1 /*
2  * Copyright(c) 2015 EZchip Technologies.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * The full GNU General Public License is included in this distribution in
14  * the file called "COPYING".
15  */
16 
17 #include <linux/module.h>
18 #include <linux/etherdevice.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_net.h>
22 #include <linux/of_platform.h>
23 #include "nps_enet.h"
24 
25 #define DRV_NAME			"nps_mgt_enet"
26 
27 static void nps_enet_clean_rx_fifo(struct net_device *ndev, u32 frame_len)
28 {
29 	struct nps_enet_priv *priv = netdev_priv(ndev);
30 	u32 i, len = DIV_ROUND_UP(frame_len, sizeof(u32));
31 
32 	/* Empty Rx FIFO buffer by reading all words */
33 	for (i = 0; i < len; i++)
34 		nps_enet_reg_get(priv, NPS_ENET_REG_RX_BUF);
35 }
36 
37 static void nps_enet_read_rx_fifo(struct net_device *ndev,
38 				  unsigned char *dst, u32 length)
39 {
40 	struct nps_enet_priv *priv = netdev_priv(ndev);
41 	s32 i, last = length & (sizeof(u32) - 1);
42 	u32 *reg = (u32 *)dst, len = length / sizeof(u32);
43 	bool dst_is_aligned = IS_ALIGNED((unsigned long)dst, sizeof(u32));
44 
45 	/* In case dst is not aligned we need an intermediate buffer */
46 	if (dst_is_aligned) {
47 		ioread32_rep(priv->regs_base + NPS_ENET_REG_RX_BUF, reg, len);
48 		reg += len;
49 	}
50 	else { /* !dst_is_aligned */
51 		for (i = 0; i < len; i++, reg++) {
52 			u32 buf = nps_enet_reg_get(priv, NPS_ENET_REG_RX_BUF);
53 			put_unaligned_be32(buf, reg);
54 		}
55 	}
56 	/* copy last bytes (if any) */
57 	if (last) {
58 		u32 buf;
59 		ioread32_rep(priv->regs_base + NPS_ENET_REG_RX_BUF, &buf, 1);
60 		memcpy((u8 *)reg, &buf, last);
61 	}
62 }
63 
64 static u32 nps_enet_rx_handler(struct net_device *ndev)
65 {
66 	u32 frame_len, err = 0;
67 	u32 work_done = 0;
68 	struct nps_enet_priv *priv = netdev_priv(ndev);
69 	struct sk_buff *skb;
70 	u32 rx_ctrl_value = nps_enet_reg_get(priv, NPS_ENET_REG_RX_CTL);
71 	u32 rx_ctrl_cr = (rx_ctrl_value & RX_CTL_CR_MASK) >> RX_CTL_CR_SHIFT;
72 	u32 rx_ctrl_er = (rx_ctrl_value & RX_CTL_ER_MASK) >> RX_CTL_ER_SHIFT;
73 	u32 rx_ctrl_crc = (rx_ctrl_value & RX_CTL_CRC_MASK) >> RX_CTL_CRC_SHIFT;
74 
75 	frame_len = (rx_ctrl_value & RX_CTL_NR_MASK) >> RX_CTL_NR_SHIFT;
76 
77 	/* Check if we got RX */
78 	if (!rx_ctrl_cr)
79 		return work_done;
80 
81 	/* If we got here there is a work for us */
82 	work_done++;
83 
84 	/* Check Rx error */
85 	if (rx_ctrl_er) {
86 		ndev->stats.rx_errors++;
87 		err = 1;
88 	}
89 
90 	/* Check Rx CRC error */
91 	if (rx_ctrl_crc) {
92 		ndev->stats.rx_crc_errors++;
93 		ndev->stats.rx_dropped++;
94 		err = 1;
95 	}
96 
97 	/* Check Frame length Min 64b */
98 	if (unlikely(frame_len < ETH_ZLEN)) {
99 		ndev->stats.rx_length_errors++;
100 		ndev->stats.rx_dropped++;
101 		err = 1;
102 	}
103 
104 	if (err)
105 		goto rx_irq_clean;
106 
107 	/* Skb allocation */
108 	skb = netdev_alloc_skb_ip_align(ndev, frame_len);
109 	if (unlikely(!skb)) {
