While PHY time stamping drivers can simply attach their interface
directly to the PHY instance, stand alone drivers require support in
order to manage their services. Non-PHY MII time stamping drivers
have a control interface over another bus like I2C, SPI, UART, or via
a memory mapped peripheral. The controller device will be associated
with one or more time stamping channels, each of which sits snoops in
on a MII bus.
This patch provides a glue layer that will enable time stamping
channels to find their controlling device.
Signed-off-by: Richard Cochran <richardcochran@xxxxxxxxx>
---
drivers/net/phy/Makefile | 2 +
drivers/net/phy/mii_timestamper.c | 121 ++++++++++++++++++++++++++++++++++++++
include/linux/mii_timestamper.h | 63 ++++++++++++++++++++
net/Kconfig | 7 ++-
4 files changed, 190 insertions(+), 3 deletions(-)
create mode 100644 drivers/net/phy/mii_timestamper.c
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 5805c0b7d60e..584c7c6f40e7 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -40,6 +40,8 @@ obj-$(CONFIG_MDIO_SUN4I) += mdio-sun4i.o
obj-$(CONFIG_MDIO_THUNDER) += mdio-thunder.o
obj-$(CONFIG_MDIO_XGENE) += mdio-xgene.o
+obj-$(CONFIG_NETWORK_PHY_TIMESTAMPING) += mii_timestamper.o
+
obj-$(CONFIG_SFP) += sfp.o
sfp-obj-$(CONFIG_SFP) += sfp-bus.o
obj-y += $(sfp-obj-y) $(sfp-obj-m)
diff --git a/drivers/net/phy/mii_timestamper.c b/drivers/net/phy/mii_timestamper.c
new file mode 100644
index 000000000000..51b77fc92475
--- /dev/null
+++ b/drivers/net/phy/mii_timestamper.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Support for generic time stamping devices on MII buses.
+// Copyright (C) 2018 Richard Cochran <richardcochran@xxxxxxxxx>
+//
+
+#include <linux/mii_timestamper.h>
+
+static LIST_HEAD(mii_timestamping_devices);
+static DEFINE_MUTEX(tstamping_devices_lock);
+
+struct mii_timestamping_desc {
+ struct list_head list;
+ struct mii_timestamping_ctrl *ctrl;
+ struct device *device;
+};
+
+/**
+ * register_mii_tstamp_controller() - registers an MII time stamping device.
+ *
+ * @device: The device to be registered.
+ * @ctrl: Pointer to device's control interface.
+ *
+ * Returns zero on success or non-zero on failure.
+ */
+int register_mii_tstamp_controller(struct device *device,
+ struct mii_timestamping_ctrl *ctrl)
+{
+ struct mii_timestamping_desc *desc;
+
+ desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&desc->list);
+ desc->ctrl = ctrl;
+ desc->device = device;
+
+ mutex_lock(&tstamping_devices_lock);
+ list_add_tail(&mii_timestamping_devices, &desc->list);
+ mutex_unlock(&tstamping_devices_lock);
+
+ return 0;
+}
+
+/**
+ * unregister_mii_tstamp_controller() - unregisters an MII time stamping device.
+ *
+ * @device: A device previously passed to register_mii_tstamp_controller().
+ */
+void unregister_mii_tstamp_controller(struct device *device)
+{
+ struct mii_timestamping_desc *desc;
+ struct list_head *this, *next;
+
+ mutex_lock(&tstamping_devices_lock);
+ list_for_each_safe(this, next, &mii_timestamping_devices) {
+ desc = list_entry(this, struct mii_timestamping_desc, list);
+ if (desc->device == device) {
+ list_del_init(&desc->list);
+ kfree(desc);
+ break;
+ }
+ }
+ mutex_unlock(&tstamping_devices_lock);
+}
+
+/**
+ * register_mii_timestamper - Enables a given port of an MII time stamper.
+ *
+ * @node: The device tree node of the MII time stamp controller.
+ * @port: The index of the port to be enabled.
+ *
+ * Returns a valid interface on success or ERR_PTR otherwise.
