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  1// SPDX-License-Identifier: GPL-2.0-only
  2#include <linux/export.h>
  3#include <linux/kref.h>
  4#include <linux/list.h>
  5#include <linux/mutex.h>
  6#include <linux/phylink.h>
  7#include <linux/property.h>
  8#include <linux/rtnetlink.h>
  9#include <linux/slab.h>
 10
 11#include "sfp.h"
 12
 13/**
 14 * struct sfp_bus - internal representation of a sfp bus
 15 */
 16struct sfp_bus {
 17	/* private: */
 18	struct kref kref;
 19	struct list_head node;
 20	const struct fwnode_handle *fwnode;
 21
 22	const struct sfp_socket_ops *socket_ops;
 23	struct device *sfp_dev;
 24	struct sfp *sfp;
 25	const struct sfp_quirk *sfp_quirk;
 26
 27	const struct sfp_upstream_ops *upstream_ops;
 28	void *upstream;
 29	struct phy_device *phydev;
 30
 31	bool registered;
 32	bool started;
 33};
 34
 35/**
 36 * sfp_parse_port() - Parse the EEPROM base ID, setting the port type
 37 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 38 * @id: a pointer to the module's &struct sfp_eeprom_id
 39 * @support: optional pointer to an array of unsigned long for the
 40 *   ethtool support mask
 41 *
 42 * Parse the EEPROM identification given in @id, and return one of
 43 * %PORT_TP, %PORT_FIBRE or %PORT_OTHER. If @support is non-%NULL,
 44 * also set the ethtool %ETHTOOL_LINK_MODE_xxx_BIT corresponding with
 45 * the connector type.
 46 *
 47 * If the port type is not known, returns %PORT_OTHER.
 48 */
 49int sfp_parse_port(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
 50		   unsigned long *support)
 51{
 52	int port;
 53
 54	/* port is the physical connector, set this from the connector field. */
 55	switch (id->base.connector) {
 56	case SFF8024_CONNECTOR_SC:
 57	case SFF8024_CONNECTOR_FIBERJACK:
 58	case SFF8024_CONNECTOR_LC:
 59	case SFF8024_CONNECTOR_MT_RJ:
 60	case SFF8024_CONNECTOR_MU:
 61	case SFF8024_CONNECTOR_OPTICAL_PIGTAIL:
 62	case SFF8024_CONNECTOR_MPO_1X12:
 63	case SFF8024_CONNECTOR_MPO_2X16:
 64		port = PORT_FIBRE;
 65		break;
 66
 67	case SFF8024_CONNECTOR_RJ45:
 68		port = PORT_TP;
 69		break;
 70
 71	case SFF8024_CONNECTOR_COPPER_PIGTAIL:
 72		port = PORT_DA;
 73		break;
 74
 75	case SFF8024_CONNECTOR_UNSPEC:
 76		if (id->base.e1000_base_t) {
 77			port = PORT_TP;
 78			break;
 79		}
 80		fallthrough;
 81	case SFF8024_CONNECTOR_SG: /* guess */
 82	case SFF8024_CONNECTOR_HSSDC_II:
 83	case SFF8024_CONNECTOR_NOSEPARATE:
 84	case SFF8024_CONNECTOR_MXC_2X16:
 85		port = PORT_OTHER;
 86		break;
 87	default:
 88		dev_warn(bus->sfp_dev, "SFP: unknown connector id 0x%02x\n",
 89			 id->base.connector);
 90		port = PORT_OTHER;
 91		break;
 92	}
 93
 94	if (support) {
 95		switch (port) {
 96		case PORT_FIBRE:
 97			phylink_set(support, FIBRE);
 98			break;
 99
100		case PORT_TP:
101			phylink_set(support, TP);
102			break;
103		}
104	}
105
106	return port;
107}
108EXPORT_SYMBOL_GPL(sfp_parse_port);
109
110/**
111 * sfp_may_have_phy() - indicate whether the module may have a PHY
112 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
113 * @id: a pointer to the module's &struct sfp_eeprom_id
114 *
115 * Parse the EEPROM identification given in @id, and return whether
116 * this module may have a PHY.
