xref: /linux/drivers/net/pcs/pcs-lynx.c (revision 6e7fd890f1d6ac83805409e9c346240de2705584)
1 // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
2 /* Copyright 2020 NXP
3  * Lynx PCS MDIO helpers
4  */
5 
6 #include <linux/mdio.h>
7 #include <linux/phylink.h>
8 #include <linux/pcs-lynx.h>
9 #include <linux/property.h>
10 
11 #define SGMII_CLOCK_PERIOD_NS		8 /* PCS is clocked at 125 MHz */
12 #define LINK_TIMER_VAL(ns)		((u32)((ns) / SGMII_CLOCK_PERIOD_NS))
13 
14 #define LINK_TIMER_LO			0x12
15 #define LINK_TIMER_HI			0x13
16 #define IF_MODE				0x14
17 #define IF_MODE_SGMII_EN		BIT(0)
18 #define IF_MODE_USE_SGMII_AN		BIT(1)
19 #define IF_MODE_SPEED(x)		(((x) << 2) & GENMASK(3, 2))
20 #define IF_MODE_SPEED_MSK		GENMASK(3, 2)
21 #define IF_MODE_HALF_DUPLEX		BIT(4)
22 
23 struct lynx_pcs {
24 	struct phylink_pcs pcs;
25 	struct mdio_device *mdio;
26 };
27 
28 enum sgmii_speed {
29 	SGMII_SPEED_10		= 0,
30 	SGMII_SPEED_100		= 1,
31 	SGMII_SPEED_1000	= 2,
32 	SGMII_SPEED_2500	= 2,
33 };
34 
35 #define phylink_pcs_to_lynx(pl_pcs) container_of((pl_pcs), struct lynx_pcs, pcs)
36 #define lynx_to_phylink_pcs(lynx) (&(lynx)->pcs)
37 
38 static void lynx_pcs_get_state_usxgmii(struct mdio_device *pcs,
39 				       struct phylink_link_state *state)
40 {
41 	struct mii_bus *bus = pcs->bus;
42 	int addr = pcs->addr;
43 	int status, lpa;
44 
45 	status = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_BMSR);
46 	if (status < 0)
47 		return;
48 
49 	state->link = !!(status & MDIO_STAT1_LSTATUS);
50 	state->an_complete = !!(status & MDIO_AN_STAT1_COMPLETE);
51 	if (!state->link || !state->an_complete)
52 		return;
53 
54 	lpa = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_LPA);
55 	if (lpa < 0)
56 		return;
57 
58 	phylink_decode_usxgmii_word(state, lpa);
59 }
60 
61 static void lynx_pcs_get_state_2500basex(struct mdio_device *pcs,
62 					 struct phylink_link_state *state)
63 {
64 	int bmsr;
65 
66 	bmsr = mdiodev_read(pcs, MII_BMSR);
67 	if (bmsr < 0) {
68 		state->link = false;
69 		return;
70 	}
71 
72 	state->link = !!(bmsr & BMSR_LSTATUS);
73 	state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
74 	if (!state->link)
75 		return;
76 
77 	state->speed = SPEED_2500;
78 	state->pause |= MLO_PAUSE_TX | MLO_PAUSE_RX;
79 	state->duplex = DUPLEX_FULL;
80 }
81 
82 static void lynx_pcs_get_state(struct phylink_pcs *pcs,
83 			       struct phylink_link_state *state)
84 {
85 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
86 
87 	switch (state->interface) {
88 	case PHY_INTERFACE_MODE_1000BASEX:
89 	case PHY_INTERFACE_MODE_SGMII:
90 	case PHY_INTERFACE_MODE_QSGMII:
91 		phylink_mii_c22_pcs_get_state(lynx->mdio, state);
92 		break;
93 	case PHY_INTERFACE_MODE_2500BASEX:
94 		lynx_pcs_get_state_2500basex(lynx->mdio, state);
95 		break;
96 	case PHY_INTERFACE_MODE_USXGMII:
97 		lynx_pcs_get_state_usxgmii(lynx->mdio, state);
98 		break;
99 	case PHY_INTERFACE_MODE_10GBASER:
100 		phylink_mii_c45_pcs_get_state(lynx->mdio, state);
101 		break;
102 	default:
103 		break;
104 	}
105 
106 	dev_dbg(&lynx->mdio->dev,
107 		"mode=%s/%s/%s link=%u an_complete=%u\n",