+ */
+struct mii_timestamper *register_mii_timestamper(struct device_node *node,
+ unsigned int port)
+{
+ struct mii_timestamper *mii_ts = NULL;
+ struct mii_timestamping_desc *desc;
+ struct list_head *this;
+
+ mutex_lock(&tstamping_devices_lock);
+ list_for_each(this, &mii_timestamping_devices) {
+ desc = list_entry(this, struct mii_timestamping_desc, list);
+ if (desc->device->of_node == node) {
+ mii_ts = desc->ctrl->probe_channel(desc->device, port);
+ if (mii_ts) {
+ mii_ts->device = desc->device;
+ get_device(desc->device);
+ }
+ break;
+ }
+ }
+ mutex_unlock(&tstamping_devices_lock);
+
+ return mii_ts ? mii_ts : ERR_PTR(-EPROBE_DEFER);
+}
+
+/**
+ * unregister_mii_timestamper - Disables a given MII time stamper.
+ *
+ * @mii_ts: An interface obtained via register_mii_timestamper().
+ *
+ */
+void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
+{
+ struct mii_timestamping_desc *desc;
+ struct list_head *this;
+
+ mutex_lock(&tstamping_devices_lock);
+ list_for_each(this, &mii_timestamping_devices) {
+ desc = list_entry(this, struct mii_timestamping_desc, list);
+ if (desc->device == mii_ts->device) {
+ desc->ctrl->release_channel(desc->device, mii_ts);
+ put_device(desc->device);
+ break;
+ }
+ }
+ mutex_unlock(&tstamping_devices_lock);
+}
diff --git a/include/linux/mii_timestamper.h b/include/linux/mii_timestamper.h
index 97e20e7033f6..5fa014ba77ff 100644
--- a/include/linux/mii_timestamper.h
+++ b/include/linux/mii_timestamper.h
@@ -27,10 +27,15 @@
* @hwtstamp: Handles SIOCSHWTSTAMP ioctl for hardware time stamping.
* @link_state: Allows the device to respond to changes in the link state.
* @ts_info: Handles ethtool queries for hardware time stamping.
+ * @device: Remembers the device to which the instance belongs.
*
* Drivers for PHY time stamping devices should embed their
* mii_timestamper within a private structure, obtaining a reference
* to it using container_of().
+ *
+ * Drivers for non-PHY time stamping devices should return a pointer
+ * to a mii_timestamper from the probe_channel() callback of their
+ * mii_timestamping_ctrl interface.
*/
struct mii_timestamper {
bool (*rxtstamp)(struct mii_timestamper *mii_ts,
@@ -47,6 +52,64 @@ struct mii_timestamper {
int (*ts_info)(struct mii_timestamper *mii_ts,
struct ethtool_ts_info *ts_info);
+
+ struct device *device;
+};
+
+/**
+ * struct mii_timestamping_ctrl - MII time stamping controller interface.
+ *
+ * @probe_channel: Callback into the controller driver announcing the
+ * presence of the 'port' channel. The 'device' field
+ * had been passed to register_mii_tstamp_controller().
+ * The driver must return either a pointer to a valid
+ * MII timestamper instance or PTR_ERR.
+ *
+ * @release_channel: Releases an instance obtained via .probe_channel.
+ */
+struct mii_timestamping_ctrl {
+ struct mii_timestamper *(*probe_channel)(struct device *device,
+ unsigned int port);
+ void (*release_channel)(struct device *device,
+ struct mii_timestamper *mii_ts);
};
+#ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
+
+int register_mii_tstamp_controller(struct device *device,
+ struct mii_timestamping_ctrl *ctrl);
+
+void unregister_mii_tstamp_controller(struct device *device);
+
+struct mii_timestamper *register_mii_timestamper(struct device_node *node,
+ unsigned int port);
+
+void unregister_mii_timestamper(struct mii_timestamper *mii_ts);
+
+#else
+
+static inline
+int register_mii_tstamp_controller(struct device *device,
+ struct mii_timestamping_ctrl *ctrl)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline void unregister_mii_tstamp_controller(struct device *device)
+{
+}
+
+static inline
+struct mii_timestamper *register_mii_timestamper(struct device_node *node,
+ unsigned int port)
+{
+ return NULL;
+}
+
+static inline void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
+{
+}
+
+#endif
+
#endif
diff --git a/net/Kconfig b/net/Kconfig
index 228dfa382eec..49872c5f4165 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -106,9 +106,10 @@ config NETWORK_PHY_TIMESTAMPING
bool "Timestamping in PHY devices"
select NET_PTP_CLASSIFY
help
- This allows timestamping of network packets by PHYs with
- hardware timestamping capabilities. This option adds some
- overhead in the transmit and receive paths.
+ This allows timestamping of network packets by PHYs (or
+ other MII bus snooping devices) with hardware timestamping
+ capabilities. This option adds some overhead in the transmit
+ and receive paths.
If you are unsure how to answer this question, answer N.
--
2.11.0
