xref: /openbmc/linux/drivers/net/pcs/pcs-lynx.c (revision 2cf1c348)
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 
10 #define SGMII_CLOCK_PERIOD_NS		8 /* PCS is clocked at 125 MHz */
11 #define LINK_TIMER_VAL(ns)		((u32)((ns) / SGMII_CLOCK_PERIOD_NS))
12 
13 #define SGMII_AN_LINK_TIMER_NS		1600000 /* defined by SGMII spec */
14 #define IEEE8023_LINK_TIMER_NS		10000000
15 
16 #define LINK_TIMER_LO			0x12
17 #define LINK_TIMER_HI			0x13
18 #define IF_MODE				0x14
19 #define IF_MODE_SGMII_EN		BIT(0)
20 #define IF_MODE_USE_SGMII_AN		BIT(1)
21 #define IF_MODE_SPEED(x)		(((x) << 2) & GENMASK(3, 2))
22 #define IF_MODE_SPEED_MSK		GENMASK(3, 2)
23 #define IF_MODE_HALF_DUPLEX		BIT(4)
24 
25 struct lynx_pcs {
26 	struct phylink_pcs pcs;
27 	struct mdio_device *mdio;
28 };
29 
30 enum sgmii_speed {
31 	SGMII_SPEED_10		= 0,
32 	SGMII_SPEED_100		= 1,
33 	SGMII_SPEED_1000	= 2,
34 	SGMII_SPEED_2500	= 2,
35 };
36 
37 #define phylink_pcs_to_lynx(pl_pcs) container_of((pl_pcs), struct lynx_pcs, pcs)
38 #define lynx_to_phylink_pcs(lynx) (&(lynx)->pcs)
39 
40 struct mdio_device *lynx_get_mdio_device(struct phylink_pcs *pcs)
41 {
42 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
43 
44 	return lynx->mdio;
45 }
46 EXPORT_SYMBOL(lynx_get_mdio_device);
47 
48 static void lynx_pcs_get_state_usxgmii(struct mdio_device *pcs,
49 				       struct phylink_link_state *state)
50 {
51 	struct mii_bus *bus = pcs->bus;
52 	int addr = pcs->addr;
53 	int status, lpa;
54 
55 	status = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_BMSR);
56 	if (status < 0)
57 		return;
58 
59 	state->link = !!(status & MDIO_STAT1_LSTATUS);
60 	state->an_complete = !!(status & MDIO_AN_STAT1_COMPLETE);
61 	if (!state->link || !state->an_complete)
62 		return;
63 
64 	lpa = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_LPA);
65 	if (lpa < 0)
66 		return;
67 
68 	phylink_decode_usxgmii_word(state, lpa);
69 }
70 
71 static void lynx_pcs_get_state_2500basex(struct mdio_device *pcs,
72 					 struct phylink_link_state *state)
73 {
74 	struct mii_bus *bus = pcs->bus;
75 	int addr = pcs->addr;
76 	int bmsr, lpa;
77 
78 	bmsr = mdiobus_read(bus, addr, MII_BMSR);
79 	lpa = mdiobus_read(bus, addr, MII_LPA);
80 	if (bmsr < 0 || lpa < 0) {
81 		state->link = false;
82 		return;
83 	}
84 
85 	state->link = !!(bmsr & BMSR_LSTATUS);
86 	state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
87 	if (!state->link)
88 		return;
89 
90 	state->speed = SPEED_2500;
91 	state->pause |= MLO_PAUSE_TX | MLO_PAUSE_RX;
92 	state->duplex = DUPLEX_FULL;
93 }
94 
95 static void lynx_pcs_get_state(struct phylink_pcs *pcs,
96 			       struct phylink_link_state *state)
97 {
98 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
99 
100 	switch (state->interface) {
101 	case PHY_INTERFACE_MODE_1000BASEX:
102 	case PHY_INTERFACE_MODE_SGMII:
103 	case PHY_INTERFACE_MODE_QSGMII:
104 		phylink_mii_c22_pcs_get_state(lynx->mdio, state);
105 		break;
106 	case PHY_INTERFACE_MODE_2500BASEX:
107 		lynx_pcs_get_state_2500basex(lynx->mdio, state);
108 		break;
109 	case PHY_INTERFACE_MODE_USXGMII:
110 		lynx_pcs_get_state_usxgmii(lynx->mdio, state);
111 		break;
112 	case PHY_INTERFACE_MODE_10GBASER:
113 		phylink_mii_c45_pcs_get_state(lynx->mdio, state);
114 		break;
115 	default:
116 		break;
117 	}
118 
119 	dev_dbg(&lynx->mdio->dev,
120 		"mode=%s/%s/%s link=%u an_enabled=%u an_complete=%u\n",
121 		phy_modes(state->interface),
122 		phy_speed_to_str(state->speed),
123 		phy_duplex_to_str(state->duplex),
124 		state->link, state->an_enabled, state->an_complete);
125 }
126 
127 static int lynx_pcs_config_1000basex(struct mdio_device *pcs,
128 				     unsigned int mode,
129 				     const unsigned long *advertising)
130 {
