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); 417