[PATCH net-next v13 08/14] ptp: Add phc source and helpers to register specific PTP clock or get information

[Kory Maincent]

Prepare for future hardware timestamp selection by adding source and
corresponding pointers to ptp_clock structure.
Additionally, introduce helpers for registering specific phydev or netdev
PTP clocks, retrieving PTP clock information such as hwtstamp source or
phydev/netdev pointers, and obtaining the ptp_clock structure from the
phc index.
These helpers are added to a new ptp_clock_consumer.c file, built as
builtin. This is necessary because these helpers will be called by
ethtool or net timestamping, which are builtin code.

Signed-off-by: Kory Maincent <kory.maincent@xxxxxxxxxxx>
---

Change in v8:
- New patch.

Change in v10:
- Add get and put function to avoid unregistering a ptp clock object used.
- Fix kdoc issues.

Change in v11:
- Remove useless extern.

Change in v12:
- Add missing return description in the kdoc.

Change in v13:
- Remove a semicolon which bring errors while not building PTP driver.
- Remove few useless EXPORT_SYMBOL().
- Separate PTP consumer symbole which are builtin from PTP provider.
---
 drivers/ptp/Makefile             |   5 ++
 drivers/ptp/ptp_clock.c          |  33 ++++++++++-
 drivers/ptp/ptp_clock_consumer.c |  99 +++++++++++++++++++++++++++++++
 drivers/ptp/ptp_private.h        |   7 +++
 include/linux/ptp_clock_kernel.h | 125 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 268 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
index 68bf02078053..9d7226b995cf 100644
--- a/drivers/ptp/Makefile
+++ b/drivers/ptp/Makefile
@@ -3,6 +3,11 @@
 # Makefile for PTP 1588 clock support.
 #
 
+ifdef CONFIG_PTP_1588_CLOCK
+# The ptp_clock consumer is built-in whenever PTP_1588_CLOCK is built-in
+# or module
+obj-y					:= ptp_clock_consumer.o
+endif
 ptp-y					:= ptp_clock.o ptp_chardev.o ptp_sysfs.o ptp_vclock.o
 ptp_kvm-$(CONFIG_X86)			:= ptp_kvm_x86.o ptp_kvm_common.o
 ptp_kvm-$(CONFIG_HAVE_ARM_SMCCC)	:= ptp_kvm_arm.o ptp_kvm_common.o
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index c56cd0f63909..593b5c906314 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -34,7 +34,6 @@ const struct class ptp_class = {
 
 static dev_t ptp_devt;
 
-static DEFINE_XARRAY_ALLOC(ptp_clocks_map);
 
 /* time stamp event queue operations */
 
@@ -512,6 +511,38 @@ void ptp_cancel_worker_sync(struct ptp_clock *ptp)
 }
 EXPORT_SYMBOL(ptp_cancel_worker_sync);
 
+struct ptp_clock *netdev_ptp_clock_register(struct ptp_clock_info *info,
+					    struct net_device *dev)
+{
+	struct ptp_clock *ptp;
+
+	ptp = ptp_clock_register(info, &dev->dev);
+	if (IS_ERR(ptp))
+		return ptp;
+
+	ptp->phc_source = HWTSTAMP_SOURCE_NETDEV;
+	ptp->netdev = dev;
+
+	return ptp;
+}
+EXPORT_SYMBOL(netdev_ptp_clock_register);
+
+struct ptp_clock *phydev_ptp_clock_register(struct ptp_clock_info *info,
+					    struct phy_device *phydev)
+{
+	struct ptp_clock *ptp;
+
+	ptp = ptp_clock_register(info, &phydev->mdio.dev);
+	if (IS_ERR(ptp))
+		return ptp;
+
+	ptp->phc_source = HWTSTAMP_SOURCE_PHYLIB;
+	ptp->phydev = phydev;
+
+	return ptp;
+}
+EXPORT_SYMBOL(phydev_ptp_clock_register);
+
 /* module operations */
 