110 		ndev->stats.rx_errors++;
111 		ndev->stats.rx_dropped++;
112 		goto rx_irq_clean;
113 	}
114 
115 	/* Copy frame from Rx fifo into the skb */
116 	nps_enet_read_rx_fifo(ndev, skb->data, frame_len);
117 
118 	skb_put(skb, frame_len);
119 	skb->protocol = eth_type_trans(skb, ndev);
120 	skb->ip_summed = CHECKSUM_UNNECESSARY;
121 
122 	ndev->stats.rx_packets++;
123 	ndev->stats.rx_bytes += frame_len;
124 	netif_receive_skb(skb);
125 
126 	goto rx_irq_frame_done;
127 
128 rx_irq_clean:
129 	/* Clean Rx fifo */
130 	nps_enet_clean_rx_fifo(ndev, frame_len);
131 
132 rx_irq_frame_done:
133 	/* Ack Rx ctrl register */
134 	nps_enet_reg_set(priv, NPS_ENET_REG_RX_CTL, 0);
135 
136 	return work_done;
137 }
138 
139 static void nps_enet_tx_handler(struct net_device *ndev)
140 {
141 	struct nps_enet_priv *priv = netdev_priv(ndev);
142 	u32 tx_ctrl_value = nps_enet_reg_get(priv, NPS_ENET_REG_TX_CTL);
143 	u32 tx_ctrl_ct = (tx_ctrl_value & TX_CTL_CT_MASK) >> TX_CTL_CT_SHIFT;
144 	u32 tx_ctrl_et = (tx_ctrl_value & TX_CTL_ET_MASK) >> TX_CTL_ET_SHIFT;
145 	u32 tx_ctrl_nt = (tx_ctrl_value & TX_CTL_NT_MASK) >> TX_CTL_NT_SHIFT;
146 
147 	/* Check if we got TX */
148 	if (!priv->tx_packet_sent || tx_ctrl_ct)
149 		return;
150 
151 	/* Ack Tx ctrl register */
152 	nps_enet_reg_set(priv, NPS_ENET_REG_TX_CTL, 0);
153 
154 	/* Check Tx transmit error */
155 	if (unlikely(tx_ctrl_et)) {
156 		ndev->stats.tx_errors++;
157 	} else {
158 		ndev->stats.tx_packets++;
159 		ndev->stats.tx_bytes += tx_ctrl_nt;
160 	}
161 
162 	dev_kfree_skb(priv->tx_skb);
163 	priv->tx_packet_sent = false;
164 
165 	if (netif_queue_stopped(ndev))
166 		netif_wake_queue(ndev);
167 }
168 
169 /**
170  * nps_enet_poll - NAPI poll handler.
171  * @napi:       Pointer to napi_struct structure.
172  * @budget:     How many frames to process on one call.
173  *
174  * returns:     Number of processed frames
175  */
176 static int nps_enet_poll(struct napi_struct *napi, int budget)
177 {
178 	struct net_device *ndev = napi->dev;
179 	struct nps_enet_priv *priv = netdev_priv(ndev);
180 	u32 work_done;
181 
182 	nps_enet_tx_handler(ndev);
183 	work_done = nps_enet_rx_handler(ndev);
184 	if (work_done < budget) {
185 		u32 buf_int_enable_value = 0;
186 
187 		napi_complete(napi);
188 
189 		/* set tx_done and rx_rdy bits */
190 		buf_int_enable_value |= NPS_ENET_ENABLE << RX_RDY_SHIFT;
191 		buf_int_enable_value |= NPS_ENET_ENABLE << TX_DONE_SHIFT;
192 
193 		nps_enet_reg_set(priv, NPS_ENET_REG_BUF_INT_ENABLE,
194 				 buf_int_enable_value);
195 	}
196 
197 	return work_done;
198 }
199 
200 /**
201  * nps_enet_irq_handler - Global interrupt handler for ENET.
202  * @irq:                irq number.
203  * @dev_instance:       device instance.
204  *
205  * returns: IRQ_HANDLED for all cases.
206  *
207  * EZchip ENET has 2 interrupt causes, and depending on bits raised in
208  * CTRL registers we may tell what is a reason for interrupt to fire up.
