// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Remote processor messaging transport (OMAP platform-specific bits)
   *
   * Copyright (C) 2011 Texas Instruments, Inc.
   * Copyright (C) 2011 Google, Inc.
   *
   * Ohad Ben-Cohen <ohad@wizery.com>
   * Brian Swetland <swetland@google.com>

   */

  #include <linux/dma-map-ops.h>

  #include <linux/export.h>

  #include <linux/of_reserved_mem.h>

  #include <linux/remoteproc.h>

  #include <linux/virtio.h>
  #include <linux/virtio_config.h>
  #include <linux/virtio_ids.h>
  #include <linux/virtio_ring.h>
  #include <linux/err.h>
  #include <linux/kref.h>
  #include <linux/slab.h>
  
  #include "remoteproc_internal.h"

  /* kick the remote processor, and let it know which virtqueue to poke at */

  static bool rproc_virtio_notify(struct virtqueue *vq)

  {

  	struct rproc_vring *rvring = vq->priv;
  	struct rproc *rproc = rvring->rvdev->rproc;
  	int notifyid = rvring->notifyid;

  	dev_dbg(&rproc->dev, "kicking vq index: %d
  ", notifyid);

  	rproc->ops->kick(rproc, notifyid);

  	return true;

  }
  
  /**
   * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
   * @rproc: handle to the remote processor

   * @notifyid: index of the signalled virtqueue (unique per this @rproc)

   *
   * This function should be called by the platform-specific rproc driver,
   * when the remote processor signals that a specific virtqueue has pending
   * messages available.
   *

   * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,

   * and otherwise returns IRQ_HANDLED.
   */

  irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)

  {

  	struct rproc_vring *rvring;

  	dev_dbg(&rproc->dev, "vq index %d is interrupted
  ", notifyid);

  
  	rvring = idr_find(&rproc->notifyids, notifyid);
  	if (!rvring || !rvring->vq)
  		return IRQ_NONE;
  
  	return vring_interrupt(0, rvring->vq);

  }
  EXPORT_SYMBOL(rproc_vq_interrupt);
  
  static struct virtqueue *rp_find_vq(struct virtio_device *vdev,

  				    unsigned int id,

  				    void (*callback)(struct virtqueue *vq),

  				    const char *name, bool ctx)

  {

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);

  	struct rproc *rproc = vdev_to_rproc(vdev);

  	struct device *dev = &rproc->dev;

  	struct rproc_mem_entry *mem;

  	struct rproc_vring *rvring;

  	struct fw_rsc_vdev *rsc;

  	struct virtqueue *vq;
  	void *addr;

  	int len, size;

  	/* we're temporarily limited to two virtqueues per rvdev */
  	if (id >= ARRAY_SIZE(rvdev->vring))
  		return ERR_PTR(-EINVAL);

  	if (!name)
  		return NULL;

  	/* Search allocated memory region by name */
  	mem = rproc_find_carveout_by_name(rproc, "vdev%dvring%d", rvdev->index,
  					  id);
  	if (!mem || !mem->va)
  		return ERR_PTR(-ENOMEM);

  	rvring = &rvdev->vring[id];

  	addr = mem->va;

  	len = rvring->len;

  	/* zero vring */
  	size = vring_size(len, rvring->align);
  	memset(addr, 0, size);

  	dev_dbg(dev, "vring%d: va %pK qsz %d notifyid %d
  ",

  		id, addr, len, rvring->notifyid);

  	/*
  	 * Create the new vq, and tell virtio we're not interested in
  	 * the 'weak' smp barriers, since we're talking with a real device.
  	 */

  	vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, ctx,
  				 addr, rproc_virtio_notify, callback, name);

  	if (!vq) {

  		dev_err(dev, "vring_new_virtqueue %s failed
  ", name);

  		rproc_free_vring(rvring);

  		return ERR_PTR(-ENOMEM);

  	}

  	rvring->vq = vq;
  	vq->priv = rvring;

  	/* Update vring in resource table */
  	rsc = (void *)rproc->table_ptr + rvdev->rsc_offset;
  	rsc->vring[id].da = mem->da;

  	return vq;

  }

  static void __rproc_virtio_del_vqs(struct virtio_device *vdev)

  {
  	struct virtqueue *vq, *n;

  	struct rproc_vring *rvring;

  
  	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {

  		rvring = vq->priv;
  		rvring->vq = NULL;

  		vring_del_virtqueue(vq);

