN;
 509                        netdev_dbg(qca->net_dev, "sync: got CPU on, but signature was invalid, restart\n");
 510                } else {
 511                        /* ensure that the WRBUF is empty */
 512                        qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA,
 513                                             &wrbuf_space);
 514                        if (wrbuf_space != QCASPI_HW_BUF_LEN) {
 515                                netdev_dbg(qca->net_dev, "sync: got CPU on, but wrbuf not empty. reset!\n");
 516                                qca->sync = QCASPI_SYNC_UNKNOWN;
 517                        } else {
 518                                netdev_dbg(qca->net_dev, "sync: got CPU on, now in sync\n");
 519                                qca->sync = QCASPI_SYNC_READY;
 520                                return;
 521                        }
 522                }
 523        }
 524
 525        switch (qca->sync) {
 526        case QCASPI_SYNC_READY:
 527                /* Read signature, if not valid go to unknown state. */
 528                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 529                if (signature != QCASPI_GOOD_SIGNATURE) {
 530                        qca->sync = QCASPI_SYNC_UNKNOWN;
 531                        netdev_dbg(qca->net_dev, "sync: bad signature, restart\n");
 532                        /* don't reset right away */
 533                        return;
 534                }
 535                break;
 536        case QCASPI_SYNC_UNKNOWN:
 537                /* Read signature, if not valid stay in unknown state */
 538                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 539                if (signature != QCASPI_GOOD_SIGNATURE) {
 540                        netdev_dbg(qca->net_dev, "sync: could not read signature to reset device, retry.\n");
 541                        return;
 542                }
 543
 544                /* TODO: use GPIO to reset QCA7000 in legacy mode*/
 545                netdev_dbg(qca->net_dev, "sync: resetting device.\n");
 546                qcaspi_read_register(qca, SPI_REG_SPI_CONFIG, &spi_config);
 547                spi_config |= QCASPI_SLAVE_RESET_BIT;
 548                qcaspi_write_register(qca, SPI_REG_SPI_CONFIG, spi_config, 0);
 549
 550                qca->sync = QCASPI_SYNC_RESET;
 551                qca->stats.trig_reset++;
 552                reset_count = 0;
 553                break;
 554        case QCASPI_SYNC_RESET:
 555                reset_count++;
 556                netdev_dbg(qca->net_dev, "sync: waiting for CPU on, count %u.\n",
 557                           reset_count);
 558                if (reset_count >= QCASPI_RESET_TIMEOUT) {
 559                        /* reset did not seem to take place, try again */
 560                        qca->sync = QCASPI_SYNC_UNKNOWN;
 561                        qca->stats.reset_timeout++;
 562                        netdev_dbg(qca->net_dev, "sync: reset timeout, restarting process.\n");
 563                }
 564                break;
 565        }
 566}
 567
 568static int
 569qcaspi_spi_thread(void *data)
 570{
 571        struct qcaspi *qca = data;
 572        u16 intr_cause = 0;
 573
 574        netdev_info(qca->net_dev, "SPI thread created\n");
 575        while (!kthread_should_stop()) {
 576                set_current_state(TASK_INTERRUPTIBLE);
 577                if ((qca->intr_req == qca->intr_svc) &&
 578                    (qca->txr.skb[qca->txr.head] == NULL) &&
 579                    (qca->sync == QCASPI_SYNC_READY))
 580                        schedule();
 581
 582                set_current_state(TASK_RUNNING);
 583
 584                netdev_dbg(qca->net_dev, "have work to do. int: %d, tx_skb: %p\n",
 585                           qca->intr_req - qca->intr_svc,
 586                           qca->txr.skb[qca->txr.head]);
 587
 588                qcaspi_qca7k_sync(qca, QCASPI_EVENT_UPDATE);
 589
 590                if (qca->sync != QCASPI_SYNC_READY) {