209  * We got one for RX and the other for TX (completion).
210  */
211 static irqreturn_t nps_enet_irq_handler(s32 irq, void *dev_instance)
212 {
213 	struct net_device *ndev = dev_instance;
214 	struct nps_enet_priv *priv = netdev_priv(ndev);
215 	u32 rx_ctrl_value = nps_enet_reg_get(priv, NPS_ENET_REG_RX_CTL);
216 	u32 tx_ctrl_value = nps_enet_reg_get(priv, NPS_ENET_REG_TX_CTL);
217 	u32 tx_ctrl_ct = (tx_ctrl_value & TX_CTL_CT_MASK) >> TX_CTL_CT_SHIFT;
218 	u32 rx_ctrl_cr = (rx_ctrl_value & RX_CTL_CR_MASK) >> RX_CTL_CR_SHIFT;
219 
220 	if ((!tx_ctrl_ct && priv->tx_packet_sent) || rx_ctrl_cr)
221 		if (likely(napi_schedule_prep(&priv->napi))) {
222 			nps_enet_reg_set(priv, NPS_ENET_REG_BUF_INT_ENABLE, 0);
223 			__napi_schedule(&priv->napi);
224 		}
225 
226 	return IRQ_HANDLED;
227 }
228 
229 static void nps_enet_set_hw_mac_address(struct net_device *ndev)
230 {
231 	struct nps_enet_priv *priv = netdev_priv(ndev);
232 	u32 ge_mac_cfg_1_value = 0;
233 	u32 *ge_mac_cfg_2_value = &priv->ge_mac_cfg_2_value;
234 
235 	/* set MAC address in HW */
236 	ge_mac_cfg_1_value |= ndev->dev_addr[0] << CFG_1_OCTET_0_SHIFT;
237 	ge_mac_cfg_1_value |= ndev->dev_addr[1] << CFG_1_OCTET_1_SHIFT;
238 	ge_mac_cfg_1_value |= ndev->dev_addr[2] << CFG_1_OCTET_2_SHIFT;
239 	ge_mac_cfg_1_value |= ndev->dev_addr[3] << CFG_1_OCTET_3_SHIFT;
240 	*ge_mac_cfg_2_value = (*ge_mac_cfg_2_value & ~CFG_2_OCTET_4_MASK)
241 		 | ndev->dev_addr[4] << CFG_2_OCTET_4_SHIFT;
242 	*ge_mac_cfg_2_value = (*ge_mac_cfg_2_value & ~CFG_2_OCTET_5_MASK)
243 		 | ndev->dev_addr[5] << CFG_2_OCTET_5_SHIFT;
244 
245 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_1,
246 			 ge_mac_cfg_1_value);
247 
248 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_2,
249 			 *ge_mac_cfg_2_value);
250 }
251 
252 /**
253  * nps_enet_hw_reset - Reset the network device.
254  * @ndev:       Pointer to the network device.
255  *
256  * This function reset the PCS and TX fifo.
257  * The programming model is to set the relevant reset bits
258  * wait for some time for this to propagate and then unset
259  * the reset bits. This way we ensure that reset procedure
260  * is done successfully by device.
