staging: greybus: remove timesync protocol support

While the timesync protocol was a great idea, it never ended up getting
implemented by any known hardware devices.  It's also a bit
"interesting" in how it ties into the platform controller.

So, just remove it for now.  It's not needed, no one uses it, and it's a
stumbling block in getting the greybus core code merged out of the
staging tree.  If anyone wants it in the future, reverting this patch is
a great place to start from.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alex Elder <elder@kernel.org>
Acked-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/Makefile

@@ -10,9 +10,7 @@ greybus-y :=	core.o		\
 		control.o	\
 		svc.o		\
 		svc_watchdog.o	\
-		operation.o	\
-		timesync.o	\
-		timesync_platform.o
+		operation.o
 
 obj-$(CONFIG_GREYBUS)		+= greybus.o
 

drivers/staging/greybus/arche_platform.h

@@ -10,8 +10,6 @@
 #ifndef __ARCHE_PLATFORM_H
 #define __ARCHE_PLATFORM_H
 
-#include "timesync.h"
-
 enum arche_platform_state {
 	ARCHE_PLATFORM_STATE_OFF,
 	ARCHE_PLATFORM_STATE_ACTIVE,

drivers/staging/greybus/control.c

@@ -198,56 +198,6 @@ int gb_control_mode_switch_operation(struct gb_control *control)
 	return ret;
 }
 
-int gb_control_timesync_enable(struct gb_control *control, u8 count,
-			       u64 frame_time, u32 strobe_delay, u32 refclk)
-{
-	struct gb_control_timesync_enable_request request;
-
-	request.count = count;
-	request.frame_time = cpu_to_le64(frame_time);
-	request.strobe_delay = cpu_to_le32(strobe_delay);
-	request.refclk = cpu_to_le32(refclk);
-	return gb_operation_sync(control->connection,
-				 GB_CONTROL_TYPE_TIMESYNC_ENABLE, &request,
-				 sizeof(request), NULL, 0);
-}
-
-int gb_control_timesync_disable(struct gb_control *control)
-{
-	return gb_operation_sync(control->connection,
-				 GB_CONTROL_TYPE_TIMESYNC_DISABLE, NULL, 0,
-				 NULL, 0);
-}
-
-int gb_control_timesync_get_last_event(struct gb_control *control,
-				       u64 *frame_time)
-{
-	struct gb_control_timesync_get_last_event_response response;
-	int ret;
-
-	ret = gb_operation_sync(control->connection,
-				GB_CONTROL_TYPE_TIMESYNC_GET_LAST_EVENT,
-				NULL, 0, &response, sizeof(response));
-	if (!ret)
-		*frame_time = le64_to_cpu(response.frame_time);
-	return ret;
-}
-
-int gb_control_timesync_authoritative(struct gb_control *control,
-				      u64 *frame_time)
-{
-	struct gb_control_timesync_authoritative_request request;
-	int i;
-
-	for (i = 0; i < GB_TIMESYNC_MAX_STROBES; i++)
-		request.frame_time[i] = cpu_to_le64(frame_time[i]);
-
-	return gb_operation_sync(control->connection,
-				 GB_CONTROL_TYPE_TIMESYNC_AUTHORITATIVE,
-				 &request, sizeof(request),
-				 NULL, 0);
-}
-
 static int gb_control_bundle_pm_status_map(u8 status)
 {
 	switch (status) {

drivers/staging/greybus/control.h

@@ -48,13 +48,6 @@ void gb_control_mode_switch_complete(struct gb_control *control);
 int gb_control_get_manifest_size_operation(struct gb_interface *intf);
 int gb_control_get_manifest_operation(struct gb_interface *intf, void *manifest,
 				      size_t size);
-int gb_control_timesync_enable(struct gb_control *control, u8 count,
-			       u64 frame_time, u32 strobe_delay, u32 refclk);
-int gb_control_timesync_disable(struct gb_control *control);
-int gb_control_timesync_get_last_event(struct gb_control *control,
-				       u64 *frame_time);
-int gb_control_timesync_authoritative(struct gb_control *control,
-				      u64 *frame_time);
 int gb_control_bundle_suspend(struct gb_control *control, u8 bundle_id);
 int gb_control_bundle_resume(struct gb_control *control, u8 bundle_id);
 int gb_control_bundle_deactivate(struct gb_control *control, u8 bundle_id);

drivers/staging/greybus/core.c

@@ -218,8 +218,6 @@ static int greybus_probe(struct device *dev)
 		return retval;
 	}
 
-	gb_timesync_schedule_synchronous(bundle->intf);
-
 	pm_runtime_put(&bundle->intf->dev);
 
 	return 0;
@@ -326,16 +324,8 @@ static int __init gb_init(void)
 		pr_err("gb_operation_init failed (%d)\n", retval);
 		goto error_operation;
 	}
-
-	retval = gb_timesync_init();
-	if (retval) {
-		pr_err("gb_timesync_init failed\n");
-		goto error_timesync;
-	}
 	return 0;	/* Success */
 
-error_timesync:
-	gb_operation_exit();
 error_operation:
 	gb_hd_exit();
 error_hd:
@@ -349,7 +339,6 @@ module_init(gb_init);
 
 static void __exit gb_exit(void)
 {
-	gb_timesync_exit();
 	gb_operation_exit();
 	gb_hd_exit();
 	bus_unregister(&greybus_bus_type);

drivers/staging/greybus/es2.c

@@ -127,29 +127,6 @@ struct es2_ap_dev {
 	struct list_head arpcs;
 };
 
-/**
- * timesync_enable_request - Enable timesync in an APBridge
- * @count: number of TimeSync Pulses to expect
- * @frame_time: the initial FrameTime at the first TimeSync Pulse
- * @strobe_delay: the expected delay in microseconds between each TimeSync Pulse
- * @refclk: The AP mandated reference clock to run FrameTime at
- */
-struct timesync_enable_request {
-	__u8	count;
-	__le64	frame_time;
-	__le32	strobe_delay;
-	__le32	refclk;
-} __packed;
-
-/**
- * timesync_authoritative_request - Transmit authoritative FrameTime to APBridge
- * @frame_time: An array of authoritative FrameTimes provided by the SVC
- *              and relayed to the APBridge by the AP
- */
-struct timesync_authoritative_request {
-	__le64	frame_time[GB_TIMESYNC_MAX_STROBES];
-} __packed;
-
 struct arpc {
 	struct list_head list;
 	struct arpc_request_message *req;
@@ -754,111 +731,6 @@ static int latency_tag_disable(struct gb_host_device *hd, u16 cport_id)
 	return retval;
 }
 
-static int timesync_enable(struct gb_host_device *hd, u8 count,
-			   u64 frame_time, u32 strobe_delay, u32 refclk)
-{
-	int retval;
-	struct es2_ap_dev *es2 = hd_to_es2(hd);
-	struct usb_device *udev = es2->usb_dev;
-	struct gb_control_timesync_enable_request *request;
-
-	request = kzalloc(sizeof(*request), GFP_KERNEL);
-	if (!request)
-		return -ENOMEM;
-
-	request->count = count;
-	request->frame_time = cpu_to_le64(frame_time);
-	request->strobe_delay = cpu_to_le32(strobe_delay);
-	request->refclk = cpu_to_le32(refclk);
-	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
-				 GB_APB_REQUEST_TIMESYNC_ENABLE,
-				 USB_DIR_OUT | USB_TYPE_VENDOR |
-				 USB_RECIP_INTERFACE, 0, 0, request,
-				 sizeof(*request), ES2_USB_CTRL_TIMEOUT);
-	if (retval < 0)
-		dev_err(&udev->dev, "Cannot enable timesync %d\n", retval);
-
-	kfree(request);
-	return retval;
-}
-
-static int timesync_disable(struct gb_host_device *hd)
-{
-	int retval;
-	struct es2_ap_dev *es2 = hd_to_es2(hd);
-	struct usb_device *udev = es2->usb_dev;
-
-	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
-				 GB_APB_REQUEST_TIMESYNC_DISABLE,
-				 USB_DIR_OUT | USB_TYPE_VENDOR |
-				 USB_RECIP_INTERFACE, 0, 0, NULL,
-				 0, ES2_USB_CTRL_TIMEOUT);
-	if (retval < 0)
-		dev_err(&udev->dev, "Cannot disable timesync %d\n", retval);
-
-	return retval;
-}
-
-static int timesync_authoritative(struct gb_host_device *hd, u64 *frame_time)
-{
-	int retval, i;
-	struct es2_ap_dev *es2 = hd_to_es2(hd);
-	struct usb_device *udev = es2->usb_dev;
-	struct timesync_authoritative_request *request;
-
-	request = kzalloc(sizeof(*request), GFP_KERNEL);
-	if (!request)
-		return -ENOMEM;
-
-	for (i = 0; i < GB_TIMESYNC_MAX_STROBES; i++)
-		request->frame_time[i] = cpu_to_le64(frame_time[i]);
-
-	retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
-				 GB_APB_REQUEST_TIMESYNC_AUTHORITATIVE,
-				 USB_DIR_OUT | USB_TYPE_VENDOR |
-				 USB_RECIP_INTERFACE, 0, 0, request,
-				 sizeof(*request), ES2_USB_CTRL_TIMEOUT);
-	if (retval < 0)
-		dev_err(&udev->dev, "Cannot timesync authoritative out %d\n", retval);
-
-	kfree(request);
-	return retval;
-}
-
-static int timesync_get_last_event(struct gb_host_device *hd, u64 *frame_time)
-{
-	int retval;
-	struct es2_ap_dev *es2 = hd_to_es2(hd);
-	struct usb_device *udev = es2->usb_dev;
-	__le64 *response_frame_time;
-
-	response_frame_time = kzalloc(sizeof(*response_frame_time), GFP_KERNEL);
-	if (!response_frame_time)
-		return -ENOMEM;
-
-	retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
-				 GB_APB_REQUEST_TIMESYNC_GET_LAST_EVENT,
-				 USB_DIR_IN | USB_TYPE_VENDOR |
-				 USB_RECIP_INTERFACE, 0, 0, response_frame_time,
-				 sizeof(*response_frame_time),
-				 ES2_USB_CTRL_TIMEOUT);
-
-	if (retval != sizeof(*response_frame_time)) {
-		dev_err(&udev->dev, "Cannot get last TimeSync event: %d\n",
-			retval);
-
-		if (retval >= 0)
-			retval = -EIO;
-
-		goto out;
-	}
-	*frame_time = le64_to_cpu(*response_frame_time);
-	retval = 0;
-out:
-	kfree(response_frame_time);
-	return retval;
-}
-
 static struct gb_hd_driver es2_driver = {
 	.hd_priv_size			= sizeof(struct es2_ap_dev),
 	.message_send			= message_send,
@@ -874,10 +746,6 @@ static struct gb_hd_driver es2_driver = {
 	.latency_tag_enable		= latency_tag_enable,
 	.latency_tag_disable		= latency_tag_disable,
 	.output				= output,
-	.timesync_enable		= timesync_enable,
-	.timesync_disable		= timesync_disable,
-	.timesync_authoritative		= timesync_authoritative,
-	.timesync_get_last_event	= timesync_get_last_event,
 };
 
