/*
 * Copyright (C) 2016 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "msm_drv.h"
#include "msm_gem.h"
#include "msm_mmu.h"

static void
msm_gem_address_space_destroy(struct kref *kref)
{
	struct msm_gem_address_space *aspace = container_of(kref,
			struct msm_gem_address_space, kref);

	drm_mm_takedown(&aspace->mm);
	if (aspace->mmu)
		aspace->mmu->funcs->destroy(aspace->mmu);
	kfree(aspace);
}


void msm_gem_address_space_put(struct msm_gem_address_space *aspace)
{
	if (aspace)
		kref_put(&aspace->kref, msm_gem_address_space_destroy);
}

/* Actually unmap memory for the vma */
void msm_gem_purge_vma(struct msm_gem_address_space *aspace,
		struct msm_gem_vma *vma)
{
	unsigned size = vma->node.size << PAGE_SHIFT;

	/* Print a message if we try to purge a vma in use */
	if (WARN_ON(vma->inuse > 0))
		return;

	/* Don't do anything if the memory isn't mapped */
	if (!vma->mapped)
		return;

	if (aspace->mmu)
		aspace->mmu->funcs->unmap(aspace->mmu, vma->iova, size);

	vma->mapped = false;
}

/* Remove reference counts for the mapping */
void msm_gem_unmap_vma(struct msm_gem_address_space *aspace,
		struct msm_gem_vma *vma)
{
	if (!WARN_ON(!vma->iova))
		vma->inuse--;
}

int
msm_gem_map_vma(struct msm_gem_address_space *aspace,
		struct msm_gem_vma *vma, struct sg_table *sgt, int npages)
{
	unsigned size = npages << PAGE_SHIFT;
	int ret = 0;

	if (WARN_ON(!vma->iova))
		return -EINVAL;

	/* Increase the usage counter */
	vma->inuse++;

	if (vma->mapped)
		return 0;

	vma->mapped = true;

	if (aspace->mmu)
		ret = aspace->mmu->funcs->map(aspace->mmu, vma->iova, sgt,
				size, IOMMU_READ | IOMMU_WRITE);

	if (ret)
		vma->mapped = false;

	return ret;
}

/* Close an iova.  Warn if it is still in use */
void msm_gem_close_vma(struct msm_gem_address_space *aspace,
		struct msm_gem_vma *vma)
{
	if (WARN_ON(vma->inuse > 0 || vma->mapped))
		return;

	spin_lock(&aspace->lock);
	if (vma->iova)
		drm_mm_remove_node(&vma->node);
	spin_unlock(&aspace->lock);

	vma->iova = 0;

	msm_gem_address_space_put(aspace);
}

/* Initialize a new vma and allocate an iova for it */
int msm_gem_init_vma(struct msm_gem_address_space *aspace,
		struct msm_gem_vma *vma, int npages)
{
	int ret;

	if (WARN_ON(vma->iova))
		return -EBUSY;

	spin_lock(&aspace->lock);
	ret = drm_mm_insert_node(&aspace->mm, &vma->node, npages);
	spin_unlock(&aspace->lock);

	if (ret)
		return ret;

	vma->iova = vma->node.start << PAGE_SHIFT;
	vma->mapped = false;

	kref_get(&aspace->kref);

	return 0;
}


struct msm_gem_address_space *
msm_gem_address_space_create(struct device *dev, struct iommu_domain *domain,
		const char *name)
{
	struct msm_gem_address_space *aspace;
	u64 size = domain->geometry.aperture_end -
		domain->geometry.aperture_start;

	aspace = kzalloc(sizeof(*aspace), GFP_KERNEL);
	if (!aspace)
		return ERR_PTR(-ENOMEM);

	spin_lock_init(&aspace->lock);
	aspace->name = name;
	aspace->mmu = msm_iommu_new(dev, domain);

	drm_mm_init(&aspace->mm, (domain->geometry.aperture_start >> PAGE_SHIFT),
		size >> PAGE_SHIFT);

	kref_init(&aspace->kref);

	return aspace;
}

struct msm_gem_address_space *
msm_gem_address_space_create_a2xx(struct device *dev, struct msm_gpu *gpu,
		const char *name, uint64_t va_start, uint64_t va_end)
{
	struct msm_gem_address_space *aspace;
	u64 size = va_end - va_start;

	aspace = kzalloc(sizeof(*aspace), GFP_KERNEL);
	if (!aspace)
		return ERR_PTR(-ENOMEM);

	spin_lock_init(&aspace->lock);
	aspace->name = name;
	aspace->mmu = msm_gpummu_new(dev, gpu);

	drm_mm_init(&aspace->mm, (va_start >> PAGE_SHIFT),
		size >> PAGE_SHIFT);

	kref_init(&aspace->kref);

	return aspace;
}