261  */
262 static void nps_enet_hw_reset(struct net_device *ndev)
263 {
264 	struct nps_enet_priv *priv = netdev_priv(ndev);
265 	u32 ge_rst_value = 0, phase_fifo_ctl_value = 0;
266 
267 	/* Pcs reset sequence*/
268 	ge_rst_value |= NPS_ENET_ENABLE << RST_GMAC_0_SHIFT;
269 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_RST, ge_rst_value);
270 	usleep_range(10, 20);
271 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_RST, ge_rst_value);
272 
273 	/* Tx fifo reset sequence */
274 	phase_fifo_ctl_value |= NPS_ENET_ENABLE << PHASE_FIFO_CTL_RST_SHIFT;
275 	phase_fifo_ctl_value |= NPS_ENET_ENABLE << PHASE_FIFO_CTL_INIT_SHIFT;
276 	nps_enet_reg_set(priv, NPS_ENET_REG_PHASE_FIFO_CTL,
277 			 phase_fifo_ctl_value);
278 	usleep_range(10, 20);
279 	phase_fifo_ctl_value = 0;
280 	nps_enet_reg_set(priv, NPS_ENET_REG_PHASE_FIFO_CTL,
281 			 phase_fifo_ctl_value);
282 }
283 
284 static void nps_enet_hw_enable_control(struct net_device *ndev)
285 {
286 	struct nps_enet_priv *priv = netdev_priv(ndev);
287 	u32 ge_mac_cfg_0_value = 0, buf_int_enable_value = 0;
288 	u32 *ge_mac_cfg_2_value = &priv->ge_mac_cfg_2_value;
289 	u32 *ge_mac_cfg_3_value = &priv->ge_mac_cfg_3_value;
290 	s32 max_frame_length;
291 
292 	/* Enable Rx and Tx statistics */
293 	*ge_mac_cfg_2_value = (*ge_mac_cfg_2_value & ~CFG_2_STAT_EN_MASK)
294 		 | NPS_ENET_GE_MAC_CFG_2_STAT_EN << CFG_2_STAT_EN_SHIFT;
295 
296 	/* Discard packets with different MAC address */
297 	*ge_mac_cfg_2_value = (*ge_mac_cfg_2_value & ~CFG_2_DISK_DA_MASK)
298 		 | NPS_ENET_ENABLE << CFG_2_DISK_DA_SHIFT;
299 
300 	/* Discard multicast packets */
301 	*ge_mac_cfg_2_value = (*ge_mac_cfg_2_value & ~CFG_2_DISK_MC_MASK)
302 		 | NPS_ENET_ENABLE << CFG_2_DISK_MC_SHIFT;
303 
304 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_2,
305 			 *ge_mac_cfg_2_value);
306 
307 	/* Discard Packets bigger than max frame length */
308 	max_frame_length = ETH_HLEN + ndev->mtu + ETH_FCS_LEN;
309 	if (max_frame_length <= NPS_ENET_MAX_FRAME_LENGTH) {
310 		*ge_mac_cfg_3_value =
311 			 (*ge_mac_cfg_3_value & ~CFG_3_MAX_LEN_MASK)
312 			 | max_frame_length << CFG_3_MAX_LEN_SHIFT;
313 	}
314 
315 	/* Enable interrupts */
316 	buf_int_enable_value |= NPS_ENET_ENABLE << RX_RDY_SHIFT;
317 	buf_int_enable_value |= NPS_ENET_ENABLE << TX_DONE_SHIFT;
318 	nps_enet_reg_set(priv, NPS_ENET_REG_BUF_INT_ENABLE,
319 			 buf_int_enable_value);
320 
321 	/* Write device MAC address to HW */
322 	nps_enet_set_hw_mac_address(ndev);
323 
324 	/* Rx and Tx HW features */
325 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_TX_PAD_EN_SHIFT;
326 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_TX_CRC_EN_SHIFT;
327 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_RX_CRC_STRIP_SHIFT;
328 
329 	/* IFG configuration */
330 	ge_mac_cfg_0_value |=
331 		 NPS_ENET_GE_MAC_CFG_0_RX_IFG << CFG_0_RX_IFG_SHIFT;
332 	ge_mac_cfg_0_value |=
333 		 NPS_ENET_GE_MAC_CFG_0_TX_IFG << CFG_0_TX_IFG_SHIFT;
334 
335 	/* preamble configuration */
336 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_RX_PR_CHECK_EN_SHIFT;
337 	ge_mac_cfg_0_value |=
338 		 NPS_ENET_GE_MAC_CFG_0_TX_PR_LEN << CFG_0_TX_PR_LEN_SHIFT;
339 
340 	/* enable flow control frames */
341 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_TX_FC_EN_SHIFT;
342 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_RX_FC_EN_SHIFT;
343 	ge_mac_cfg_0_value |=
344 		 NPS_ENET_GE_MAC_CFG_0_TX_FC_RETR << CFG_0_TX_FC_RETR_SHIFT;
345 	*ge_mac_cfg_3_value = (*ge_mac_cfg_3_value & ~CFG_3_CF_DROP_MASK)
346 		 | NPS_ENET_ENABLE << CFG_3_CF_DROP_SHIFT;
347 
348 	/* Enable Rx and Tx */