117 */
118bool sfp_may_have_phy(struct sfp_bus *bus, const struct sfp_eeprom_id *id)
119{
120	if (id->base.e1000_base_t)
121		return true;
122
123	if (id->base.phys_id != SFF8024_ID_DWDM_SFP) {
124		switch (id->base.extended_cc) {
125		case SFF8024_ECC_10GBASE_T_SFI:
126		case SFF8024_ECC_10GBASE_T_SR:
127		case SFF8024_ECC_5GBASE_T:
128		case SFF8024_ECC_2_5GBASE_T:
129			return true;
130		}
131	}
132
133	return false;
134}
135EXPORT_SYMBOL_GPL(sfp_may_have_phy);
136
137/**
138 * sfp_parse_support() - Parse the eeprom id for supported link modes
139 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
140 * @id: a pointer to the module's &struct sfp_eeprom_id
141 * @support: pointer to an array of unsigned long for the ethtool support mask
142 * @interfaces: pointer to an array of unsigned long for phy interface modes
143 *		mask
144 *
145 * Parse the EEPROM identification information and derive the supported
146 * ethtool link modes for the module.
147 */
148void sfp_parse_support(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
149		       unsigned long *support, unsigned long *interfaces)
150{
151	unsigned int br_min, br_nom, br_max;
152	__ETHTOOL_DECLARE_LINK_MODE_MASK(modes) = { 0, };
153
154	/* Decode the bitrate information to MBd */
155	br_min = br_nom = br_max = 0;
156	if (id->base.br_nominal) {
157		if (id->base.br_nominal != 255) {
158			br_nom = id->base.br_nominal * 100;
159			br_min = br_nom - id->base.br_nominal * id->ext.br_min;
160			br_max = br_nom + id->base.br_nominal * id->ext.br_max;
161		} else if (id->ext.br_max) {
162			br_nom = 250 * id->ext.br_max;
163			br_max = br_nom + br_nom * id->ext.br_min / 100;
164			br_min = br_nom - br_nom * id->ext.br_min / 100;
165		}
166
167		/* When using passive cables, in case neither BR,min nor BR,max
168		 * are specified, set br_min to 0 as the nominal value is then
169		 * used as the maximum.
170		 */
171		if (br_min == br_max && id->base.sfp_ct_passive)
172			br_min = 0;
173	}
174
175	/* Set ethtool support from the compliance fields. */
176	if (id->base.e10g_base_sr) {
177		phylink_set(modes, 10000baseSR_Full);
178		__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
179	}
180	if (id->base.e10g_base_lr) {
181		phylink_set(modes, 10000baseLR_Full);
182		__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
183	}
184	if (id->base.e10g_base_lrm) {
185		phylink_set(modes, 10000baseLRM_Full);
186		__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
187	}
188	if (id->base.e10g_base_er) {
189		phylink_set(modes, 10000baseER_Full);
190		__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
191	}
192	if (id->base.e1000_base_sx ||
193	    id->base.e1000_base_lx ||
194	    id->base.e1000_base_cx) {
195		phylink_set(modes, 1000baseX_Full);
196		__set_bit(PHY_INTERFACE_MODE_1000BASEX, interfaces);
197	}
198	if (id->base.e1000_base_t) {
199		phylink_set(modes, 1000baseT_Half);
200		phylink_set(modes, 1000baseT_Full);
201		__set_bit(PHY_INTERFACE_MODE_1000BASEX, interfaces);
202		__set_bit(PHY_INTERFACE_MODE_SGMII, interfaces);
203	}
204
205	/* 1000Base-PX or 1000Base-BX10 */
206	if ((id->base.e_base_px || id->base.e_base_bx10) &&
207	    br_min <= 1300 && br_max >= 1200) {
208		phylink_set(modes, 1000baseX_Full);
209		__set_bit(PHY_INTERFACE_MODE_1000BASEX, interfaces);
210	}
211
212	/* 100Base-FX, 100Base-LX, 100Base-PX, 100Base-BX10 */
213	if (id->base.e100_base_fx || id->base.e100_base_lx) {
214		phylink_set(modes, 100baseFX_Full);
215		__set_bit(PHY_INTERFACE_MODE_100BASEX, interfaces);
216	}
217	if ((id->base.e_base_px || id->base.e_base_bx10) && br_nom == 100) {
218		phylink_set(modes, 100baseFX_Full);
219		__set_bit(PHY_INTERFACE_MODE_100BASEX, interfaces);
220	}
221
222	/* For active or passive cables, select the link modes
223	 * based on the bit rates and the cable compliance bytes.
