/* -*- mode: c; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* vi: set ts=8 sw=8 sts=8: */
/*************************************************************************/ /*!
@File
@Title          PowerVR Linux fence interface
@Codingstyle    LinuxKernel
@Copyright      Copyright (c) Imagination Technologies Ltd. All Rights Reserved
@License        MIT

The contents of this file are subject to the MIT license as set out below.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

This License is also included in this distribution in the file called
"MIT-COPYING".

EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) THE SOFTWARE IS
PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT; AND (B) IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/ /**************************************************************************/

#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "pvr_fence.h"
#include "services_kernel_client.h"
#include "sync_checkpoint_external.h"

#define CREATE_TRACE_POINTS
#include "pvr_fence_trace.h"

/* This header must always be included last */
#include "kernel_compatibility.h"

#define	PVR_FENCE_CONTEXT_DESTROY_INITAL_WAIT_MS	100
#define	PVR_FENCE_CONTEXT_DESTROY_RETRIES		5

#define PVR_DUMPDEBUG_LOG(pfnDumpDebugPrintf, pvDumpDebugFile, fmt, ...) \
	do {                                                             \
		if (pfnDumpDebugPrintf)                                  \
			pfnDumpDebugPrintf(pvDumpDebugFile, fmt,         \
					   ## __VA_ARGS__);              \
		else                                                     \
			pr_err(fmt "\n", ## __VA_ARGS__);                \
	} while (0)

static inline void
pvr_fence_sync_signal(struct pvr_fence *pvr_fence, u32 fence_sync_flags)
{
	SyncCheckpointSignal(pvr_fence->sync_checkpoint, fence_sync_flags);
}

static inline bool
pvr_fence_sync_is_signaled(struct pvr_fence *pvr_fence, u32 fence_sync_flags)
{
	return SyncCheckpointIsSignalled(pvr_fence->sync_checkpoint, fence_sync_flags);
}

static inline u32
pvr_fence_sync_value(struct pvr_fence *pvr_fence)
{
	if (SyncCheckpointIsErrored(pvr_fence->sync_checkpoint, PVRSRV_FENCE_FLAG_SUPPRESS_HWP_PKT))
		return PVRSRV_SYNC_CHECKPOINT_ERRORED;
	else if (SyncCheckpointIsSignalled(pvr_fence->sync_checkpoint, PVRSRV_FENCE_FLAG_SUPPRESS_HWP_PKT))
		return PVRSRV_SYNC_CHECKPOINT_SIGNALLED;
	else
		return PVRSRV_SYNC_CHECKPOINT_NOT_SIGNALLED;
}

static void
pvr_fence_context_check_status(struct work_struct *data)
{
	PVRSRVCheckStatus(NULL);
}

void
pvr_context_value_str(struct pvr_fence_context *fctx, char *str, int size)
{
	snprintf(str, size,
		 "%u ctx=%llu refs=%u",
		 atomic_read(&fctx->fence_seqno),
		 fctx->fence_context,
		 refcount_read(&fctx->kref.refcount));
}

static void
pvr_fence_context_fences_dump(struct pvr_fence_context *fctx,
			      DUMPDEBUG_PRINTF_FUNC *pfnDumpDebugPrintf,
			      void *pvDumpDebugFile)
{
	struct pvr_fence *pvr_fence;
	unsigned long flags;
	char value[128];

	spin_lock_irqsave(&fctx->list_lock, flags);
	pvr_context_value_str(fctx, value, sizeof(value));
	PVR_DUMPDEBUG_LOG(pfnDumpDebugPrintf, pvDumpDebugFile,
			 "%s: @%s", fctx->name, value);
	list_for_each_entry(pvr_fence, &fctx->fence_list, fence_head) {
		pvr_fence->base.ops->fence_value_str(&pvr_fence->base, value,
						     sizeof(value));
		PVR_DUMPDEBUG_LOG(pfnDumpDebugPrintf, pvDumpDebugFile,
				  " @%s", value);

		if (!is_pvr_fence(pvr_fence->fence)) {
			struct dma_fence *fence = pvr_fence->fence;
			const char *timeline_value_str = "unknown timeline value";
			const char *fence_value_str = "unknown fence value";

			if (fence->ops->timeline_value_str) {
				fence->ops->timeline_value_str(fence, value,
							       sizeof(value));
				timeline_value_str = value;
			}

			PVR_DUMPDEBUG_LOG(pfnDumpDebugPrintf, pvDumpDebugFile,
					  " | %s: %s (driver: %s)",
					  fence->ops->get_timeline_name(fence),
					  timeline_value_str,
					  fence->ops->get_driver_name(fence));

			if (fence->ops->fence_value_str) {
				fence->ops->fence_value_str(fence, value,
							    sizeof(value));
				fence_value_str = value;
			}