349 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_RX_EN_SHIFT;
350 	ge_mac_cfg_0_value |= NPS_ENET_ENABLE << CFG_0_TX_EN_SHIFT;
351 
352 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_3,
353 			 *ge_mac_cfg_3_value);
354 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_0,
355 			 ge_mac_cfg_0_value);
356 }
357 
358 static void nps_enet_hw_disable_control(struct net_device *ndev)
359 {
360 	struct nps_enet_priv *priv = netdev_priv(ndev);
361 
362 	/* Disable interrupts */
363 	nps_enet_reg_set(priv, NPS_ENET_REG_BUF_INT_ENABLE, 0);
364 
365 	/* Disable Rx and Tx */
366 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_0, 0);
367 }
368 
369 static void nps_enet_send_frame(struct net_device *ndev,
370 				struct sk_buff *skb)
371 {
372 	struct nps_enet_priv *priv = netdev_priv(ndev);
373 	u32 tx_ctrl_value = 0;
374 	short length = skb->len;
375 	u32 i, len = DIV_ROUND_UP(length, sizeof(u32));
376 	u32 *src = (void *)skb->data;
377 	bool src_is_aligned = IS_ALIGNED((unsigned long)src, sizeof(u32));
378 
379 	/* In case src is not aligned we need an intermediate buffer */
380 	if (src_is_aligned)
381 		iowrite32_rep(priv->regs_base + NPS_ENET_REG_TX_BUF, src, len);
382 	else /* !src_is_aligned */
383 		for (i = 0; i < len; i++, src++)
384 			nps_enet_reg_set(priv, NPS_ENET_REG_TX_BUF,
385 					 get_unaligned_be32(src));
386 
387 	/* Write the length of the Frame */
388 	tx_ctrl_value |= length << TX_CTL_NT_SHIFT;
389 
390 	/* Indicate SW is done */
391 	priv->tx_packet_sent = true;
392 	tx_ctrl_value |= NPS_ENET_ENABLE << TX_CTL_CT_SHIFT;
393 	/* Send Frame */
394 	nps_enet_reg_set(priv, NPS_ENET_REG_TX_CTL, tx_ctrl_value);
395 }
396 
397 /**
398  * nps_enet_set_mac_address - Set the MAC address for this device.
399  * @ndev:       Pointer to net_device structure.
400  * @p:          6 byte Address to be written as MAC address.
401  *
402  * This function copies the HW address from the sockaddr structure to the
403  * net_device structure and updates the address in HW.
404  *
405  * returns:     -EBUSY if the net device is busy or 0 if the address is set
406  *              successfully.
407  */
408 static s32 nps_enet_set_mac_address(struct net_device *ndev, void *p)
409 {
410 	struct sockaddr *addr = p;
411 	s32 res;
412 
413 	if (netif_running(ndev))
414 		return -EBUSY;
415 
416 	res = eth_mac_addr(ndev, p);
417 	if (!res) {
418 		ether_addr_copy(ndev->dev_addr, addr->sa_data);
419 		nps_enet_set_hw_mac_address(ndev);
420 	}
421 
422 	return res;
423 }
424 
425 /**
426  * nps_enet_set_rx_mode - Change the receive filtering mode.
427  * @ndev:       Pointer to the network device.
428  *
429  * This function enables/disables promiscuous mode
430  */
431 static void nps_enet_set_rx_mode(struct net_device *ndev)
432 {
433 	struct nps_enet_priv *priv = netdev_priv(ndev);
434 	u32 ge_mac_cfg_2_value = priv->ge_mac_cfg_2_value;
435 
436 	if (ndev->flags & IFF_PROMISC) {
437 		ge_mac_cfg_2_value = (ge_mac_cfg_2_value & ~CFG_2_DISK_DA_MASK)
438 			 | NPS_ENET_DISABLE << CFG_2_DISK_DA_SHIFT;
439 		ge_mac_cfg_2_value = (ge_mac_cfg_2_value & ~CFG_2_DISK_MC_MASK)
440 			 | NPS_ENET_DISABLE << CFG_2_DISK_MC_SHIFT;
441 
442 	} else {
443 		ge_mac_cfg_2_value = (ge_mac_cfg_2_value & ~CFG_2_DISK_DA_MASK)
444 			 | NPS_ENET_ENABLE << CFG_2_DISK_DA_SHIFT;
445 		ge_mac_cfg_2_value = (ge_mac_cfg_2_value & ~CFG_2_DISK_MC_MASK)
446 			 | NPS_ENET_ENABLE << CFG_2_DISK_MC_SHIFT;
447 
448 	}
449 
450 	nps_enet_reg_set(priv, NPS_ENET_REG_GE_MAC_CFG_2, ge_mac_cfg_2_value);
451 }
452 
453 /**
454  * nps_enet_open - Open the network device.
