aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/generic/backport-5.4/717-v5.5-net-sfp-rework-upstream-interface.patch
blob: 9175f2557a38a95a25696f233c69d72450f09b29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
From 863b5b6941f9f43b924393b6ba2b36647e7dee42 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Thu, 7 Nov 2019 17:06:08 +0000
Subject: [PATCH 615/660] net: sfp: rework upstream interface

The current upstream interface is an all-or-nothing, which is
sub-optimal for future changes, as it doesn't allow the upstream driver
to prepare for the SFP module becoming available, as it is at boot.

Switch to a find-sfp-bus, add-upstream, del-upstream, put-sfp-bus
interface structure instead, which allows the upstream driver to
prepare for a module being available as soon as add-upstream is called.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phylink.c | 10 +++--
 drivers/net/phy/sfp-bus.c | 92 +++++++++++++++++++++++++++------------
 include/linux/sfp.h       | 25 +++++++----
 3 files changed, 88 insertions(+), 39 deletions(-)

--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -568,7 +568,7 @@ static int phylink_register_sfp(struct p
 	struct sfp_bus *bus;
 	int ret;
 
-	bus = sfp_register_upstream_node(fwnode, pl, &sfp_phylink_ops);
+	bus = sfp_bus_find_fwnode(fwnode);
 	if (IS_ERR(bus)) {
 		ret = PTR_ERR(bus);
 		phylink_err(pl, "unable to attach SFP bus: %d\n", ret);
@@ -577,7 +577,10 @@ static int phylink_register_sfp(struct p
 
 	pl->sfp_bus = bus;
 
-	return 0;
+	ret = sfp_bus_add_upstream(bus, pl, &sfp_phylink_ops);
+	sfp_bus_put(bus);
+
+	return ret;
 }
 
 /**
@@ -675,8 +678,7 @@ EXPORT_SYMBOL_GPL(phylink_create);
  */
 void phylink_destroy(struct phylink *pl)
 {
-	if (pl->sfp_bus)
-		sfp_unregister_upstream(pl->sfp_bus);
+	sfp_bus_del_upstream(pl->sfp_bus);
 	if (pl->link_gpio)
 		gpiod_put(pl->link_gpio);
 
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -404,10 +404,19 @@ static void sfp_bus_release(struct kref
 	kfree(bus);
 }
 
-static void sfp_bus_put(struct sfp_bus *bus)
+/**
+ * sfp_bus_put() - put a reference on the &struct sfp_bus
+ * bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
+ *
+ * Put a reference on the &struct sfp_bus and free the underlying structure
+ * if this was the last reference.
+ */
+void sfp_bus_put(struct sfp_bus *bus)
 {
-	kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
+	if (bus)
+		kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
 }
+EXPORT_SYMBOL_GPL(sfp_bus_put);
 
 static int sfp_register_bus(struct sfp_bus *bus)
 {
@@ -423,11 +432,11 @@ static int sfp_register_bus(struct sfp_b
 				return ret;
 		}
 	}
+	bus->registered = true;
 	bus->socket_ops->attach(bus->sfp);
 	if (bus->started)
 		bus->socket_ops->start(bus->sfp);
 	bus->upstream_ops->attach(bus->upstream, bus);
-	bus->registered = true;
 	return 0;
 }
 
@@ -521,13 +530,12 @@ static void sfp_upstream_clear(struct sf
 }
 
 /**
- * sfp_register_upstream_node() - parse and register the neighbouring device
+ * sfp_bus_find_fwnode() - parse and locate the SFP bus from fwnode
  * @fwnode: firmware node for the parent device (MAC or PHY)
- * @upstream: the upstream private data
- * @ops: the upstream's &struct sfp_upstream_ops
  *
- * Parse the parent device's firmware node for a SFP bus, and register the
- * SFP bus using sfp_register_upstream().
+ * Parse the parent device's firmware node for a SFP bus, and locate
+ * the sfp_bus structure, incrementing its reference count.  This must
+ * be put via sfp_bus_put() when done.
  *
  * Returns: on success, a pointer to the sfp_bus structure,
  *	    %NULL if no SFP is specified,
@@ -537,9 +545,7 @@ static void sfp_upstream_clear(struct sf
  * 	        %-ENOMEM if we failed to allocate the bus.
  *		an error from the upstream's connect_phy() method.
  */
-struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
-					   void *upstream,
-					   const struct sfp_upstream_ops *ops)
+struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
 {
 	struct fwnode_reference_args ref;
 	struct sfp_bus *bus;
@@ -557,7 +563,39 @@ struct sfp_bus *sfp_register_upstream_no
 	if (!bus)
 		return ERR_PTR(-ENOMEM);
 
