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