 /* Common function to report consistent warnings based on URB status */

drivers/staging/greybus/greybus.h

@@ -33,7 +33,6 @@
 #include "bundle.h"
 #include "connection.h"
 #include "operation.h"
-#include "timesync.h"
 
 /* Matches up with the Greybus Protocol specification document */
 #define GREYBUS_VERSION_MAJOR	0x00

drivers/staging/greybus/greybus_protocols.h

@@ -173,26 +173,6 @@ struct gb_control_disconnected_request {
 } __packed;
 /* Control protocol [dis]connected response has no payload */
 
-#define GB_TIMESYNC_MAX_STROBES			0x04
-
-struct gb_control_timesync_enable_request {
-	__u8	count;
-	__le64	frame_time;
-	__le32	strobe_delay;
-	__le32	refclk;
-} __packed;
-/* timesync enable response has no payload */
-
-struct gb_control_timesync_authoritative_request {
-	__le64	frame_time[GB_TIMESYNC_MAX_STROBES];
-} __packed;
-/* timesync authoritative response has no payload */
-
-/* timesync get_last_event_request has no payload */
-struct gb_control_timesync_get_last_event_response {
-	__le64	frame_time;
-} __packed;
-
 /*
  * All Bundle power management operations use the same request and response
  * layout and status codes.
@@ -1169,33 +1149,6 @@ struct gb_svc_intf_unipro_response {
 #define GB_SVC_INTF_UNIPRO_NOT_OFF			0x03
 } __packed;
 
-struct gb_svc_timesync_enable_request {
-	__u8	count;
-	__le64	frame_time;
-	__le32	strobe_delay;
-	__le32	refclk;
-} __packed;
-/* timesync enable response has no payload */
-
-/* timesync authoritative request has no payload */
-struct gb_svc_timesync_authoritative_response {
-	__le64	frame_time[GB_TIMESYNC_MAX_STROBES];
-};
-
-struct gb_svc_timesync_wake_pins_acquire_request {
-	__le32	strobe_mask;
-};
-
-/* timesync wake pins acquire response has no payload */
-
-/* timesync wake pins release request has no payload */
-/* timesync wake pins release response has no payload */
-
-/* timesync svc ping request has no payload */
-struct gb_svc_timesync_ping_response {
-	__le64	frame_time;
-} __packed;
-
 #define GB_SVC_UNIPRO_FAST_MODE			0x01
 #define GB_SVC_UNIPRO_SLOW_MODE			0x02
 #define GB_SVC_UNIPRO_FAST_AUTO_MODE		0x04

drivers/staging/greybus/greybus_trace.h

@@ -488,34 +488,6 @@ DEFINE_HD_EVENT(gb_hd_in);
 
 #undef DEFINE_HD_EVENT
 
-/*
- * Occurs on a TimeSync synchronization event or a TimeSync ping event.
- */
-TRACE_EVENT(gb_timesync_irq,
-
-	TP_PROTO(u8 ping, u8 strobe, u8 count, u64 frame_time),
-
-	TP_ARGS(ping, strobe, count, frame_time),
-
-	TP_STRUCT__entry(
-		__field(u8, ping)
-		__field(u8, strobe)
-		__field(u8, count)
-		__field(u64, frame_time)
-	),
-
-	TP_fast_assign(
-		__entry->ping = ping;
-		__entry->strobe = strobe;
-		__entry->count = count;
-		__entry->frame_time = frame_time;
-	),
-
-	TP_printk("%s %d/%d frame-time %llu\n",
-		  __entry->ping ? "ping" : "strobe", __entry->strobe,
-		  __entry->count, __entry->frame_time)
-);
-
 #endif /* _TRACE_GREYBUS_H */
 
 /* This part must be outside protection */

drivers/staging/greybus/hd.h

@@ -37,13 +37,6 @@ struct gb_hd_driver {
 	int (*latency_tag_disable)(struct gb_host_device *hd, u16 cport_id);
 	int (*output)(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
 		      bool async);
-	int (*timesync_enable)(struct gb_host_device *hd, u8 count,
-			       u64 frame_time, u32 strobe_delay, u32 refclk);
-	int (*timesync_disable)(struct gb_host_device *hd);
-	int (*timesync_authoritative)(struct gb_host_device *hd,
-				      u64 *frame_time);
-	int (*timesync_get_last_event)(struct gb_host_device *hd,
-				       u64 *frame_time);
 };
 
 struct gb_host_device {

drivers/staging/greybus/interface.c

@@ -702,14 +702,12 @@ static void gb_interface_release(struct device *dev)
 static int gb_interface_suspend(struct device *dev)
 {
 	struct gb_interface *intf = to_gb_interface(dev);
-	int ret, timesync_ret;
+	int ret;
 
 	ret = gb_control_interface_suspend_prepare(intf->control);
 	if (ret)
 		return ret;
 
-	gb_timesync_interface_remove(intf);
-
 	ret = gb_control_suspend(intf->control);
 	if (ret)
 		goto err_hibernate_abort;
@@ -730,12 +728,6 @@ static int gb_interface_suspend(struct device *dev)
 err_hibernate_abort:
 	gb_control_interface_hibernate_abort(intf->control);
 
-	timesync_ret = gb_timesync_interface_add(intf);
-	if (timesync_ret) {
-		dev_err(dev, "failed to add to timesync: %d\n", timesync_ret);
-		return timesync_ret;
-	}
-
 	return ret;
 }
 
@@ -757,18 +749,6 @@ static int gb_interface_resume(struct device *dev)
 	if (ret)
 		return ret;
 
-	ret = gb_timesync_interface_add(intf);
-	if (ret) {
-		dev_err(dev, "failed to add to timesync: %d\n", ret);
-		return ret;
-	}
-
-	ret = gb_timesync_schedule_synchronous(intf);
-	if (ret) {
-		dev_err(dev, "failed to synchronize FrameTime: %d\n", ret);
-		return ret;
-	}
-
 	return 0;
 }
 
@@ -1152,16 +1132,10 @@ int gb_interface_enable(struct gb_interface *intf)
 	if (ret)
 		goto err_destroy_bundles;
 
-	ret = gb_timesync_interface_add(intf);
-	if (ret) {
-		dev_err(&intf->dev, "failed to add to timesync: %d\n", ret);
-		goto err_destroy_bundles;
-	}
-
 	/* Register the control device and any bundles */
 	ret = gb_control_add(intf->control);
 	if (ret)
-		goto err_remove_timesync;
+		goto err_destroy_bundles;
 
 	pm_runtime_use_autosuspend(&intf->dev);
 	pm_runtime_get_noresume(&intf->dev);
@@ -1186,8 +1160,6 @@ int gb_interface_enable(struct gb_interface *intf)
 
 	return 0;
 
-err_remove_timesync:
-	gb_timesync_interface_remove(intf);
 err_destroy_bundles:
 	list_for_each_entry_safe(bundle, tmp, &intf->bundles, links)
 		gb_bundle_destroy(bundle);
@@ -1230,7 +1202,6 @@ void gb_interface_disable(struct gb_interface *intf)
 		gb_control_interface_deactivate_prepare(intf->control);
 
 	gb_control_del(intf->control);
-	gb_timesync_interface_remove(intf);
 	gb_control_disable(intf->control);
 	gb_control_put(intf->control);
 	intf->control = NULL;
@@ -1243,29 +1214,6 @@ void gb_interface_disable(struct gb_interface *intf)
 	pm_runtime_put_noidle(&intf->dev);
 }
 
-/* Enable TimeSync on an Interface control connection. */
-int gb_interface_timesync_enable(struct gb_interface *intf, u8 count,
-				 u64 frame_time, u32 strobe_delay, u32 refclk)
-{
-	return gb_control_timesync_enable(intf->control, count,
-					  frame_time, strobe_delay,
-					  refclk);
-}
-
-/* Disable TimeSync on an Interface control connection. */
-int gb_interface_timesync_disable(struct gb_interface *intf)
-{
-	return gb_control_timesync_disable(intf->control);
-}
-
-/* Transmit the Authoritative FrameTime via an Interface control connection. */
-int gb_interface_timesync_authoritative(struct gb_interface *intf,
-					u64 *frame_time)
-{
-	return gb_control_timesync_authoritative(intf->control,
-						frame_time);
-}
-
 /* Register an interface. */
 int gb_interface_add(struct gb_interface *intf)
 {

drivers/staging/greybus/interface.h

@@ -72,11 +72,6 @@ int gb_interface_activate(struct gb_interface *intf);
 void gb_interface_deactivate(struct gb_interface *intf);
 int gb_interface_enable(struct gb_interface *intf);
 void gb_interface_disable(struct gb_interface *intf);
-int gb_interface_timesync_enable(struct gb_interface *intf, u8 count,
-				 u64 frame_time, u32 strobe_delay, u32 refclk);
-int gb_interface_timesync_authoritative(struct gb_interface *intf,
-					u64 *frame_time);
-int gb_interface_timesync_disable(struct gb_interface *intf);
 int gb_interface_add(struct gb_interface *intf);
 void gb_interface_del(struct gb_interface *intf);
 void gb_interface_put(struct gb_interface *intf);

drivers/staging/greybus/svc.c

@@ -518,85 +518,6 @@ void gb_svc_connection_destroy(struct gb_svc *svc, u8 intf1_id, u16 cport1_id,
 	}
 }
 
