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Subject[PATCH net-next] net: phy: Maintain MDIO device and bus statistics
Date
Maintain per MDIO device and MDIO bus statistics comprised of the number
of transfers/operations, reads and writes and errors. This is useful for
tracking the per-device and global MDIO bus bandwidth and doing
optimizations as necessary.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
Documentation/ABI/testing/sysfs-bus-mdio | 34 +++++++
drivers/net/phy/mdio_bus.c | 116 +++++++++++++++++++++++
drivers/net/phy/mdio_device.c | 1 +
include/linux/mdio.h | 10 ++
include/linux/phy.h | 2 +
5 files changed, 163 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-bus-mdio

diff --git a/Documentation/ABI/testing/sysfs-bus-mdio b/Documentation/ABI/testing/sysfs-bus-mdio
new file mode 100644
index 000000000000..a552d92890f1
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-mdio
@@ -0,0 +1,34 @@
+What: /sys/bus/mdio_bus/devices/.../statistics/
+Date: January 2020
+KernelVersion: 5.6
+Contact: netdev@vger.kernel.org
+Description:
+ This folder contains statistics about MDIO bus transactions.
+
+What: /sys/bus/mdio_bus/devices/.../statistics/transfers
+Date: January 2020
+KernelVersion: 5.6
+Contact: netdev@vger.kernel.org
+Description:
+ Total number of transfers for this MDIO bus.
+
+What: /sys/bus/mdio_bus/devices/.../statistics/errors
+Date: January 2020
+KernelVersion: 5.6
+Contact: netdev@vger.kernel.org
+Description:
+ Total number of transfer errors for this MDIO bus.
+
+What: /sys/bus/mdio_bus/devices/.../statistics/writes
+Date: January 2020
+KernelVersion: 5.6
+Contact: netdev@vger.kernel.org
+Description:
+ Total number of write transactions for this MDIO bus.
+
+What: /sys/bus/mdio_bus/devices/.../statistics/reads
+Date: January 2020
+KernelVersion: 5.6
+Contact: netdev@vger.kernel.org
+Description:
+ Total number of read transactions for this MDIO bus.
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 229e480179ff..805bc2e3b139 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -168,6 +168,9 @@ struct mii_bus *mdiobus_alloc_size(size_t size)
for (i = 0; i < PHY_MAX_ADDR; i++)
bus->irq[i] = PHY_POLL;

+ /* Initialize 64-bit seqcounts */
+ u64_stats_init(&bus->stats.syncp);
+
return bus;
}
EXPORT_SYMBOL(mdiobus_alloc_size);
@@ -255,9 +258,77 @@ static void mdiobus_release(struct device *d)
kfree(bus);
}

+#define MDIO_BUS_STATS_ATTR(field, file) \
+static ssize_t mdio_bus_##field##_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+{ \
+ struct mii_bus *bus = to_mii_bus(dev); \
+ return mdio_bus_stats_##field##_show(&bus->stats, buf); \
+} \
+static struct device_attribute dev_attr_mdio_bus_##field = { \
+ .attr = { .name = file, .mode = 0444 }, \
+ .show = mdio_bus_##field##_show, \
+}; \
+static ssize_t mdio_bus_device_##field##_show(struct device *dev, \
+ struct device_attribute *attr,\
+ char *buf) \
+{ \
+ struct mdio_device *mdiodev = to_mdio_device(dev); \
+ return mdio_bus_stats_##field##_show(&mdiodev->stats, buf); \
+} \
+static struct device_attribute dev_attr_mdio_bus_device_##field = { \
+ .attr = { .name = file, .mode = 0444 }, \
+ .show = mdio_bus_device_##field##_show, \
+}
+
+#define MDIO_BUS_STATS_SHOW_NAME(name, file, field, format_string) \
+static ssize_t mdio_bus_stats_##name##_show(struct mdio_bus_stats *s, \
+ char *buf) \
+{ \
+ unsigned int start; \
+ ssize_t len; \
+ u64 tmp; \
+ do { \
+ start = u64_stats_fetch_begin(&s->syncp); \
+ tmp = u64_stats_read(&s->field); \
+ } while (u64_stats_fetch_retry(&s->syncp, start)); \
+ len = sprintf(buf, format_string ## "\n", tmp); \
+ return len; \
+} \
+MDIO_BUS_STATS_ATTR(name, file)
+
+#define MDIO_BUS_STATS_SHOW(field, format_string) \
+ MDIO_BUS_STATS_SHOW_NAME(field, __stringify(field), \
+ field, format_string)
+
+MDIO_BUS_STATS_SHOW(transfers, "%llu");
+MDIO_BUS_STATS_SHOW(errors, "%llu");
+MDIO_BUS_STATS_SHOW(writes, "%llu");
+MDIO_BUS_STATS_SHOW(reads, "%llu");
+
+static struct attribute *mdio_bus_statistics_attrs[] = {
+ &dev_attr_mdio_bus_transfers.attr,
+ &dev_attr_mdio_bus_errors.attr,
+ &dev_attr_mdio_bus_writes.attr,
+ &dev_attr_mdio_bus_reads.attr,
+ NULL,
+};
+
+static const struct attribute_group mdio_bus_statistics_group = {
+ .name = "statistics",
+ .attrs = mdio_bus_statistics_attrs,
+};
+
+static const struct attribute_group *mdio_bus_groups[] = {
+ &mdio_bus_statistics_group,
+ NULL,
+};
+
static struct class mdio_bus_class = {
.name = "mdio_bus",
.dev_release = mdiobus_release,
+ .dev_groups = mdio_bus_groups,
};

