drivers/net/ethernet/qualcomm/qca_uart.c

   1 /*
   2  *   Copyright (c) 2011, 2012, Qualcomm Atheros Communications Inc.
   3  *   Copyright (c) 2017, 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 UART protocol for
  21  *   kernel-based UART device; it is essentially an Ethernet-to-UART
  22  *   serial converter;
  23  */
  24
  25 #include <linux/device.h>
  26 #include <linux/errno.h>
  27 #include <linux/etherdevice.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/of.h>
  35 #include <linux/of_net.h>
  36 #include <linux/sched.h>
  37 #include <linux/serdev.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/types.h>
  40
  41 #include "qca_7k_common.h"
  42
  43 #define QCAUART_DRV_VERSION "0.1.0"
  44 #define QCAUART_DRV_NAME "qcauart"
  45 #define QCAUART_TX_TIMEOUT (1 * HZ)
  46
  47 struct qcauart {
  48         struct net_device *net_dev;
  49         spinlock_t lock;                        /* transmit lock */
  50         struct work_struct tx_work;             /* Flushes transmit buffer   */
  51
  52         struct serdev_device *serdev;
  53         struct qcafrm_handle frm_handle;
  54         struct sk_buff *rx_skb;
  55
  56         unsigned char *tx_head;                 /* pointer to next XMIT byte */
  57         int tx_left;                            /* bytes left in XMIT queue  */
  58         unsigned char *tx_buffer;
  59 };
  60
  61 static ssize_t
  62 qca_tty_receive(struct serdev_device *serdev, const u8 *data, size_t count)
  63 {
  64         struct qcauart *qca = serdev_device_get_drvdata(serdev);
  65         struct net_device *netdev = qca->net_dev;
  66         struct net_device_stats *n_stats = &netdev->stats;
  67         size_t i;
  68
  69         if (!qca->rx_skb) {
  70                 qca->rx_skb = netdev_alloc_skb_ip_align(netdev,
  71                                                         netdev->mtu +
  72                                                         VLAN_ETH_HLEN);
  73                 if (!qca->rx_skb) {
  74                         n_stats->rx_errors++;
  75                         n_stats->rx_dropped++;
  76                         return 0;
  77                 }
  78         }
  79
  80         for (i = 0; i < count; i++) {
  81                 s32 retcode;
  82
  83                 retcode = qcafrm_fsm_decode(&qca->frm_handle,
  84                                             qca->rx_skb->data,
  85                                             skb_tailroom(qca->rx_skb),
  86                                             data[i]);
  87
  88                 switch (retcode) {
  89                 case QCAFRM_GATHER:
  90                 case QCAFRM_NOHEAD:
  91                         break;
  92                 case QCAFRM_NOTAIL:
  93                         netdev_dbg(netdev, "recv: no RX tail\n");
  94                         n_stats->rx_errors++;
  95                         n_stats->rx_dropped++;
  96                         break;
  97                 case QCAFRM_INVLEN:
  98                         netdev_dbg(netdev, "recv: invalid RX length\n");
  99                         n_stats->rx_errors++;
 100                         n_stats->rx_dropped++;
 101                         break;
 102                 default:
 103                         n_stats->rx_packets++;
 104                         n_stats->rx_bytes += retcode;
 105                         skb_put(qca->rx_skb, retcode);
 106                         qca->rx_skb->protocol = eth_type_trans(
 107                                                 qca->rx_skb, qca->rx_skb->dev);
 108                         skb_checksum_none_assert(qca->rx_skb);
 109                         netif_rx(qca->rx_skb);
 110                         qca->rx_skb = netdev_alloc_skb_ip_align(netdev,
 111                                                                 netdev->mtu +
 112                                                                 VLAN_ETH_HLEN);
 113                         if (!qca->rx_skb) {
 114                                 netdev_dbg(netdev, "recv: out of RX resources\n");
 115                                 n_stats->rx_errors++;
 116                                 return i;
 117                         }
 118                 }
 119         }
 120
 121         return i;
 122 }
 123
 124 /* Write out any remaining transmit buffer. Scheduled when tty is writable */
 125 static void qcauart_transmit(struct work_struct *work)
 126 {
 127         struct qcauart *qca = container_of(work, struct qcauart, tx_work);
 128         struct net_device_stats *n_stats = &qca->net_dev->stats;
 129         int written;
 130
 131         spin_lock_bh(&qca->lock);
 132
 133         /* First make sure we're connected. */
 134         if (!netif_running(qca->net_dev)) {
 135                 spin_unlock_bh(&qca->lock);
 136                 return;
 137         }
 138
 139         if (qca->tx_left <= 0)  {
 140                 /* Now serial buffer is almost free & we can start
 141                  * transmission of another packet
 142                  */
 143                 n_stats->tx_packets++;
 144                 spin_unlock_bh(&qca->lock);
 145                 netif_wake_queue(qca->net_dev);
 146                 return;
 147         }
 148
 149         written = serdev_device_write_buf(qca->serdev, qca->tx_head,
 150                                           qca->tx_left);
 151         if (written > 0) {
 152                 qca->tx_left -= written;
 153                 qca->tx_head += written;
 154         }
 155         spin_unlock_bh(&qca->lock);
 156 }
 157
 158 /* Called by the driver when there's room for more data.