-int gb_svc_timesync_enable(struct gb_svc *svc, u8 count, u64 frame_time,
-			   u32 strobe_delay, u32 refclk)
-{
-	struct gb_connection *connection = svc->connection;
-	struct gb_svc_timesync_enable_request request;
-
-	request.count = count;
-	request.frame_time = cpu_to_le64(frame_time);
-	request.strobe_delay = cpu_to_le32(strobe_delay);
-	request.refclk = cpu_to_le32(refclk);
-	return gb_operation_sync(connection,
-				 GB_SVC_TYPE_TIMESYNC_ENABLE,
-				 &request, sizeof(request), NULL, 0);
-}
-
-int gb_svc_timesync_disable(struct gb_svc *svc)
-{
-	struct gb_connection *connection = svc->connection;
-
-	return gb_operation_sync(connection,
-				 GB_SVC_TYPE_TIMESYNC_DISABLE,
-				 NULL, 0, NULL, 0);
-}
-
-int gb_svc_timesync_authoritative(struct gb_svc *svc, u64 *frame_time)
-{
-	struct gb_connection *connection = svc->connection;
-	struct gb_svc_timesync_authoritative_response response;
-	int ret, i;
-
-	ret = gb_operation_sync(connection,
-				GB_SVC_TYPE_TIMESYNC_AUTHORITATIVE, NULL, 0,
-				&response, sizeof(response));
-	if (ret < 0)
-		return ret;
-
-	for (i = 0; i < GB_TIMESYNC_MAX_STROBES; i++)
-		frame_time[i] = le64_to_cpu(response.frame_time[i]);
-	return 0;
-}
-
-int gb_svc_timesync_ping(struct gb_svc *svc, u64 *frame_time)
-{
-	struct gb_connection *connection = svc->connection;
-	struct gb_svc_timesync_ping_response response;
-	int ret;
-
-	ret = gb_operation_sync(connection,
-				GB_SVC_TYPE_TIMESYNC_PING,
-				NULL, 0,
-				&response, sizeof(response));
-	if (ret < 0)
-		return ret;
-
-	*frame_time = le64_to_cpu(response.frame_time);
-	return 0;
-}
-
-int gb_svc_timesync_wake_pins_acquire(struct gb_svc *svc, u32 strobe_mask)
-{
-	struct gb_connection *connection = svc->connection;
-	struct gb_svc_timesync_wake_pins_acquire_request request;
-
-	request.strobe_mask = cpu_to_le32(strobe_mask);
-	return gb_operation_sync(connection,
-				 GB_SVC_TYPE_TIMESYNC_WAKE_PINS_ACQUIRE,
-				 &request, sizeof(request),
-				 NULL, 0);
-}
-
-int gb_svc_timesync_wake_pins_release(struct gb_svc *svc)
-{
-	struct gb_connection *connection = svc->connection;
-
-	return gb_operation_sync(connection,
-				 GB_SVC_TYPE_TIMESYNC_WAKE_PINS_RELEASE,
-				 NULL, 0, NULL, 0);
-}
-
 /* Creates bi-directional routes between the devices */
 int gb_svc_route_create(struct gb_svc *svc, u8 intf1_id, u8 dev1_id,
 			       u8 intf2_id, u8 dev2_id)
@@ -945,13 +866,6 @@ static int gb_svc_hello(struct gb_operation *op)
 
 	gb_svc_debugfs_init(svc);
 
-	ret = gb_timesync_svc_add(svc);
-	if (ret) {
-		dev_err(&svc->dev, "failed to add SVC to timesync: %d\n", ret);
-		gb_svc_debugfs_exit(svc);
-		goto err_unregister_device;
-	}
-
 	return gb_svc_queue_deferred_request(op);
 
 err_unregister_device:
@@ -1467,7 +1381,6 @@ void gb_svc_del(struct gb_svc *svc)
 	 * The SVC device may have been registered from the request handler.
 	 */
 	if (device_is_registered(&svc->dev)) {
-		gb_timesync_svc_remove(svc);
 		gb_svc_debugfs_exit(svc);
 		gb_svc_watchdog_destroy(svc);
 		device_del(&svc->dev);

drivers/staging/greybus/svc.h

@@ -95,13 +95,6 @@ void gb_svc_watchdog_destroy(struct gb_svc *svc);
 bool gb_svc_watchdog_enabled(struct gb_svc *svc);
 int gb_svc_watchdog_enable(struct gb_svc *svc);
 int gb_svc_watchdog_disable(struct gb_svc *svc);
-int gb_svc_timesync_enable(struct gb_svc *svc, u8 count, u64 frame_time,
-			   u32 strobe_delay, u32 refclk);
-int gb_svc_timesync_disable(struct gb_svc *svc);
-int gb_svc_timesync_authoritative(struct gb_svc *svc, u64 *frame_time);
-int gb_svc_timesync_ping(struct gb_svc *svc, u64 *frame_time);
-int gb_svc_timesync_wake_pins_acquire(struct gb_svc *svc, u32 strobe_mask);
-int gb_svc_timesync_wake_pins_release(struct gb_svc *svc);
 
 int gb_svc_protocol_init(void);
 void gb_svc_protocol_exit(void);