224	 */
225	if ((id->base.sfp_ct_passive || id->base.sfp_ct_active) && br_nom) {
226		/* This may look odd, but some manufacturers use 12000MBd */
227		if (br_min <= 12000 && br_max >= 10300) {
228			phylink_set(modes, 10000baseCR_Full);
229			__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
230		}
231		if (br_min <= 3200 && br_max >= 3100) {
232			phylink_set(modes, 2500baseX_Full);
233			__set_bit(PHY_INTERFACE_MODE_2500BASEX, interfaces);
234		}
235		if (br_min <= 1300 && br_max >= 1200) {
236			phylink_set(modes, 1000baseX_Full);
237			__set_bit(PHY_INTERFACE_MODE_1000BASEX, interfaces);
238		}
239	}
240	if (id->base.sfp_ct_passive) {
241		if (id->base.passive.sff8431_app_e) {
242			phylink_set(modes, 10000baseCR_Full);
243			__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
244		}
245	}
246	if (id->base.sfp_ct_active) {
247		if (id->base.active.sff8431_app_e ||
248		    id->base.active.sff8431_lim) {
249			phylink_set(modes, 10000baseCR_Full);
250			__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
251		}
252	}
253
254	switch (id->base.extended_cc) {
255	case SFF8024_ECC_UNSPEC:
256		break;
257	case SFF8024_ECC_100G_25GAUI_C2M_AOC:
258		if (br_min <= 28000 && br_max >= 25000) {
259			/* 25GBASE-R, possibly with FEC */
260			__set_bit(PHY_INTERFACE_MODE_25GBASER, interfaces);
261			/* There is currently no link mode for 25000base
262			 * with unspecified range, reuse SR.
263			 */
264			phylink_set(modes, 25000baseSR_Full);
265		}
266		break;
267	case SFF8024_ECC_100GBASE_SR4_25GBASE_SR:
268		phylink_set(modes, 100000baseSR4_Full);
269		phylink_set(modes, 25000baseSR_Full);
270		__set_bit(PHY_INTERFACE_MODE_25GBASER, interfaces);
271		break;
272	case SFF8024_ECC_100GBASE_LR4_25GBASE_LR:
273	case SFF8024_ECC_100GBASE_ER4_25GBASE_ER:
274		phylink_set(modes, 100000baseLR4_ER4_Full);
275		break;
276	case SFF8024_ECC_100GBASE_CR4:
277		phylink_set(modes, 100000baseCR4_Full);
278		fallthrough;
279	case SFF8024_ECC_25GBASE_CR_S:
280	case SFF8024_ECC_25GBASE_CR_N:
281		phylink_set(modes, 25000baseCR_Full);
282		__set_bit(PHY_INTERFACE_MODE_25GBASER, interfaces);
283		break;
284	case SFF8024_ECC_10GBASE_T_SFI:
285	case SFF8024_ECC_10GBASE_T_SR:
286		phylink_set(modes, 10000baseT_Full);
287		__set_bit(PHY_INTERFACE_MODE_10GBASER, interfaces);
288		break;
289	case SFF8024_ECC_5GBASE_T:
290		phylink_set(modes, 5000baseT_Full);
291		__set_bit(PHY_INTERFACE_MODE_5GBASER, interfaces);
292		break;
293	case SFF8024_ECC_2_5GBASE_T:
294		phylink_set(modes, 2500baseT_Full);
295		__set_bit(PHY_INTERFACE_MODE_2500BASEX, interfaces);
296		break;
297	default:
298		dev_warn(bus->sfp_dev,
299			 "Unknown/unsupported extended compliance code: 0x%02x\n",
300			 id->base.extended_cc);
301		break;
302	}
303
304	/* For fibre channel SFP, derive possible BaseX modes */
305	if (id->base.fc_speed_100 ||
306	    id->base.fc_speed_200 ||
307	    id->base.fc_speed_400) {
308		if (id->base.br_nominal >= 31) {
309			phylink_set(modes, 2500baseX_Full);
310			__set_bit(PHY_INTERFACE_MODE_2500BASEX, interfaces);
311		}
312		if (id->base.br_nominal >= 12) {
313			phylink_set(modes, 1000baseX_Full);
314			__set_bit(PHY_INTERFACE_MODE_1000BASEX, interfaces);
315		}
316	}
317
318	/* If we haven't discovered any modes that this module supports, try
319	 * the bitrate to determine supported modes. Some BiDi modules (eg,
320	 * 1310nm/1550nm) are not 1000BASE-BX compliant due to the differing
321	 * wavelengths, so do not set any transceiver bits.
