Merge branch 'dsa-tag-modules'

Andrew Lunn says:

====================
Make DSA tag drivers kernel modules

Historically, DSA tag drivers have been compiled into the kernel as
part of the DSA core. With the growing number of tag drivers, it makes
sense to allow this driver code to be compiled as a module, and loaded
on demand.

v2
--
Move name to end of structure, keeping the hot entries at the beginning.
More tag protocol to end of structure to keep hot members at the beginning.
Fix indent of #endif
Rewrite to move list pointer into a new structure
void functions, since there cannot be errors
Fix fall-through comment
Reorder patch for unused symbols to before tag drivers can be modules
tab/space cleanup
Help text wording
NET_DSA_TAG_BRCM_COMMON and NET_DSA_TAG_KZS_COMMON hidden

v3
--
boilerplate: Move kdoc next to macro
boilerplate: Fix THIS_MODULE indentation
Kconfig: More tabification
Kconfig: Punctuation

v4
--
Cover note {H}istorically
Kconfig: trailer
====================

Tested-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 97 insertions, 13 deletions

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 0cfc2f828b87..b550f7bb5314 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -30,20 +30,32 @@ struct phy_device;
 struct fixed_phy_status;
 struct phylink_link_state;
 
+#define DSA_TAG_PROTO_NONE_VALUE		0
+#define DSA_TAG_PROTO_BRCM_VALUE		1
+#define DSA_TAG_PROTO_BRCM_PREPEND_VALUE	2
+#define DSA_TAG_PROTO_DSA_VALUE			3
+#define DSA_TAG_PROTO_EDSA_VALUE		4
+#define DSA_TAG_PROTO_GSWIP_VALUE		5
+#define DSA_TAG_PROTO_KSZ9477_VALUE		6
+#define DSA_TAG_PROTO_KSZ9893_VALUE		7
+#define DSA_TAG_PROTO_LAN9303_VALUE		8
+#define DSA_TAG_PROTO_MTK_VALUE			9
+#define DSA_TAG_PROTO_QCA_VALUE			10
+#define DSA_TAG_PROTO_TRAILER_VALUE		11
+
 enum dsa_tag_protocol {
-	DSA_TAG_PROTO_NONE = 0,
-	DSA_TAG_PROTO_BRCM,
-	DSA_TAG_PROTO_BRCM_PREPEND,
-	DSA_TAG_PROTO_DSA,
-	DSA_TAG_PROTO_EDSA,
-	DSA_TAG_PROTO_GSWIP,
-	DSA_TAG_PROTO_KSZ9477,
-	DSA_TAG_PROTO_KSZ9893,
-	DSA_TAG_PROTO_LAN9303,
-	DSA_TAG_PROTO_MTK,
-	DSA_TAG_PROTO_QCA,
-	DSA_TAG_PROTO_TRAILER,
-	DSA_TAG_LAST,		/* MUST BE LAST */
+	DSA_TAG_PROTO_NONE		= DSA_TAG_PROTO_NONE_VALUE,
+	DSA_TAG_PROTO_BRCM		= DSA_TAG_PROTO_BRCM_VALUE,
+	DSA_TAG_PROTO_BRCM_PREPEND	= DSA_TAG_PROTO_BRCM_PREPEND_VALUE,
+	DSA_TAG_PROTO_DSA		= DSA_TAG_PROTO_DSA_VALUE,
+	DSA_TAG_PROTO_EDSA		= DSA_TAG_PROTO_EDSA_VALUE,
+	DSA_TAG_PROTO_GSWIP		= DSA_TAG_PROTO_GSWIP_VALUE,
+	DSA_TAG_PROTO_KSZ9477		= DSA_TAG_PROTO_KSZ9477_VALUE,
+	DSA_TAG_PROTO_KSZ9893		= DSA_TAG_PROTO_KSZ9893_VALUE,
+	DSA_TAG_PROTO_LAN9303		= DSA_TAG_PROTO_LAN9303_VALUE,
+	DSA_TAG_PROTO_MTK		= DSA_TAG_PROTO_MTK_VALUE,
+	DSA_TAG_PROTO_QCA		= DSA_TAG_PROTO_QCA_VALUE,
+	DSA_TAG_PROTO_TRAILER		= DSA_TAG_PROTO_TRAILER_VALUE,
 };
 
 struct packet_type;
@@ -56,8 +68,14 @@ struct dsa_device_ops {
 	int (*flow_dissect)(const struct sk_buff *skb, __be16 *proto,
 			    int *offset);
 	unsigned int overhead;
+	const char *name;
+	enum dsa_tag_protocol proto;
 };
 
+#define DSA_TAG_DRIVER_ALIAS "dsa_tag-"
+#define MODULE_ALIAS_DSA_TAG_DRIVER(__proto)				\
+	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __stringify(__proto##_VALUE))
+
 struct dsa_switch_tree {
 	struct list_head	list;
 
@@ -575,4 +593,70 @@ int dsa_port_get_ethtool_phy_stats(struct dsa_port *dp, uint64_t *data);
 int dsa_port_get_phy_sset_count(struct dsa_port *dp);
 void dsa_port_phylink_mac_change(struct dsa_switch *ds, int port, bool up);
 
+struct dsa_tag_driver {
+	const struct dsa_device_ops *ops;
+	struct list_head list;
+	struct module *owner;
+};
+
+void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
+			      unsigned int count,
+			      struct module *owner);
+void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
+				unsigned int count);
+
+#define dsa_tag_driver_module_drivers(__dsa_tag_drivers_array, __count)	\
+static int __init dsa_tag_driver_module_init(void)			\
+{									\
+	dsa_tag_drivers_register(__dsa_tag_drivers_array, __count,	\
+				 THIS_MODULE);				\
+	return 0;							\
+}									\
+module_init(dsa_tag_driver_module_init);				\
+									\
+static void __exit dsa_tag_driver_module_exit(void)			\
+{									\
+	dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count);	\
+}									\
+module_exit(dsa_tag_driver_module_exit)
+
+/**
+ * module_dsa_tag_drivers() - Helper macro for registering DSA tag
+ * drivers
+ * @__ops_array: Array of tag driver strucutres
+ *
+ * Helper macro for DSA tag drivers which do not do anything special
+ * in module init/exit. Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit().
+ */
+#define module_dsa_tag_drivers(__ops_array)				\
+dsa_tag_driver_module_drivers(__ops_array, ARRAY_SIZE(__ops_array))
+
+#define DSA_TAG_DRIVER_NAME(__ops) dsa_tag_driver ## _ ## __ops
+
+/* Create a static structure we can build a linked list of dsa_tag
+ * drivers
+ */
+#define DSA_TAG_DRIVER(__ops)						\
+static struct dsa_tag_driver DSA_TAG_DRIVER_NAME(__ops) = {		\
+	.ops = &__ops,							\
+}
+
+/**
+ * module_dsa_tag_driver() - Helper macro for registering a single DSA tag
+ * driver
+ * @__ops: Single tag driver structures
+ *
+ * Helper macro for DSA tag drivers which do not do anything special
+ * in module init/exit. Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit().
+ */
+#define module_dsa_tag_driver(__ops)					\
+DSA_TAG_DRIVER(__ops);							\
+									\
+static struct dsa_tag_driver *dsa_tag_driver_array[] =	{		\
+	&DSA_TAG_DRIVER_NAME(__ops)					\
+};									\
+module_dsa_tag_drivers(dsa_tag_driver_array)
 #endif
+