  	}

  }

  static void rproc_virtio_del_vqs(struct virtio_device *vdev)
  {

  	__rproc_virtio_del_vqs(vdev);
  }

  static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,

  				 struct virtqueue *vqs[],
  				 vq_callback_t *callbacks[],

  				 const char * const names[],

  				 const bool * ctx,

  				 struct irq_affinity *desc)

  {

  	int i, ret, queue_idx = 0;

  	for (i = 0; i < nvqs; ++i) {

  		if (!names[i]) {
  			vqs[i] = NULL;
  			continue;
  		}
  
  		vqs[i] = rp_find_vq(vdev, queue_idx++, callbacks[i], names[i],

  				    ctx ? ctx[i] : false);

  		if (IS_ERR(vqs[i])) {
  			ret = PTR_ERR(vqs[i]);
  			goto error;
  		}
  	}
  
  	return 0;
  
  error:

  	__rproc_virtio_del_vqs(vdev);

  	return ret;
  }

  static u8 rproc_virtio_get_status(struct virtio_device *vdev)
  {

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  	struct fw_rsc_vdev *rsc;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
  
  	return rsc->status;

  }
  
  static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
  {

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  	struct fw_rsc_vdev *rsc;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
  
  	rsc->status = status;

  	dev_dbg(&vdev->dev, "status: %d
  ", status);

  }
  
  static void rproc_virtio_reset(struct virtio_device *vdev)
  {

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  	struct fw_rsc_vdev *rsc;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
  
  	rsc->status = 0;

  	dev_dbg(&vdev->dev, "reset !
  ");
  }
  
  /* provide the vdev features as retrieved from the firmware */

  static u64 rproc_virtio_get_features(struct virtio_device *vdev)

  {

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);

  	struct fw_rsc_vdev *rsc;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;

  	return rsc->dfeatures;

  }

  static void rproc_transport_features(struct virtio_device *vdev)
  {
  	/*
  	 * Packed ring isn't enabled on remoteproc for now,
  	 * because remoteproc uses vring_new_virtqueue() which
  	 * creates virtio rings on preallocated memory.
  	 */
  	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
  }

  static int rproc_virtio_finalize_features(struct virtio_device *vdev)

  {

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);

  	struct fw_rsc_vdev *rsc;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;

  
  	/* Give virtio_ring a chance to accept features */
  	vring_transport_features(vdev);

  	/* Give virtio_rproc a chance to accept features. */
  	rproc_transport_features(vdev);

  	/* Make sure we don't have any features > 32 bits! */
  	BUG_ON((u32)vdev->features != vdev->features);

  	/*
  	 * Remember the finalized features of our vdev, and provide it
  	 * to the remote processor once it is powered on.

  	 */

  	rsc->gfeatures = vdev->features;

  
  	return 0;

  }

  static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
  			     void *buf, unsigned int len)

  {
  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  	struct fw_rsc_vdev *rsc;
  	void *cfg;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
  	cfg = &rsc->vring[rsc->num_of_vrings];
  
  	if (offset + len > rsc->config_len || offset + len < len) {
  		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds
  ");
  		return;
  	}
  
  	memcpy(buf, cfg + offset, len);
  }

  static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
  			     const void *buf, unsigned int len)

  {
  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  	struct fw_rsc_vdev *rsc;
  	void *cfg;
  
  	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
  	cfg = &rsc->vring[rsc->num_of_vrings];
  
  	if (offset + len > rsc->config_len || offset + len < len) {
  		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds
  ");
  		return;
  	}
  
  	memcpy(cfg + offset, buf, len);

  }

  static const struct virtio_config_ops rproc_virtio_config_ops = {

  	.get_features	= rproc_virtio_get_features,
  	.finalize_features = rproc_virtio_finalize_features,
  	.find_vqs	= rproc_virtio_find_vqs,
  	.del_vqs	= rproc_virtio_del_vqs,
  	.reset		= rproc_virtio_reset,
  	.set_status	= rproc_virtio_set_status,
  	.get_status	= rproc_virtio_get_status,

  	.get		= rproc_virtio_get,
  	.set		= rproc_virtio_set,

  };
  
  /*
   * This function is called whenever vdev is released, and is responsible

   * to decrement the remote processor's refcount which was taken when vdev was

   * added.
   *
   * Never call this function directly; it will be called by the driver
   * core when needed.
   */

  static void rproc_virtio_dev_release(struct device *dev)

  {
  	struct virtio_device *vdev = dev_to_virtio(dev);

  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);

  	struct rproc *rproc = vdev_to_rproc(vdev);

  	kfree(vdev);

  	kref_put(&rvdev->refcount, rproc_vdev_release);

  	put_device(&rproc->dev);

  }
  
  /**

   * rproc_add_virtio_dev() - register an rproc-induced virtio device
   * @rvdev: the remote vdev

   * @id: the device type identification (used to match it with a driver).