322	 *
323	 * Do the same for modules supporting 2500BASE-X. Note that some
324	 * modules use 2500Mbaud rather than 3100 or 3200Mbaud for
325	 * 2500BASE-X, so we allow some slack here.
326	 */
327	if (linkmode_empty(modes) && br_nom) {
328		if (br_min <= 1300 && br_max >= 1200) {
329			phylink_set(modes, 1000baseX_Full);
330			__set_bit(PHY_INTERFACE_MODE_1000BASEX, interfaces);
331		}
332		if (br_min <= 3200 && br_max >= 2500) {
333			phylink_set(modes, 2500baseX_Full);
334			__set_bit(PHY_INTERFACE_MODE_2500BASEX, interfaces);
335		}
336	}
337
338	phylink_set(modes, Autoneg);
339	phylink_set(modes, Pause);
340	phylink_set(modes, Asym_Pause);
341
342	if (bus->sfp_quirk && bus->sfp_quirk->modes)
343		bus->sfp_quirk->modes(id, modes, interfaces);
344
345	linkmode_or(support, support, modes);
346}
347EXPORT_SYMBOL_GPL(sfp_parse_support);
348
349/**
350 * sfp_select_interface() - Select appropriate phy_interface_t mode
351 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
352 * @link_modes: ethtool link modes mask
353 *
354 * Derive the phy_interface_t mode for the SFP module from the link
355 * modes mask.
356 */
357phy_interface_t sfp_select_interface(struct sfp_bus *bus,
358				     const unsigned long *link_modes)
359{
360	if (phylink_test(link_modes, 25000baseCR_Full) ||
361	    phylink_test(link_modes, 25000baseKR_Full) ||
362	    phylink_test(link_modes, 25000baseSR_Full))
363		return PHY_INTERFACE_MODE_25GBASER;
364
365	if (phylink_test(link_modes, 10000baseCR_Full) ||
366	    phylink_test(link_modes, 10000baseSR_Full) ||
367	    phylink_test(link_modes, 10000baseLR_Full) ||
368	    phylink_test(link_modes, 10000baseLRM_Full) ||
369	    phylink_test(link_modes, 10000baseER_Full) ||
370	    phylink_test(link_modes, 10000baseT_Full))
371		return PHY_INTERFACE_MODE_10GBASER;
372
373	if (phylink_test(link_modes, 5000baseT_Full))
374		return PHY_INTERFACE_MODE_5GBASER;
375
376	if (phylink_test(link_modes, 2500baseX_Full) ||
377	    phylink_test(link_modes, 2500baseT_Full))
378		return PHY_INTERFACE_MODE_2500BASEX;
379
380	if (phylink_test(link_modes, 1000baseT_Half) ||
381	    phylink_test(link_modes, 1000baseT_Full))
382		return PHY_INTERFACE_MODE_SGMII;
383
384	if (phylink_test(link_modes, 1000baseX_Full))
385		return PHY_INTERFACE_MODE_1000BASEX;
386
387	if (phylink_test(link_modes, 100baseFX_Full))
388		return PHY_INTERFACE_MODE_100BASEX;
389
390	dev_warn(bus->sfp_dev, "Unable to ascertain link mode\n");
391
392	return PHY_INTERFACE_MODE_NA;
393}
394EXPORT_SYMBOL_GPL(sfp_select_interface);
395
396static LIST_HEAD(sfp_buses);
397static DEFINE_MUTEX(sfp_mutex);
398
399static const struct sfp_upstream_ops *sfp_get_upstream_ops(struct sfp_bus *bus)