			PVR_DUMPDEBUG_LOG(pfnDumpDebugPrintf, pvDumpDebugFile,
					  " |  @%s (foreign)", value);
		}
	}
	spin_unlock_irqrestore(&fctx->list_lock, flags);
}

static inline unsigned int
pvr_fence_context_seqno_next(struct pvr_fence_context *fctx)
{
	return atomic_inc_return(&fctx->fence_seqno) - 1;
}

static inline void
pvr_fence_context_free_deferred(struct pvr_fence_context *fctx)
{
	struct pvr_fence *pvr_fence, *tmp;
	LIST_HEAD(deferred_free_list);
	unsigned long flags;

	spin_lock_irqsave(&fctx->list_lock, flags);
	list_for_each_entry_safe(pvr_fence, tmp,
				 &fctx->deferred_free_list,
				 fence_head)
		list_move(&pvr_fence->fence_head, &deferred_free_list);
	spin_unlock_irqrestore(&fctx->list_lock, flags);

	list_for_each_entry_safe(pvr_fence, tmp,
				 &deferred_free_list,
				 fence_head) {
		list_del(&pvr_fence->fence_head);
		SyncCheckpointFree(pvr_fence->sync_checkpoint);
		dma_fence_free(&pvr_fence->base);
	}
}

static void
pvr_fence_context_signal_fences(void *data)
{
	struct pvr_fence_context *fctx = (struct pvr_fence_context *)data;
	struct pvr_fence *pvr_fence, *tmp;
	unsigned long flags;
	LIST_HEAD(signal_list);

	/*
	 * We can't call fence_signal while holding the lock as we can end up
	 * in a situation whereby pvr_fence_foreign_signal_sync, which also
	 * takes the list lock, ends up being called as a result of the
	 * fence_signal below, i.e. fence_signal(fence) -> fence->callback()
	 *  -> fence_signal(foreign_fence) -> foreign_fence->callback() where
	 * the foreign_fence callback is pvr_fence_foreign_signal_sync.
	 *
	 * So extract the items we intend to signal and add them to their own
	 * queue.
	 */
	spin_lock_irqsave(&fctx->list_lock, flags);
	list_for_each_entry_safe(pvr_fence, tmp, &fctx->signal_list,
				 signal_head) {
		if (pvr_fence_sync_is_signaled(pvr_fence, PVRSRV_FENCE_FLAG_SUPPRESS_HWP_PKT))
			list_move(&pvr_fence->signal_head, &signal_list);
	}
	spin_unlock_irqrestore(&fctx->list_lock, flags);

	list_for_each_entry_safe(pvr_fence, tmp, &signal_list, signal_head) {

		PVR_FENCE_TRACE(&pvr_fence->base, "signalled fence (%s)\n",
				pvr_fence->name);
		trace_pvr_fence_signal_fence(pvr_fence);
		list_del(&pvr_fence->signal_head);
		dma_fence_signal(pvr_fence->fence);
		dma_fence_put(pvr_fence->fence);
	}

	/*
	 * Take this opportunity to free up any fence objects we
	 * have deferred freeing.
	 */
	pvr_fence_context_free_deferred(fctx);
}

void
pvr_fence_context_signal_fences_nohw(void *data)
{
	pvr_fence_context_signal_fences(data);
}

static void
pvr_fence_context_destroy_work(struct work_struct *data)
{
	struct delayed_work *dwork =
		container_of(data, struct delayed_work, work);
	struct pvr_fence_context *fctx =
		container_of(dwork, struct pvr_fence_context, destroy_work);
	PVRSRV_ERROR srv_err;

	PVR_FENCE_CTX_TRACE(fctx, "destroyed fence context (%s)\n", fctx->name);

	pvr_fence_context_free_deferred(fctx);

	srv_err = SyncCheckpointContextDestroy(fctx->sync_checkpoint_context);
	if (srv_err != PVRSRV_OK) {
		if (fctx->destroy_retries_left) {
			unsigned long destroy_delay_jiffies =
				msecs_to_jiffies(fctx->destroy_delay_ms);

			pr_debug("%s: SyncCheckpointContextDestroy of %p failed, retrying in %ums\n",
				 __func__, fctx->sync_checkpoint_context,
				 fctx->destroy_delay_ms);

			fctx->destroy_retries_left--;
			fctx->destroy_delay_ms *= 2;

			schedule_delayed_work(&fctx->destroy_work,
						destroy_delay_jiffies);
			return;
		} else {
			if (fctx->global_complete)
				pr_err("%s: SyncCheckpointContextDestroy of %p failed, Sync Checkpoint context leaked\n",
					__func__, fctx->sync_checkpoint_context);
			else
				pr_err("%s: SyncCheckpointContextDestroy of %p failed, module unloadable\n",
					__func__, fctx->sync_checkpoint_context);
		}
	} else {
		unsigned int retries =
			PVR_FENCE_CONTEXT_DESTROY_RETRIES -
			fctx->destroy_retries_left;

		if (retries)
			pr_debug("%s: SyncCheckpointContextDestroy of %p successful, after %u %s\n",
				 __func__,
				 fctx->sync_checkpoint_context,
				retries,
				(retries == 1) ? "retry" : "retries");

		if (!fctx->global_complete)
			module_put(THIS_MODULE);
	}

	if (WARN_ON(!list_empty_careful(&fctx->fence_list)))
		pvr_fence_context_fences_dump(fctx, NULL, NULL);