   *

   * This function registers a virtio device. This vdev's partent is
   * the rproc device.

   *

   * Returns 0 on success or an appropriate error value otherwise.

   */

  int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)

  {

  	struct rproc *rproc = rvdev->rproc;

  	struct device *dev = &rvdev->dev;

  	struct virtio_device *vdev;

  	struct rproc_mem_entry *mem;

  	int ret;

  	if (rproc->ops->kick == NULL) {
  		ret = -EINVAL;

  		dev_err(dev, ".kick method not defined for %s
  ", rproc->name);

  		goto out;
  	}

  	/* Try to find dedicated vdev buffer carveout */
  	mem = rproc_find_carveout_by_name(rproc, "vdev%dbuffer", rvdev->index);
  	if (mem) {
  		phys_addr_t pa;
  
  		if (mem->of_resm_idx != -1) {
  			struct device_node *np = rproc->dev.parent->of_node;
  
  			/* Associate reserved memory to vdev device */
  			ret = of_reserved_mem_device_init_by_idx(dev, np,
  								 mem->of_resm_idx);
  			if (ret) {
  				dev_err(dev, "Can't associate reserved memory
  ");
  				goto out;
  			}
  		} else {
  			if (mem->va) {
  				dev_warn(dev, "vdev %d buffer already mapped
  ",
  					 rvdev->index);
  				pa = rproc_va_to_pa(mem->va);
  			} else {
  				/* Use dma address as carveout no memmapped yet */
  				pa = (phys_addr_t)mem->dma;
  			}
  
  			/* Associate vdev buffer memory pool to vdev subdev */
  			ret = dma_declare_coherent_memory(dev, pa,
  							   mem->da,

  							   mem->len);

  			if (ret < 0) {
  				dev_err(dev, "Failed to associate buffer
  ");
  				goto out;
  			}
  		}

  	} else {
  		struct device_node *np = rproc->dev.parent->of_node;
  
  		/*
  		 * If we don't have dedicated buffer, just attempt to re-assign
  		 * the reserved memory from our parent. A default memory-region
  		 * at index 0 from the parent's memory-regions is assigned for
  		 * the rvdev dev to allocate from. Failure is non-critical and
  		 * the allocations will fall back to global pools, so don't
  		 * check return value either.
  		 */
  		of_reserved_mem_device_init_by_idx(dev, np, 0);

  	}

  	/* Allocate virtio device */
  	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
  	if (!vdev) {
  		ret = -ENOMEM;
  		goto out;
  	}

  	vdev->id.device	= id,
  	vdev->config = &rproc_virtio_config_ops,
  	vdev->dev.parent = dev;

  	vdev->dev.release = rproc_virtio_dev_release;

  
  	/*
  	 * We're indirectly making a non-temporary copy of the rproc pointer
  	 * here, because drivers probed with this vdev will indirectly
  	 * access the wrapping rproc.
  	 *
  	 * Therefore we must increment the rproc refcount here, and decrement
  	 * it _only_ when the vdev is released.
  	 */

  	get_device(&rproc->dev);

  	/* Reference the vdev and vring allocations */
  	kref_get(&rvdev->refcount);

  	ret = register_virtio_device(vdev);

  	if (ret) {

  		put_device(&vdev->dev);

  		dev_err(dev, "failed to register vdev: %d
  ", ret);

  		goto out;

  	}

  	dev_info(dev, "registered %s (type %d)
  ", dev_name(&vdev->dev), id);
  
  out:

  	return ret;
  }
  
  /**

   * rproc_remove_virtio_dev() - remove an rproc-induced virtio device

   * @dev: the virtio device
   * @data: must be null

   *

   * This function unregisters an existing virtio device.

   */

  int rproc_remove_virtio_dev(struct device *dev, void *data)

  {

  	struct virtio_device *vdev = dev_to_virtio(dev);
  
  	unregister_virtio_device(vdev);
  	return 0;

  }