net: phy: Maintain MDIO device and bus statistics

We maintain global statistics for an entire MDIO bus, as well as broken
down, per MDIO bus address statistics. Given that it is possible for
MDIO devices such as switches to access MDIO bus addresses for which
there is not a mdio_device instance created (therefore not a a
corresponding device directory in sysfs either), we also maintain
per-address statistics under the statistics folder. The layout looks
like this:

/sys/class/mdio_bus/../statistics/
	transfers
	errrors
	writes
	reads
	transfers_<addr>
	errors_<addr>
	writes_<addr>
	reads_<addr>

When a mdio_device instance is registered, a statistics/ folder is
created with the tranfers, errors, writes and reads attributes which
point to the appropriate MDIO bus statistics structure.

Statistics are 64-bit unsigned quantities and maintained through the
u64_stats_sync.h helper functions.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 2929d0bc307f..99a87f02667f 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -22,6 +22,7 @@
 #include <linux/timer.h>
 #include <linux/workqueue.h>
 #include <linux/mod_devicetable.h>
+#include <linux/u64_stats_sync.h>
 
 #include <linux/atomic.h>
 
@@ -212,6 +213,15 @@ struct sfp_bus;
 struct sfp_upstream_ops;
 struct sk_buff;
 
+struct mdio_bus_stats {
+	u64_stats_t transfers;
+	u64_stats_t errors;
+	u64_stats_t writes;
+	u64_stats_t reads;
+	/* Must be last, add new statistics above */
+	struct u64_stats_sync syncp;
+};
+
 /*
  * The Bus class for PHYs.  Devices which provide access to
  * PHYs should register using this structure
@@ -224,6 +234,7 @@ struct mii_bus {
 	int (*read)(struct mii_bus *bus, int addr, int regnum);
 	int (*write)(struct mii_bus *bus, int addr, int regnum, u16 val);
 	int (*reset)(struct mii_bus *bus);
+	struct mdio_bus_stats stats[PHY_MAX_ADDR];
 
 	/*
 	 * A lock to ensure that only one thing can read/write