400{
401	return bus->registered ? bus->upstream_ops : NULL;
402}
403
404static struct sfp_bus *sfp_bus_get(const struct fwnode_handle *fwnode)
405{
406	struct sfp_bus *sfp, *new, *found = NULL;
407
408	new = kzalloc(sizeof(*new), GFP_KERNEL);
409
410	mutex_lock(&sfp_mutex);
411
412	list_for_each_entry(sfp, &sfp_buses, node) {
413		if (sfp->fwnode == fwnode) {
414			kref_get(&sfp->kref);
415			found = sfp;
416			break;
417		}
418	}
419
420	if (!found && new) {
421		kref_init(&new->kref);
422		new->fwnode = fwnode;
423		list_add(&new->node, &sfp_buses);
424		found = new;
425		new = NULL;
426	}
427
428	mutex_unlock(&sfp_mutex);
429
430	kfree(new);
431
432	return found;
433}
434
435static void sfp_bus_release(struct kref *kref)
436{
437	struct sfp_bus *bus = container_of(kref, struct sfp_bus, kref);
438
439	list_del(&bus->node);
440	mutex_unlock(&sfp_mutex);
441	kfree(bus);
442}
443
444/**
445 * sfp_bus_put() - put a reference on the &struct sfp_bus
446 * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
447 *
448 * Put a reference on the &struct sfp_bus and free the underlying structure
449 * if this was the last reference.
450 */
451void sfp_bus_put(struct sfp_bus *bus)
452{
453	if (bus)
454		kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
455}
456EXPORT_SYMBOL_GPL(sfp_bus_put);
457
458static int sfp_register_bus(struct sfp_bus *bus)
459{
460	const struct sfp_upstream_ops *ops = bus->upstream_ops;
461	int ret;
462
463	if (ops) {
464		if (ops->link_down)
465			ops->link_down(bus->upstream);
466		if (ops->connect_phy && bus->phydev) {
467			ret = ops->connect_phy(bus->upstream, bus->phydev);
468			if (ret)
469				return ret;
470		}
471	}
472	bus->registered = true;
473	bus->socket_ops->attach(bus->sfp);
474	if (bus->started)
475		bus->socket_ops->start(bus->sfp);
476	bus->upstream_ops->attach(bus->upstream, bus);
477	return 0;
478}
479
480static void sfp_unregister_bus(struct sfp_bus *bus)
481{
482	const struct sfp_upstream_ops *ops = bus->upstream_ops;
483
484	if (bus->registered) {
485		bus->upstream_ops->detach(bus->upstream, bus);
486		if (bus->started)
487			bus->socket_ops->stop(bus->sfp);
488		bus->socket_ops->detach(bus->sfp);
489		if (bus->phydev && ops && ops->disconnect_phy)
490			ops->disconnect_phy(bus->upstream, bus->phydev);
491	}
492	bus->registered = false;
493}
494
495/**
496 * sfp_get_module_info() - Get the ethtool_modinfo for a SFP module
497 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
498 * @modinfo: a &struct ethtool_modinfo
499 *
500 * Fill in the type and eeprom_len parameters in @modinfo for a module on
501 * the sfp bus specified by @bus.
502 *
503 * Returns 0 on success or a negative errno number.