drivers/staging/greybus/timesync.c

-/*
- * TimeSync API driver.
- *
- * Copyright 2016 Google Inc.
- * Copyright 2016 Linaro Ltd.
- *
- * Released under the GPLv2 only.
- */
-#include <linux/debugfs.h>
-#include <linux/hrtimer.h>
-#include "greybus.h"
-#include "timesync.h"
-#include "greybus_trace.h"
-
-/*
- * Minimum inter-strobe value of one millisecond is chosen because it
- * just-about fits the common definition of a jiffy.
- *
- * Maximum value OTOH is constrained by the number of bits the SVC can fit
- * into a 16 bit up-counter. The SVC configures the timer in microseconds
- * so the maximum allowable value is 65535 microseconds. We clip that value
- * to 10000 microseconds for the sake of using nice round base 10 numbers
- * and since right-now there's no imaginable use-case requiring anything
- * other than a one millisecond inter-strobe time, let alone something
- * higher than ten milliseconds.
- */
-#define GB_TIMESYNC_STROBE_DELAY_US		1000
-#define GB_TIMESYNC_DEFAULT_OFFSET_US		1000
-
-/* Work queue timers long, short and SVC strobe timeout */
-#define GB_TIMESYNC_DELAYED_WORK_LONG		msecs_to_jiffies(10)
-#define GB_TIMESYNC_DELAYED_WORK_SHORT		msecs_to_jiffies(1)
-#define GB_TIMESYNC_MAX_WAIT_SVC		msecs_to_jiffies(5000)
-#define GB_TIMESYNC_KTIME_UPDATE		msecs_to_jiffies(1000)
-#define GB_TIMESYNC_MAX_KTIME_CONVERSION	15
-
-/* Maximum number of times we'll retry a failed synchronous sync */
-#define GB_TIMESYNC_MAX_RETRIES			5
-
-/* Reported nanoseconds/femtoseconds per clock */
-static u64 gb_timesync_ns_per_clock;
-static u64 gb_timesync_fs_per_clock;
-
-/* Maximum difference we will accept converting FrameTime to ktime */
-static u32 gb_timesync_max_ktime_diff;
-
-/* Reported clock rate */
-static unsigned long gb_timesync_clock_rate;
-
-/* Workqueue */
-static void gb_timesync_worker(struct work_struct *work);
-
-/* List of SVCs with one FrameTime per SVC */
-static LIST_HEAD(gb_timesync_svc_list);
-
-/* Synchronize parallel contexts accessing a valid timesync_svc pointer */
-static DEFINE_MUTEX(gb_timesync_svc_list_mutex);
-
-/* Structure to convert from FrameTime to timespec/ktime */
-struct gb_timesync_frame_time_data {
-	u64 frame_time;
-	struct timespec ts;
-};
-
-struct gb_timesync_svc {
-	struct list_head list;
-	struct list_head interface_list;
-	struct gb_svc *svc;
-	struct gb_timesync_host_device *timesync_hd;
-
-	spinlock_t spinlock;	/* Per SVC spinlock to sync with ISR */
-	struct mutex mutex;	/* Per SVC mutex for regular synchronization */
-
-	struct dentry *frame_time_dentry;
-	struct dentry *frame_ktime_dentry;
-	struct workqueue_struct *work_queue;
-	wait_queue_head_t wait_queue;
-	struct delayed_work delayed_work;
-	struct timer_list ktime_timer;
-
-	/* The current local FrameTime */
-	u64 frame_time_offset;
-	struct gb_timesync_frame_time_data strobe_data[GB_TIMESYNC_MAX_STROBES];
-	struct gb_timesync_frame_time_data ktime_data;
-
-	/* The SVC FrameTime and relative AP FrameTime @ last TIMESYNC_PING */
-	u64 svc_ping_frame_time;
-	u64 ap_ping_frame_time;
-
-	/* Transitory settings */
-	u32 strobe_mask;
-	bool offset_down;
-	bool print_ping;
-	bool capture_ping;
-	int strobe;
-
-	/* Current state */
-	int state;
-};
-
-struct gb_timesync_host_device {
-	struct list_head list;
-	struct gb_host_device *hd;
-	u64 ping_frame_time;
-};
-
-struct gb_timesync_interface {
-	struct list_head list;
-	struct gb_interface *interface;
-	u64 ping_frame_time;
-};
-
-enum gb_timesync_state {
-	GB_TIMESYNC_STATE_INVALID		= 0,
-	GB_TIMESYNC_STATE_INACTIVE		= 1,
-	GB_TIMESYNC_STATE_INIT			= 2,
-	GB_TIMESYNC_STATE_WAIT_SVC		= 3,
-	GB_TIMESYNC_STATE_AUTHORITATIVE		= 4,
-	GB_TIMESYNC_STATE_PING			= 5,
-	GB_TIMESYNC_STATE_ACTIVE		= 6,
-};
-
-static void gb_timesync_ktime_timer_fn(unsigned long data);
-
-static u64 gb_timesync_adjust_count(struct gb_timesync_svc *timesync_svc,
-				    u64 counts)
-{
-	if (timesync_svc->offset_down)
-		return counts - timesync_svc->frame_time_offset;
-	else
-		return counts + timesync_svc->frame_time_offset;
-}
-
-/*
- * This function provides the authoritative FrameTime to a calling function. It
- * is designed to be lockless and should remain that way the caller is assumed
- * to be state-aware.
- */
-static u64 __gb_timesync_get_frame_time(struct gb_timesync_svc *timesync_svc)
-{
-	u64 clocks = gb_timesync_platform_get_counter();
-
-	return gb_timesync_adjust_count(timesync_svc, clocks);
-}
-
-static void gb_timesync_schedule_svc_timeout(struct gb_timesync_svc
-					     *timesync_svc)
-{
-	queue_delayed_work(timesync_svc->work_queue,
-			   &timesync_svc->delayed_work,
-			   GB_TIMESYNC_MAX_WAIT_SVC);
-}
-
-static void gb_timesync_set_state(struct gb_timesync_svc *timesync_svc,
-				  int state)
-{
-	switch (state) {
-	case GB_TIMESYNC_STATE_INVALID:
-		timesync_svc->state = state;
-		wake_up(&timesync_svc->wait_queue);
-		break;
-	case GB_TIMESYNC_STATE_INACTIVE:
-		timesync_svc->state = state;
-		wake_up(&timesync_svc->wait_queue);
-		break;
-	case GB_TIMESYNC_STATE_INIT:
-		if (timesync_svc->state != GB_TIMESYNC_STATE_INVALID) {
-			timesync_svc->strobe = 0;
-			timesync_svc->frame_time_offset = 0;
-			timesync_svc->state = state;
-			cancel_delayed_work(&timesync_svc->delayed_work);
-			queue_delayed_work(timesync_svc->work_queue,
-					   &timesync_svc->delayed_work,
-					   GB_TIMESYNC_DELAYED_WORK_LONG);
-		}
-		break;
-	case GB_TIMESYNC_STATE_WAIT_SVC:
-		if (timesync_svc->state == GB_TIMESYNC_STATE_INIT)
-			timesync_svc->state = state;
-		break;
-	case GB_TIMESYNC_STATE_AUTHORITATIVE:
-		if (timesync_svc->state == GB_TIMESYNC_STATE_WAIT_SVC) {
-			timesync_svc->state = state;
-			cancel_delayed_work(&timesync_svc->delayed_work);
-			queue_delayed_work(timesync_svc->work_queue,
-					   &timesync_svc->delayed_work, 0);
-		}
-		break;
-	case GB_TIMESYNC_STATE_PING:
-		if (timesync_svc->state == GB_TIMESYNC_STATE_ACTIVE) {
-			timesync_svc->state = state;
-			queue_delayed_work(timesync_svc->work_queue,
-					   &timesync_svc->delayed_work,
-					   GB_TIMESYNC_DELAYED_WORK_SHORT);
-		}
-		break;
-	case GB_TIMESYNC_STATE_ACTIVE:
-		if (timesync_svc->state == GB_TIMESYNC_STATE_AUTHORITATIVE ||
-		    timesync_svc->state == GB_TIMESYNC_STATE_PING) {
-			timesync_svc->state = state;
-			wake_up(&timesync_svc->wait_queue);
-		}
-		break;
-	}
-
-	if (WARN_ON(timesync_svc->state != state)) {
-		pr_err("Invalid state transition %d=>%d\n",
-		       timesync_svc->state, state);
-	}
-}
-
-static void gb_timesync_set_state_atomic(struct gb_timesync_svc *timesync_svc,
-					 int state)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&timesync_svc->spinlock, flags);
-	gb_timesync_set_state(timesync_svc, state);
-	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
-}
-
-static u64 gb_timesync_diff(u64 x, u64 y)
-{
-	if (x > y)
-		return x - y;
-	else
-		return y - x;
-}
-
-static void gb_timesync_adjust_to_svc(struct gb_timesync_svc *svc,
-				      u64 svc_frame_time, u64 ap_frame_time)
-{
-	if (svc_frame_time > ap_frame_time) {
-		svc->frame_time_offset = svc_frame_time - ap_frame_time;
-		svc->offset_down = false;
-	} else {
-		svc->frame_time_offset = ap_frame_time - svc_frame_time;
-		svc->offset_down = true;
-	}
-}
-
-/*
- * Associate a FrameTime with a ktime timestamp represented as struct timespec
- * Requires the calling context to hold timesync_svc->mutex
- */
-static void gb_timesync_store_ktime(struct gb_timesync_svc *timesync_svc,
-				    struct timespec ts, u64 frame_time)
-{
-	timesync_svc->ktime_data.ts = ts;
-	timesync_svc->ktime_data.frame_time = frame_time;
-}
-
-/*
- * Find the two pulses that best-match our expected inter-strobe gap and
- * then calculate the difference between the SVC time at the second pulse
- * to the local time at the second pulse.
- */
-static void gb_timesync_collate_frame_time(struct gb_timesync_svc *timesync_svc,
-					   u64 *frame_time)
-{
-	int i = 0;
-	u64 delta, ap_frame_time;
-	u64 strobe_delay_ns = GB_TIMESYNC_STROBE_DELAY_US * NSEC_PER_USEC;
-	u64 least = 0;
-
-	for (i = 1; i < GB_TIMESYNC_MAX_STROBES; i++) {
-		delta = timesync_svc->strobe_data[i].frame_time -
-			timesync_svc->strobe_data[i - 1].frame_time;
-		delta *= gb_timesync_ns_per_clock;
-		delta = gb_timesync_diff(delta, strobe_delay_ns);
-
-		if (!least || delta < least) {
-			least = delta;
-			gb_timesync_adjust_to_svc(timesync_svc, frame_time[i],
-						  timesync_svc->strobe_data[i].frame_time);
-
-			ap_frame_time = timesync_svc->strobe_data[i].frame_time;
-			ap_frame_time = gb_timesync_adjust_count(timesync_svc,
-								 ap_frame_time);
-			gb_timesync_store_ktime(timesync_svc,
-						timesync_svc->strobe_data[i].ts,
-						ap_frame_time);
-
-			pr_debug("adjust %s local %llu svc %llu delta %llu\n",
-				 timesync_svc->offset_down ? "down" : "up",
-				 timesync_svc->strobe_data[i].frame_time,
-				 frame_time[i], delta);
-		}
-	}
-}
-
-static void gb_timesync_teardown(struct gb_timesync_svc *timesync_svc)
-{
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_svc *svc = timesync_svc->svc;
-	struct gb_interface *interface;
-	struct gb_host_device *hd;
-	int ret;
-
-	list_for_each_entry(timesync_interface,
-			    &timesync_svc->interface_list, list) {
-		interface = timesync_interface->interface;
-		ret = gb_interface_timesync_disable(interface);
-		if (ret) {
-			dev_err(&interface->dev,
-				"interface timesync_disable %d\n", ret);
-		}
-	}
-
-	hd = timesync_svc->timesync_hd->hd;
-	ret = hd->driver->timesync_disable(hd);
-	if (ret < 0) {
-		dev_err(&hd->dev, "host timesync_disable %d\n",
-			ret);
-	}
-
-	gb_svc_timesync_wake_pins_release(svc);
-	gb_svc_timesync_disable(svc);
-	gb_timesync_platform_unlock_bus();
-
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_INACTIVE);
