text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Tegra host1x Syncpoints
   *
   * Copyright (c) 2010-2015, NVIDIA Corporation.
   */
  
  #include <linux/module.h>
  #include <linux/device.h>
  #include <linux/slab.h>
  
  #include <trace/events/host1x.h>
  
  #include "syncpt.h"
  #include "dev.h"
  #include "intr.h"
  #include "debug.h"
  
  #define SYNCPT_CHECK_PERIOD (2 * HZ)
  #define MAX_STUCK_CHECK_COUNT 15
  
  static struct host1x_syncpt_base *
  host1x_syncpt_base_request(struct host1x *host)
  {
  	struct host1x_syncpt_base *bases = host->bases;
  	unsigned int i;
  
  	for (i = 0; i < host->info->nb_bases; i++)
  		if (!bases[i].requested)
  			break;
  
  	if (i >= host->info->nb_bases)
  		return NULL;
  
  	bases[i].requested = true;
  	return &bases[i];
  }
  
  static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
  {
  	if (base)
  		base->requested = false;
  }
  
  /**
   * host1x_syncpt_alloc() - allocate a syncpoint
   * @host: host1x device data
   * @flags: bitfield of HOST1X_SYNCPT_* flags
   * @name: name for the syncpoint for use in debug prints
   *
   * Allocates a hardware syncpoint for the caller's use. The caller then has
   * the sole authority to mutate the syncpoint's value until it is freed again.
   *
   * If no free syncpoints are available, or a NULL name was specified, returns
   * NULL.
   */
  struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
  					  unsigned long flags,
  					  const char *name)
  {
  	struct host1x_syncpt *sp = host->syncpt;
  	char *full_name;
  	unsigned int i;
  
  	if (!name)
  		return NULL;
  
  	mutex_lock(&host->syncpt_mutex);
  
  	for (i = 0; i < host->info->nb_pts && kref_read(&sp->ref); i++, sp++)
  		;
  
  	if (i >= host->info->nb_pts)
  		goto unlock;
  
  	if (flags & HOST1X_SYNCPT_HAS_BASE) {
  		sp->base = host1x_syncpt_base_request(host);
  		if (!sp->base)
  			goto unlock;
  	}
  
  	full_name = kasprintf(GFP_KERNEL, "%u-%s", sp->id, name);
  	if (!full_name)
  		goto free_base;
  
  	sp->name = full_name;
  
  	if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
  		sp->client_managed = true;
  	else
  		sp->client_managed = false;
  
  	kref_init(&sp->ref);
  
  	mutex_unlock(&host->syncpt_mutex);
  	return sp;
  
  free_base:
  	host1x_syncpt_base_free(sp->base);
  	sp->base = NULL;
  unlock:
  	mutex_unlock(&host->syncpt_mutex);
  	return NULL;
  }
  EXPORT_SYMBOL(host1x_syncpt_alloc);
  
  /**
   * host1x_syncpt_id() - retrieve syncpoint ID
   * @sp: host1x syncpoint
   *
   * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
   * often used as a value to program into registers that control how hardware
   * blocks interact with syncpoints.
   */
  u32 host1x_syncpt_id(struct host1x_syncpt *sp)
  {
  	return sp->id;
  }
  EXPORT_SYMBOL(host1x_syncpt_id);
  
  /**
   * host1x_syncpt_incr_max() - update the value sent to hardware
   * @sp: host1x syncpoint
   * @incrs: number of increments
   */
  u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
  {
  	return (u32)atomic_add_return(incrs, &sp->max_val);
  }
  EXPORT_SYMBOL(host1x_syncpt_incr_max);
  
   /*
   * Write cached syncpoint and waitbase values to hardware.
   */
  void host1x_syncpt_restore(struct host1x *host)
  {
  	struct host1x_syncpt *sp_base = host->syncpt;
  	unsigned int i;
  
  	for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
  		host1x_hw_syncpt_restore(host, sp_base + i);
  
  	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
  		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
  
  	wmb();
  }
  
  /*
   * Update the cached syncpoint and waitbase values by reading them
   * from the registers.
    */
  void host1x_syncpt_save(struct host1x *host)
  {
  	struct host1x_syncpt *sp_base = host->syncpt;
  	unsigned int i;
  