455  * @ndev:       Pointer to the network device.
456  *
457  * returns: 0, on success or non-zero error value on failure.
458  *
459  * This function sets the MAC address, requests and enables an IRQ
460  * for the ENET device and starts the Tx queue.
461  */
462 static s32 nps_enet_open(struct net_device *ndev)
463 {
464 	struct nps_enet_priv *priv = netdev_priv(ndev);
465 	s32 err;
466 
467 	/* Reset private variables */
468 	priv->tx_packet_sent = false;
469 	priv->ge_mac_cfg_2_value = 0;
470 	priv->ge_mac_cfg_3_value = 0;
471 
472 	/* ge_mac_cfg_3 default values */
473 	priv->ge_mac_cfg_3_value |=
474 		 NPS_ENET_GE_MAC_CFG_3_RX_IFG_TH << CFG_3_RX_IFG_TH_SHIFT;
475 
476 	priv->ge_mac_cfg_3_value |=
477 		 NPS_ENET_GE_MAC_CFG_3_MAX_LEN << CFG_3_MAX_LEN_SHIFT;
478 
479 	/* Disable HW device */
480 	nps_enet_hw_disable_control(ndev);
481 
482 	/* irq Rx allocation */
483 	err = request_irq(priv->irq, nps_enet_irq_handler,
484 			  0, "enet-rx-tx", ndev);
485 	if (err)
486 		return err;
487 
488 	napi_enable(&priv->napi);
489 
490 	/* Enable HW device */
491 	nps_enet_hw_reset(ndev);
492 	nps_enet_hw_enable_control(ndev);
493 
494 	netif_start_queue(ndev);
495 
496 	return 0;
497 }
498 
499 /**
500  * nps_enet_stop - Close the network device.
501  * @ndev:       Pointer to the network device.
502  *
503  * This function stops the Tx queue, disables interrupts for the ENET device.
504  */
505 static s32 nps_enet_stop(struct net_device *ndev)
506 {
507 	struct nps_enet_priv *priv = netdev_priv(ndev);
508 
509 	napi_disable(&priv->napi);
510 	netif_stop_queue(ndev);
511 	nps_enet_hw_disable_control(ndev);
512 	free_irq(priv->irq, ndev);
513 
514 	return 0;
515 }
516 
517 /**
518  * nps_enet_start_xmit - Starts the data transmission.
519  * @skb:        sk_buff pointer that contains data to be Transmitted.
520  * @ndev:       Pointer to net_device structure.
521  *
522  * returns: NETDEV_TX_OK, on success
523  *              NETDEV_TX_BUSY, if any of the descriptors are not free.
524  *
525  * This function is invoked from upper layers to initiate transmission.
