xref: /openbmc/linux/drivers/net/pcs/pcs-lynx.c (revision 6db6b729)
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, lpa;
65 
66 	bmsr = mdiodev_read(pcs, MII_BMSR);
67 	lpa = mdiodev_read(pcs, MII_LPA);
68 	if (bmsr < 0 || lpa < 0) {
69 		state->link = false;
70 		return;
71 	}
72 
73 	state->link = !!(bmsr & BMSR_LSTATUS);
74 	state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
75 	if (!state->link)
76 		return;
77 
78 	state->speed = SPEED_2500;
79 	state->pause |= MLO_PAUSE_TX | MLO_PAUSE_RX;
80 	state->duplex = DUPLEX_FULL;
81 }
82 
83 static void lynx_pcs_get_state(struct phylink_pcs *pcs,
84 			       struct phylink_link_state *state)
85 {
86 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
87 
88 	switch (state->interface) {
89 	case PHY_INTERFACE_MODE_1000BASEX:
90 	case PHY_INTERFACE_MODE_SGMII:
91 	case PHY_INTERFACE_MODE_QSGMII:
92 		phylink_mii_c22_pcs_get_state(lynx->mdio, state);
93 		break;
94 	case PHY_INTERFACE_MODE_2500BASEX:
95 		lynx_pcs_get_state_2500basex(lynx->mdio, state);
96 		break;
97 	case PHY_INTERFACE_MODE_USXGMII:
98 		lynx_pcs_get_state_usxgmii(lynx->mdio, state);
99 		break;
100 	case PHY_INTERFACE_MODE_10GBASER:
101 		phylink_mii_c45_pcs_get_state(lynx->mdio, state);
102 		break;
103 	default:
104 		break;
105 	}
106 
107 	dev_dbg(&lynx->mdio->dev,
108 		"mode=%s/%s/%s link=%u an_complete=%u\n",
109 		phy_modes(state->interface),
110 		phy_speed_to_str(state->speed),
111 		phy_duplex_to_str(state->duplex),
112 		state->link, state->an_complete);
113 }
114 
115 static int lynx_pcs_config_giga(struct mdio_device *pcs,
116 				phy_interface_t interface,
117 				const unsigned long *advertising,
118 				unsigned int neg_mode)
119 {
120 	int link_timer_ns;
121 	u32 link_timer;
122 	u16 if_mode;
123 	int err;
124 
125 	link_timer_ns = phylink_get_link_timer_ns(interface);
126 	if (link_timer_ns > 0) {
127 		link_timer = LINK_TIMER_VAL(link_timer_ns);
128 
129 		mdiodev_write(pcs, LINK_TIMER_LO, link_timer & 0xffff);
130 		mdiodev_write(pcs, LINK_TIMER_HI, link_timer >> 16);
131 	}
132 
133 	if (interface == PHY_INTERFACE_MODE_1000BASEX) {
134 		if_mode = 0;
135 	} else {
136 		/* SGMII and QSGMII */
137 		if_mode = IF_MODE_SGMII_EN;
138 		if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED)
139 			if_mode |= IF_MODE_USE_SGMII_AN;
140 	}
141 
142 	err = mdiodev_modify(pcs, IF_MODE,
143 			     IF_MODE_SGMII_EN | IF_MODE_USE_SGMII_AN,
144 			     if_mode);
145 	if (err)
146 		return err;
147 
148 	return phylink_mii_c22_pcs_config(pcs, interface, advertising,
149 					  neg_mode);
150 }
151 
152 static int lynx_pcs_config_usxgmii(struct mdio_device *pcs,
153 				   const unsigned long *advertising,
154 				   unsigned int neg_mode)
155 {
156 	struct mii_bus *bus = pcs->bus;
157 	int addr = pcs->addr;
158 
159 	if (neg_mode != PHYLINK_PCS_NEG_INBAND_ENABLED) {
160 		dev_err(&pcs->dev, "USXGMII only supports in-band AN for now\n");
161 		return -EOPNOTSUPP;
162 	}
163 
164 	/* Configure device ability for the USXGMII Replicator */
165 	return mdiobus_c45_write(bus, addr, MDIO_MMD_VEND2, MII_ADVERTISE,
166 				 MDIO_USXGMII_10G | MDIO_USXGMII_LINK |
167 				 MDIO_USXGMII_FULL_DUPLEX |
168 				 ADVERTISE_SGMII | ADVERTISE_LPACK);
