[PATCH net-next v2 01/10] net: dsa: add debugfs interface

Vivien Didelot
2017-08-28T19:17:39Z

This commit adds a DEBUG_FS dependent DSA core file creating a generic
debug filesystem interface for the DSA switch devices.

The interface can be mounted with:

# mount -t debugfs none /sys/kernel/debug

The dsa directory contains one directory per switch chip:

# cd /sys/kernel/debug/dsa/
# ls
switch0 switch1 switch2

Each chip directory contains one directory per port:

# ls -l switch0/
drwxr-xr-x 2 root root 0 Jan 1 00:00 port0
drwxr-xr-x 2 root root 0 Jan 1 00:00 port1
drwxr-xr-x 2 root root 0 Jan 1 00:00 port2
drwxr-xr-x 2 root root 0 Jan 1 00:00 port5
drwxr-xr-x 2 root root 0 Jan 1 00:00 port6

Future patches will add entry files to these directories.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
---
include/net/dsa.h | 7 ++++
net/dsa/Kconfig | 14 +++++++
net/dsa/Makefile | 1 +
net/dsa/debugfs.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++
net/dsa/dsa.c | 3 ++
net/dsa/dsa2.c | 4 ++
net/dsa/dsa_priv.h | 13 ++++++
net/dsa/legacy.c | 4 ++
8 files changed, 164 insertions(+)
create mode 100644 net/dsa/debugfs.c

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 398ca8d70ccd..7341178319f5 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -210,6 +210,13 @@ struct dsa_switch {
*/
void *priv;

+#ifdef CONFIG_NET_DSA_DEBUGFS
+ /*
+ * Debugfs interface.
+ */
+ struct dentry *debugfs_dir;
+#endif
+
/*
* Configuration data for this switch.
*/
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index cc5f8f971689..0f05a1e59dd2 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -15,6 +15,20 @@ config NET_DSA

if NET_DSA

+config NET_DSA_DEBUGFS
+ bool "Distributed Switch Architecture debugfs interface"
+ depends on DEBUG_FS
+ ---help---
+ Enable creation of debugfs files for the DSA core.
+
+ These debugfs files provide per-switch information, such as the tag
+ protocol in use and ports connectivity. They also allow querying the
+ hardware directly through the switch operations for debugging instead
+ of going through the bridge, switchdev and DSA layers.
+
+ This is also a way to inspect the stats and FDB, MDB or VLAN entries
+ of CPU and DSA links, since they are not exposed to userspace.
+
# tagging formats
config NET_DSA_TAG_BRCM
bool
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index fcce25da937c..7f60c6dfaffb 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -1,6 +1,7 @@
# the core
obj-$(CONFIG_NET_DSA) += dsa_core.o
dsa_core-y += dsa.o dsa2.o legacy.o port.o slave.o switch.o
+dsa_core-$(CONFIG_NET_DSA_DEBUGFS) += debugfs.o