526  */
527 static netdev_tx_t nps_enet_start_xmit(struct sk_buff *skb,
528 				       struct net_device *ndev)
529 {
530 	struct nps_enet_priv *priv = netdev_priv(ndev);
531 
532 	/* This driver handles one frame at a time  */
533 	netif_stop_queue(ndev);
534 
535 	priv->tx_skb = skb;
536 
537 	nps_enet_send_frame(ndev, skb);
538 
539 	return NETDEV_TX_OK;
540 }
541 
542 #ifdef CONFIG_NET_POLL_CONTROLLER
543 static void nps_enet_poll_controller(struct net_device *ndev)
544 {
545 	disable_irq(ndev->irq);
546 	nps_enet_irq_handler(ndev->irq, ndev);
547 	enable_irq(ndev->irq);
548 }
549 #endif
550 
551 static const struct net_device_ops nps_netdev_ops = {
552 	.ndo_open		= nps_enet_open,
553 	.ndo_stop		= nps_enet_stop,
554 	.ndo_start_xmit		= nps_enet_start_xmit,
555 	.ndo_set_mac_address	= nps_enet_set_mac_address,
556 	.ndo_set_rx_mode        = nps_enet_set_rx_mode,
557 #ifdef CONFIG_NET_POLL_CONTROLLER
558 	.ndo_poll_controller	= nps_enet_poll_controller,
559 #endif
560 };
561 
562 static s32 nps_enet_probe(struct platform_device *pdev)
563 {
564 	struct device *dev = &pdev->dev;
565 	struct net_device *ndev;
566 	struct nps_enet_priv *priv;
567 	s32 err = 0;
568 	const char *mac_addr;
569 	struct resource *res_regs;
570 
571 	if (!dev->of_node)
572 		return -ENODEV;
573 
574 	ndev = alloc_etherdev(sizeof(struct nps_enet_priv));
575 	if (!ndev)
576 		return -ENOMEM;
577 
578 	platform_set_drvdata(pdev, ndev);
579 	SET_NETDEV_DEV(ndev, dev);
580 	priv = netdev_priv(ndev);
581 
582 	/* The EZ NET specific entries in the device structure. */
583 	ndev->netdev_ops = &nps_netdev_ops;
584 	ndev->watchdog_timeo = (400 * HZ / 1000);
585 	/* FIXME :: no multicast support yet */
586 	ndev->flags &= ~IFF_MULTICAST;
587 
588 	res_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
589 	priv->regs_base = devm_ioremap_resource(dev, res_regs);
590 	if (IS_ERR(priv->regs_base)) {
591 		err = PTR_ERR(priv->regs_base);
592 		goto out_netdev;
593 	}
594 	dev_dbg(dev, "Registers base address is 0x%p\n", priv->regs_base);
595 
596 	/* set kernel MAC address to dev */
597 	mac_addr = of_get_mac_address(dev->of_node);
598 	if (mac_addr)
599 		ether_addr_copy(ndev->dev_addr, mac_addr);
600 	else
601 		eth_hw_addr_random(ndev);
602 
603 	/* Get IRQ number */
604 	priv->irq = platform_get_irq(pdev, 0);
605 	if (!priv->irq) {
606 		dev_err(dev, "failed to retrieve <irq Rx-Tx> value from device tree\n");
607 		err = -ENODEV;
608 		goto out_netdev;
609 	}
610 
611 	netif_napi_add(ndev, &priv->napi, nps_enet_poll,
612 		       NPS_ENET_NAPI_POLL_WEIGHT);
613 
614 	/* Register the driver. Should be the last thing in probe */
615 	err = register_netdev(ndev);
616 	if (err) {
617 		dev_err(dev, "Failed to register ndev for %s, err = 0x%08x\n",
618 			ndev->name, (s32)err);
619 		goto out_netif_api;
620 	}
621 
622 	dev_info(dev, "(rx/tx=%d)\n", priv->irq);
623 	return 0;
624 
625 out_netif_api:
626 	netif_napi_del(&priv->napi);
627 out_netdev:
628 	if (err)
629 		free_netdev(ndev);
630 
631 	return err;
632 }
633 
634 static s32 nps_enet_remove(struct platform_device *pdev)
635 {
636 	struct net_device *ndev = platform_get_drvdata(pdev);
637 	struct nps_enet_priv *priv = netdev_priv(ndev);
638 
639 	unregister_netdev(ndev);
640 	free_netdev(ndev);
641 	netif_napi_del(&priv->napi);
642 
643 	return 0;
644 }
645 
646 static const struct of_device_id nps_enet_dt_ids[] = {
647 	{ .compatible = "ezchip,nps-mgt-enet" },
648 	{ /* Sentinel */ }
649 };
650 
651 static struct platform_driver nps_enet_driver = {
652 	.probe = nps_enet_probe,
653 	.remove = nps_enet_remove,
654 	.driver = {
655 		.name = DRV_NAME,
656 		.of_match_table  = nps_enet_dt_ids,
657 	},
658 };
659 
660 module_platform_driver(nps_enet_driver);
661 
662 MODULE_AUTHOR("EZchip Semiconductor");
663 MODULE_LICENSE("GPL v2");
664