 591                        netdev_dbg(qca->net_dev, "sync: not ready %u, turn off carrier and flush\n",
 592                                   (unsigned int)qca->sync);
 593                        netif_stop_queue(qca->net_dev);
 594                        netif_carrier_off(qca->net_dev);
 595                        qcaspi_flush_tx_ring(qca);
 596                        msleep(QCASPI_QCA7K_REBOOT_TIME_MS);
 597                }
 598
 599                if (qca->intr_svc != qca->intr_req) {
 600                        qca->intr_svc = qca->intr_req;
 601                        start_spi_intr_handling(qca, &intr_cause);
 602
 603                        if (intr_cause & SPI_INT_CPU_ON) {
 604                                qcaspi_qca7k_sync(qca, QCASPI_EVENT_CPUON);
 605
 606                                /* not synced. */
 607                                if (qca->sync != QCASPI_SYNC_READY)
 608                                        continue;
 609
 610                                qca->stats.device_reset++;
 611                                netif_wake_queue(qca->net_dev);
 612                                netif_carrier_on(qca->net_dev);
 613                        }
 614
 615                        if (intr_cause & SPI_INT_RDBUF_ERR) {
 616                                /* restart sync */
 617                                netdev_dbg(qca->net_dev, "===> rdbuf error!\n");
 618                                qca->stats.read_buf_err++;
 619                                qca->sync = QCASPI_SYNC_UNKNOWN;
 620                                continue;
 621                        }
 622
 623                        if (intr_cause & SPI_INT_WRBUF_ERR) {
 624                                /* restart sync */
 625                                netdev_dbg(qca->net_dev, "===> wrbuf error!\n");
 626                                qca->stats.write_buf_err++;
 627                                qca->sync = QCASPI_SYNC_UNKNOWN;
 628                                continue;
 629                        }
 630
 631                        /* can only handle other interrupts
 632                         * if sync has occurred
 633                         */
 634                        if (qca->sync == QCASPI_SYNC_READY) {
 635                                if (intr_cause & SPI_INT_PKT_AVLBL)
 636                                        qcaspi_receive(qca);
 637                        }
 638
 639                        end_spi_intr_handling(qca, intr_cause);
 640                }
 641
 642                if (qca->sync == QCASPI_SYNC_READY)
 643                        qcaspi_transmit(qca);
 644        }
 645        set_current_state(TASK_RUNNING);
 646        netdev_info(qca->net_dev, "SPI thread exit\n");
 647
 648        return 0;
 649}
 650
 651static irqreturn_t
 652qcaspi_intr_handler(int irq, void *data)
 653{
 654        struct qcaspi *qca = data;
 655
 656        qca->intr_req++;
 657        if (qca->spi_thread &&
 658            qca->spi_thread->state != TASK_RUNNING)
 659                wake_up_process(qca->spi_thread);
 660
 661        return IRQ_HANDLED;
 662}
 663
 664static int
 665qcaspi_netdev_open(struct net_device *dev)
 666{
 667        struct qcaspi *qca = netdev_priv(dev);
 668        int ret = 0;
 669
 670        if (!qca)
 671                return -EINVAL;
 672
 673        qca->intr_req = 1;
 674        qca->intr_svc = 0;
 675        qca->sync = QCASPI_SYNC_UNKNOWN;
 676        qcafrm_fsm_init_spi(&qca->frm_handle);
 677
 678        qca->spi_thread = kthread_run((void *)qcaspi_spi_thread,
 679                                      qca, "%s", dev->name);
 680
 681        if (IS_ERR(qca->spi_thread)) {
 682                netdev_err(dev, "%s: unable to start kernel thread.\n",
 683                           QCASPI_DRV_NAME);
 684                return PTR_ERR(qca->spi_thread);
 685        }
 686
 687        ret = request_irq(qca->spi_dev->irq, qcaspi_intr_handler, 0,
 688                          dev->name, qca);
