xref: /openbmc/linux/drivers/net/pcs/pcs-lynx.c (revision 236bdb88)
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 LINK_TIMER_LO			0x12
14 #define LINK_TIMER_HI			0x13
15 #define IF_MODE				0x14
16 #define IF_MODE_SGMII_EN		BIT(0)
17 #define IF_MODE_USE_SGMII_AN		BIT(1)
18 #define IF_MODE_SPEED(x)		(((x) << 2) & GENMASK(3, 2))
19 #define IF_MODE_SPEED_MSK		GENMASK(3, 2)
20 #define IF_MODE_HALF_DUPLEX		BIT(4)
21 
22 struct lynx_pcs {
23 	struct phylink_pcs pcs;
24 	struct mdio_device *mdio;
25 };
26 
27 enum sgmii_speed {
28 	SGMII_SPEED_10		= 0,
29 	SGMII_SPEED_100		= 1,
30 	SGMII_SPEED_1000	= 2,
31 	SGMII_SPEED_2500	= 2,
32 };
33 
34 #define phylink_pcs_to_lynx(pl_pcs) container_of((pl_pcs), struct lynx_pcs, pcs)
35 #define lynx_to_phylink_pcs(lynx) (&(lynx)->pcs)
36 
37 struct mdio_device *lynx_get_mdio_device(struct phylink_pcs *pcs)
38 {
39 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
40 
41 	return lynx->mdio;
42 }
43 EXPORT_SYMBOL(lynx_get_mdio_device);
44 
45 static void lynx_pcs_get_state_usxgmii(struct mdio_device *pcs,
46 				       struct phylink_link_state *state)
47 {
48 	struct mii_bus *bus = pcs->bus;
49 	int addr = pcs->addr;
50 	int status, lpa;
51 
52 	status = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_BMSR);
53 	if (status < 0)
54 		return;
55 
56 	state->link = !!(status & MDIO_STAT1_LSTATUS);
57 	state->an_complete = !!(status & MDIO_AN_STAT1_COMPLETE);
58 	if (!state->link || !state->an_complete)
59 		return;
60 
61 	lpa = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_LPA);
62 	if (lpa < 0)
63 		return;
64 
65 	phylink_decode_usxgmii_word(state, lpa);
66 }
67 
68 static void lynx_pcs_get_state_2500basex(struct mdio_device *pcs,
69 					 struct phylink_link_state *state)
70 {
71 	int bmsr, lpa;
72 
73 	bmsr = mdiodev_read(pcs, MII_BMSR);
74 	lpa = mdiodev_read(pcs, MII_LPA);
75 	if (bmsr < 0 || lpa < 0) {
76 		state->link = false;
77 		return;
78 	}
79 
80 	state->link = !!(bmsr & BMSR_LSTATUS);
81 	state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
82 	if (!state->link)
83 		return;
84 
85 	state->speed = SPEED_2500;
86 	state->pause |= MLO_PAUSE_TX | MLO_PAUSE_RX;
87 	state->duplex = DUPLEX_FULL;
88 }
89 
90 static void lynx_pcs_get_state(struct phylink_pcs *pcs,
91 			       struct phylink_link_state *state)
92 {
93 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
94 
95 	switch (state->interface) {
96 	case PHY_INTERFACE_MODE_1000BASEX:
97 	case PHY_INTERFACE_MODE_SGMII:
98 	case PHY_INTERFACE_MODE_QSGMII:
99 		phylink_mii_c22_pcs_get_state(lynx->mdio, state);
100 		break;
101 	case PHY_INTERFACE_MODE_2500BASEX:
102 		lynx_pcs_get_state_2500basex(lynx->mdio, state);
103 		break;
104 	case PHY_INTERFACE_MODE_USXGMII:
105 		lynx_pcs_get_state_usxgmii(lynx->mdio, state);
106 		break;
107 	case PHY_INTERFACE_MODE_10GBASER:
108 		phylink_mii_c45_pcs_get_state(lynx->mdio, state);
109 		break;
110 	default:
111 		break;
112 	}
113 
114 	dev_dbg(&lynx->mdio->dev,
115 		"mode=%s/%s/%s link=%u an_enabled=%u an_complete=%u\n",
116 		phy_modes(state->interface),
117 		phy_speed_to_str(state->speed),
118 		phy_duplex_to_str(state->duplex),
119 		state->link, state->an_enabled, state->an_complete);
120 }
121 
122 static int lynx_pcs_config_giga(struct mdio_device *pcs, unsigned int mode,
123 				phy_interface_t interface,
124 				const unsigned long *advertising)
125 {
126 	int link_timer_ns;
127 	u32 link_timer;
128 	u16 if_mode;
129 	int err;
130 
131 	link_timer_ns = phylink_get_link_timer_ns(interface);
132 	if (link_timer_ns > 0) {
133 		link_timer = LINK_TIMER_VAL(link_timer_ns);