131 	struct mii_bus *bus = pcs->bus;
132 	int addr = pcs->addr;
133 	u32 link_timer;
134 	int err;
135 
136 	link_timer = LINK_TIMER_VAL(IEEE8023_LINK_TIMER_NS);
137 	mdiobus_write(bus, addr, LINK_TIMER_LO, link_timer & 0xffff);
138 	mdiobus_write(bus, addr, LINK_TIMER_HI, link_timer >> 16);
139 
140 	err = mdiobus_modify(bus, addr, IF_MODE,
141 			     IF_MODE_SGMII_EN | IF_MODE_USE_SGMII_AN,
142 			     0);
143 	if (err)
144 		return err;
145 
146 	return phylink_mii_c22_pcs_config(pcs, mode,
147 					  PHY_INTERFACE_MODE_1000BASEX,
148 					  advertising);
149 }
150 
151 static int lynx_pcs_config_sgmii(struct mdio_device *pcs, unsigned int mode,
152 				 const unsigned long *advertising)
153 {
154 	struct mii_bus *bus = pcs->bus;
155 	int addr = pcs->addr;
156 	u16 if_mode;
157 	int err;
158 
159 	if_mode = IF_MODE_SGMII_EN;
160 	if (mode == MLO_AN_INBAND) {
161 		u32 link_timer;
162 
163 		if_mode |= IF_MODE_USE_SGMII_AN;
164 
165 		/* Adjust link timer for SGMII */
166 		link_timer = LINK_TIMER_VAL(SGMII_AN_LINK_TIMER_NS);
167 		mdiobus_write(bus, addr, LINK_TIMER_LO, link_timer & 0xffff);
168 		mdiobus_write(bus, addr, LINK_TIMER_HI, link_timer >> 16);
169 	}
170 	err = mdiobus_modify(bus, addr, IF_MODE,
171 			     IF_MODE_SGMII_EN | IF_MODE_USE_SGMII_AN,
172 			     if_mode);
173 	if (err)
174 		return err;
175 
176 	return phylink_mii_c22_pcs_config(pcs, mode, PHY_INTERFACE_MODE_SGMII,
177 					 advertising);
178 }
179 
180 static int lynx_pcs_config_usxgmii(struct mdio_device *pcs, unsigned int mode,
181 				   const unsigned long *advertising)
182 {
183 	struct mii_bus *bus = pcs->bus;
184 	int addr = pcs->addr;
185 
186 	if (!phylink_autoneg_inband(mode)) {
187 		dev_err(&pcs->dev, "USXGMII only supports in-band AN for now\n");
188 		return -EOPNOTSUPP;
189 	}
190 
191 	/* Configure device ability for the USXGMII Replicator */
192 	return mdiobus_c45_write(bus, addr, MDIO_MMD_VEND2, MII_ADVERTISE,
193 				 MDIO_USXGMII_10G | MDIO_USXGMII_LINK |
194 				 MDIO_USXGMII_FULL_DUPLEX |
195 				 ADVERTISE_SGMII | ADVERTISE_LPACK);
196 }
197 
198 static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
199 			   phy_interface_t ifmode,
200 			   const unsigned long *advertising,
201 			   bool permit)
202 {
203 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
204 
205 	switch (ifmode) {
206 	case PHY_INTERFACE_MODE_1000BASEX:
207 		return lynx_pcs_config_1000basex(lynx->mdio, mode, advertising);
208 	case PHY_INTERFACE_MODE_SGMII:
209 	case PHY_INTERFACE_MODE_QSGMII:
210 		return lynx_pcs_config_sgmii(lynx->mdio, mode, advertising);
211 	case PHY_INTERFACE_MODE_2500BASEX:
212 		if (phylink_autoneg_inband(mode)) {
213 			dev_err(&lynx->mdio->dev,
214 				"AN not supported on 3.125GHz SerDes lane\n");
215 			return -EOPNOTSUPP;
216 		}
217 		break;
218 	case PHY_INTERFACE_MODE_USXGMII:
219 		return lynx_pcs_config_usxgmii(lynx->mdio, mode, advertising);
220 	case PHY_INTERFACE_MODE_10GBASER:
221 		/* Nothing to do here for 10GBASER */
222 		break;
223 	default:
224 		return -EOPNOTSUPP;
225 	}
226 
227 	return 0;
228 }
229 
230 static void lynx_pcs_an_restart(struct phylink_pcs *pcs)
231 {
232 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
233 
234 	phylink_mii_c22_pcs_an_restart(lynx->mdio);
235 }
236 
237 static void lynx_pcs_link_up_sgmii(struct mdio_device *pcs, unsigned int mode,
238 				   int speed, int duplex)
239 {
240 	struct mii_bus *bus = pcs->bus;
241 	u16 if_mode = 0, sgmii_speed;
242 	int addr = pcs->addr;
243 
244 	/* The PCS needs to be configured manually only
245 	 * when not operating on in-band mode
246 	 */
247 	if (mode == MLO_AN_INBAND)
248 		return;
249 
250 	if (duplex == DUPLEX_HALF)
251 		if_mode |= IF_MODE_HALF_DUPLEX;
252 
253 	switch (speed) {