504 */
505int sfp_get_module_info(struct sfp_bus *bus, struct ethtool_modinfo *modinfo)
506{
507	return bus->socket_ops->module_info(bus->sfp, modinfo);
508}
509EXPORT_SYMBOL_GPL(sfp_get_module_info);
510
511/**
512 * sfp_get_module_eeprom() - Read the SFP module EEPROM
513 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
514 * @ee: a &struct ethtool_eeprom
515 * @data: buffer to contain the EEPROM data (must be at least @ee->len bytes)
516 *
517 * Read the EEPROM as specified by the supplied @ee. See the documentation
518 * for &struct ethtool_eeprom for the region to be read.
519 *
520 * Returns 0 on success or a negative errno number.
521 */
522int sfp_get_module_eeprom(struct sfp_bus *bus, struct ethtool_eeprom *ee,
523			  u8 *data)
524{
525	return bus->socket_ops->module_eeprom(bus->sfp, ee, data);
526}
527EXPORT_SYMBOL_GPL(sfp_get_module_eeprom);
528
529/**
530 * sfp_get_module_eeprom_by_page() - Read a page from the SFP module EEPROM
531 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
532 * @page: a &struct ethtool_module_eeprom
533 * @extack: extack for reporting problems
534 *
535 * Read an EEPROM page as specified by the supplied @page. See the
536 * documentation for &struct ethtool_module_eeprom for the page to be read.
537 *
538 * Returns 0 on success or a negative errno number. More error
539 * information might be provided via extack
540 */
541int sfp_get_module_eeprom_by_page(struct sfp_bus *bus,
542				  const struct ethtool_module_eeprom *page,
543				  struct netlink_ext_ack *extack)
544{
545	return bus->socket_ops->module_eeprom_by_page(bus->sfp, page, extack);
546}
547EXPORT_SYMBOL_GPL(sfp_get_module_eeprom_by_page);
548
549/**
550 * sfp_upstream_start() - Inform the SFP that the network device is up
551 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
552 *
553 * Inform the SFP socket that the network device is now up, so that the
554 * module can be enabled by allowing TX_DISABLE to be deasserted. This
555 * should be called from the network device driver's &struct net_device_ops
556 * ndo_open() method.
557 */
558void sfp_upstream_start(struct sfp_bus *bus)
559{
560	if (bus->registered)
561		bus->socket_ops->start(bus->sfp);
562	bus->started = true;
563}
564EXPORT_SYMBOL_GPL(sfp_upstream_start);
565
566/**
567 * sfp_upstream_stop() - Inform the SFP that the network device is down
568 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
569 *
570 * Inform the SFP socket that the network device is now up, so that the
571 * module can be disabled by asserting TX_DISABLE, disabling the laser
572 * in optical modules. This should be called from the network device
573 * driver's &struct net_device_ops ndo_stop() method.
574 */
575void sfp_upstream_stop(struct sfp_bus *bus)
576{
577	if (bus->registered)
578		bus->socket_ops->stop(bus->sfp);
579	bus->started = false;
580}
581EXPORT_SYMBOL_GPL(sfp_upstream_stop);
582
583static void sfp_upstream_clear(struct sfp_bus *bus)
584{
585	bus->upstream_ops = NULL;
586	bus->upstream = NULL;
587}
588
589/**
590 * sfp_upstream_set_signal_rate() - set data signalling rate
591 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
592 * @rate_kbd: signalling rate in units of 1000 baud
593 *
594 * Configure the rate select settings on the SFP module for the signalling
595 * rate (not the same as the data rate).
596 *
597 * Locks that may be held:
598 *  Phylink's state_mutex
599 *  rtnl lock
600 *  SFP's sm_mutex
601 */
602void sfp_upstream_set_signal_rate(struct sfp_bus *bus, unsigned int rate_kbd)
603{
604	if (bus->registered)
605		bus->socket_ops->set_signal_rate(bus->sfp, rate_kbd);
606}
607EXPORT_SYMBOL_GPL(sfp_upstream_set_signal_rate);
608
609/**
610 * sfp_bus_find_fwnode() - parse and locate the SFP bus from fwnode
611 * @fwnode: firmware node for the parent device (MAC or PHY)
612 *
613 * Parse the parent device's firmware node for a SFP bus, and locate
614 * the sfp_bus structure, incrementing its reference count.  This must
615 * be put via sfp_bus_put() when done.