# tagging formats
dsa_core-$(CONFIG_NET_DSA_TAG_BRCM) += tag_brcm.o
diff --git a/net/dsa/debugfs.c b/net/dsa/debugfs.c
new file mode 100644
index 000000000000..b6b5e5c97389
--- /dev/null
+++ b/net/dsa/debugfs.c
@@ -0,0 +1,118 @@
+/*
+ * net/dsa/debugfs.c - DSA debugfs interface
+ * Copyright (c) 2017 Savoir-faire Linux, Inc.
+ * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/debugfs.h>
+
+#include "dsa_priv.h"
+
+#define DSA_SWITCH_FMT "switch%d"
+#define DSA_PORT_FMT "port%d"
+
+/* DSA module debugfs directory */
+static struct dentry *dsa_debugfs_dir;
+
+static int dsa_debugfs_create_port(struct dsa_switch *ds, int port)
+{
+ struct dentry *dir;
+ char name[32];
+
+ snprintf(name, sizeof(name), DSA_PORT_FMT, port);
+
+ dir = debugfs_create_dir(name, ds->debugfs_dir);
+ if (IS_ERR_OR_NULL(dir))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int dsa_debugfs_create_switch(struct dsa_switch *ds)
+{
+ char name[32];
+ int i, err;
+
+ /* skip if there is no debugfs support */
+ if (!dsa_debugfs_dir)
+ return 0;
+
+ snprintf(name, sizeof(name), DSA_SWITCH_FMT, ds->index);
+
+ ds->debugfs_dir = debugfs_create_dir(name, dsa_debugfs_dir);
+ if (IS_ERR_OR_NULL(ds->debugfs_dir))
+ return -EFAULT;
+
+ for (i = 0; i < ds->num_ports; i++) {
+ if (ds->enabled_port_mask & BIT(i)) {
+ err = dsa_debugfs_create_port(ds, i);
+ if (err)
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+static void dsa_debugfs_destroy_switch(struct dsa_switch *ds)
+{
+ /* handles NULL */
+ debugfs_remove_recursive(ds->debugfs_dir);
+}
+
+void dsa_debugfs_create_tree(struct dsa_switch_tree *dst)
+{
+ struct dsa_switch *ds;
+ int i, err;
+
+ for (i = 0; i < DSA_MAX_SWITCHES; i++) {
+ ds = dst->ds[i];
+ if (!ds)
+ continue;
+
+ err = dsa_debugfs_create_switch(ds);
+ if (err) {
+ pr_warn("DSA: failed to create debugfs interface for switch %d (%d)\n",
+ ds->index, err);
+ dsa_debugfs_destroy_tree(dst);
+ break;
+ }
+ }
+}
+
+void dsa_debugfs_destroy_tree(struct dsa_switch_tree *dst)
+{
+ struct dsa_switch *ds;
+ int i;
+
+ for (i = 0; i < DSA_MAX_SWITCHES; i++) {
+ ds = dst->ds[i];
+ if (!ds)
+ continue;
+
+ dsa_debugfs_destroy_switch(ds);
+ }
+}
+
+void dsa_debugfs_create_module(void)
+{
+ dsa_debugfs_dir = debugfs_create_dir("dsa", NULL);
+ if (IS_ERR(dsa_debugfs_dir)) {
+ pr_warn("DSA: failed to create debugfs interface\n");
+ dsa_debugfs_dir = NULL;
+ }
+
+ if (dsa_debugfs_dir)
+ pr_info("DSA: debugfs interface created\n");
+}
+
+void dsa_debugfs_destroy_module(void)
+{
+ /* handles NULL */
+ debugfs_remove_recursive(dsa_debugfs_dir);
+}
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 03c58b0eb082..b23f1be50c71 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -308,12 +308,15 @@ static int __init dsa_init_module(void)

dev_add_pack(&dsa_pack_type);

+ dsa_debugfs_create_module();
+
return 0;
}
module_init(dsa_init_module);

static void __exit dsa_cleanup_module(void)
{
+ dsa_debugfs_destroy_module();
dsa_slave_unregister_notifier();
dev_remove_pack(&dsa_pack_type);
dsa_legacy_unregister();
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index cceaa4dd9f53..5912618ad63d 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -447,6 +447,8 @@ static int dsa_dst_apply(struct dsa_switch_tree *dst)
dst->cpu_dp->netdev->dsa_ptr = dst;
dst->applied = true;

+ dsa_debugfs_create_tree(dst);
+
return 0;
}

@@ -458,6 +460,8 @@ static void dsa_dst_unapply(struct dsa_switch_tree *dst)
if (!dst->applied)
return;

+ dsa_debugfs_destroy_tree(dst);
+
dst->cpu_dp->netdev->dsa_ptr = NULL;

/* If we used a tagging format that doesn't have an ethertype
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 9c3eeb72462d..84ca3a50a58b 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -93,6 +93,19 @@ struct dsa_slave_priv {
struct list_head mall_tc_list;
};

+/* debugfs.c */
+#ifdef CONFIG_NET_DSA_DEBUGFS
+void dsa_debugfs_create_module(void);
+void dsa_debugfs_destroy_module(void);
+void dsa_debugfs_create_tree(struct dsa_switch_tree *dst);
+void dsa_debugfs_destroy_tree(struct dsa_switch_tree *dst);
+#else
+static inline void dsa_debugfs_create_module(void) { }
+static inline void dsa_debugfs_destroy_module(void) { }
+static inline void dsa_debugfs_create_tree(struct dsa_switch_tree *dst) { }
+static inline void dsa_debugfs_destroy_tree(struct dsa_switch_tree *dst) { }
+#endif
+
/* dsa.c */
int dsa_cpu_dsa_setup(struct dsa_port *port);
void dsa_cpu_dsa_destroy(struct dsa_port *dport);
diff --git a/net/dsa/legacy.c b/net/dsa/legacy.c
index 91e6f7981d39..8aa3de540552 100644
--- a/net/dsa/legacy.c
+++ b/net/dsa/legacy.c
@@ -606,6 +606,8 @@ static int dsa_setup_dst(struct dsa_switch_tree *dst, struct net_device *dev,
wmb();
dev->dsa_ptr = dst;

+ dsa_debugfs_create_tree(dst);
+
return 0;
}

@@ -671,6 +673,8 @@ static void dsa_remove_dst(struct dsa_switch_tree *dst)
{
int i;

+ dsa_debugfs_destroy_tree(dst);
+
dst->cpu_dp->netdev->dsa_ptr = NULL;

/* If we used a tagging format that doesn't have an ethertype
--
2.14.1