254 	case SPEED_1000:
255 		sgmii_speed = SGMII_SPEED_1000;
256 		break;
257 	case SPEED_100:
258 		sgmii_speed = SGMII_SPEED_100;
259 		break;
260 	case SPEED_10:
261 		sgmii_speed = SGMII_SPEED_10;
262 		break;
263 	case SPEED_UNKNOWN:
264 		/* Silently don't do anything */
265 		return;
266 	default:
267 		dev_err(&pcs->dev, "Invalid PCS speed %d\n", speed);
268 		return;
269 	}
270 	if_mode |= IF_MODE_SPEED(sgmii_speed);
271 
272 	mdiobus_modify(bus, addr, IF_MODE,
273 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
274 		       if_mode);
275 }
276 
277 /* 2500Base-X is SerDes protocol 7 on Felix and 6 on ENETC. It is a SerDes lane
278  * clocked at 3.125 GHz which encodes symbols with 8b/10b and does not have
279  * auto-negotiation of any link parameters. Electrically it is compatible with
280  * a single lane of XAUI.
281  * The hardware reference manual wants to call this mode SGMII, but it isn't
282  * really, since the fundamental features of SGMII:
283  * - Downgrading the link speed by duplicating symbols
284  * - Auto-negotiation
285  * are not there.
286  * The speed is configured at 1000 in the IF_MODE because the clock frequency
287  * is actually given by a PLL configured in the Reset Configuration Word (RCW).
288  * Since there is no difference between fixed speed SGMII w/o AN and 802.3z w/o
289  * AN, we call this PHY interface type 2500Base-X. In case a PHY negotiates a
290  * lower link speed on line side, the system-side interface remains fixed at
291  * 2500 Mbps and we do rate adaptation through pause frames.
292  */
293 static void lynx_pcs_link_up_2500basex(struct mdio_device *pcs,
294 				       unsigned int mode,
295 				       int speed, int duplex)
296 {
297 	struct mii_bus *bus = pcs->bus;
298 	int addr = pcs->addr;
299 	u16 if_mode = 0;
300 
301 	if (mode == MLO_AN_INBAND) {
302 		dev_err(&pcs->dev, "AN not supported for 2500BaseX\n");
303 		return;
304 	}
305 
306 	if (duplex == DUPLEX_HALF)
307 		if_mode |= IF_MODE_HALF_DUPLEX;
308 	if_mode |= IF_MODE_SPEED(SGMII_SPEED_2500);
309 
310 	mdiobus_modify(bus, addr, IF_MODE,
311 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
312 		       if_mode);
313 }
314 
315 static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
316 			     phy_interface_t interface,
317 			     int speed, int duplex)
318 {
319 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
320 
321 	switch (interface) {
322 	case PHY_INTERFACE_MODE_SGMII:
323 	case PHY_INTERFACE_MODE_QSGMII:
324 		lynx_pcs_link_up_sgmii(lynx->mdio, mode, speed, duplex);
325 		break;
326 	case PHY_INTERFACE_MODE_2500BASEX:
327 		lynx_pcs_link_up_2500basex(lynx->mdio, mode, speed, duplex);
328 		break;
329 	case PHY_INTERFACE_MODE_USXGMII:
330 		/* At the moment, only in-band AN is supported for USXGMII
331 		 * so nothing to do in link_up
332 		 */
333 		break;
334 	default:
335 		break;
336 	}
337 }
338 
339 static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
340 	.pcs_get_state = lynx_pcs_get_state,
341 	.pcs_config = lynx_pcs_config,
342 	.pcs_an_restart = lynx_pcs_an_restart,
343 	.pcs_link_up = lynx_pcs_link_up,
344 };
345 
346 struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
347 {
348 	struct lynx_pcs *lynx;
349 
350 	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
351 	if (!lynx)
352 		return NULL;
353 
354 	lynx->mdio = mdio;
355 	lynx->pcs.ops = &lynx_pcs_phylink_ops;
356 	lynx->pcs.poll = true;
357 
358 	return lynx_to_phylink_pcs(lynx);
359 }
360 EXPORT_SYMBOL(lynx_pcs_create);
361 
362 void lynx_pcs_destroy(struct phylink_pcs *pcs)
363 {
364 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
365 
366 	kfree(lynx);
367 }
368 EXPORT_SYMBOL(lynx_pcs_destroy);
369 
370 MODULE_LICENSE("Dual BSD/GPL");
371