  	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
  		if (host1x_syncpt_client_managed(sp_base + i))
  			host1x_hw_syncpt_load(host, sp_base + i);
  		else
  			WARN_ON(!host1x_syncpt_idle(sp_base + i));
  	}
  
  	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
  		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
  }
  
  /*
   * Updates the cached syncpoint value by reading a new value from the hardware
   * register
   */
  u32 host1x_syncpt_load(struct host1x_syncpt *sp)
  {
  	u32 val;
  
  	val = host1x_hw_syncpt_load(sp->host, sp);
  	trace_host1x_syncpt_load_min(sp->id, val);
  
  	return val;
  }
  
  /*
   * Get the current syncpoint base
   */
  u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
  {
  	host1x_hw_syncpt_load_wait_base(sp->host, sp);
  
  	return sp->base_val;
  }
  
  /**
   * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
   * @sp: host1x syncpoint
   */
  int host1x_syncpt_incr(struct host1x_syncpt *sp)
  {
  	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
  }
  EXPORT_SYMBOL(host1x_syncpt_incr);
  
  /*
   * Updated sync point form hardware, and returns true if syncpoint is expired,
   * false if we may need to wait
   */
  static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
  {
  	host1x_hw_syncpt_load(sp->host, sp);
  
  	return host1x_syncpt_is_expired(sp, thresh);
  }
  
  /**
   * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
   * @sp: host1x syncpoint
   * @thresh: threshold
   * @timeout: maximum time to wait for the syncpoint to reach the given value
   * @value: return location for the syncpoint value
   */
  int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
  		       u32 *value)
  {
  	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
  	void *ref;
  	struct host1x_waitlist *waiter;
  	int err = 0, check_count = 0;
  	u32 val;
  
  	if (value)
  		*value = 0;
  
  	/* first check cache */
  	if (host1x_syncpt_is_expired(sp, thresh)) {
  		if (value)
  			*value = host1x_syncpt_load(sp);
  
  		return 0;
  	}
  
  	/* try to read from register */
  	val = host1x_hw_syncpt_load(sp->host, sp);
  	if (host1x_syncpt_is_expired(sp, thresh)) {
  		if (value)
  			*value = val;
  
  		goto done;
  	}
  
  	if (!timeout) {
  		err = -EAGAIN;
  		goto done;
  	}
  
  	/* allocate a waiter */
  	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
  	if (!waiter) {
  		err = -ENOMEM;
  		goto done;
  	}
  
  	/* schedule a wakeup when the syncpoint value is reached */
  	err = host1x_intr_add_action(sp->host, sp, thresh,
  				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
  				     &wq, waiter, &ref);
  	if (err)
  		goto done;
  
  	err = -EAGAIN;
  	/* Caller-specified timeout may be impractically low */
  	if (timeout < 0)
  		timeout = LONG_MAX;
  
  	/* wait for the syncpoint, or timeout, or signal */
  	while (timeout) {
  		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
  		int remain;
  
  		remain = wait_event_interruptible_timeout(wq,
  				syncpt_load_min_is_expired(sp, thresh),
  				check);
  		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
  			if (value)
  				*value = host1x_syncpt_load(sp);
  
  			err = 0;
  
  			break;
  		}
  
  		if (remain < 0) {
  			err = remain;
  			break;
  		}
  
  		timeout -= check;
  
  		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
  			dev_warn(sp->host->dev,
  				"%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
  				 current->comm, sp->id, sp->name,
  				 thresh, timeout);
  
  			host1x_debug_dump_syncpts(sp->host);
  
  			if (check_count == MAX_STUCK_CHECK_COUNT)
  				host1x_debug_dump(sp->host);
  
  			check_count++;
  		}
  	}
  
  	host1x_intr_put_ref(sp->host, sp->id, ref, true);
  
  done:
  	return err;
  }
  EXPORT_SYMBOL(host1x_syncpt_wait);
  