 static void __exit ptp_exit(void)
diff --git a/drivers/ptp/ptp_clock_consumer.c b/drivers/ptp/ptp_clock_consumer.c
new file mode 100644
index 000000000000..759dd6f63405
--- /dev/null
+++ b/drivers/ptp/ptp_clock_consumer.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PTP 1588 clock support
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ */
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/posix-clock.h>
+#include <linux/pps_kernel.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <linux/xarray.h>
+#include <uapi/linux/sched/types.h>
+
+#include "ptp_private.h"
+
+DEFINE_XARRAY_ALLOC(ptp_clocks_map);
+EXPORT_SYMBOL(ptp_clocks_map);
+
+bool ptp_clock_from_phylib(struct ptp_clock *ptp)
+{
+	return ptp->phc_source == HWTSTAMP_SOURCE_PHYLIB;
+}
+
+bool ptp_clock_from_netdev(struct ptp_clock *ptp)
+{
+	return ptp->phc_source == HWTSTAMP_SOURCE_NETDEV;
+}
+
+struct net_device *ptp_clock_netdev(struct ptp_clock *ptp)
+{
+	if (ptp->phc_source != HWTSTAMP_SOURCE_NETDEV)
+		return NULL;
+
+	return ptp->netdev;
+}
+
+struct phy_device *ptp_clock_phydev(struct ptp_clock *ptp)
+{
+	if (ptp->phc_source != HWTSTAMP_SOURCE_PHYLIB)
+		return NULL;
+
+	return ptp->phydev;
+}
+
+int ptp_clock_get(struct device *dev, struct ptp_clock *ptp)
+{
+	struct device_link *link;
+
+	if (!ptp)
+		return 0;
+
+	if (!try_module_get(ptp->info->owner))
+		return -EPROBE_DEFER;
+
+	get_device(&ptp->dev);
+
+	link = device_link_add(dev, &ptp->dev, DL_FLAG_STATELESS);
+	if (!link)
+		dev_warn(dev, "failed to create device link to %s\n",
+			 dev_name(&ptp->dev));
+
+	return 0;
+}
+
+struct ptp_clock *ptp_clock_get_by_index(struct device *dev, int index)
+{
+	struct ptp_clock *ptp;
+	int ret;
+
+	if (index < 0)
+		return NULL;
+
+	ptp = xa_load(&ptp_clocks_map, (unsigned long)index);
+	if (IS_ERR_OR_NULL(ptp))
+		return ptp;
+
+	ret = ptp_clock_get(dev, ptp);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return ptp;
+}
+
+void ptp_clock_put(struct device *dev, struct ptp_clock *ptp)
+{
+	if (!ptp)
+		return;
+
+	device_link_remove(dev, &ptp->dev);
+	put_device(&ptp->dev);
+	module_put(ptp->info->owner);
+}
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 18934e28469e..6a306e6e34c2 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -24,6 +24,8 @@
 #define PTP_DEFAULT_MAX_VCLOCKS 20
 #define PTP_MAX_CHANNELS 2048
 
+extern struct xarray ptp_clocks_map;
+
 struct timestamp_event_queue {
 	struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
 	int head;
@@ -41,6 +43,11 @@ struct ptp_clock {
 	struct ptp_clock_info *info;
 	dev_t devid;
 	int index; /* index into clocks.map */
+	enum hwtstamp_source phc_source;
+	union { /* Pointer of the phc_source device */
+		struct net_device *netdev;
+		struct phy_device *phydev;
+	};
 	struct pps_device *pps_source;
 	long dialed_frequency; /* remembers the frequency adjustment */
 	struct list_head tsevqs; /* timestamp fifo list */
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 6e4b8206c7d0..860c1e293a62 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -9,7 +9,9 @@
 #define _PTP_CLOCK_KERNEL_H_
 
 #include <linux/device.h>
+#include <linux/netdevice.h>
 #include <linux/pps_kernel.h>
+#include <linux/phy.h>
 #include <linux/ptp_clock.h>
 #include <linux/timecounter.h>
 #include <linux/skbuff.h>
@@ -340,6 +342,106 @@ extern void ptp_clock_event(struct ptp_clock *ptp,
 
 extern int ptp_clock_index(struct ptp_clock *ptp);
 