616 *
617 * Returns:
618 *	- on success, a pointer to the sfp_bus structure,
619 *	- %NULL if no SFP is specified,
620 *	- on failure, an error pointer value:
621 *
622 *	- corresponding to the errors detailed for
623 *	  fwnode_property_get_reference_args().
624 *	- %-ENOMEM if we failed to allocate the bus.
625 *	- an error from the upstream's connect_phy() method.
626 */
627struct sfp_bus *sfp_bus_find_fwnode(const struct fwnode_handle *fwnode)
628{
629	struct fwnode_reference_args ref;
630	struct sfp_bus *bus;
631	int ret;
632
633	ret = fwnode_property_get_reference_args(fwnode, "sfp", NULL,
634						 0, 0, &ref);
635	if (ret == -ENOENT)
636		return NULL;
637	else if (ret < 0)
638		return ERR_PTR(ret);
639
640	if (!fwnode_device_is_available(ref.fwnode)) {
641		fwnode_handle_put(ref.fwnode);
642		return NULL;
643	}
644
645	bus = sfp_bus_get(ref.fwnode);
646	fwnode_handle_put(ref.fwnode);
647	if (!bus)
648		return ERR_PTR(-ENOMEM);
649
650	return bus;
651}
652EXPORT_SYMBOL_GPL(sfp_bus_find_fwnode);
653
654/**
655 * sfp_bus_add_upstream() - parse and register the neighbouring device
656 * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
657 * @upstream: the upstream private data
658 * @ops: the upstream's &struct sfp_upstream_ops
659 *
660 * Add upstream driver for the SFP bus, and if the bus is complete, register
661 * the SFP bus using sfp_register_upstream().  This takes a reference on the
662 * bus, so it is safe to put the bus after this call.
663 *
664 * Returns:
665 *	- on success, a pointer to the sfp_bus structure,
666 *	- %NULL if no SFP is specified,
667 *	- on failure, an error pointer value:
668 *
669 *	- corresponding to the errors detailed for
670 *	  fwnode_property_get_reference_args().
671 *	- %-ENOMEM if we failed to allocate the bus.
672 *	- an error from the upstream's connect_phy() method.
673 */
674int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
675			 const struct sfp_upstream_ops *ops)
676{
677	int ret;
678
679	/* If no bus, return success */
680	if (!bus)
681		return 0;
682
683	rtnl_lock();
684	kref_get(&bus->kref);
685	bus->upstream_ops = ops;
686	bus->upstream = upstream;
687
688	if (bus->sfp) {
689		ret = sfp_register_bus(bus);
690		if (ret)
691			sfp_upstream_clear(bus);
692	} else {
693		ret = 0;
694	}
695	rtnl_unlock();
696
697	if (ret)
698		sfp_bus_put(bus);
699
700	return ret;
701}
702EXPORT_SYMBOL_GPL(sfp_bus_add_upstream);
703
704/**
705 * sfp_bus_del_upstream() - Delete a sfp bus
706 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
707 *
708 * Delete a previously registered upstream connection for the SFP
709 * module. @bus should have been added by sfp_bus_add_upstream().
710 */
711void sfp_bus_del_upstream(struct sfp_bus *bus)
712{
713	if (bus) {
714		rtnl_lock();
715		if (bus->sfp)
716			sfp_unregister_bus(bus);
717		sfp_upstream_clear(bus);
718		rtnl_unlock();
719
720		sfp_bus_put(bus);
721	}
722}
723EXPORT_SYMBOL_GPL(sfp_bus_del_upstream);
724
725/**
726 * sfp_get_name() - Get the SFP device name
727 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
728 *
729 * Gets the SFP device's name, if @bus has a registered socket. Callers must
730 * hold RTNL, and the returned name is only valid until RTNL is released.