169 }
170 
171 static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
172 			   phy_interface_t ifmode,
173 			   const unsigned long *advertising, bool permit)
174 {
175 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
176 
177 	switch (ifmode) {
178 	case PHY_INTERFACE_MODE_1000BASEX:
179 	case PHY_INTERFACE_MODE_SGMII:
180 	case PHY_INTERFACE_MODE_QSGMII:
181 		return lynx_pcs_config_giga(lynx->mdio, ifmode, advertising,
182 					    neg_mode);
183 	case PHY_INTERFACE_MODE_2500BASEX:
184 		if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) {
185 			dev_err(&lynx->mdio->dev,
186 				"AN not supported on 3.125GHz SerDes lane\n");
187 			return -EOPNOTSUPP;
188 		}
189 		break;
190 	case PHY_INTERFACE_MODE_USXGMII:
191 		return lynx_pcs_config_usxgmii(lynx->mdio, advertising,
192 					       neg_mode);
193 	case PHY_INTERFACE_MODE_10GBASER:
194 		/* Nothing to do here for 10GBASER */
195 		break;
196 	default:
197 		return -EOPNOTSUPP;
198 	}
199 
200 	return 0;
201 }
202 
203 static void lynx_pcs_an_restart(struct phylink_pcs *pcs)
204 {
205 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
206 
207 	phylink_mii_c22_pcs_an_restart(lynx->mdio);
208 }
209 
210 static void lynx_pcs_link_up_sgmii(struct mdio_device *pcs,
211 				   unsigned int neg_mode,
212 				   int speed, int duplex)
213 {
214 	u16 if_mode = 0, sgmii_speed;
215 
216 	/* The PCS needs to be configured manually only
217 	 * when not operating on in-band mode
218 	 */
219 	if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED)
220 		return;
221 
222 	if (duplex == DUPLEX_HALF)
223 		if_mode |= IF_MODE_HALF_DUPLEX;
224 
225 	switch (speed) {
226 	case SPEED_1000:
227 		sgmii_speed = SGMII_SPEED_1000;
228 		break;
229 	case SPEED_100:
230 		sgmii_speed = SGMII_SPEED_100;
231 		break;
232 	case SPEED_10:
233 		sgmii_speed = SGMII_SPEED_10;
234 		break;
235 	case SPEED_UNKNOWN:
236 		/* Silently don't do anything */
237 		return;
238 	default:
239 		dev_err(&pcs->dev, "Invalid PCS speed %d\n", speed);
240 		return;
241 	}
242 	if_mode |= IF_MODE_SPEED(sgmii_speed);
243 
244 	mdiodev_modify(pcs, IF_MODE,
245 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
246 		       if_mode);
247 }
248 
249 /* 2500Base-X is SerDes protocol 7 on Felix and 6 on ENETC. It is a SerDes lane
250  * clocked at 3.125 GHz which encodes symbols with 8b/10b and does not have
251  * auto-negotiation of any link parameters. Electrically it is compatible with
252  * a single lane of XAUI.
253  * The hardware reference manual wants to call this mode SGMII, but it isn't
254  * really, since the fundamental features of SGMII:
255  * - Downgrading the link speed by duplicating symbols
256  * - Auto-negotiation
257  * are not there.
258  * The speed is configured at 1000 in the IF_MODE because the clock frequency
259  * is actually given by a PLL configured in the Reset Configuration Word (RCW).
260  * Since there is no difference between fixed speed SGMII w/o AN and 802.3z w/o
261  * AN, we call this PHY interface type 2500Base-X. In case a PHY negotiates a
262  * lower link speed on line side, the system-side interface remains fixed at
263  * 2500 Mbps and we do rate adaptation through pause frames.