 689        if (ret) {
 690                netdev_err(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
 691                           QCASPI_DRV_NAME, qca->spi_dev->irq, ret);
 692                kthread_stop(qca->spi_thread);
 693                return ret;
 694        }
 695
 696        /* SPI thread takes care of TX queue */
 697
 698        return 0;
 699}
 700
 701static int
 702qcaspi_netdev_close(struct net_device *dev)
 703{
 704        struct qcaspi *qca = netdev_priv(dev);
 705
 706        netif_stop_queue(dev);
 707
 708        qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0, wr_verify);
 709        free_irq(qca->spi_dev->irq, qca);
 710
 711        kthread_stop(qca->spi_thread);
 712        qca->spi_thread = NULL;
 713        qcaspi_flush_tx_ring(qca);
 714
 715        return 0;
 716}
 717
 718static netdev_tx_t
 719qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
 720{
 721        u32 frame_len;
 722        u8 *ptmp;
 723        struct qcaspi *qca = netdev_priv(dev);
 724        u16 new_tail;
 725        struct sk_buff *tskb;
 726        u8 pad_len = 0;
 727
 728        if (skb->len < QCAFRM_MIN_LEN)
 729                pad_len = QCAFRM_MIN_LEN - skb->len;
 730
 731        if (qca->txr.skb[qca->txr.tail]) {
 732                netdev_warn(qca->net_dev, "queue was unexpectedly full!\n");
 733                netif_stop_queue(qca->net_dev);
 734                qca->stats.ring_full++;
 735                return NETDEV_TX_BUSY;
 736        }
 737
 738        if ((skb_headroom(skb) < QCAFRM_HEADER_LEN) ||
 739            (skb_tailroom(skb) < QCAFRM_FOOTER_LEN + pad_len)) {
 740                tskb = skb_copy_expand(skb, QCAFRM_HEADER_LEN,
 741                                       QCAFRM_FOOTER_LEN + pad_len, GFP_ATOMIC);
 742                if (!tskb) {
 743                        qca->stats.out_of_mem++;
 744                        return NETDEV_TX_BUSY;
 745                }
 746                dev_kfree_skb(skb);
 747                skb = tskb;
 748        }
 749
 750        frame_len = skb->len + pad_len;
 751
 752        ptmp = skb_push(skb, QCAFRM_HEADER_LEN);
 753        qcafrm_create_header(ptmp, frame_len);
 754
 755        if (pad_len) {
 756                ptmp = skb_put_zero(skb, pad_len);
 757        }
 758
 759        ptmp = skb_put(skb, QCAFRM_FOOTER_LEN);
 760        qcafrm_create_footer(ptmp);
 761
 762        netdev_dbg(qca->net_dev, "Tx-ing packet: Size: 0x%08x\n",
 763                   skb->len);
 764
 765        qca->txr.size += skb->len + QCASPI_HW_PKT_LEN;
 766
 767        new_tail = qca->txr.tail + 1;
 768        if (new_tail >= qca->txr.count)
 769                new_tail = 0;
 770
 771        qca->txr.skb[qca->txr.tail] = skb;
 772        qca->txr.tail = new_tail;
 773
 774        if (!qcaspi_tx_ring_has_space(&qca->txr)) {
 775                netif_stop_queue(qca->net_dev);
 776                qca->stats.ring_full++;
 777        }
 778
 779        netif_trans_update(dev);
 780
 781        if (qca->spi_thread &&
 782            qca->spi_thread->state != TASK_RUNNING)
 783                wake_up_process(qca->spi_thread);
 784
 785        return NETDEV_TX_OK;
 786}
 787
 788static void
 789qcaspi_netdev_tx_timeout(struct net_device *dev)
 790{
 791        struct qcaspi *qca = netdev_priv(dev);
 792
 793        netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
 794                    jiffies, jiffies - dev_trans_start(dev));
 795        qca->net_dev->stats.tx_errors++;
 796        /* Trigger tx queue flush and QCA7000 reset */
 797        qca->sync = QCASPI_SYNC_UNKNOWN;
 798
 799        if (qca->spi_thread)
 800                wake_up_process(qca->spi_thread);
 801}
 802
 803static int
 804qcaspi_netdev_init(struct net_device *dev)
 805{
 806        struct qcaspi *qca = netdev_priv(dev);
 807
 808        dev->mtu = QCAFRM_MAX_MTU;
 809        dev->type = ARPHRD_ETHER;
 810        qca->clkspeed = qcaspi_clkspeed;
 811        qca->burst_len = qcaspi_burst_len;