	PVRSRVUnregisterDbgRequestNotify(fctx->dbg_request_handle);
	PVRSRVUnregisterCmdCompleteNotify(fctx->cmd_complete_handle);

	if (fctx->global_complete)
		complete(fctx->global_complete);
	else
		kfree(fctx);
}

static void
pvr_fence_context_debug_request(void *data, u32 verbosity,
				DUMPDEBUG_PRINTF_FUNC *pfnDumpDebugPrintf,
				void *pvDumpDebugFile)
{
	struct pvr_fence_context *fctx = (struct pvr_fence_context *)data;

	if (verbosity == DEBUG_REQUEST_VERBOSITY_MEDIUM)
		pvr_fence_context_fences_dump(fctx, pfnDumpDebugPrintf,
					      pvDumpDebugFile);
}

static struct pvr_fence_context *
pvr_fence_context_create_common(void *dev_cookie,
				struct workqueue_struct *fence_status_wq,
				const char *name)
{
	struct pvr_fence_context *fctx;
	PVRSRV_ERROR srv_err;

	fctx = kzalloc(sizeof(*fctx), GFP_KERNEL);
	if (!fctx)
		return NULL;

	spin_lock_init(&fctx->lock);
	atomic_set(&fctx->fence_seqno, 0);
	INIT_WORK(&fctx->check_status_work, pvr_fence_context_check_status);
	INIT_DELAYED_WORK(&fctx->destroy_work, pvr_fence_context_destroy_work);
	spin_lock_init(&fctx->list_lock);
	INIT_LIST_HEAD(&fctx->signal_list);
	INIT_LIST_HEAD(&fctx->fence_list);
	INIT_LIST_HEAD(&fctx->deferred_free_list);

	fctx->destroy_retries_left = PVR_FENCE_CONTEXT_DESTROY_RETRIES;
	fctx->destroy_delay_ms = PVR_FENCE_CONTEXT_DESTROY_INITAL_WAIT_MS;

	fctx->fence_wq = fence_status_wq;

	fctx->fence_context = dma_fence_context_alloc(1);
	strlcpy(fctx->name, name, sizeof(fctx->name));

	srv_err = SyncCheckpointContextCreate(dev_cookie,
				&fctx->sync_checkpoint_context);
	if (srv_err != PVRSRV_OK) {
		pr_err("%s: failed to create sync checkpoint context (%s)\n",
		       __func__, PVRSRVGetErrorStringKM(srv_err));
		goto err_free_fctx;
	}

	srv_err = PVRSRVRegisterCmdCompleteNotify(&fctx->cmd_complete_handle,
				pvr_fence_context_signal_fences,
				fctx);
	if (srv_err != PVRSRV_OK) {
		pr_err("%s: failed to register command complete callback (%s)\n",
		       __func__, PVRSRVGetErrorStringKM(srv_err));
		goto err_sync_prim_context_destroy;
	}

	srv_err = PVRSRVRegisterDbgRequestNotify(&fctx->dbg_request_handle,
				dev_cookie,
				pvr_fence_context_debug_request,
				DEBUG_REQUEST_LINUXFENCE,
				fctx);
	if (srv_err != PVRSRV_OK) {
		pr_err("%s: failed to register debug request callback (%s)\n",
		       __func__, PVRSRVGetErrorStringKM(srv_err));
		goto err_unregister_cmd_complete_notify;
	}

	kref_init(&fctx->kref);

	PVR_FENCE_CTX_TRACE(fctx, "created fence context (%s)\n", name);
	trace_pvr_fence_context_create(fctx);

	return fctx;

err_unregister_cmd_complete_notify:
	PVRSRVUnregisterCmdCompleteNotify(fctx->cmd_complete_handle);
err_sync_prim_context_destroy:
	SyncCheckpointContextDestroy(fctx->sync_checkpoint_context);
err_free_fctx:
	kfree(fctx);
	return NULL;
}