-}
-
-static void gb_timesync_platform_lock_bus_fail(struct gb_timesync_svc
-						*timesync_svc, int ret)
-{
-	if (ret == -EAGAIN) {
-		gb_timesync_set_state(timesync_svc, timesync_svc->state);
-	} else {
-		pr_err("Failed to lock timesync bus %d\n", ret);
-		gb_timesync_set_state(timesync_svc, GB_TIMESYNC_STATE_INACTIVE);
-	}
-}
-
-static void gb_timesync_enable(struct gb_timesync_svc *timesync_svc)
-{
-	struct gb_svc *svc = timesync_svc->svc;
-	struct gb_host_device *hd;
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_interface *interface;
-	u64 init_frame_time;
-	unsigned long clock_rate = gb_timesync_clock_rate;
-	int ret;
-
-	/*
-	 * Get access to the wake pins in the AP and SVC
-	 * Release these pins either in gb_timesync_teardown() or in
-	 * gb_timesync_authoritative()
-	 */
-	ret = gb_timesync_platform_lock_bus(timesync_svc);
-	if (ret < 0) {
-		gb_timesync_platform_lock_bus_fail(timesync_svc, ret);
-		return;
-	}
-	ret = gb_svc_timesync_wake_pins_acquire(svc, timesync_svc->strobe_mask);
-	if (ret) {
-		dev_err(&svc->dev,
-			"gb_svc_timesync_wake_pins_acquire %d\n", ret);
-		gb_timesync_teardown(timesync_svc);
-		return;
-	}
-
-	/* Choose an initial time in the future */
-	init_frame_time = __gb_timesync_get_frame_time(timesync_svc) + 100000UL;
-
-	/* Send enable command to all relevant participants */
-	list_for_each_entry(timesync_interface, &timesync_svc->interface_list,
-			    list) {
-		interface = timesync_interface->interface;
-		ret = gb_interface_timesync_enable(interface,
-						   GB_TIMESYNC_MAX_STROBES,
-						   init_frame_time,
-						   GB_TIMESYNC_STROBE_DELAY_US,
-						   clock_rate);
-		if (ret) {
-			dev_err(&interface->dev,
-				"interface timesync_enable %d\n", ret);
-		}
-	}
-
-	hd = timesync_svc->timesync_hd->hd;
-	ret = hd->driver->timesync_enable(hd, GB_TIMESYNC_MAX_STROBES,
-					  init_frame_time,
-					  GB_TIMESYNC_STROBE_DELAY_US,
-					  clock_rate);
-	if (ret < 0) {
-		dev_err(&hd->dev, "host timesync_enable %d\n",
-			ret);
-	}
-
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_WAIT_SVC);
-	ret = gb_svc_timesync_enable(svc, GB_TIMESYNC_MAX_STROBES,
-				     init_frame_time,
-				     GB_TIMESYNC_STROBE_DELAY_US,
-				     clock_rate);
-	if (ret) {
-		dev_err(&svc->dev,
-			"gb_svc_timesync_enable %d\n", ret);
-		gb_timesync_teardown(timesync_svc);
-		return;
-	}
-
-	/* Schedule a timeout waiting for SVC to complete strobing */
-	gb_timesync_schedule_svc_timeout(timesync_svc);
-}
-
-static void gb_timesync_authoritative(struct gb_timesync_svc *timesync_svc)
-{
-	struct gb_svc *svc = timesync_svc->svc;
-	struct gb_host_device *hd;
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_interface *interface;
-	u64 svc_frame_time[GB_TIMESYNC_MAX_STROBES];
-	int ret;
-
-	/* Get authoritative time from SVC and adjust local clock */
-	ret = gb_svc_timesync_authoritative(svc, svc_frame_time);
-	if (ret) {
-		dev_err(&svc->dev,
-			"gb_svc_timesync_authoritative %d\n", ret);
-		gb_timesync_teardown(timesync_svc);
-		return;
-	}
-	gb_timesync_collate_frame_time(timesync_svc, svc_frame_time);
-
-	/* Transmit authoritative time to downstream slaves */
-	hd = timesync_svc->timesync_hd->hd;
-	ret = hd->driver->timesync_authoritative(hd, svc_frame_time);
-	if (ret < 0)
-		dev_err(&hd->dev, "host timesync_authoritative %d\n", ret);
-
-	list_for_each_entry(timesync_interface,
-			    &timesync_svc->interface_list, list) {
-		interface = timesync_interface->interface;
-		ret = gb_interface_timesync_authoritative(
-						interface,
-						svc_frame_time);
-		if (ret) {
-			dev_err(&interface->dev,
-				"interface timesync_authoritative %d\n", ret);
-		}
-	}
-
-	/* Release wake pins */
-	gb_svc_timesync_wake_pins_release(svc);
-	gb_timesync_platform_unlock_bus();
-
-	/* Transition to state ACTIVE */
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_ACTIVE);
-
-	/* Schedule a ping to verify the synchronized system time */
-	timesync_svc->print_ping = true;
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_PING);
-}
-
-static int __gb_timesync_get_status(struct gb_timesync_svc *timesync_svc)
-{
-	int ret = -EINVAL;
-
-	switch (timesync_svc->state) {
-	case GB_TIMESYNC_STATE_INVALID:
-	case GB_TIMESYNC_STATE_INACTIVE:
-		ret = -ENODEV;
-		break;
-	case GB_TIMESYNC_STATE_INIT:
-	case GB_TIMESYNC_STATE_WAIT_SVC:
-	case GB_TIMESYNC_STATE_AUTHORITATIVE:
-		ret = -EAGAIN;
-		break;
-	case GB_TIMESYNC_STATE_PING:
-	case GB_TIMESYNC_STATE_ACTIVE:
-		ret = 0;
-		break;
-	}
-	return ret;
-}
-
-/*
- * This routine takes a FrameTime and derives the difference with-respect
- * to a reference FrameTime/ktime pair. It then returns the calculated
- * ktime based on the difference between the supplied FrameTime and
- * the reference FrameTime.
- *
- * The time difference is calculated to six decimal places. Taking 19.2MHz
- * as an example this means we have 52.083333~ nanoseconds per clock or
- * 52083333~ femtoseconds per clock.
- *
- * Naively taking the count difference and converting to
- * seconds/nanoseconds would quickly see the 0.0833 component produce
- * noticeable errors. For example a time difference of one second would
- * loose 19200000 * 0.08333x nanoseconds or 1.59 seconds.
- *
- * In contrast calculating in femtoseconds the same example of 19200000 *
- * 0.000000083333x nanoseconds per count of error is just 1.59 nanoseconds!
- *
- * Continuing the example of 19.2 MHz we cap the maximum error difference
- * at a worst-case 0.3 microseconds over a potential calculation window of
- * abount 15 seconds, meaning you can convert a FrameTime that is <= 15
- * seconds older/younger than the reference time with a maximum error of
- * 0.2385 useconds. Note 19.2MHz is an example frequency not a requirement.
- */
-static int gb_timesync_to_timespec(struct gb_timesync_svc *timesync_svc,
-				   u64 frame_time, struct timespec *ts)
-{
-	unsigned long flags;
-	u64 delta_fs, counts, sec, nsec;
-	bool add;
-	int ret = 0;
-
-	memset(ts, 0x00, sizeof(*ts));
-	mutex_lock(&timesync_svc->mutex);
-	spin_lock_irqsave(&timesync_svc->spinlock, flags);
-
-	ret = __gb_timesync_get_status(timesync_svc);
-	if (ret)
-		goto done;
-
-	/* Support calculating ktime upwards or downwards from the reference */
-	if (frame_time < timesync_svc->ktime_data.frame_time) {
-		add = false;
-		counts = timesync_svc->ktime_data.frame_time - frame_time;
-	} else {
-		add = true;
-		counts = frame_time - timesync_svc->ktime_data.frame_time;
-	}
-
-	/* Enforce the .23 of a usecond boundary @ 19.2MHz */
-	if (counts > gb_timesync_max_ktime_diff) {
-		ret = -EINVAL;
-		goto done;
-	}
-
-	/* Determine the time difference in femtoseconds */
-	delta_fs = counts * gb_timesync_fs_per_clock;
-
-	/* Convert to seconds */
-	sec = delta_fs;
-	do_div(sec, NSEC_PER_SEC);
-	do_div(sec, 1000000UL);
-
-	/* Get the nanosecond remainder */
-	nsec = do_div(delta_fs, sec);
-	do_div(nsec, 1000000UL);
-
-	if (add) {
-		/* Add the calculated offset - overflow nanoseconds upwards */
-		ts->tv_sec = timesync_svc->ktime_data.ts.tv_sec + sec;
-		ts->tv_nsec = timesync_svc->ktime_data.ts.tv_nsec + nsec;
-		if (ts->tv_nsec >= NSEC_PER_SEC) {
-			ts->tv_sec++;
-			ts->tv_nsec -= NSEC_PER_SEC;
-		}
-	} else {
-		/* Subtract the difference over/underflow as necessary */
-		if (nsec > timesync_svc->ktime_data.ts.tv_nsec) {
-			sec++;
-			nsec = nsec + timesync_svc->ktime_data.ts.tv_nsec;
-			nsec = do_div(nsec, NSEC_PER_SEC);
-		} else {
-			nsec = timesync_svc->ktime_data.ts.tv_nsec - nsec;
-		}
-		/* Cannot return a negative second value */
-		if (sec > timesync_svc->ktime_data.ts.tv_sec) {
-			ret = -EINVAL;
-			goto done;
-		}
-		ts->tv_sec = timesync_svc->ktime_data.ts.tv_sec - sec;
-		ts->tv_nsec = nsec;
-	}
-done:
-	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
-	mutex_unlock(&timesync_svc->mutex);
-	return ret;
-}
-
-static size_t gb_timesync_log_frame_time(struct gb_timesync_svc *timesync_svc,
-					 char *buf, size_t buflen)
-{
-	struct gb_svc *svc = timesync_svc->svc;
-	struct gb_host_device *hd;
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_interface *interface;
-	unsigned int len;
-	size_t off;
-
-	/* AP/SVC */
-	off = snprintf(buf, buflen, "%s frametime: ap=%llu %s=%llu ",
-		       greybus_bus_type.name,
-		       timesync_svc->ap_ping_frame_time, dev_name(&svc->dev),
-		       timesync_svc->svc_ping_frame_time);
-	len = buflen - off;
-
-	/* APB/GPB */
-	if (len < buflen) {
-		hd = timesync_svc->timesync_hd->hd;
-		off += snprintf(&buf[off], len, "%s=%llu ", dev_name(&hd->dev),
-				timesync_svc->timesync_hd->ping_frame_time);
-		len = buflen - off;
-	}
-
-	list_for_each_entry(timesync_interface,
-			    &timesync_svc->interface_list, list) {
-		if (len < buflen) {
-			interface = timesync_interface->interface;
-			off += snprintf(&buf[off], len, "%s=%llu ",
-					dev_name(&interface->dev),
-					timesync_interface->ping_frame_time);
-			len = buflen - off;
-		}
-	}
-	if (len < buflen)
-		off += snprintf(&buf[off], len, "\n");
-	return off;
-}
-
-static size_t gb_timesync_log_frame_ktime(struct gb_timesync_svc *timesync_svc,
-					  char *buf, size_t buflen)
-{
-	struct gb_svc *svc = timesync_svc->svc;
-	struct gb_host_device *hd;
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_interface *interface;
-	struct timespec ts;
-	unsigned int len;
-	size_t off;
-
-	/* AP */
-	gb_timesync_to_timespec(timesync_svc, timesync_svc->ap_ping_frame_time,
-				&ts);
-	off = snprintf(buf, buflen, "%s frametime: ap=%lu.%lu ",
-		       greybus_bus_type.name, ts.tv_sec, ts.tv_nsec);
-	len = buflen - off;
-	if (len >= buflen)
-		goto done;
-
-	/* SVC */
-	gb_timesync_to_timespec(timesync_svc, timesync_svc->svc_ping_frame_time,
-				&ts);