  /*
   * Returns true if syncpoint is expired, false if we may need to wait
   */
  bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
  {
  	u32 current_val;
  
  	smp_rmb();
  
  	current_val = (u32)atomic_read(&sp->min_val);
  
  	return ((current_val - thresh) & 0x80000000U) == 0U;
  }
  
  int host1x_syncpt_init(struct host1x *host)
  {
  	struct host1x_syncpt_base *bases;
  	struct host1x_syncpt *syncpt;
  	unsigned int i;
  
  	syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
  			      GFP_KERNEL);
  	if (!syncpt)
  		return -ENOMEM;
  
  	bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
  			     GFP_KERNEL);
  	if (!bases)
  		return -ENOMEM;
  
  	for (i = 0; i < host->info->nb_pts; i++) {
  		syncpt[i].id = i;
  		syncpt[i].host = host;
  
  		/*
  		 * Unassign syncpt from channels for purposes of Tegra186
  		 * syncpoint protection. This prevents any channel from
  		 * accessing it until it is reassigned.
  		 */
  		host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
  	}
  
  	for (i = 0; i < host->info->nb_bases; i++)
  		bases[i].id = i;
  
  	mutex_init(&host->syncpt_mutex);
  	host->syncpt = syncpt;
  	host->bases = bases;
  
  	host1x_syncpt_restore(host);
  	host1x_hw_syncpt_enable_protection(host);
  
  	/* Allocate sync point to use for clearing waits for expired fences */
  	host->nop_sp = host1x_syncpt_alloc(host, 0, "reserved-nop");
  	if (!host->nop_sp)
  		return -ENOMEM;
  
  	if (host->info->reserve_vblank_syncpts) {
  		kref_init(&host->syncpt[26].ref);
  		kref_init(&host->syncpt[27].ref);
  	}
  
  	return 0;
  }
  
  /**
   * host1x_syncpt_request() - request a syncpoint
   * @client: client requesting the syncpoint
   * @flags: flags
   *
   * host1x client drivers can use this function to allocate a syncpoint for
   * subsequent use. A syncpoint returned by this function will be reserved for
   * use by the client exclusively. When no longer using a syncpoint, a host1x
   * client driver needs to release it using host1x_syncpt_put().
   */
  struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
  					    unsigned long flags)
  {
  	struct host1x *host = dev_get_drvdata(client->host->parent);
  
  	return host1x_syncpt_alloc(host, flags, dev_name(client->dev));
  }
  EXPORT_SYMBOL(host1x_syncpt_request);
  
  static void syncpt_release(struct kref *ref)
  {
  	struct host1x_syncpt *sp = container_of(ref, struct host1x_syncpt, ref);
  
  	atomic_set(&sp->max_val, host1x_syncpt_read(sp));
  
  	sp->locked = false;
  
  	mutex_lock(&sp->host->syncpt_mutex);
  
  	host1x_syncpt_base_free(sp->base);
  	kfree(sp->name);
  	sp->base = NULL;
  	sp->name = NULL;
  	sp->client_managed = false;
  
  	mutex_unlock(&sp->host->syncpt_mutex);
  }
  
  /**
   * host1x_syncpt_put() - free a requested syncpoint
   * @sp: host1x syncpoint
   *
   * Release a syncpoint previously allocated using host1x_syncpt_request(). A
   * host1x client driver should call this when the syncpoint is no longer in
   * use.
   */
  void host1x_syncpt_put(struct host1x_syncpt *sp)
  {
  	if (!sp)
  		return;
  
  	kref_put(&sp->ref, syncpt_release);
  }
  EXPORT_SYMBOL(host1x_syncpt_put);
  
  void host1x_syncpt_deinit(struct host1x *host)
  {
  	struct host1x_syncpt *sp = host->syncpt;
  	unsigned int i;
  
  	for (i = 0; i < host->info->nb_pts; i++, sp++)
  		kfree(sp->name);
  }
  
  /**
   * host1x_syncpt_read_max() - read maximum syncpoint value
   * @sp: host1x syncpoint
   *
   * The maximum syncpoint value indicates how many operations there are in
   * queue, either in channel or in a software thread.
   */
  u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
  {
  	smp_rmb();
  
  	return (u32)atomic_read(&sp->max_val);
  }
  EXPORT_SYMBOL(host1x_syncpt_read_max);
  