/**
 * pvr_fence_context_create - creates a PVR fence context
 * @dev_cookie: services device cookie
 * @name: context name (used for debugging)
 *
 * Creates a PVR fence context that can be used to create PVR fences or to
 * create PVR fences from an existing fence.
 *
 * pvr_fence_context_destroy should be called to clean up the fence context.
 *
 * Returns NULL if a context cannot be created.
 */
struct pvr_fence_context *
pvr_fence_context_create(void *dev_cookie,
			 struct workqueue_struct *fence_status_wq,
			 const char *name)
{
	struct pvr_fence_context *fctx;

	if (!try_module_get(THIS_MODULE)) {
		pr_err("%s: failed to get module reference\n", __func__);
		return NULL;
	}

	fctx = pvr_fence_context_create_common(dev_cookie, fence_status_wq,
					       name);
	if (!fctx)
		module_put(THIS_MODULE);

	return fctx;
}

/**
 * pvr_global_fence_context_create - creates a global PVR fence context
 * @dev_cookie: services device cookie
 * @name: context name (used for debugging)
 *
 * Creates a PVR fence context that can be used to create PVR fences or to
 * create PVR fences from an existing fence. Unlike pvr_fence_context_create,
 * this doesn't take a module reference, so can be used to create fence
 * contexts at module load time, without preventing module unload.
 *
 * pvr_fence_context_destroy should be called to clean up the fence context.
 *
 * Returns NULL if a context cannot be created.
 */
struct pvr_fence_context *
pvr_global_fence_context_create(void *dev_cookie,
				struct workqueue_struct *fence_status_wq,
				const char *name)
{
	struct pvr_fence_context *fctx;
	struct completion *global_complete;

	global_complete = kmalloc(sizeof(*global_complete), GFP_KERNEL);
	if (!global_complete)
		return NULL;

	fctx = pvr_fence_context_create_common(dev_cookie, fence_status_wq,
					       name);

	if (fctx) {
		init_completion(global_complete);
		fctx->global_complete = global_complete;
	} else {
		kfree(global_complete);
	}

	return fctx;
}

static void pvr_fence_context_destroy_kref(struct kref *kref)
{
	struct pvr_fence_context *fctx =
		container_of(kref, struct pvr_fence_context, kref);
	bool is_global_context = (fctx->global_complete != NULL);

	PVR_FENCE_CTX_TRACE(fctx,
			    "scheduling destruction of fence context (%s)\n",
			    fctx->name);
	trace_pvr_fence_context_destroy_kref(fctx);

	schedule_delayed_work(&fctx->destroy_work, 0);

	if (is_global_context) {
		wait_for_completion(fctx->global_complete);
		kfree(fctx->global_complete);
		kfree(fctx);
	}
}

/**
 * pvr_fence_context_destroy - destroys a context
 * @fctx: PVR fence context to destroy
 *
 * Destroys a PVR fence context with the expectation that all fences have been
 * destroyed.
 */
void
pvr_fence_context_destroy(struct pvr_fence_context *fctx)
{
	trace_pvr_fence_context_destroy(fctx);

	kref_put(&fctx->kref, pvr_fence_context_destroy_kref);
}

static const char *
pvr_fence_get_driver_name(struct dma_fence *fence)
{
	return PVR_LDM_DRIVER_REGISTRATION_NAME;
}

static const char *
pvr_fence_get_timeline_name(struct dma_fence *fence)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

	if (pvr_fence)
		return pvr_fence->fctx->name;
	return NULL;
}

static
void pvr_fence_fence_value_str(struct dma_fence *fence, char *str, int size)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

	if (pvr_fence) {
		snprintf(str, size,
			 "%u: (%s%s) refs=%u fwaddr=%#08x enqueue=%u status=%-9s %s%s",
			 pvr_fence->fence->seqno,
			 test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
				  &pvr_fence->fence->flags) ? "+" : "-",
			 test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
				  &pvr_fence->fence->flags) ? "+" : "-",
			 refcount_read(&pvr_fence->fence->refcount.refcount),
			 SyncCheckpointGetFirmwareAddr(
				pvr_fence->sync_checkpoint),
			 SyncCheckpointGetEnqueuedCount(pvr_fence->sync_checkpoint),
			 SyncCheckpointGetStateString(pvr_fence->sync_checkpoint),
			 pvr_fence->name,
			 (&pvr_fence->base != pvr_fence->fence) ?
				 "(foreign)" : "");
	}
}

static
void pvr_fence_timeline_value_str(struct dma_fence *fence, char *str, int size)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

	if (pvr_fence)
		pvr_context_value_str(pvr_fence->fctx, str, size);
}

static bool
pvr_fence_enable_signaling(struct dma_fence *fence)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);
	unsigned long flags;

	if (!pvr_fence)
		return false;

	WARN_ON_SMP(!spin_is_locked(&pvr_fence->fctx->lock));

	if (pvr_fence_sync_is_signaled(pvr_fence, PVRSRV_FENCE_FLAG_SUPPRESS_HWP_PKT))
		return false;

	dma_fence_get(&pvr_fence->base);

	spin_lock_irqsave(&pvr_fence->fctx->list_lock, flags);
	list_add_tail(&pvr_fence->signal_head, &pvr_fence->fctx->signal_list);
	spin_unlock_irqrestore(&pvr_fence->fctx->list_lock, flags);