 812        qca->spi_thread = NULL;
 813        qca->buffer_size = (dev->mtu + VLAN_ETH_HLEN + QCAFRM_HEADER_LEN +
 814                QCAFRM_FOOTER_LEN + 4) * 4;
 815
 816        memset(&qca->stats, 0, sizeof(struct qcaspi_stats));
 817
 818        qca->rx_buffer = kmalloc(qca->buffer_size, GFP_KERNEL);
 819        if (!qca->rx_buffer)
 820                return -ENOBUFS;
 821
 822        qca->rx_skb = netdev_alloc_skb_ip_align(dev, qca->net_dev->mtu +
 823                                                VLAN_ETH_HLEN);
 824        if (!qca->rx_skb) {
 825                kfree(qca->rx_buffer);
 826                netdev_info(qca->net_dev, "Failed to allocate RX sk_buff.\n");
 827                return -ENOBUFS;
 828        }
 829
 830        return 0;
 831}
 832
 833static void
 834qcaspi_netdev_uninit(struct net_device *dev)
 835{
 836        struct qcaspi *qca = netdev_priv(dev);
 837
 838        kfree(qca->rx_buffer);
 839        qca->buffer_size = 0;
 840        if (qca->rx_skb)
 841                dev_kfree_skb(qca->rx_skb);
 842}
 843
 844static const struct net_device_ops qcaspi_netdev_ops = {
 845        .ndo_init = qcaspi_netdev_init,
 846        .ndo_uninit = qcaspi_netdev_uninit,
 847        .ndo_open = qcaspi_netdev_open,
 848        .ndo_stop = qcaspi_netdev_close,
 849        .ndo_start_xmit = qcaspi_netdev_xmit,
 850        .ndo_set_mac_address = eth_mac_addr,
 851        .ndo_tx_timeout = qcaspi_netdev_tx_timeout,
 852        .ndo_validate_addr = eth_validate_addr,
 853};
 854
 855static void
 856qcaspi_netdev_setup(struct net_device *dev)
 857{
 858        struct qcaspi *qca = NULL;
 859
 860        dev->netdev_ops = &qcaspi_netdev_ops;
 861        qcaspi_set_ethtool_ops(dev);
 862        dev->watchdog_timeo = QCASPI_TX_TIMEOUT;
 863        dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 864        dev->tx_queue_len = 100;
 865
 866        /* MTU range: 46 - 1500 */
 867        dev->min_mtu = QCAFRM_MIN_MTU;
 868        dev->max_mtu = QCAFRM_MAX_MTU;
 869
 870        qca = netdev_priv(dev);
 871        memset(qca, 0, sizeof(struct qcaspi));
 872
 873        memset(&qca->txr, 0, sizeof(qca->txr));
 874        qca->txr.count = TX_RING_MAX_LEN;
 875}
 876
 877static const struct of_device_id qca_spi_of_match[] = {
 878        { .compatible = "qca,qca7000" },
 879        { /* sentinel */ }
 880};
 881MODULE_DEVICE_TABLE(of, qca_spi_of_match);
 882
 883static int
 884qca_spi_probe(struct spi_device *spi)
 885{
 886        struct qcaspi *qca = NULL;
 887        struct net_device *qcaspi_devs = NULL;
 888        u8 legacy_mode = 0;
 889        u16 signature;
 890        const char *mac;
 891
 892        if (!spi->dev.of_node) {
 893                dev_err(&spi->dev, "Missing device tree\n");
 894                return -EINVAL;
 895        }
 896
 897        legacy_mode = of_property_read_bool(spi->dev.of_node,
 898                                            "qca,legacy-mode");
 899
 900        if (qcaspi_clkspeed == 0) {
 901                if (spi->max_speed_hz)
 902                        qcaspi_clkspeed = spi->max_speed_hz;
 903                else
 904                        qcaspi_clkspeed = QCASPI_CLK_SPEED;
 905        }
 906
 907        if ((qcaspi_clkspeed < QCASPI_CLK_SPEED_MIN) ||
 908            (qcaspi_clkspeed > QCASPI_CLK_SPEED_MAX)) {
 909                dev_err(&spi->dev, "Invalid clkspeed: %d\n",
 910                        qcaspi_clkspeed);
 911                return -EINVAL;
 912        }
 913
 914        if ((qcaspi_burst_len < QCASPI_BURST_LEN_MIN) ||
 915            (qcaspi_burst_len > QCASPI_BURST_LEN_MAX)) {
 916                dev_err(&spi->dev, "Invalid burst len: %d\n",
 917                        qcaspi_burst_len);
 918                return -EINVAL;
 919        }
 920
 921        if ((qcaspi_pluggable < QCASPI_PLUGGABLE_MIN) ||
 922            (qcaspi_pluggable > QCASPI_PLUGGABLE_MAX)) {
 923                dev_err(&spi->dev, "Invalid pluggable: %d\n",
 924                        qcaspi_pluggable);
