[PATCH net-next v2 05/10] net: dsa: debugfs: add port regs

Vivien Didelot
2017-08-28T19:17:43Z

Add a debug filesystem "regs" entry to query a port's hardware registers
through the .get_regs_len and .get_regs_len switch operations.

This is very convenient because it allows one to dump the registers of
DSA links, which are not exposed to userspace.

Here are the registers of a zii-rev-b CPU and DSA ports:

# pr -mt switch0/port{5,6}/regs
0: 4e07 0: 4d04
1: 403e 1: 003d
2: 0000 2: 0000
3: 3521 3: 3521
4: 0533 4: 373f
5: 8000 5: 0000
6: 005f 6: 003f
7: 002a 7: 002a
8: 2080 8: 2080
9: 0001 9: 0001
10: 0000 10: 0000
11: 0020 11: 0000
12: 0000 12: 0000
13: 0000 13: 0000
14: 0000 14: 0000
15: 9100 15: dada
16: 0000 16: 0000
17: 0000 17: 0000
18: 0000 18: 0000
19: 0000 19: 00d8
20: 0000 20: 0000
21: 0000 21: 0000
22: 0022 22: 0000
23: 0000 23: 0000
24: 3210 24: 3210
25: 7654 25: 7654
26: 0000 26: 0000
27: 8000 27: 8000
28: 0000 28: 0000
29: 0000 29: 0000
30: 0000 30: 0000
31: 0000 31: 0000

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
net/dsa/debugfs.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/net/dsa/debugfs.c b/net/dsa/debugfs.c
index 997bbc8eb502..7b299c9d9892 100644
--- a/net/dsa/debugfs.c
+++ b/net/dsa/debugfs.c
@@ -109,6 +109,40 @@ static int dsa_debugfs_create_file(struct dsa_switch *ds, struct dentry *dir,
return 0;
}

+static void dsa_debugfs_regs_read_count(struct dsa_switch *ds, int id,
+ struct seq_file *seq, int count)
+{
+ u16 data[count * ETH_GSTRING_LEN];
+ struct ethtool_regs regs;
+ int i;
+
+ ds->ops->get_regs(ds, id, &regs, data);
+
+ for (i = 0; i < count / 2; i++)
+ seq_printf(seq, "%2d: %04x\n", i, data[i]);
+}
+
+static int dsa_debugfs_regs_read(struct dsa_switch *ds, int id,
+ struct seq_file *seq)
+{
+ int count;
+
+ if (!ds->ops->get_regs_len || !ds->ops->get_regs)
+ return -EOPNOTSUPP;
+
+ count = ds->ops->get_regs_len(ds, id);
+ if (count < 0)
+ return count;
+
+ dsa_debugfs_regs_read_count(ds, id, seq, count);
+
+ return 0;
+}
+
+static const struct dsa_debugfs_ops dsa_debugfs_regs_ops = {
+ .read = dsa_debugfs_regs_read,
+};
+
static void dsa_debugfs_stats_read_count(struct dsa_switch *ds, int id,
struct seq_file *seq, int count)
{
@@ -188,6 +222,11 @@ static int dsa_debugfs_create_port(struct dsa_switch *ds, int port)
if (IS_ERR_OR_NULL(dir))
return -EFAULT;

+ err = dsa_debugfs_create_file(ds, dir, "regs", port,
+ &dsa_debugfs_regs_ops);
+ if (err)
+ return err;
+
err = dsa_debugfs_create_file(ds, dir, "stats", port,
&dsa_debugfs_stats_ops);
if (err)
--
2.14.1