	PVR_FENCE_TRACE(&pvr_fence->base, "signalling enabled (%s)\n",
			pvr_fence->name);
	trace_pvr_fence_enable_signaling(pvr_fence);

	return true;
}

static bool
pvr_fence_is_signaled(struct dma_fence *fence)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

	if (pvr_fence)
		return pvr_fence_sync_is_signaled(pvr_fence, PVRSRV_FENCE_FLAG_CTX_ATOMIC);
	return false;
}

static void
pvr_fence_release(struct dma_fence *fence)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);
	unsigned long flags;

	if (pvr_fence) {
		struct pvr_fence_context *fctx = pvr_fence->fctx;
		bool is_global_context = (fctx->global_complete != NULL);

		PVR_FENCE_TRACE(&pvr_fence->base, "released fence (%s)\n",
				pvr_fence->name);
		trace_pvr_fence_release(pvr_fence);

		spin_lock_irqsave(&fctx->list_lock, flags);
		list_move(&pvr_fence->fence_head,
			  &fctx->deferred_free_list);
		spin_unlock_irqrestore(&fctx->list_lock, flags);

		kref_put(&fctx->kref, pvr_fence_context_destroy_kref);

		if (is_global_context)
			module_put(THIS_MODULE);
	}
}

const struct dma_fence_ops pvr_fence_ops = {
	.get_driver_name = pvr_fence_get_driver_name,
	.get_timeline_name = pvr_fence_get_timeline_name,
	.fence_value_str = pvr_fence_fence_value_str,
	.timeline_value_str = pvr_fence_timeline_value_str,
	.enable_signaling = pvr_fence_enable_signaling,
	.signaled = pvr_fence_is_signaled,
	.wait = dma_fence_default_wait,
	.release = pvr_fence_release,
};

/**
 * pvr_fence_create - creates a PVR fence
 * @fctx: PVR fence context on which the PVR fence should be created
 * @name: PVR fence name (used for debugging)
 *
 * Creates a PVR fence.
 *
 * Once the fence is finished with, pvr_fence_destroy should be called.
 *
 * Returns NULL if a PVR fence cannot be created.
 */
struct pvr_fence *
pvr_fence_create(struct pvr_fence_context *fctx, int timeline_fd,
		const char *name)
{
	struct pvr_fence *pvr_fence;
	unsigned int seqno;
	unsigned long flags;
	PVRSRV_ERROR srv_err;

	/*
	 * If the fence context is global, take a reference on the module
	 * to ensure the driver can't be unloaded while there are outstanding
	 * fences.
	 */
	if (fctx->global_complete && !try_module_get(THIS_MODULE))
		return NULL;

	pvr_fence = kzalloc(sizeof(*pvr_fence), GFP_KERNEL);
	if (!pvr_fence)
		goto err_put_module;

	srv_err = SyncCheckpointAlloc(fctx->sync_checkpoint_context,
			(PVRSRV_TIMELINE) timeline_fd, name, &pvr_fence->sync_checkpoint);

	if (srv_err != PVRSRV_OK)
		goto err_free_fence;

	INIT_LIST_HEAD(&pvr_fence->fence_head);
	INIT_LIST_HEAD(&pvr_fence->signal_head);
	pvr_fence->fctx = fctx;
	seqno = pvr_fence_context_seqno_next(fctx);
	/* Add the seqno to the fence name for easier debugging */
	snprintf(pvr_fence->name, sizeof(pvr_fence->name), "%d-%s",
		 seqno, name);
	pvr_fence->fence = &pvr_fence->base;

	dma_fence_init(&pvr_fence->base, &pvr_fence_ops, &fctx->lock,
		       fctx->fence_context, seqno);

	spin_lock_irqsave(&fctx->list_lock, flags);
	list_add_tail(&pvr_fence->fence_head, &fctx->fence_list);
	spin_unlock_irqrestore(&fctx->list_lock, flags);

	kref_get(&fctx->kref);

	PVR_FENCE_TRACE(&pvr_fence->base, "created fence (%s)\n", name);
	trace_pvr_fence_create(pvr_fence);

	return pvr_fence;

err_free_fence:
	kfree(pvr_fence);
err_put_module:
	if (fctx->global_complete)
		module_put(THIS_MODULE);
	return NULL;
}

static const char *
pvr_fence_foreign_get_driver_name(struct dma_fence *fence)
{
	return PVR_LDM_DRIVER_REGISTRATION_NAME;
}

static const char *
pvr_fence_foreign_get_timeline_name(struct dma_fence *fence)
{
	return "foreign";
}

static
void pvr_fence_foreign_fence_value_str(struct dma_fence *fence, char *str, int size)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);
	u32 sync_addr = 0;
	u32 sync_value_next;

	if (WARN_ON(!pvr_fence))
		return;

	sync_addr = SyncCheckpointGetFirmwareAddr(pvr_fence->sync_checkpoint);
	sync_value_next = PVRSRV_SYNC_CHECKPOINT_SIGNALLED;