134 
135 		mdiodev_write(pcs, LINK_TIMER_LO, link_timer & 0xffff);
136 		mdiodev_write(pcs, LINK_TIMER_HI, link_timer >> 16);
137 	}
138 
139 	if (interface == PHY_INTERFACE_MODE_1000BASEX) {
140 		if_mode = 0;
141 	} else {
142 		if_mode = IF_MODE_SGMII_EN;
143 		if (mode == MLO_AN_INBAND)
144 			if_mode |= IF_MODE_USE_SGMII_AN;
145 	}
146 
147 	err = mdiodev_modify(pcs, IF_MODE,
148 			     IF_MODE_SGMII_EN | IF_MODE_USE_SGMII_AN,
149 			     if_mode);
150 	if (err)
151 		return err;
152 
153 	return phylink_mii_c22_pcs_config(pcs, mode, interface, advertising);
154 }
155 
156 static int lynx_pcs_config_usxgmii(struct mdio_device *pcs, unsigned int mode,
157 				   const unsigned long *advertising)
158 {
159 	struct mii_bus *bus = pcs->bus;
160 	int addr = pcs->addr;
161 
162 	if (!phylink_autoneg_inband(mode)) {
163 		dev_err(&pcs->dev, "USXGMII only supports in-band AN for now\n");
164 		return -EOPNOTSUPP;
165 	}
166 
167 	/* Configure device ability for the USXGMII Replicator */
168 	return mdiobus_c45_write(bus, addr, MDIO_MMD_VEND2, MII_ADVERTISE,
169 				 MDIO_USXGMII_10G | MDIO_USXGMII_LINK |
170 				 MDIO_USXGMII_FULL_DUPLEX |
171 				 ADVERTISE_SGMII | ADVERTISE_LPACK);
172 }
173 
174 static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
175 			   phy_interface_t ifmode,
176 			   const unsigned long *advertising,
177 			   bool permit)
178 {
179 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
180 
181 	switch (ifmode) {
182 	case PHY_INTERFACE_MODE_1000BASEX:
183 	case PHY_INTERFACE_MODE_SGMII:
184 	case PHY_INTERFACE_MODE_QSGMII:
185 		return lynx_pcs_config_giga(lynx->mdio, mode, ifmode,
186 					    advertising);
187 	case PHY_INTERFACE_MODE_2500BASEX:
188 		if (phylink_autoneg_inband(mode)) {
189 			dev_err(&lynx->mdio->dev,
190 				"AN not supported on 3.125GHz SerDes lane\n");
191 			return -EOPNOTSUPP;
192 		}
193 		break;
194 	case PHY_INTERFACE_MODE_USXGMII:
195 		return lynx_pcs_config_usxgmii(lynx->mdio, mode, advertising);
196 	case PHY_INTERFACE_MODE_10GBASER:
197 		/* Nothing to do here for 10GBASER */
198 		break;
199 	default:
200 		return -EOPNOTSUPP;
201 	}
202 
203 	return 0;
204 }
205 
206 static void lynx_pcs_an_restart(struct phylink_pcs *pcs)
207 {
208 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
209 
210 	phylink_mii_c22_pcs_an_restart(lynx->mdio);
211 }
212 
213 static void lynx_pcs_link_up_sgmii(struct mdio_device *pcs, unsigned int mode,
214 				   int speed, int duplex)
215 {
216 	u16 if_mode = 0, sgmii_speed;
217 
218 	/* The PCS needs to be configured manually only
219 	 * when not operating on in-band mode
220 	 */
221 	if (mode == MLO_AN_INBAND)
222 		return;
223 
224 	if (duplex == DUPLEX_HALF)
225 		if_mode |= IF_MODE_HALF_DUPLEX;
226 
227 	switch (speed) {
228 	case SPEED_1000:
229 		sgmii_speed = SGMII_SPEED_1000;
230 		break;
231 	case SPEED_100:
232 		sgmii_speed = SGMII_SPEED_100;
233 		break;
234 	case SPEED_10:
235 		sgmii_speed = SGMII_SPEED_10;
236 		break;
237 	case SPEED_UNKNOWN:
238 		/* Silently don't do anything */
239 		return;
240 	default:
241 		dev_err(&pcs->dev, "Invalid PCS speed %d\n", speed);
242 		return;
243 	}
244 	if_mode |= IF_MODE_SPEED(sgmii_speed);
245 
246 	mdiodev_modify(pcs, IF_MODE,
247 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
248 		       if_mode);
249 }
250 
251 /* 2500Base-X is SerDes protocol 7 on Felix and 6 on ENETC. It is a SerDes lane
252  * clocked at 3.125 GHz which encodes symbols with 8b/10b and does not have
253  * auto-negotiation of any link parameters. Electrically it is compatible with
254  * a single lane of XAUI.