-	off += snprintf(&buf[off], len, "%s=%lu.%lu ", dev_name(&svc->dev),
-			ts.tv_sec, ts.tv_nsec);
-	len = buflen - off;
-	if (len >= buflen)
-		goto done;
-
-	/* APB/GPB */
-	hd = timesync_svc->timesync_hd->hd;
-	gb_timesync_to_timespec(timesync_svc,
-				timesync_svc->timesync_hd->ping_frame_time,
-				&ts);
-	off += snprintf(&buf[off], len, "%s=%lu.%lu ",
-			dev_name(&hd->dev),
-			ts.tv_sec, ts.tv_nsec);
-	len = buflen - off;
-	if (len >= buflen)
-		goto done;
-
-	list_for_each_entry(timesync_interface,
-			    &timesync_svc->interface_list, list) {
-		interface = timesync_interface->interface;
-		gb_timesync_to_timespec(timesync_svc,
-					timesync_interface->ping_frame_time,
-					&ts);
-		off += snprintf(&buf[off], len, "%s=%lu.%lu ",
-				dev_name(&interface->dev),
-				ts.tv_sec, ts.tv_nsec);
-		len = buflen - off;
-		if (len >= buflen)
-			goto done;
-	}
-	off += snprintf(&buf[off], len, "\n");
-done:
-	return off;
-}
-
-/*
- * Send an SVC initiated wake 'ping' to each TimeSync participant.
- * Get the FrameTime from each participant associated with the wake
- * ping.
- */
-static void gb_timesync_ping(struct gb_timesync_svc *timesync_svc)
-{
-	struct gb_svc *svc = timesync_svc->svc;
-	struct gb_host_device *hd;
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_control *control;
-	u64 *ping_frame_time;
-	int ret;
-
-	/* Get access to the wake pins in the AP and SVC */
-	ret = gb_timesync_platform_lock_bus(timesync_svc);
-	if (ret < 0) {
-		gb_timesync_platform_lock_bus_fail(timesync_svc, ret);
-		return;
-	}
-	ret = gb_svc_timesync_wake_pins_acquire(svc, timesync_svc->strobe_mask);
-	if (ret) {
-		dev_err(&svc->dev,
-			"gb_svc_timesync_wake_pins_acquire %d\n", ret);
-		gb_timesync_teardown(timesync_svc);
-		return;
-	}
-
-	/* Have SVC generate a timesync ping */
-	timesync_svc->capture_ping = true;
-	timesync_svc->svc_ping_frame_time = 0;
-	ret = gb_svc_timesync_ping(svc, &timesync_svc->svc_ping_frame_time);
-	timesync_svc->capture_ping = false;
-	if (ret) {
-		dev_err(&svc->dev,
-			"gb_svc_timesync_ping %d\n", ret);
-		gb_timesync_teardown(timesync_svc);
-		return;
-	}
-
-	/* Get the ping FrameTime from each APB/GPB */
-	hd = timesync_svc->timesync_hd->hd;
-	timesync_svc->timesync_hd->ping_frame_time = 0;
-	ret = hd->driver->timesync_get_last_event(hd,
-		&timesync_svc->timesync_hd->ping_frame_time);
-	if (ret)
-		dev_err(&hd->dev, "host timesync_get_last_event %d\n", ret);
-
-	list_for_each_entry(timesync_interface,
-			    &timesync_svc->interface_list, list) {
-		control = timesync_interface->interface->control;
-		timesync_interface->ping_frame_time = 0;
-		ping_frame_time = &timesync_interface->ping_frame_time;
-		ret = gb_control_timesync_get_last_event(control,
-							 ping_frame_time);
-		if (ret) {
-			dev_err(&timesync_interface->interface->dev,
-				"gb_control_timesync_get_last_event %d\n", ret);
-		}
-	}
-
-	/* Ping success - move to timesync active */
-	gb_svc_timesync_wake_pins_release(svc);
-	gb_timesync_platform_unlock_bus();
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_ACTIVE);
-}
-
-static void gb_timesync_log_ping_time(struct gb_timesync_svc *timesync_svc)
-{
-	char *buf;
-
-	if (!timesync_svc->print_ping)
-		return;
-
-	buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
-	if (buf) {
-		gb_timesync_log_frame_time(timesync_svc, buf, PAGE_SIZE);
-		dev_dbg(&timesync_svc->svc->dev, "%s", buf);
-		kfree(buf);
-	}
-}
-
-/*
- * Perform the actual work of scheduled TimeSync logic.
- */
-static void gb_timesync_worker(struct work_struct *work)
-{
-	struct delayed_work *delayed_work = to_delayed_work(work);
-	struct gb_timesync_svc *timesync_svc =
-		container_of(delayed_work, struct gb_timesync_svc, delayed_work);
-
-	mutex_lock(&timesync_svc->mutex);
-
-	switch (timesync_svc->state) {
-	case GB_TIMESYNC_STATE_INIT:
-		gb_timesync_enable(timesync_svc);
-		break;
-
-	case GB_TIMESYNC_STATE_WAIT_SVC:
-		dev_err(&timesync_svc->svc->dev,
-			"timeout SVC strobe completion %d/%d\n",
-			timesync_svc->strobe, GB_TIMESYNC_MAX_STROBES);
-		gb_timesync_teardown(timesync_svc);
-		break;
-
-	case GB_TIMESYNC_STATE_AUTHORITATIVE:
-		gb_timesync_authoritative(timesync_svc);
-		break;
-
-	case GB_TIMESYNC_STATE_PING:
-		gb_timesync_ping(timesync_svc);
-		gb_timesync_log_ping_time(timesync_svc);
-		break;
-
-	default:
-		pr_err("Invalid state %d for delayed work\n",
-		       timesync_svc->state);
-		break;
-	}
-
-	mutex_unlock(&timesync_svc->mutex);
-}
-
-/*
- * Schedule a new TimeSync INIT or PING operation serialized w/r to
- * gb_timesync_worker().
- */
-static int gb_timesync_schedule(struct gb_timesync_svc *timesync_svc, int state)
-{
-	int ret = 0;
-
-	if (state != GB_TIMESYNC_STATE_INIT && state != GB_TIMESYNC_STATE_PING)
-		return -EINVAL;
-
-	mutex_lock(&timesync_svc->mutex);
-	if (timesync_svc->state !=  GB_TIMESYNC_STATE_INVALID)
-		gb_timesync_set_state_atomic(timesync_svc, state);
-	else
-		ret = -ENODEV;
-
-	mutex_unlock(&timesync_svc->mutex);
-	return ret;
-}
-
-static int __gb_timesync_schedule_synchronous(
-	struct gb_timesync_svc *timesync_svc, int state)
-{
-	unsigned long flags;
-	int ret;
-
-	ret = gb_timesync_schedule(timesync_svc, state);
-	if (ret)
-		return ret;
-
-	ret = wait_event_interruptible(timesync_svc->wait_queue,
-			(timesync_svc->state == GB_TIMESYNC_STATE_ACTIVE ||
-			 timesync_svc->state == GB_TIMESYNC_STATE_INACTIVE ||
-			 timesync_svc->state == GB_TIMESYNC_STATE_INVALID));
-	if (ret)
-		return ret;
-
-	mutex_lock(&timesync_svc->mutex);
-	spin_lock_irqsave(&timesync_svc->spinlock, flags);
-
-	ret = __gb_timesync_get_status(timesync_svc);
-
-	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
-	mutex_unlock(&timesync_svc->mutex);
-
-	return ret;
-}
-
-static struct gb_timesync_svc *gb_timesync_find_timesync_svc(
-	struct gb_host_device *hd)
-{
-	struct gb_timesync_svc *timesync_svc;
-
-	list_for_each_entry(timesync_svc, &gb_timesync_svc_list, list) {
-		if (timesync_svc->svc == hd->svc)
-			return timesync_svc;
-	}
-	return NULL;
-}
-
-static struct gb_timesync_interface *gb_timesync_find_timesync_interface(
-	struct gb_timesync_svc *timesync_svc,
-	struct gb_interface *interface)
-{
-	struct gb_timesync_interface *timesync_interface;
-
-	list_for_each_entry(timesync_interface, &timesync_svc->interface_list, list) {
-		if (timesync_interface->interface == interface)
-			return timesync_interface;
-	}
-	return NULL;
-}
-
-int gb_timesync_schedule_synchronous(struct gb_interface *interface)
-{
-	int ret;
-	struct gb_timesync_svc *timesync_svc;
-	int retries;
-
-	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
-		return 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	for (retries = 0; retries < GB_TIMESYNC_MAX_RETRIES; retries++) {
-		timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
-		if (!timesync_svc) {
-			ret = -ENODEV;
-			goto done;
-		}
-
-		ret = __gb_timesync_schedule_synchronous(timesync_svc,
-						 GB_TIMESYNC_STATE_INIT);
-		if (!ret)
-			break;
-	}
-	if (ret && retries == GB_TIMESYNC_MAX_RETRIES)
-		ret = -ETIMEDOUT;
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_schedule_synchronous);
-
-void gb_timesync_schedule_asynchronous(struct gb_interface *interface)
-{
-	struct gb_timesync_svc *timesync_svc;
-
-	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
-		return;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
-	if (!timesync_svc)
-		goto done;
-
-	gb_timesync_schedule(timesync_svc, GB_TIMESYNC_STATE_INIT);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_schedule_asynchronous);
-
-static ssize_t gb_timesync_ping_read(struct file *file, char __user *ubuf,
-				     size_t len, loff_t *offset, bool ktime)
-{
-	struct gb_timesync_svc *timesync_svc = file_inode(file)->i_private;
-	char *buf;
-	ssize_t ret = 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	mutex_lock(&timesync_svc->mutex);
-	if (list_empty(&timesync_svc->interface_list))
-		ret = -ENODEV;
-	timesync_svc->print_ping = false;
-	mutex_unlock(&timesync_svc->mutex);
-	if (ret)
-		goto done;
-
-	ret = __gb_timesync_schedule_synchronous(timesync_svc,
-						 GB_TIMESYNC_STATE_PING);
-	if (ret)
-		goto done;
-
-	buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!buf) {
-		ret = -ENOMEM;
-		goto done;
-	}
-
-	if (ktime)
-		ret = gb_timesync_log_frame_ktime(timesync_svc, buf, PAGE_SIZE);
-	else
-		ret = gb_timesync_log_frame_time(timesync_svc, buf, PAGE_SIZE);
-	if (ret > 0)
-		ret = simple_read_from_buffer(ubuf, len, offset, buf, ret);
-	kfree(buf);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-
-static ssize_t gb_timesync_ping_read_frame_time(struct file *file,
-						char __user *buf,
-						size_t len, loff_t *offset)
-{
-	return gb_timesync_ping_read(file, buf, len, offset, false);
-}
-
-static ssize_t gb_timesync_ping_read_frame_ktime(struct file *file,
-						 char __user *buf,
-						 size_t len, loff_t *offset)
-{
-	return gb_timesync_ping_read(file, buf, len, offset, true);
-}
-
-static const struct file_operations gb_timesync_debugfs_frame_time_ops = {
-	.read		= gb_timesync_ping_read_frame_time,
-};
-
-static const struct file_operations gb_timesync_debugfs_frame_ktime_ops = {
-	.read		= gb_timesync_ping_read_frame_ktime,
-};
-
-static int gb_timesync_hd_add(struct gb_timesync_svc *timesync_svc,
-			      struct gb_host_device *hd)
-{
-	struct gb_timesync_host_device *timesync_hd;
-
-	timesync_hd = kzalloc(sizeof(*timesync_hd), GFP_KERNEL);
-	if (!timesync_hd)
-		return -ENOMEM;
-
-	WARN_ON(timesync_svc->timesync_hd);
-	timesync_hd->hd = hd;
-	timesync_svc->timesync_hd = timesync_hd;
-
-	return 0;
-}
-
-static void gb_timesync_hd_remove(struct gb_timesync_svc *timesync_svc,
-				  struct gb_host_device *hd)
-{
-	if (timesync_svc->timesync_hd->hd == hd) {