	/*
	 * Include the fence flag bits from the foreign fence instead of our
	 * shadow copy. This is done as the shadow fence flag bits aren't used.
	 */
	snprintf(str, size,
		 "%u: (%s%s) refs=%u fwaddr=%#08x cur=%#08x nxt=%#08x %s",
		 fence->seqno,
		 test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
			  &pvr_fence->fence->flags) ? "+" : "-",
		 test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
			  &pvr_fence->fence->flags) ? "+" : "-",
		 refcount_read(&fence->refcount.refcount),
		 sync_addr,
		 pvr_fence_sync_value(pvr_fence),
		 sync_value_next,
		 pvr_fence->name);
}

static
void pvr_fence_foreign_timeline_value_str(struct dma_fence *fence, char *str, int size)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);

	if (pvr_fence)
		pvr_context_value_str(pvr_fence->fctx, str, size);
}

static bool
pvr_fence_foreign_enable_signaling(struct dma_fence *fence)
{
	WARN_ON("cannot enable signalling on foreign fence");
	return false;
}

static signed long
pvr_fence_foreign_wait(struct dma_fence *fence, bool intr, signed long timeout)
{
	WARN_ON("cannot wait on foreign fence");
	return 0;
}

static void
pvr_fence_foreign_release(struct dma_fence *fence)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);
	unsigned long flags;

	if (pvr_fence) {
		struct pvr_fence_context *fctx = pvr_fence->fctx;
		bool is_global_context = (fctx->global_complete != NULL);
		struct dma_fence *foreign_fence = pvr_fence->fence;

		PVR_FENCE_TRACE(&pvr_fence->base,
				"released fence for foreign fence %llu#%d (%s)\n",
				(u64) pvr_fence->fence->context,
				pvr_fence->fence->seqno, pvr_fence->name);
		trace_pvr_fence_foreign_release(pvr_fence);

		spin_lock_irqsave(&fctx->list_lock, flags);
		list_move(&pvr_fence->fence_head,
			  &fctx->deferred_free_list);
		spin_unlock_irqrestore(&fctx->list_lock, flags);

		dma_fence_put(foreign_fence);

		kref_put(&fctx->kref,
			 pvr_fence_context_destroy_kref);

		if (is_global_context)
			module_put(THIS_MODULE);
	}
}

const struct dma_fence_ops pvr_fence_foreign_ops = {
	.get_driver_name = pvr_fence_foreign_get_driver_name,
	.get_timeline_name = pvr_fence_foreign_get_timeline_name,
	.fence_value_str = pvr_fence_foreign_fence_value_str,
	.timeline_value_str = pvr_fence_foreign_timeline_value_str,
	.enable_signaling = pvr_fence_foreign_enable_signaling,
	.wait = pvr_fence_foreign_wait,
	.release = pvr_fence_foreign_release,
};

static void
pvr_fence_foreign_signal_sync(struct dma_fence *fence, struct dma_fence_cb *cb)
{
	struct pvr_fence *pvr_fence = container_of(cb, struct pvr_fence, cb);
	struct pvr_fence_context *fctx = pvr_fence->fctx;

	WARN_ON_ONCE(is_pvr_fence(fence));

	/* Callback registered by dma_fence_add_callback can be called from an atomic ctx */
	pvr_fence_sync_signal(pvr_fence, PVRSRV_FENCE_FLAG_CTX_ATOMIC);

	trace_pvr_fence_foreign_signal(pvr_fence);

	queue_work(fctx->fence_wq, &fctx->check_status_work);

	PVR_FENCE_TRACE(&pvr_fence->base,
			"foreign fence %llu#%d signalled (%s)\n",
			(u64) pvr_fence->fence->context,
			pvr_fence->fence->seqno, pvr_fence->name);

	/* Drop the reference on the base fence */
	dma_fence_put(&pvr_fence->base);
}

/**
 * pvr_fence_create_from_fence - creates a PVR fence from a fence
 * @fctx: PVR fence context on which the PVR fence should be created
 * @fence: fence from which the PVR fence should be created
 * @name: PVR fence name (used for debugging)
 *
 * Creates a PVR fence from an existing fence. If the fence is a foreign fence,
 * i.e. one that doesn't originate from a PVR fence context, then a new PVR
 * fence will be created. Otherwise, a reference will be taken on the underlying
 * fence and the PVR fence will be returned.
 *
 * Once the fence is finished with, pvr_fence_destroy should be called.
 *
 * Returns NULL if a PVR fence cannot be created.
 */

struct pvr_fence *
pvr_fence_create_from_fence(struct pvr_fence_context *fctx,
			    struct dma_fence *fence,
			    const char *name)
{
	struct pvr_fence *pvr_fence = to_pvr_fence(fence);
	unsigned int seqno;
	unsigned long flags;
	PVRSRV_ERROR srv_err;
	int err;

	if (pvr_fence) {
		if (WARN_ON(fence->ops == &pvr_fence_foreign_ops))
			return NULL;
		dma_fence_get(fence);