 159  * Schedule the transmit.
 160  */
 161 static void qca_tty_wakeup(struct serdev_device *serdev)
 162 {
 163         struct qcauart *qca = serdev_device_get_drvdata(serdev);
 164
 165         schedule_work(&qca->tx_work);
 166 }
 167
 168 static const struct serdev_device_ops qca_serdev_ops = {
 169         .receive_buf = qca_tty_receive,
 170         .write_wakeup = qca_tty_wakeup,
 171 };
 172
 173 static int qcauart_netdev_open(struct net_device *dev)
 174 {
 175         struct qcauart *qca = netdev_priv(dev);
 176
 177         netif_start_queue(qca->net_dev);
 178
 179         return 0;
 180 }
 181
 182 static int qcauart_netdev_close(struct net_device *dev)
 183 {
 184         struct qcauart *qca = netdev_priv(dev);
 185
 186         netif_stop_queue(dev);
 187         flush_work(&qca->tx_work);
 188
 189         spin_lock_bh(&qca->lock);
 190         qca->tx_left = 0;
 191         spin_unlock_bh(&qca->lock);
 192
 193         return 0;
 194 }
 195
 196 static netdev_tx_t
 197 qcauart_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
 198 {
 199         struct net_device_stats *n_stats = &dev->stats;
 200         struct qcauart *qca = netdev_priv(dev);
 201         u8 pad_len = 0;
 202         int written;
 203         u8 *pos;
 204
 205         spin_lock(&qca->lock);
 206
 207         WARN_ON(qca->tx_left);
 208
 209         if (!netif_running(dev))  {
 210                 spin_unlock(&qca->lock);
 211                 netdev_warn(qca->net_dev, "xmit: iface is down\n");
 212                 goto out;
 213         }
 214
 215         pos = qca->tx_buffer;
 216
 217         if (skb->len < QCAFRM_MIN_LEN)
 218                 pad_len = QCAFRM_MIN_LEN - skb->len;
 219
 220         pos += qcafrm_create_header(pos, skb->len + pad_len);
 221
 222         memcpy(pos, skb->data, skb->len);
 223         pos += skb->len;
 224
 225         if (pad_len) {
 226                 memset(pos, 0, pad_len);
 227                 pos += pad_len;
 228         }
 229
 230         pos += qcafrm_create_footer(pos);
 231
 232         netif_stop_queue(qca->net_dev);
 233
 234         written = serdev_device_write_buf(qca->serdev, qca->tx_buffer,
 235                                           pos - qca->tx_buffer);
 236         if (written > 0) {
 237                 qca->tx_left = (pos - qca->tx_buffer) - written;
 238                 qca->tx_head = qca->tx_buffer + written;
 239                 n_stats->tx_bytes += written;
 240         }
 241         spin_unlock(&qca->lock);
 242
 243         netif_trans_update(dev);
 244 out:
 245         dev_kfree_skb_any(skb);
 246         return NETDEV_TX_OK;
 247 }
 248
 249 static void qcauart_netdev_tx_timeout(struct net_device *dev, unsigned int txqueue)
 250 {
 251         struct qcauart *qca = netdev_priv(dev);
 252
 253         netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
 254                     jiffies, dev_trans_start(dev));
 255         dev->stats.tx_errors++;
 256         dev->stats.tx_dropped++;
 257 }
 258
 259 static int qcauart_netdev_init(struct net_device *dev)
 260 {
 261         struct qcauart *qca = netdev_priv(dev);
 262         size_t len;
 263
 264         /* Finish setting up the device info. */
 265         dev->mtu = QCAFRM_MAX_MTU;
 266         dev->type = ARPHRD_ETHER;
 267
 268         len = QCAFRM_HEADER_LEN + QCAFRM_MAX_LEN + QCAFRM_FOOTER_LEN;
 269         qca->tx_buffer = devm_kmalloc(&qca->serdev->dev, len, GFP_KERNEL);
 270         if (!qca->tx_buffer)
 271                 return -ENOMEM;
 272
 273         qca->rx_skb = netdev_alloc_skb_ip_align(qca->net_dev,
 274                                                 qca->net_dev->mtu +
 275                                                 VLAN_ETH_HLEN);
 276         if (!qca->rx_skb)
 277                 return -ENOBUFS;
 278
 279         return 0;
 280 }
 281
 282 static void qcauart_netdev_uninit(struct net_device *dev)
 283 {
 284         struct qcauart *qca = netdev_priv(dev);
 285
 286         dev_kfree_skb(qca->rx_skb);
 287 }
 288
 289 static const struct net_device_ops qcauart_netdev_ops = {
 290         .ndo_init = qcauart_netdev_init,
 291         .ndo_uninit = qcauart_netdev_uninit,
 292         .ndo_open = qcauart_netdev_open,
 293         .ndo_stop = qcauart_netdev_close,