255  * The hardware reference manual wants to call this mode SGMII, but it isn't
256  * really, since the fundamental features of SGMII:
257  * - Downgrading the link speed by duplicating symbols
258  * - Auto-negotiation
259  * are not there.
260  * The speed is configured at 1000 in the IF_MODE because the clock frequency
261  * is actually given by a PLL configured in the Reset Configuration Word (RCW).
262  * Since there is no difference between fixed speed SGMII w/o AN and 802.3z w/o
263  * AN, we call this PHY interface type 2500Base-X. In case a PHY negotiates a
264  * lower link speed on line side, the system-side interface remains fixed at
265  * 2500 Mbps and we do rate adaptation through pause frames.
266  */
267 static void lynx_pcs_link_up_2500basex(struct mdio_device *pcs,
268 				       unsigned int mode,
269 				       int speed, int duplex)
270 {
271 	u16 if_mode = 0;
272 
273 	if (mode == MLO_AN_INBAND) {
274 		dev_err(&pcs->dev, "AN not supported for 2500BaseX\n");
275 		return;
276 	}
277 
278 	if (duplex == DUPLEX_HALF)
279 		if_mode |= IF_MODE_HALF_DUPLEX;
280 	if_mode |= IF_MODE_SPEED(SGMII_SPEED_2500);
281 
282 	mdiodev_modify(pcs, IF_MODE,
283 		       IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
284 		       if_mode);
285 }
286 
287 static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
288 			     phy_interface_t interface,
289 			     int speed, int duplex)
290 {
291 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
292 
293 	switch (interface) {
294 	case PHY_INTERFACE_MODE_SGMII:
295 	case PHY_INTERFACE_MODE_QSGMII:
296 		lynx_pcs_link_up_sgmii(lynx->mdio, mode, speed, duplex);
297 		break;
298 	case PHY_INTERFACE_MODE_2500BASEX:
299 		lynx_pcs_link_up_2500basex(lynx->mdio, mode, speed, duplex);
300 		break;
301 	case PHY_INTERFACE_MODE_USXGMII:
302 		/* At the moment, only in-band AN is supported for USXGMII
303 		 * so nothing to do in link_up
304 		 */
305 		break;
306 	default:
307 		break;
308 	}
309 }
310 
311 static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
312 	.pcs_get_state = lynx_pcs_get_state,
313 	.pcs_config = lynx_pcs_config,
314 	.pcs_an_restart = lynx_pcs_an_restart,
315 	.pcs_link_up = lynx_pcs_link_up,
316 };
317 
318 struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
319 {
320 	struct lynx_pcs *lynx;
321 
322 	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
323 	if (!lynx)
324 		return NULL;
325 
326 	lynx->mdio = mdio;
327 	lynx->pcs.ops = &lynx_pcs_phylink_ops;
328 	lynx->pcs.poll = true;
329 
330 	return lynx_to_phylink_pcs(lynx);
331 }
332 EXPORT_SYMBOL(lynx_pcs_create);
333 
334 void lynx_pcs_destroy(struct phylink_pcs *pcs)
335 {
336 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
337 
338 	kfree(lynx);
339 }
340 EXPORT_SYMBOL(lynx_pcs_destroy);
341 
342 MODULE_LICENSE("Dual BSD/GPL");
343