 925                return -EINVAL;
 926        }
 927
 928        if (wr_verify < QCASPI_WRITE_VERIFY_MIN ||
 929            wr_verify > QCASPI_WRITE_VERIFY_MAX) {
 930                dev_err(&spi->dev, "Invalid write verify: %d\n",
 931                        wr_verify);
 932                return -EINVAL;
 933        }
 934
 935        dev_info(&spi->dev, "ver=%s, clkspeed=%d, burst_len=%d, pluggable=%d\n",
 936                 QCASPI_DRV_VERSION,
 937                 qcaspi_clkspeed,
 938                 qcaspi_burst_len,
 939                 qcaspi_pluggable);
 940
 941        spi->mode = SPI_MODE_3;
 942        spi->max_speed_hz = qcaspi_clkspeed;
 943        if (spi_setup(spi) < 0) {
 944                dev_err(&spi->dev, "Unable to setup SPI device\n");
 945                return -EFAULT;
 946        }
 947
 948        qcaspi_devs = alloc_etherdev(sizeof(struct qcaspi));
 949        if (!qcaspi_devs)
 950                return -ENOMEM;
 951
 952        qcaspi_netdev_setup(qcaspi_devs);
 953        SET_NETDEV_DEV(qcaspi_devs, &spi->dev);
 954
 955        qca = netdev_priv(qcaspi_devs);
 956        if (!qca) {
 957                free_netdev(qcaspi_devs);
 958                dev_err(&spi->dev, "Fail to retrieve private structure\n");
 959                return -ENOMEM;
 960        }
 961        qca->net_dev = qcaspi_devs;
 962        qca->spi_dev = spi;
 963        qca->legacy_mode = legacy_mode;
 964
 965        spi_set_drvdata(spi, qcaspi_devs);
 966
 967        mac = of_get_mac_address(spi->dev.of_node);
 968
 969        if (!IS_ERR(mac))
 970                ether_addr_copy(qca->net_dev->dev_addr, mac);
 971
 972        if (!is_valid_ether_addr(qca->net_dev->dev_addr)) {
 973                eth_hw_addr_random(qca->net_dev);
 974                dev_info(&spi->dev, "Using random MAC address: %pM\n",
 975                         qca->net_dev->dev_addr);
 976        }
 977
 978        netif_carrier_off(qca->net_dev);
 979
 980        if (!qcaspi_pluggable) {
 981                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 982                qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
 983
 984                if (signature != QCASPI_GOOD_SIGNATURE) {
 985                        dev_err(&spi->dev, "Invalid signature (0x%04X)\n",
 986                                signature);
 987                        free_netdev(qcaspi_devs);
 988                        return -EFAULT;
 989                }
 990        }
 991
 992        if (register_netdev(qcaspi_devs)) {
 993                dev_err(&spi->dev, "Unable to register net device %s\n",
 994                        qcaspi_devs->name);
 995                free_netdev(qcaspi_devs);
 996                return -EFAULT;
 997        }
 998
 999        qcaspi_init_device_debugfs(qca);
1000
1001        return 0;
1002}
1003
1004static int
1005qca_spi_remove(struct spi_device *spi)
1006{
1007        struct net_device *qcaspi_devs = spi_get_drvdata(spi);
1008        struct qcaspi *qca = netdev_priv(qcaspi_devs);
1009
1010        qcaspi_remove_device_debugfs(qca);
1011
1012        unregister_netdev(qcaspi_devs);
1013        free_netdev(qcaspi_devs);
1014
1015        return 0;
1016}
1017
1018static const struct spi_device_id qca_spi_id[] = {
1019        { "qca7000", 0 },
1020        { /* sentinel */ }
1021};
1022MODULE_DEVICE_TABLE(spi, qca_spi_id);
1023
1024static struct spi_driver qca_spi_driver = {
1025        .driver = {
1026                .name   = QCASPI_DRV_NAME,
1027                .of_match_table = qca_spi_of_match,
1028        },
1029        .id_table = qca_spi_id,
1030        .probe    = qca_spi_probe,
1031        .remove   = qca_spi_remove,
1032};
1033module_spi_driver(qca_spi_driver);
1034
1035MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 SPI Driver");
1036MODULE_AUTHOR("Qualcomm Atheros Communications");
1037MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
1038MODULE_LICENSE("Dual BSD/GPL");
1039MODULE_VERSION(QCASPI_DRV_VERSION);
1040