731 *
732 * Returns:
733 *	- The name of the SFP device registered with sfp_register_socket()
734 *	- %NULL if no device was registered on @bus
735 */
736const char *sfp_get_name(struct sfp_bus *bus)
737{
738	ASSERT_RTNL();
739
740	if (bus->sfp_dev)
741		return dev_name(bus->sfp_dev);
742
743	return NULL;
744}
745EXPORT_SYMBOL_GPL(sfp_get_name);
746
747/* Socket driver entry points */
748int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
749{
750	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
751	int ret = 0;
752
753	if (ops && ops->connect_phy)
754		ret = ops->connect_phy(bus->upstream, phydev);
755
756	if (ret == 0)
757		bus->phydev = phydev;
758
759	return ret;
760}
761EXPORT_SYMBOL_GPL(sfp_add_phy);
762
763void sfp_remove_phy(struct sfp_bus *bus)
764{
765	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
766
767	if (ops && ops->disconnect_phy)
768		ops->disconnect_phy(bus->upstream, bus->phydev);
769	bus->phydev = NULL;
770}
771EXPORT_SYMBOL_GPL(sfp_remove_phy);
772
773void sfp_link_up(struct sfp_bus *bus)
774{
775	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
776
777	if (ops && ops->link_up)
778		ops->link_up(bus->upstream);
779}
780EXPORT_SYMBOL_GPL(sfp_link_up);
781
782void sfp_link_down(struct sfp_bus *bus)
783{
784	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
785
786	if (ops && ops->link_down)
787		ops->link_down(bus->upstream);
788}
789EXPORT_SYMBOL_GPL(sfp_link_down);
790
791int sfp_module_insert(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
792		      const struct sfp_quirk *quirk)
793{
794	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
795	int ret = 0;
796
797	bus->sfp_quirk = quirk;
798
799	if (ops && ops->module_insert)
800		ret = ops->module_insert(bus->upstream, id);
801
802	return ret;
803}
804EXPORT_SYMBOL_GPL(sfp_module_insert);
805
806void sfp_module_remove(struct sfp_bus *bus)
807{
808	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
809
810	if (ops && ops->module_remove)
811		ops->module_remove(bus->upstream);
812
813	bus->sfp_quirk = NULL;
814}
815EXPORT_SYMBOL_GPL(sfp_module_remove);
816
817int sfp_module_start(struct sfp_bus *bus)
818{
819	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
820	int ret = 0;
821
822	if (ops && ops->module_start)
823		ret = ops->module_start(bus->upstream);
824
825	return ret;
826}
827EXPORT_SYMBOL_GPL(sfp_module_start);
828
829void sfp_module_stop(struct sfp_bus *bus)
830{
831	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
832
833	if (ops && ops->module_stop)
834		ops->module_stop(bus->upstream);
835}
836EXPORT_SYMBOL_GPL(sfp_module_stop);
837
838static void sfp_socket_clear(struct sfp_bus *bus)
839{
840	bus->sfp_dev = NULL;
841	bus->sfp = NULL;
842	bus->socket_ops = NULL;
843}
844
845struct sfp_bus *sfp_register_socket(struct device *dev, struct sfp *sfp,
846				    const struct sfp_socket_ops *ops)
847{
848	struct sfp_bus *bus = sfp_bus_get(dev->fwnode);
849	int ret = 0;
850
851	if (bus) {
852		rtnl_lock();
853		bus->sfp_dev = dev;
854		bus->sfp = sfp;
855		bus->socket_ops = ops;
856
857		if (bus->upstream_ops) {
858			ret = sfp_register_bus(bus);
859			if (ret)
860				sfp_socket_clear(bus);
861		}
862		rtnl_unlock();
863	}
864
865	if (ret) {
866		sfp_bus_put(bus);
867		bus = NULL;
868	}
869
870	return bus;
871}
872EXPORT_SYMBOL_GPL(sfp_register_socket);
873
874void sfp_unregister_socket(struct sfp_bus *bus)
875{
876	rtnl_lock();
877	if (bus->upstream_ops)
878		sfp_unregister_bus(bus);
879	sfp_socket_clear(bus);
880	rtnl_unlock();
881
882	sfp_bus_put(bus);
883}
884EXPORT_SYMBOL_GPL(sfp_unregister_socket);