-		kfree(timesync_svc->timesync_hd);
-		timesync_svc->timesync_hd = NULL;
-		return;
-	}
-	WARN_ON(1);
-}
-
-int gb_timesync_svc_add(struct gb_svc *svc)
-{
-	struct gb_timesync_svc *timesync_svc;
-	int ret;
-
-	timesync_svc = kzalloc(sizeof(*timesync_svc), GFP_KERNEL);
-	if (!timesync_svc)
-		return -ENOMEM;
-
-	timesync_svc->work_queue =
-		create_singlethread_workqueue("gb-timesync-work_queue");
-
-	if (!timesync_svc->work_queue) {
-		kfree(timesync_svc);
-		return -ENOMEM;
-	}
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	INIT_LIST_HEAD(&timesync_svc->interface_list);
-	INIT_DELAYED_WORK(&timesync_svc->delayed_work, gb_timesync_worker);
-	mutex_init(&timesync_svc->mutex);
-	spin_lock_init(&timesync_svc->spinlock);
-	init_waitqueue_head(&timesync_svc->wait_queue);
-
-	timesync_svc->svc = svc;
-	timesync_svc->frame_time_offset = 0;
-	timesync_svc->capture_ping = false;
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_INACTIVE);
-
-	timesync_svc->frame_time_dentry =
-		debugfs_create_file("frame-time", S_IRUGO, svc->debugfs_dentry,
-				    timesync_svc,
-				    &gb_timesync_debugfs_frame_time_ops);
-	timesync_svc->frame_ktime_dentry =
-		debugfs_create_file("frame-ktime", S_IRUGO, svc->debugfs_dentry,
-				    timesync_svc,
-				    &gb_timesync_debugfs_frame_ktime_ops);
-
-	list_add(&timesync_svc->list, &gb_timesync_svc_list);
-	ret = gb_timesync_hd_add(timesync_svc, svc->hd);
-	if (ret) {
-		list_del(&timesync_svc->list);
-		debugfs_remove(timesync_svc->frame_ktime_dentry);
-		debugfs_remove(timesync_svc->frame_time_dentry);
-		destroy_workqueue(timesync_svc->work_queue);
-		kfree(timesync_svc);
-		goto done;
-	}
-
-	init_timer(&timesync_svc->ktime_timer);
-	timesync_svc->ktime_timer.function = gb_timesync_ktime_timer_fn;
-	timesync_svc->ktime_timer.expires = jiffies + GB_TIMESYNC_KTIME_UPDATE;
-	timesync_svc->ktime_timer.data = (unsigned long)timesync_svc;
-	add_timer(&timesync_svc->ktime_timer);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_svc_add);
-
-void gb_timesync_svc_remove(struct gb_svc *svc)
-{
-	struct gb_timesync_svc *timesync_svc;
-	struct gb_timesync_interface *timesync_interface;
-	struct gb_timesync_interface *next;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(svc->hd);
-	if (!timesync_svc)
-		goto done;
-
-	cancel_delayed_work_sync(&timesync_svc->delayed_work);
-
-	mutex_lock(&timesync_svc->mutex);
-
-	gb_timesync_set_state_atomic(timesync_svc, GB_TIMESYNC_STATE_INVALID);
-	del_timer_sync(&timesync_svc->ktime_timer);
-	gb_timesync_teardown(timesync_svc);
-
-	gb_timesync_hd_remove(timesync_svc, svc->hd);
-	list_for_each_entry_safe(timesync_interface, next,
-				 &timesync_svc->interface_list, list) {
-		list_del(&timesync_interface->list);
-		kfree(timesync_interface);
-	}
-	debugfs_remove(timesync_svc->frame_ktime_dentry);
-	debugfs_remove(timesync_svc->frame_time_dentry);
-	destroy_workqueue(timesync_svc->work_queue);
-	list_del(&timesync_svc->list);
-
-	mutex_unlock(&timesync_svc->mutex);
-
-	kfree(timesync_svc);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-}
-EXPORT_SYMBOL_GPL(gb_timesync_svc_remove);
-
-/*
- * Add a Greybus Interface to the set of TimeSync Interfaces.
- */
-int gb_timesync_interface_add(struct gb_interface *interface)
-{
-	struct gb_timesync_svc *timesync_svc;
-	struct gb_timesync_interface *timesync_interface;
-	int ret = 0;
-
-	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
-		return 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
-	if (!timesync_svc) {
-		ret = -ENODEV;
-		goto done;
-	}
-
-	timesync_interface = kzalloc(sizeof(*timesync_interface), GFP_KERNEL);
-	if (!timesync_interface) {
-		ret = -ENOMEM;
-		goto done;
-	}
-
-	mutex_lock(&timesync_svc->mutex);
-	timesync_interface->interface = interface;
-	list_add(&timesync_interface->list, &timesync_svc->interface_list);
-	timesync_svc->strobe_mask |= 1 << interface->interface_id;
-	mutex_unlock(&timesync_svc->mutex);
-
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_interface_add);
-
-/*
- * Remove a Greybus Interface from the set of TimeSync Interfaces.
- */
-void gb_timesync_interface_remove(struct gb_interface *interface)
-{
-	struct gb_timesync_svc *timesync_svc;
-	struct gb_timesync_interface *timesync_interface;
-
-	if (!(interface->features & GREYBUS_INTERFACE_FEATURE_TIMESYNC))
-		return;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
-	if (!timesync_svc)
-		goto done;
-
-	timesync_interface = gb_timesync_find_timesync_interface(timesync_svc,
-								 interface);
-	if (!timesync_interface)
-		goto done;
-
-	mutex_lock(&timesync_svc->mutex);
-	timesync_svc->strobe_mask &= ~(1 << interface->interface_id);
-	list_del(&timesync_interface->list);
-	kfree(timesync_interface);
-	mutex_unlock(&timesync_svc->mutex);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-}
-EXPORT_SYMBOL_GPL(gb_timesync_interface_remove);
-
-/*
- * Give the authoritative FrameTime to the calling function. Returns zero if we
- * are not in GB_TIMESYNC_STATE_ACTIVE.
- */
-static u64 gb_timesync_get_frame_time(struct gb_timesync_svc *timesync_svc)
-{
-	unsigned long flags;
-	u64 ret;
-
-	spin_lock_irqsave(&timesync_svc->spinlock, flags);
-	if (timesync_svc->state == GB_TIMESYNC_STATE_ACTIVE)
-		ret = __gb_timesync_get_frame_time(timesync_svc);
-	else
-		ret = 0;
-	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
-	return ret;
-}
-
-u64 gb_timesync_get_frame_time_by_interface(struct gb_interface *interface)
-{
-	struct gb_timesync_svc *timesync_svc;
-	u64 ret = 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
-	if (!timesync_svc)
-		goto done;
-
-	ret = gb_timesync_get_frame_time(timesync_svc);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_get_frame_time_by_interface);
-
-u64 gb_timesync_get_frame_time_by_svc(struct gb_svc *svc)
-{
-	struct gb_timesync_svc *timesync_svc;
-	u64 ret = 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(svc->hd);
-	if (!timesync_svc)
-		goto done;
-
-	ret = gb_timesync_get_frame_time(timesync_svc);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_get_frame_time_by_svc);
-
-/* Incrementally updates the conversion base from FrameTime to ktime */
-static void gb_timesync_ktime_timer_fn(unsigned long data)
-{
-	struct gb_timesync_svc *timesync_svc =
-		(struct gb_timesync_svc *)data;
-	unsigned long flags;
-	u64 frame_time;
-	struct timespec ts;
-
-	spin_lock_irqsave(&timesync_svc->spinlock, flags);
-
-	if (timesync_svc->state != GB_TIMESYNC_STATE_ACTIVE)
-		goto done;
-
-	ktime_get_ts(&ts);
-	frame_time = __gb_timesync_get_frame_time(timesync_svc);
-	gb_timesync_store_ktime(timesync_svc, ts, frame_time);
-
-done:
-	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
-	mod_timer(&timesync_svc->ktime_timer,
-		  jiffies + GB_TIMESYNC_KTIME_UPDATE);
-}
-
-int gb_timesync_to_timespec_by_svc(struct gb_svc *svc, u64 frame_time,
-				   struct timespec *ts)
-{
-	struct gb_timesync_svc *timesync_svc;
-	int ret = 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(svc->hd);
-	if (!timesync_svc) {
-		ret = -ENODEV;
-		goto done;
-	}
-	ret = gb_timesync_to_timespec(timesync_svc, frame_time, ts);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_to_timespec_by_svc);
-
-int gb_timesync_to_timespec_by_interface(struct gb_interface *interface,
-					 u64 frame_time, struct timespec *ts)
-{
-	struct gb_timesync_svc *timesync_svc;
-	int ret = 0;
-
-	mutex_lock(&gb_timesync_svc_list_mutex);
-	timesync_svc = gb_timesync_find_timesync_svc(interface->hd);
-	if (!timesync_svc) {
-		ret = -ENODEV;
-		goto done;
-	}
-
-	ret = gb_timesync_to_timespec(timesync_svc, frame_time, ts);
-done:
-	mutex_unlock(&gb_timesync_svc_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(gb_timesync_to_timespec_by_interface);
-
-void gb_timesync_irq(struct gb_timesync_svc *timesync_svc)
-{
-	unsigned long flags;
-	u64 strobe_time;
-	bool strobe_is_ping = true;
-	struct timespec ts;
-
-	ktime_get_ts(&ts);
-	strobe_time = __gb_timesync_get_frame_time(timesync_svc);
-
-	spin_lock_irqsave(&timesync_svc->spinlock, flags);
-
-	if (timesync_svc->state == GB_TIMESYNC_STATE_PING) {
-		if (!timesync_svc->capture_ping)
-			goto done_nolog;
-		timesync_svc->ap_ping_frame_time = strobe_time;
-		goto done_log;
-	} else if (timesync_svc->state != GB_TIMESYNC_STATE_WAIT_SVC) {
-		goto done_nolog;
-	}
-
-	timesync_svc->strobe_data[timesync_svc->strobe].frame_time = strobe_time;
-	timesync_svc->strobe_data[timesync_svc->strobe].ts = ts;
-
-	if (++timesync_svc->strobe == GB_TIMESYNC_MAX_STROBES) {
-		gb_timesync_set_state(timesync_svc,
-				      GB_TIMESYNC_STATE_AUTHORITATIVE);
-	}
-	strobe_is_ping = false;
-done_log:
-	trace_gb_timesync_irq(strobe_is_ping, timesync_svc->strobe,
-			      GB_TIMESYNC_MAX_STROBES, strobe_time);
-done_nolog:
-	spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
-}
-EXPORT_SYMBOL(gb_timesync_irq);
-
-int __init gb_timesync_init(void)
-{
-	int ret = 0;
-
-	ret = gb_timesync_platform_init();
-	if (ret) {
-		pr_err("timesync platform init fail!\n");
-		return ret;
-	}
-
-	gb_timesync_clock_rate = gb_timesync_platform_get_clock_rate();
-
-	/* Calculate nanoseconds and femtoseconds per clock */
-	gb_timesync_fs_per_clock = FSEC_PER_SEC;
-	do_div(gb_timesync_fs_per_clock, gb_timesync_clock_rate);
-	gb_timesync_ns_per_clock = NSEC_PER_SEC;
-	do_div(gb_timesync_ns_per_clock, gb_timesync_clock_rate);
-
-	/* Calculate the maximum number of clocks we will convert to ktime */
-	gb_timesync_max_ktime_diff =
-		GB_TIMESYNC_MAX_KTIME_CONVERSION * gb_timesync_clock_rate;
-
-	pr_info("Time-Sync @ %lu Hz max ktime conversion +/- %d seconds\n",
-		gb_timesync_clock_rate, GB_TIMESYNC_MAX_KTIME_CONVERSION);
-	return 0;
-}
-
-void gb_timesync_exit(void)
-{
-	gb_timesync_platform_exit();
-}