264  */
265 static void lynx_pcs_link_up_2500basex(struct mdio_device *pcs,
266 				       unsigned int neg_mode,
267 				       int speed, int duplex)
268 {
269 	u16 if_mode = 0;
270 
271 	if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) {
272 		dev_err(&pcs->dev, "AN not supported for 2500BaseX\n");
273 		return;
274 	}
275 
276 	if (duplex == DUPLEX_HALF)
277 		if_mode |= IF_MODE_HALF_DUPLEX;
278 	if_mode |= IF_MODE_SPEED(SGMII_SPEED_2500);
279 
280 	mdiodev_modify(pcs, IF_MODE,
281 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
282 		       if_mode);
283 }
284 
285 static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
286 			     phy_interface_t interface,
287 			     int speed, int duplex)
288 {
289 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
290 
291 	switch (interface) {
292 	case PHY_INTERFACE_MODE_SGMII:
293 	case PHY_INTERFACE_MODE_QSGMII:
294 		lynx_pcs_link_up_sgmii(lynx->mdio, neg_mode, speed, duplex);
295 		break;
296 	case PHY_INTERFACE_MODE_2500BASEX:
297 		lynx_pcs_link_up_2500basex(lynx->mdio, neg_mode, speed, duplex);
298 		break;
299 	case PHY_INTERFACE_MODE_USXGMII:
300 		/* At the moment, only in-band AN is supported for USXGMII
301 		 * so nothing to do in link_up
302 		 */
303 		break;
304 	default:
305 		break;
306 	}
307 }
308 
309 static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
310 	.pcs_get_state = lynx_pcs_get_state,
311 	.pcs_config = lynx_pcs_config,
312 	.pcs_an_restart = lynx_pcs_an_restart,
313 	.pcs_link_up = lynx_pcs_link_up,
314 };
315 
316 static struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
317 {
318 	struct lynx_pcs *lynx;
319 
320 	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
321 	if (!lynx)
322 		return ERR_PTR(-ENOMEM);
323 
324 	mdio_device_get(mdio);
325 	lynx->mdio = mdio;
326 	lynx->pcs.ops = &lynx_pcs_phylink_ops;
327 	lynx->pcs.neg_mode = true;
328 	lynx->pcs.poll = true;
329 
330 	return lynx_to_phylink_pcs(lynx);
331 }
332 
333 struct phylink_pcs *lynx_pcs_create_mdiodev(struct mii_bus *bus, int addr)
334 {
335 	struct mdio_device *mdio;
336 	struct phylink_pcs *pcs;
337 
338 	mdio = mdio_device_create(bus, addr);
339 	if (IS_ERR(mdio))
340 		return ERR_CAST(mdio);
341 
342 	pcs = lynx_pcs_create(mdio);
343 
344 	/* lynx_create() has taken a refcount on the mdiodev if it was
345 	 * successful. If lynx_create() fails, this will free the mdio
346 	 * device here. In any case, we don't need to hold our reference
347 	 * anymore, and putting it here will allow mdio_device_put() in
348 	 * lynx_destroy() to automatically free the mdio device.
349 	 */
350 	mdio_device_put(mdio);
351 
352 	return pcs;
353 }
354 EXPORT_SYMBOL(lynx_pcs_create_mdiodev);
355 
356 /*
357  * lynx_pcs_create_fwnode() creates a lynx PCS instance from the fwnode
358  * device indicated by node.
359  *
360  * Returns:
361  *  -ENODEV if the fwnode is marked unavailable
362  *  -EPROBE_DEFER if we fail to find the device
363  *  -ENOMEM if we fail to allocate memory
364  *  pointer to a phylink_pcs on success
365  */
366 struct phylink_pcs *lynx_pcs_create_fwnode(struct fwnode_handle *node)
367 {
368 	struct mdio_device *mdio;
369 	struct phylink_pcs *pcs;
370 
371 	if (!fwnode_device_is_available(node))
372 		return ERR_PTR(-ENODEV);
373 
374 	mdio = fwnode_mdio_find_device(node);
375 	if (!mdio)
376 		return ERR_PTR(-EPROBE_DEFER);
377 
378 	pcs = lynx_pcs_create(mdio);
379 
380 	/* lynx_create() has taken a refcount on the mdiodev if it was
381 	 * successful. If lynx_create() fails, this will free the mdio
382 	 * device here. In any case, we don't need to hold our reference
383 	 * anymore, and putting it here will allow mdio_device_put() in
384 	 * lynx_destroy() to automatically free the mdio device.
385 	 */
386 	mdio_device_put(mdio);
387 
388 	return pcs;
389 }
390 EXPORT_SYMBOL_GPL(lynx_pcs_create_fwnode);
391 
392 void lynx_pcs_destroy(struct phylink_pcs *pcs)
393 {
394 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
395 
396 	mdio_device_put(lynx->mdio);
397 	kfree(lynx);
398 }
399 EXPORT_SYMBOL(lynx_pcs_destroy);
400 
401 MODULE_LICENSE("Dual BSD/GPL");
402