 294         .ndo_start_xmit = qcauart_netdev_xmit,
 295         .ndo_set_mac_address = eth_mac_addr,
 296         .ndo_tx_timeout = qcauart_netdev_tx_timeout,
 297         .ndo_validate_addr = eth_validate_addr,
 298 };
 299
 300 static void qcauart_netdev_setup(struct net_device *dev)
 301 {
 302         dev->netdev_ops = &qcauart_netdev_ops;
 303         dev->watchdog_timeo = QCAUART_TX_TIMEOUT;
 304         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 305         dev->tx_queue_len = 100;
 306
 307         /* MTU range: 46 - 1500 */
 308         dev->min_mtu = QCAFRM_MIN_MTU;
 309         dev->max_mtu = QCAFRM_MAX_MTU;
 310 }
 311
 312 static const struct of_device_id qca_uart_of_match[] = {
 313         {
 314          .compatible = "qca,qca7000",
 315         },
 316         {}
 317 };
 318 MODULE_DEVICE_TABLE(of, qca_uart_of_match);
 319
 320 static int qca_uart_probe(struct serdev_device *serdev)
 321 {
 322         struct net_device *qcauart_dev = alloc_etherdev(sizeof(struct qcauart));
 323         struct qcauart *qca;
 324         u32 speed = 115200;
 325         int ret;
 326
 327         if (!qcauart_dev)
 328                 return -ENOMEM;
 329
 330         qcauart_netdev_setup(qcauart_dev);
 331         SET_NETDEV_DEV(qcauart_dev, &serdev->dev);
 332
 333         qca = netdev_priv(qcauart_dev);
 334         if (!qca) {
 335                 pr_err("qca_uart: Fail to retrieve private structure\n");
 336                 ret = -ENOMEM;
 337                 goto free;
 338         }
 339         qca->net_dev = qcauart_dev;
 340         qca->serdev = serdev;
 341         qcafrm_fsm_init_uart(&qca->frm_handle);
 342
 343         spin_lock_init(&qca->lock);
 344         INIT_WORK(&qca->tx_work, qcauart_transmit);
 345
 346         of_property_read_u32(serdev->dev.of_node, "current-speed", &speed);
 347
 348         ret = of_get_ethdev_address(serdev->dev.of_node, qca->net_dev);
 349         if (ret) {
 350                 eth_hw_addr_random(qca->net_dev);
 351                 dev_info(&serdev->dev, "Using random MAC address: %pM\n",
 352                          qca->net_dev->dev_addr);
 353         }
 354
 355         netif_carrier_on(qca->net_dev);
 356         serdev_device_set_drvdata(serdev, qca);
 357         serdev_device_set_client_ops(serdev, &qca_serdev_ops);
 358
 359         ret = serdev_device_open(serdev);
 360         if (ret) {
 361                 dev_err(&serdev->dev, "Unable to open device %s\n",
 362                         qcauart_dev->name);
 363                 goto free;
 364         }
 365
 366         speed = serdev_device_set_baudrate(serdev, speed);
 367         dev_info(&serdev->dev, "Using baudrate: %u\n", speed);
 368
 369         serdev_device_set_flow_control(serdev, false);
 370
 371         ret = register_netdev(qcauart_dev);
 372         if (ret) {
 373                 dev_err(&serdev->dev, "Unable to register net device %s\n",
 374                         qcauart_dev->name);
 375                 serdev_device_close(serdev);
 376                 cancel_work_sync(&qca->tx_work);
 377                 goto free;
 378         }
 379
 380         return 0;
 381
 382 free:
 383         free_netdev(qcauart_dev);
 384         return ret;
 385 }
 386
 387 static void qca_uart_remove(struct serdev_device *serdev)
 388 {
 389         struct qcauart *qca = serdev_device_get_drvdata(serdev);
 390
 391         unregister_netdev(qca->net_dev);
 392
 393         /* Flush any pending characters in the driver. */
 394         serdev_device_close(serdev);
 395         cancel_work_sync(&qca->tx_work);
 396
 397         free_netdev(qca->net_dev);
 398 }
 399
 400 static struct serdev_device_driver qca_uart_driver = {
 401         .probe = qca_uart_probe,
 402         .remove = qca_uart_remove,
 403         .driver = {
 404                 .name = QCAUART_DRV_NAME,
 405                 .of_match_table = qca_uart_of_match,
 406         },
 407 };
 408
 409 module_serdev_device_driver(qca_uart_driver);
 410
 411 MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 UART Driver");
 412 MODULE_AUTHOR("Qualcomm Atheros Communications");
 413 MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
 414 MODULE_LICENSE("Dual BSD/GPL");
 415 MODULE_VERSION(QCAUART_DRV_VERSION);