  /**
   * host1x_syncpt_read_min() - read minimum syncpoint value
   * @sp: host1x syncpoint
   *
   * The minimum syncpoint value is a shadow of the current sync point value in
   * hardware.
   */
  u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
  {
  	smp_rmb();
  
  	return (u32)atomic_read(&sp->min_val);
  }
  EXPORT_SYMBOL(host1x_syncpt_read_min);
  
  /**
   * host1x_syncpt_read() - read the current syncpoint value
   * @sp: host1x syncpoint
   */
  u32 host1x_syncpt_read(struct host1x_syncpt *sp)
  {
  	return host1x_syncpt_load(sp);
  }
  EXPORT_SYMBOL(host1x_syncpt_read);
  
  unsigned int host1x_syncpt_nb_pts(struct host1x *host)
  {
  	return host->info->nb_pts;
  }
  
  unsigned int host1x_syncpt_nb_bases(struct host1x *host)
  {
  	return host->info->nb_bases;
  }
  
  unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
  {
  	return host->info->nb_mlocks;
  }
  
  /**
   * host1x_syncpt_get_by_id() - obtain a syncpoint by ID
   * @host: host1x controller
   * @id: syncpoint ID
   */
  struct host1x_syncpt *host1x_syncpt_get_by_id(struct host1x *host,
  					      unsigned int id)
  {
  	if (id >= host->info->nb_pts)
  		return NULL;
  
  	if (kref_get_unless_zero(&host->syncpt[id].ref))
  		return &host->syncpt[id];
  	else
  		return NULL;
  }
  EXPORT_SYMBOL(host1x_syncpt_get_by_id);
  
  /**
   * host1x_syncpt_get_by_id_noref() - obtain a syncpoint by ID but don't
   * 	increase the refcount.
   * @host: host1x controller
   * @id: syncpoint ID
   */
  struct host1x_syncpt *host1x_syncpt_get_by_id_noref(struct host1x *host,
  						    unsigned int id)
  {
  	if (id >= host->info->nb_pts)
  		return NULL;
  
  	return &host->syncpt[id];
  }
  EXPORT_SYMBOL(host1x_syncpt_get_by_id_noref);
  
  /**
   * host1x_syncpt_get() - increment syncpoint refcount
   * @sp: syncpoint
   */
  struct host1x_syncpt *host1x_syncpt_get(struct host1x_syncpt *sp)
  {
  	kref_get(&sp->ref);
  
  	return sp;
  }
  EXPORT_SYMBOL(host1x_syncpt_get);
  
  /**
   * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
   * @sp: host1x syncpoint
   */
  struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
  {
  	return sp ? sp->base : NULL;
  }
  EXPORT_SYMBOL(host1x_syncpt_get_base);
  
  /**
   * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
   * @base: host1x syncpoint wait base
   */
  u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
  {
  	return base->id;
  }
  EXPORT_SYMBOL(host1x_syncpt_base_id);
  
  static void do_nothing(struct kref *ref)
  {
  }
  
  /**
   * host1x_syncpt_release_vblank_reservation() - Make VBLANK syncpoint
   *   available for allocation
   *
   * @client: host1x bus client
   * @syncpt_id: syncpoint ID to make available
   *
   * Makes VBLANK<i> syncpoint available for allocatation if it was
   * reserved at initialization time. This should be called by the display
   * driver after it has ensured that any VBLANK increment programming configured
   * by the boot chain has been disabled.
   */
  void host1x_syncpt_release_vblank_reservation(struct host1x_client *client,
  					      u32 syncpt_id)
  {
  	struct host1x *host = dev_get_drvdata(client->host->parent);
  
  	if (!host->info->reserve_vblank_syncpts)
  		return;
  
  	kref_put(&host->syncpt[syncpt_id].ref, do_nothing);
  }
  EXPORT_SYMBOL(host1x_syncpt_release_vblank_reservation);
  