drivers/staging/greybus/timesync.h

-/*
- * TimeSync API driver.
- *
- * Copyright 2016 Google Inc.
- * Copyright 2016 Linaro Ltd.
- *
- * Released under the GPLv2 only.
- */
-
-#ifndef __TIMESYNC_H
-#define __TIMESYNC_H
-
-struct gb_svc;
-struct gb_interface;
-struct gb_timesync_svc;
-
-/* Platform */
-u64 gb_timesync_platform_get_counter(void);
-u32 gb_timesync_platform_get_clock_rate(void);
-int gb_timesync_platform_lock_bus(struct gb_timesync_svc *pdata);
-void gb_timesync_platform_unlock_bus(void);
-
-int gb_timesync_platform_init(void);
-void gb_timesync_platform_exit(void);
-
-/* Core API */
-int gb_timesync_interface_add(struct gb_interface *interface);
-void gb_timesync_interface_remove(struct gb_interface *interface);
-int gb_timesync_svc_add(struct gb_svc *svc);
-void gb_timesync_svc_remove(struct gb_svc *svc);
-
-u64 gb_timesync_get_frame_time_by_interface(struct gb_interface *interface);
-u64 gb_timesync_get_frame_time_by_svc(struct gb_svc *svc);
-int gb_timesync_to_timespec_by_svc(struct gb_svc *svc, u64 frame_time,
-				   struct timespec *ts);
-int gb_timesync_to_timespec_by_interface(struct gb_interface *interface,
-					 u64 frame_time, struct timespec *ts);
-
-int gb_timesync_schedule_synchronous(struct gb_interface *intf);
-void gb_timesync_schedule_asynchronous(struct gb_interface *intf);
-void gb_timesync_irq(struct gb_timesync_svc *timesync_svc);
-int gb_timesync_init(void);
-void gb_timesync_exit(void);
-
-#endif /* __TIMESYNC_H */

drivers/staging/greybus/timesync_platform.c

-/*
- * TimeSync API driver.
- *
- * Copyright 2016 Google Inc.
- * Copyright 2016 Linaro Ltd.
- *
- * Released under the GPLv2 only.
- *
- * This code reads directly from an ARMv7 memory-mapped timer that lives in
- * MMIO space. Since this counter lives inside of MMIO space its shared between
- * cores and that means we don't have to worry about issues like TSC on x86
- * where each time-stamp-counter (TSC) is local to a particular core.
- *
- * Register-level access code is based on
- * drivers/clocksource/arm_arch_timer.c
- */
-#include <linux/cpufreq.h>
-#include <linux/of_platform.h>
-
-#include "greybus.h"
-#include "arche_platform.h"
-
-#define DEFAULT_FRAMETIME_CLOCK_HZ 19200000
-
-static u32 gb_timesync_clock_frequency;
-int (*arche_platform_change_state_cb)(enum arche_platform_state state,
-				      struct gb_timesync_svc *pdata);
-EXPORT_SYMBOL_GPL(arche_platform_change_state_cb);
-
-u64 gb_timesync_platform_get_counter(void)
-{
-	return (u64)get_cycles();
-}
-
-u32 gb_timesync_platform_get_clock_rate(void)
-{
-	if (unlikely(!gb_timesync_clock_frequency)) {
-		gb_timesync_clock_frequency = cpufreq_get(0);
-		if (!gb_timesync_clock_frequency)
-			gb_timesync_clock_frequency = DEFAULT_FRAMETIME_CLOCK_HZ;
-	}
-
-	return gb_timesync_clock_frequency;
-}
-
-int gb_timesync_platform_lock_bus(struct gb_timesync_svc *pdata)
-{
-	return arche_platform_change_state_cb(ARCHE_PLATFORM_STATE_TIME_SYNC,
-					      pdata);
-}
-
-void gb_timesync_platform_unlock_bus(void)
-{
-	arche_platform_change_state_cb(ARCHE_PLATFORM_STATE_ACTIVE, NULL);
-}
-
-static const struct of_device_id arch_timer_of_match[] = {
-	{ .compatible   = "google,greybus-frame-time-counter", },
-	{},
-};
-
-int __init gb_timesync_platform_init(void)
-{
-	struct device_node *np;
-
-	np = of_find_matching_node(NULL, arch_timer_of_match);
-	if (!np) {
-		/* Tolerate not finding to allow BBB etc to continue */
-		pr_warn("Unable to find a compatible ARMv7 timer\n");
-		return 0;
-	}
-
-	if (of_property_read_u32(np, "clock-frequency",
-				 &gb_timesync_clock_frequency)) {
-		pr_err("Unable to find timer clock-frequency\n");
-		return -ENODEV;
-	}
-
-	return 0;
-}
-
-void gb_timesync_platform_exit(void) {}