		PVR_FENCE_TRACE(fence, "created fence from PVR fence (%s)\n",
				name);
		return pvr_fence;
	}

	/*
	 * If the fence context is global, take a reference on the module
	 * to ensure the driver can't be unloaded while there are outstanding
	 * fences.
	 */
	if (fctx->global_complete && !try_module_get(THIS_MODULE))
		return NULL;

	pvr_fence = kzalloc(sizeof(*pvr_fence), GFP_KERNEL);
	if (!pvr_fence)
		goto err_put_module;

	srv_err = SyncCheckpointAlloc(fctx->sync_checkpoint_context,
					  SYNC_CHECKPOINT_FOREIGN_CHECKPOINT,
				      name, &pvr_fence->sync_checkpoint);
	if (srv_err != PVRSRV_OK)
		goto err_free_pvr_fence;

	INIT_LIST_HEAD(&pvr_fence->fence_head);
	INIT_LIST_HEAD(&pvr_fence->signal_head);
	pvr_fence->fctx = fctx;
	pvr_fence->fence = dma_fence_get(fence);
	seqno = pvr_fence_context_seqno_next(fctx);
	/* Add the seqno to the fence name for easier debugging */
	snprintf(pvr_fence->name, sizeof(pvr_fence->name), "%d-%s",
		 seqno, name);
	/*
	 * We use the base fence to refcount the PVR fence and to do the
	 * necessary clean up once the refcount drops to 0.
	 */
	dma_fence_init(&pvr_fence->base, &pvr_fence_foreign_ops, &fctx->lock,
		       fctx->fence_context, seqno);

	/*
	 * Take an extra reference on the base fence that gets dropped when the
	 * foreign fence is signalled.
	 */
	dma_fence_get(&pvr_fence->base);

	spin_lock_irqsave(&fctx->list_lock, flags);
	list_add_tail(&pvr_fence->fence_head, &fctx->fence_list);
	spin_unlock_irqrestore(&fctx->list_lock, flags);
	kref_get(&fctx->kref);

	PVR_FENCE_TRACE(&pvr_fence->base,
			"created fence from foreign fence %llu#%d (%s)\n",
			(u64) pvr_fence->fence->context,
			pvr_fence->fence->seqno, name);

	err = dma_fence_add_callback(fence, &pvr_fence->cb,
				     pvr_fence_foreign_signal_sync);
	if (err) {
		if (err != -ENOENT)
			goto err_put_ref;

		/*
		 * The fence has already signalled so set the sync as signalled.
		 * The "signalled" hwperf packet should be emitted because the
		 * callback won't be called for already signalled fence hence,
		 * PVRSRV_FENCE_FLAG_NONE flag.
		 */
		pvr_fence_sync_signal(pvr_fence, PVRSRV_FENCE_FLAG_NONE);
		PVR_FENCE_TRACE(&pvr_fence->base,
				"foreign fence %llu#%d already signaled (%s)\n",
				(u64) pvr_fence->fence->context,
				pvr_fence->fence->seqno,
				name);
		dma_fence_put(&pvr_fence->base);
	}

	trace_pvr_fence_foreign_create(pvr_fence);

	return pvr_fence;

err_put_ref:
	kref_put(&fctx->kref, pvr_fence_context_destroy_kref);
	spin_lock_irqsave(&fctx->list_lock, flags);
	list_del(&pvr_fence->fence_head);
	spin_unlock_irqrestore(&fctx->list_lock, flags);
	SyncCheckpointFree(pvr_fence->sync_checkpoint);
err_free_pvr_fence:
	kfree(pvr_fence);
err_put_module:
	if (fctx->global_complete)
		module_put(THIS_MODULE);
	return NULL;
}

/**
 * pvr_fence_destroy - destroys a PVR fence
 * @pvr_fence: PVR fence to destroy
 *
 * Destroys a PVR fence. Upon return, the PVR fence may still exist if something
 * else still references the underlying fence, e.g. a reservation object, or if
 * software signalling has been enabled and the fence hasn't yet been signalled.
 */
void
pvr_fence_destroy(struct pvr_fence *pvr_fence)
{
	PVR_FENCE_TRACE(&pvr_fence->base, "destroyed fence (%s)\n",
			pvr_fence->name);

	dma_fence_put(&pvr_fence->base);
}

/**
 * pvr_fence_sw_signal - signals a PVR fence sync
 * @pvr_fence: PVR fence to signal
 *
 * Sets the PVR fence sync value to signalled.
 *
 * Returns -EINVAL if the PVR fence represents a foreign fence.
 */
int
pvr_fence_sw_signal(struct pvr_fence *pvr_fence)
{
	if (!is_our_fence(pvr_fence->fctx, &pvr_fence->base))
		return -EINVAL;

	pvr_fence_sync_signal(pvr_fence, PVRSRV_FENCE_FLAG_NONE);

	queue_work(pvr_fence->fctx->fence_wq,
		   &pvr_fence->fctx->check_status_work);