108 		phy_modes(state->interface),
109 		phy_speed_to_str(state->speed),
110 		phy_duplex_to_str(state->duplex),
111 		state->link, state->an_complete);
112 }
113 
114 static int lynx_pcs_config_giga(struct mdio_device *pcs,
115 				phy_interface_t interface,
116 				const unsigned long *advertising,
117 				unsigned int neg_mode)
118 {
119 	int link_timer_ns;
120 	u32 link_timer;
121 	u16 if_mode;
122 	int err;
123 
124 	link_timer_ns = phylink_get_link_timer_ns(interface);
125 	if (link_timer_ns > 0) {
126 		link_timer = LINK_TIMER_VAL(link_timer_ns);
127 
128 		mdiodev_write(pcs, LINK_TIMER_LO, link_timer & 0xffff);
129 		mdiodev_write(pcs, LINK_TIMER_HI, link_timer >> 16);
130 	}
131 
132 	if (interface == PHY_INTERFACE_MODE_1000BASEX) {
133 		if_mode = 0;
134 	} else {
135 		/* SGMII and QSGMII */
136 		if_mode = IF_MODE_SGMII_EN;
137 		if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED)
138 			if_mode |= IF_MODE_USE_SGMII_AN;
139 	}
140 
141 	err = mdiodev_modify(pcs, IF_MODE,
142 			     IF_MODE_SGMII_EN | IF_MODE_USE_SGMII_AN,
143 			     if_mode);
144 	if (err)
145 		return err;
146 
147 	return phylink_mii_c22_pcs_config(pcs, interface, advertising,
148 					  neg_mode);
149 }
150 
151 static int lynx_pcs_config_usxgmii(struct mdio_device *pcs,
152 				   const unsigned long *advertising,
153 				   unsigned int neg_mode)
154 {
155 	struct mii_bus *bus = pcs->bus;
156 	int addr = pcs->addr;
157 
158 	if (neg_mode != PHYLINK_PCS_NEG_INBAND_ENABLED) {
159 		dev_err(&pcs->dev, "USXGMII only supports in-band AN for now\n");
160 		return -EOPNOTSUPP;
161 	}
162 
163 	/* Configure device ability for the USXGMII Replicator */
164 	return mdiobus_c45_write(bus, addr, MDIO_MMD_VEND2, MII_ADVERTISE,
165 				 MDIO_USXGMII_10G | MDIO_USXGMII_LINK |
166 				 MDIO_USXGMII_FULL_DUPLEX |
167 				 ADVERTISE_SGMII | ADVERTISE_LPACK);
168 }
169 
170 static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
171 			   phy_interface_t ifmode,
172 			   const unsigned long *advertising, bool permit)
173 {
174 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
175 
176 	switch (ifmode) {
177 	case PHY_INTERFACE_MODE_1000BASEX:
178 	case PHY_INTERFACE_MODE_SGMII:
179 	case PHY_INTERFACE_MODE_QSGMII:
180 		return lynx_pcs_config_giga(lynx->mdio, ifmode, advertising,
181 					    neg_mode);
182 	case PHY_INTERFACE_MODE_2500BASEX:
183 		if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) {
184 			dev_err(&lynx->mdio->dev,
185 				"AN not supported on 3.125GHz SerDes lane\n");
186 			return -EOPNOTSUPP;
187 		}
188 		break;
189 	case PHY_INTERFACE_MODE_USXGMII:
190 		return lynx_pcs_config_usxgmii(lynx->mdio, advertising,
191 					       neg_mode);
192 	case PHY_INTERFACE_MODE_10GBASER:
193 		/* Nothing to do here for 10GBASER */
194 		break;
195 	default:
196 		return -EOPNOTSUPP;
197 	}
198 
199 	return 0;
200 }
201 
202 static void lynx_pcs_an_restart(struct phylink_pcs *pcs)
203 {
204 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
205 
206 	phylink_mii_c22_pcs_an_restart(lynx->mdio);
207 }
208 