+/**
+ * netdev_ptp_clock_register() - Register a PTP hardware clock driver for
+ *				 a net device
+ *
+ * @info: Structure describing the new clock.
+ * @dev:  Pointer of the net device.
+ *
+ * Return: Pointer of the PTP clock, error pointer otherwise.
+ */
+
+struct ptp_clock *
+netdev_ptp_clock_register(struct ptp_clock_info *info,
+			  struct net_device *dev);
+
+/**
+ * phydev_ptp_clock_register() - Register a PTP hardware clock driver for
+ *				 a phy device
+ *
+ * @info:   Structure describing the new clock.
+ * @phydev:  Pointer of the phy device.
+ *
+ * Return: Pointer of the PTP clock, error pointer otherwise.
+ */
+
+struct ptp_clock *
+phydev_ptp_clock_register(struct ptp_clock_info *info,
+			  struct phy_device *phydev);
+
+/**
+ * ptp_clock_from_phylib() - Does the PTP clock comes from phylib
+ *
+ * @ptp:  The clock obtained from net/phy_ptp_clock_register().
+ *
+ * Return: True if the PTP clock comes from phylib, false otherwise.
+ */
+
+bool ptp_clock_from_phylib(struct ptp_clock *ptp);
+
+/**
+ * ptp_clock_from_netdev() - Does the PTP clock comes from netdev
+ *
+ * @ptp:  The clock obtained from net/phy_ptp_clock_register().
+ *
+ * Return: True if the PTP clock comes from netdev, false otherwise.
+ */
+
+bool ptp_clock_from_netdev(struct ptp_clock *ptp);
+
+/**
+ * ptp_clock_netdev() - Obtain the net_device reference of PTP clock
+ *
+ * @ptp:  The clock obtained from netdev_ptp_clock_register().
+ *
+ * Return: Pointer of the net device, NULL otherwise.
+ */
+
+struct net_device *ptp_clock_netdev(struct ptp_clock *ptp);
+
+/**
+ * ptp_clock_phydev() - Obtain the phy_device reference of a PTP clock
+ *
+ * @ptp:  The clock obtained from phydev_ptp_clock_register().
+ *
+ * Return: Pointer of the phy device, NULL otherwise.
+ */
+
+struct phy_device *ptp_clock_phydev(struct ptp_clock *ptp);
+
+/**
+ * ptp_clock_get() - Increment refcount of the PTP clock
+ *
+ * @dev:  The device which get the PTP clock.
+ * @ptp:  Pointer of a PTP clock.
+ *
+ * Return: 0 in case of success, error otherwise.
+ */
+
+int ptp_clock_get(struct device *dev, struct ptp_clock *ptp);
+
+/**
+ * ptp_clock_get_by_index() - Obtain the PTP clock reference from a given
+ *			      PHC index
+ *
+ * @dev:  The device which get the PTP clock.
+ * @index:  The device index of a PTP clock.
+ *
+ * Return: Pointer of the PTP clock, error pointer otherwise.
+ */
+
+struct ptp_clock *ptp_clock_get_by_index(struct device *dev, int index);
+
+/**
+ * ptp_clock_put() - decrement refcount of the PTP clock
+ *
+ * @dev:  The device which get the PTP clock.
+ * @ptp:  Pointer of a PTP clock.
+ */
+
+void ptp_clock_put(struct device *dev, struct ptp_clock *ptp);
+
 /**
  * ptp_find_pin() - obtain the pin index of a given auxiliary function
  *
@@ -405,6 +507,29 @@ static inline void ptp_clock_event(struct ptp_clock *ptp,
 { }
 static inline int ptp_clock_index(struct ptp_clock *ptp)
 { return -1; }
+static inline struct ptp_clock *
+netdev_ptp_clock_register(struct ptp_clock_info *info,
+			  struct net_device *dev)
+{ return NULL; }
+static inline struct ptp_clock *
+phydev_ptp_clock_register(struct ptp_clock_info *info,
+			  struct phy_device *phydev)
+{ return NULL; }
+static inline bool ptp_clock_from_phylib(struct ptp_clock *ptp)
+{ return false; }
+static inline bool ptp_clock_from_netdev(struct ptp_clock *ptp)
+{ return false; }
+static inline struct net_device *ptp_clock_netdev(struct ptp_clock *ptp)
+{ return NULL; }
+static inline struct phy_device *ptp_clock_phydev(struct ptp_clock *ptp)
+{ return NULL; }
+static inline int ptp_clock_get(struct device *dev, struct ptp_clock *ptp)
+{ return -ENODEV; }
+static inline void ptp_clock_put(struct device *dev, struct ptp_clock *ptp)
+{ }
+static inline struct ptp_clock *ptp_clock_get_by_index(struct device *dev,
+						       int index)
+{ return NULL; }
 static inline int ptp_find_pin(struct ptp_clock *ptp,
 			       enum ptp_pin_function func, unsigned int chan)
 { return -1; }

-- 
2.34.1