#if IS_ENABLED(CONFIG_OF_MDIO)
@@ -536,6 +607,24 @@ struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
}
EXPORT_SYMBOL(mdiobus_scan);

+static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
+{
+ u64_stats_update_begin(&stats->syncp);
+
+ u64_stats_inc(&stats->transfers);
+ if (ret < 0) {
+ u64_stats_inc(&stats->errors);
+ goto out;
+ }
+
+ if (op)
+ u64_stats_inc(&stats->reads);
+ else
+ u64_stats_inc(&stats->writes);
+out:
+ u64_stats_update_end(&stats->syncp);
+}
+
/**
* __mdiobus_read - Unlocked version of the mdiobus_read function
* @bus: the mii_bus struct
@@ -548,6 +637,7 @@ EXPORT_SYMBOL(mdiobus_scan);
*/
int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
{
+ struct mdio_device *mdiodev = bus->mdio_map[addr];
int retval;

WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
@@ -555,6 +645,9 @@ int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
retval = bus->read(bus, addr, regnum);

trace_mdio_access(bus, 1, addr, regnum, retval, retval);
+ mdiobus_stats_acct(&bus->stats, true, retval);
+ if (mdiodev)
+ mdiobus_stats_acct(&mdiodev->stats, true, retval);

return retval;
}
@@ -573,6 +666,7 @@ EXPORT_SYMBOL(__mdiobus_read);
*/
int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
{
+ struct mdio_device *mdiodev = bus->mdio_map[addr];
int err;

WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
@@ -580,6 +674,9 @@ int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
err = bus->write(bus, addr, regnum, val);

trace_mdio_access(bus, 0, addr, regnum, val, err);
+ mdiobus_stats_acct(&bus->stats, false, err);
+ if (mdiodev)
+ mdiobus_stats_acct(&mdiodev->stats, false, err);

return err;
}
@@ -725,8 +822,27 @@ static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
return 0;
}

+static struct attribute *mdio_bus_device_statistics_attrs[] = {
+ &dev_attr_mdio_bus_device_transfers.attr,
+ &dev_attr_mdio_bus_device_errors.attr,
+ &dev_attr_mdio_bus_device_writes.attr,
+ &dev_attr_mdio_bus_device_reads.attr,
+ NULL,
+};
+
+static const struct attribute_group mdio_bus_device_statistics_group = {
+ .name = "statistics",
+ .attrs = mdio_bus_device_statistics_attrs,
+};
+
+static const struct attribute_group *mdio_bus_dev_groups[] = {
+ &mdio_bus_device_statistics_group,
+ NULL,
+};
+
struct bus_type mdio_bus_type = {
.name = "mdio_bus",
+ .dev_groups = mdio_bus_dev_groups,
.match = mdio_bus_match,
.uevent = mdio_uevent,
};
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index c1d345c3cab3..e89ed990de7d 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -53,6 +53,7 @@ struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr)
if (!mdiodev)
return ERR_PTR(-ENOMEM);

+ u64_stats_init(&mdiodev->stats.syncp);
mdiodev->dev.release = mdio_device_release;
mdiodev->dev.parent = &bus->dev;
mdiodev->dev.bus = &mdio_bus_type;
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index a7604248777b..d6035d973a0d 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -8,6 +8,7 @@

#include <uapi/linux/mdio.h>
#include <linux/mod_devicetable.h>
+#include <linux/u64_stats_sync.h>

struct gpio_desc;
struct mii_bus;
@@ -23,11 +24,20 @@ enum mdio_mutex_lock_class {
MDIO_MUTEX_NESTED,
};

+struct mdio_bus_stats {
+ struct u64_stats_sync syncp;
+ u64_stats_t transfers;
+ u64_stats_t errors;
+ u64_stats_t writes;
+ u64_stats_t reads;
+};
+
struct mdio_device {
struct device dev;

struct mii_bus *bus;
char modalias[MDIO_NAME_SIZE];
+ struct mdio_bus_stats stats;

int (*bus_match)(struct device *dev, struct device_driver *drv);
void (*device_free)(struct mdio_device *mdiodev);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 5932bb8e9c35..8d3ac1ebfef2 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>

@@ -224,6 +225,7 @@ 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;

/*
* A lock to ensure that only one thing can read/write
--
2.19.1
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