	PVR_FENCE_TRACE(&pvr_fence->base, "sw set fence sync signalled (%s)\n",
			pvr_fence->name);

	return 0;
}

/**
 * pvr_fence_sw_error - errors the sync checkpoint backing a PVR fence
 * @pvr_fence: PVR fence to error
 *
 * Sets the PVR fence sync checkpoint value to errored.
 *
 * Returns -EINVAL if the PVR fence represents a foreign fence.
 */
int
pvr_fence_sw_error(struct pvr_fence *pvr_fence)
{
	if (!is_our_fence(pvr_fence->fctx, &pvr_fence->base))
		return -EINVAL;

	SyncCheckpointError(pvr_fence->sync_checkpoint, PVRSRV_FENCE_FLAG_NONE);
	PVR_FENCE_TRACE(&pvr_fence->base, "sw set fence sync errored (%s)\n",
	            pvr_fence->name);

	return 0;
}

int
pvr_fence_get_checkpoints(struct pvr_fence **pvr_fences, u32 nr_fences,
			  struct _SYNC_CHECKPOINT **fence_checkpoints)
{
	struct _SYNC_CHECKPOINT **next_fence_checkpoint = fence_checkpoints;
	struct pvr_fence **next_pvr_fence = pvr_fences;
	int fence_checkpoint_idx;

	if (nr_fences > 0) {

		for (fence_checkpoint_idx = 0; fence_checkpoint_idx < nr_fences;
		     fence_checkpoint_idx++) {
			struct pvr_fence *next_fence = *next_pvr_fence++;
			*next_fence_checkpoint++ = next_fence->sync_checkpoint;
			/* Take reference on sync checkpoint (will be dropped
			 * later by kick code)
			 */
			SyncCheckpointTakeRef(next_fence->sync_checkpoint);
		}
	}

	return 0;
}

struct _SYNC_CHECKPOINT *
pvr_fence_get_checkpoint(struct pvr_fence *update_fence)
{
	return update_fence->sync_checkpoint;
}

/**
 * pvr_fence_dump_info_on_stalled_ufos - displays debug
 * information on a native fence associated with any of
 * the ufos provided. This function will be called from
 * pvr_sync_file.c if the driver determines any GPU work
 * is stuck waiting for a sync checkpoint representing a
 * foreign sync to be signalled.
 * @nr_ufos: number of ufos in vaddrs
 * @vaddrs:  array of FW addresses of UFOs which the
 *           driver is waiting on.
 *
 * Output debug information to kernel log on linux fences
 * which would be responsible for signalling the sync
 * checkpoints indicated by the ufo vaddresses.
 *
 * Returns the number of ufos in the array which were found
 * to be associated with foreign syncs.
 */
u32 pvr_fence_dump_info_on_stalled_ufos(struct pvr_fence_context *fctx,
                                        u32 nr_ufos,
                                        u32 *vaddrs)
{
	int our_ufo_ct = 0;
	struct pvr_fence *pvr_fence;
	unsigned long flags;

	spin_lock_irqsave(&fctx->list_lock, flags);
	/* dump info on any ufos in our active list */
	list_for_each_entry(pvr_fence, &fctx->fence_list, fence_head) {
		u32 *this_ufo_vaddr = vaddrs;
		int ufo_num;
		DUMPDEBUG_PRINTF_FUNC *pfnDummy = NULL;

		for (ufo_num=0; ufo_num < nr_ufos; ufo_num++, this_ufo_vaddr++) {
			u32 fence_ufo_addr = SyncCheckpointGetFirmwareAddr(pvr_fence->sync_checkpoint);

			if (fence_ufo_addr == *this_ufo_vaddr) {
				/* Dump sync info */
				PVR_DUMPDEBUG_LOG(pfnDummy, NULL,
						  "\tSyncID = %d, FWAddr = 0x%08x: TLID = %d (Foreign Fence - [%p] %s)",
						  SyncCheckpointGetId(pvr_fence->sync_checkpoint),
						  SyncCheckpointGetFirmwareAddr(pvr_fence->sync_checkpoint),
						  SyncCheckpointGetTimeline(pvr_fence->sync_checkpoint),
						  pvr_fence->fence,//sync->foreign_sync_fence,
						  pvr_fence->name);//sync->foreign_sync_name);
				our_ufo_ct++;
			}
		}
	}
	spin_unlock_irqrestore(&fctx->list_lock, flags);
	return our_ufo_ct;
}