209 static void lynx_pcs_link_up_sgmii(struct mdio_device *pcs,
210 				   unsigned int neg_mode,
211 				   int speed, int duplex)
212 {
213 	u16 if_mode = 0, sgmii_speed;
214 
215 	/* The PCS needs to be configured manually only
216 	 * when not operating on in-band mode
217 	 */
218 	if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED)
219 		return;
220 
221 	if (duplex == DUPLEX_HALF)
222 		if_mode |= IF_MODE_HALF_DUPLEX;
223 
224 	switch (speed) {
225 	case SPEED_1000:
226 		sgmii_speed = SGMII_SPEED_1000;
227 		break;
228 	case SPEED_100:
229 		sgmii_speed = SGMII_SPEED_100;
230 		break;
231 	case SPEED_10:
232 		sgmii_speed = SGMII_SPEED_10;
233 		break;
234 	case SPEED_UNKNOWN:
235 		/* Silently don't do anything */
236 		return;
237 	default:
238 		dev_err(&pcs->dev, "Invalid PCS speed %d\n", speed);
239 		return;
240 	}
241 	if_mode |= IF_MODE_SPEED(sgmii_speed);
242 
243 	mdiodev_modify(pcs, IF_MODE,
244 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
245 		       if_mode);
246 }
247 
248 /* 2500Base-X is SerDes protocol 7 on Felix and 6 on ENETC. It is a SerDes lane
249  * clocked at 3.125 GHz which encodes symbols with 8b/10b and does not have
250  * auto-negotiation of any link parameters. Electrically it is compatible with
251  * a single lane of XAUI.
252  * The hardware reference manual wants to call this mode SGMII, but it isn't
253  * really, since the fundamental features of SGMII:
254  * - Downgrading the link speed by duplicating symbols
255  * - Auto-negotiation
256  * are not there.
257  * The speed is configured at 1000 in the IF_MODE because the clock frequency
258  * is actually given by a PLL configured in the Reset Configuration Word (RCW).
259  * Since there is no difference between fixed speed SGMII w/o AN and 802.3z w/o
260  * AN, we call this PHY interface type 2500Base-X. In case a PHY negotiates a
261  * lower link speed on line side, the system-side interface remains fixed at
262  * 2500 Mbps and we do rate adaptation through pause frames.
263  */
264 static void lynx_pcs_link_up_2500basex(struct mdio_device *pcs,
265 				       unsigned int neg_mode,
266 				       int speed, int duplex)
267 {
268 	u16 if_mode = 0;
269 
270 	if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) {
271 		dev_err(&pcs->dev, "AN not supported for 2500BaseX\n");
272 		return;
273 	}
274 
275 	if (duplex == DUPLEX_HALF)
276 		if_mode |= IF_MODE_HALF_DUPLEX;
277 	if_mode |= IF_MODE_SPEED(SGMII_SPEED_2500);
278 
279 	mdiodev_modify(pcs, IF_MODE,
280 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
281 		       if_mode);
282 }
283 
284 static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
285 			     phy_interface_t interface,
286 			     int speed, int duplex)
287 {
288 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
289 
290 	switch (interface) {
291 	case PHY_INTERFACE_MODE_SGMII:
292 	case PHY_INTERFACE_MODE_QSGMII:
293 		lynx_pcs_link_up_sgmii(lynx->mdio, neg_mode, speed, duplex);
294 		break;
295 	case PHY_INTERFACE_MODE_2500BASEX:
296 		lynx_pcs_link_up_2500basex(lynx->mdio, neg_mode, speed, duplex);
297 		break;