+	return bus;
+}
+EXPORT_SYMBOL_GPL(sfp_bus_find_fwnode);
+
+/**
+ * sfp_bus_add_upstream() - parse and register the neighbouring device
+ * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
+ * @upstream: the upstream private data
+ * @ops: the upstream's &struct sfp_upstream_ops
+ *
+ * Add upstream driver for the SFP bus, and if the bus is complete, register
+ * the SFP bus using sfp_register_upstream().  This takes a reference on the
+ * bus, so it is safe to put the bus after this call.
+ *
+ * Returns: on success, a pointer to the sfp_bus structure,
+ *	    %NULL if no SFP is specified,
+ * 	    on failure, an error pointer value:
+ * 		corresponding to the errors detailed for
+ * 		fwnode_property_get_reference_args().
+ * 	        %-ENOMEM if we failed to allocate the bus.
+ *		an error from the upstream's connect_phy() method.
+ */
+int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
+			 const struct sfp_upstream_ops *ops)
+{
+	int ret;
+
+	/* If no bus, return success */
+	if (!bus)
+		return 0;
+
 	rtnl_lock();
+	kref_get(&bus->kref);
 	bus->upstream_ops = ops;
 	bus->upstream = upstream;
 
@@ -570,33 +608,33 @@ struct sfp_bus *sfp_register_upstream_no
 	}
 	rtnl_unlock();
 
-	if (ret) {
+	if (ret)
 		sfp_bus_put(bus);
-		bus = ERR_PTR(ret);
-	}
 
-	return bus;
+	return ret;
 }
-EXPORT_SYMBOL_GPL(sfp_register_upstream_node);
+EXPORT_SYMBOL_GPL(sfp_bus_add_upstream);
 
 /**
- * sfp_unregister_upstream() - Unregister sfp bus
+ * sfp_bus_del_upstream() - Delete a sfp bus
  * @bus: a pointer to the &struct sfp_bus structure for the sfp module
  *
- * Unregister a previously registered upstream connection for the SFP
- * module. @bus is returned from sfp_register_upstream().
+ * Delete a previously registered upstream connection for the SFP
+ * module. @bus should have been added by sfp_bus_add_upstream().
  */
-void sfp_unregister_upstream(struct sfp_bus *bus)
+void sfp_bus_del_upstream(struct sfp_bus *bus)
 {
-	rtnl_lock();
-	if (bus->sfp)
-		sfp_unregister_bus(bus);
-	sfp_upstream_clear(bus);
-	rtnl_unlock();
+	if (bus) {
+		rtnl_lock();
+		if (bus->sfp)
+			sfp_unregister_bus(bus);
+		sfp_upstream_clear(bus);
+		rtnl_unlock();
 
-	sfp_bus_put(bus);
+		sfp_bus_put(bus);
+	}
 }
-EXPORT_SYMBOL_GPL(sfp_unregister_upstream);
+EXPORT_SYMBOL_GPL(sfp_bus_del_upstream);
 
 /* Socket driver entry points */
 int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
--- a/include/linux/sfp.h
+++ b/include/linux/sfp.h
@@ -508,10 +508,11 @@ int sfp_get_module_eeprom(struct sfp_bus
 			  u8 *data);
 void sfp_upstream_start(struct sfp_bus *bus);
 void sfp_upstream_stop(struct sfp_bus *bus);
-struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
-					   void *upstream,
-					   const struct sfp_upstream_ops *ops);
-void sfp_unregister_upstream(struct sfp_bus *bus);
+void sfp_bus_put(struct sfp_bus *bus);
+struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode);
+int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
+			 const struct sfp_upstream_ops *ops);
+void sfp_bus_del_upstream(struct sfp_bus *bus);
 #else
 static inline int sfp_parse_port(struct sfp_bus *bus,
 				 const struct sfp_eeprom_id *id,
@@ -553,14 +554,22 @@ static inline void sfp_upstream_stop(str
 {
 }
 
-static inline struct sfp_bus *sfp_register_upstream_node(
-	struct fwnode_handle *fwnode, void *upstream,
-	const struct sfp_upstream_ops *ops)
+static inline void sfp_bus_put(struct sfp_bus *bus)
+{
+}
+
+static inline struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
 {
 	return NULL;
 }
 
-static inline void sfp_unregister_upstream(struct sfp_bus *bus)
+static int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
+				const struct sfp_upstream_ops *ops)
+{
+	return 0;
+}
+
+static inline void sfp_bus_del_upstream(struct sfp_bus *bus)
 {
 }
 #endif