298 	case PHY_INTERFACE_MODE_USXGMII:
299 		/* At the moment, only in-band AN is supported for USXGMII
300 		 * so nothing to do in link_up
301 		 */
302 		break;
303 	default:
304 		break;
305 	}
306 }
307 
308 static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
309 	.pcs_get_state = lynx_pcs_get_state,
310 	.pcs_config = lynx_pcs_config,
311 	.pcs_an_restart = lynx_pcs_an_restart,
312 	.pcs_link_up = lynx_pcs_link_up,
313 };
314 
315 static struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
316 {
317 	struct lynx_pcs *lynx;
318 
319 	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
320 	if (!lynx)
321 		return ERR_PTR(-ENOMEM);
322 
323 	mdio_device_get(mdio);
324 	lynx->mdio = mdio;
325 	lynx->pcs.ops = &lynx_pcs_phylink_ops;
326 	lynx->pcs.neg_mode = true;
327 	lynx->pcs.poll = true;
328 
329 	return lynx_to_phylink_pcs(lynx);
330 }
331 
332 struct phylink_pcs *lynx_pcs_create_mdiodev(struct mii_bus *bus, int addr)
333 {
334 	struct mdio_device *mdio;
335 	struct phylink_pcs *pcs;
336 
337 	mdio = mdio_device_create(bus, addr);
338 	if (IS_ERR(mdio))
339 		return ERR_CAST(mdio);
340 
341 	pcs = lynx_pcs_create(mdio);
342 
343 	/* lynx_create() has taken a refcount on the mdiodev if it was
344 	 * successful. If lynx_create() fails, this will free the mdio
345 	 * device here. In any case, we don't need to hold our reference
346 	 * anymore, and putting it here will allow mdio_device_put() in
347 	 * lynx_destroy() to automatically free the mdio device.
348 	 */
349 	mdio_device_put(mdio);
350 
351 	return pcs;
352 }
353 EXPORT_SYMBOL(lynx_pcs_create_mdiodev);
354 
355 /*
356  * lynx_pcs_create_fwnode() creates a lynx PCS instance from the fwnode
357  * device indicated by node.
358  *
359  * Returns:
360  *  -ENODEV if the fwnode is marked unavailable
361  *  -EPROBE_DEFER if we fail to find the device
362  *  -ENOMEM if we fail to allocate memory
363  *  pointer to a phylink_pcs on success
364  */
365 struct phylink_pcs *lynx_pcs_create_fwnode(struct fwnode_handle *node)
366 {
367 	struct mdio_device *mdio;
368 	struct phylink_pcs *pcs;
369 
370 	if (!fwnode_device_is_available(node))
371 		return ERR_PTR(-ENODEV);
372 
373 	mdio = fwnode_mdio_find_device(node);
374 	if (!mdio)
375 		return ERR_PTR(-EPROBE_DEFER);
376 
377 	pcs = lynx_pcs_create(mdio);
378 
379 	/* lynx_create() has taken a refcount on the mdiodev if it was
380 	 * successful. If lynx_create() fails, this will free the mdio
381 	 * device here. In any case, we don't need to hold our reference
382 	 * anymore, and putting it here will allow mdio_device_put() in
383 	 * lynx_destroy() to automatically free the mdio device.
384 	 */
385 	mdio_device_put(mdio);
386 
387 	return pcs;
388 }
389 EXPORT_SYMBOL_GPL(lynx_pcs_create_fwnode);
390 
391 void lynx_pcs_destroy(struct phylink_pcs *pcs)
392 {
393 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
394 
395 	mdio_device_put(lynx->mdio);
396 	kfree(lynx);
397 }
398 EXPORT_SYMBOL(lynx_pcs_destroy);
399 
400 MODULE_DESCRIPTION("NXP Lynx PCS phylink library");
401 MODULE_LICENSE("Dual BSD/GPL");
402