/*
 * Copyright (c) 2017, NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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 <linux/dma-buf.h>
#include <linux/scatterlist.h>
#include <uapi/linux/nvgpu.h>

#include <nvgpu/log.h>
#include <nvgpu/lock.h>
#include <nvgpu/rbtree.h>
#include <nvgpu/vm_area.h>
#include <nvgpu/nvgpu_mem.h>
#include <nvgpu/page_allocator.h>
#include <nvgpu/vidmem.h>

#include <nvgpu/linux/vm.h>
#include <nvgpu/linux/vidmem.h>
#include <nvgpu/linux/nvgpu_mem.h>

#include "gk20a/gk20a.h"
#include "gk20a/mm_gk20a.h"

#include "platform_gk20a.h"
#include "os_linux.h"
#include "dmabuf.h"

static struct nvgpu_mapped_buf *__nvgpu_vm_find_mapped_buf_reverse(
	struct vm_gk20a *vm, struct dma_buf *dmabuf, u32 kind)
{
	struct nvgpu_rbtree_node *node = NULL;
	struct nvgpu_rbtree_node *root = vm->mapped_buffers;

	nvgpu_rbtree_enum_start(0, &node, root);

	while (node) {
		struct nvgpu_mapped_buf *mapped_buffer =
				mapped_buffer_from_rbtree_node(node);

		if (mapped_buffer->dmabuf == dmabuf &&
		    kind == mapped_buffer->kind)
			return mapped_buffer;

		nvgpu_rbtree_enum_next(&node, node);
	}

	return NULL;
}

/*
 * Determine alignment for a passed buffer. Necessary since the buffer may
 * appear big to map with large pages but the SGL may have chunks that are not
 * aligned on a 64/128kB large page boundary.
 */
static u64 nvgpu_get_buffer_alignment(struct gk20a *g, struct scatterlist *sgl,
				      enum nvgpu_aperture aperture)
{
	u64 align = 0, chunk_align = 0;
	u64 buf_addr;

	if (aperture == APERTURE_VIDMEM) {
		struct nvgpu_page_alloc *alloc =
			nvgpu_vidmem_get_page_alloc(sgl);
		struct nvgpu_sgt *sgt = &alloc->sgt;
		void *sgl_vid = sgt->sgl;

		while (sgl_vid) {
			chunk_align = 1ULL <<
				__ffs(nvgpu_sgt_get_phys(sgt, sgl_vid)) |
				nvgpu_sgt_get_length(sgt, sgl_vid);

			if (align)
				align = min(align, chunk_align);
			else
				align = chunk_align;

			sgl_vid = nvgpu_sgt_get_next(sgt, sgl_vid);
		}

		return align;
	}

	buf_addr = (u64)sg_dma_address(sgl);

	if (g->mm.bypass_smmu || buf_addr == DMA_ERROR_CODE || !buf_addr) {
		while (sgl) {
			buf_addr = (u64)sg_phys(sgl);
			chunk_align = 1ULL << __ffs(buf_addr |
						    (u64)sgl->length);

			if (align)
				align = min(align, chunk_align);
			else
				align = chunk_align;
			sgl = sg_next(sgl);
		}

		return align;
	}

	align = 1ULL << __ffs(buf_addr);

	return align;
}

int nvgpu_vm_find_buf(struct vm_gk20a *vm, u64 gpu_va,
		      struct dma_buf **dmabuf,
		      u64 *offset)
{
	struct nvgpu_mapped_buf *mapped_buffer;

	gk20a_dbg_fn("gpu_va=0x%llx", gpu_va);

	nvgpu_mutex_acquire(&vm->update_gmmu_lock);

	mapped_buffer = __nvgpu_vm_find_mapped_buf_range(vm, gpu_va);
	if (!mapped_buffer) {
		nvgpu_mutex_release(&vm->update_gmmu_lock);
		return -EINVAL;
	}

	*dmabuf = mapped_buffer->dmabuf;
	*offset = gpu_va - mapped_buffer->addr;

	nvgpu_mutex_release(&vm->update_gmmu_lock);

	return 0;
}

/*
 * vm->update_gmmu_lock must be held. This checks to see if we already have
 * mapped the passed buffer into this VM. If so, just return the existing
 * mapping address.
 */
static u64 __nvgpu_vm_find_mapping(struct vm_gk20a *vm,
				   struct dma_buf *dmabuf,
				   u64 offset_align,
				   u32 flags,
				   int kind,
				   int rw_flag)
{
	struct gk20a *g = gk20a_from_vm(vm);
	struct nvgpu_mapped_buf *mapped_buffer = NULL;

	if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET) {
		mapped_buffer = __nvgpu_vm_find_mapped_buf(vm, offset_align);
		if (!mapped_buffer)
			return 0;

		if (mapped_buffer->dmabuf != dmabuf ||
		    mapped_buffer->kind != (u32)kind)
			return 0;
	} else {
		mapped_buffer =
			__nvgpu_vm_find_mapped_buf_reverse(vm, dmabuf, kind);
		if (!mapped_buffer)
			return 0;
	}

	if (mapped_buffer->flags != flags)
		return 0;

	/*
	 * If we find the mapping here then that means we have mapped it already
	 * and already have a dma_buf ref to the underlying buffer. As such
	 * release the ref taken earlier in the map path.
	 */
	dma_buf_put(mapped_buffer->dmabuf);

	nvgpu_ref_get(&mapped_buffer->ref);

	nvgpu_log(g, gpu_dbg_map,
		  "gv: 0x%04x_%08x + 0x%-7zu "
		  "[dma: 0x%02x_%08x, pa: 0x%02x_%08x] "
		  "pgsz=%-3dKb as=%-2d ctags=%d start=%d "
		  "flags=0x%x apt=%s (reused)",
		  u64_hi32(mapped_buffer->addr), u64_lo32(mapped_buffer->addr),
		  dmabuf->size,
		  u64_hi32((u64)sg_dma_address(mapped_buffer->sgt->sgl)),
		  u64_lo32((u64)sg_dma_address(mapped_buffer->sgt->sgl)),
		  u64_hi32((u64)sg_phys(mapped_buffer->sgt->sgl)),
		  u64_lo32((u64)sg_phys(mapped_buffer->sgt->sgl)),
		  vm->gmmu_page_sizes[mapped_buffer->pgsz_idx] >> 10,
		  vm_aspace_id(vm),
		  mapped_buffer->ctag_lines, mapped_buffer->ctag_offset,
		  mapped_buffer->flags,
		  nvgpu_aperture_str(gk20a_dmabuf_aperture(g, dmabuf)));

	return mapped_buffer->addr;
}

int nvgpu_vm_map_linux(struct vm_gk20a *vm,
		       struct dma_buf *dmabuf,
		       u64 offset_align,
		       u32 flags,
		       s16 compr_kind,
		       s16 incompr_kind,
		       int rw_flag,
		       u64 buffer_offset,
		       u64 mapping_size,
		       struct vm_gk20a_mapping_batch *batch,
		       u64 *gpu_va)
{
	struct gk20a *g = gk20a_from_vm(vm);
	struct device *dev = dev_from_gk20a(g);
	struct nvgpu_ctag_buffer_info binfo = { 0 };
	struct gk20a_comptags comptags;
	struct nvgpu_vm_area *vm_area = NULL;
	struct nvgpu_sgt *nvgpu_sgt;
	struct sg_table *sgt;
	struct nvgpu_mapped_buf *mapped_buffer = NULL;
	enum nvgpu_aperture aperture;
	bool va_allocated = false;
	bool clear_ctags = false;
	u64 map_offset = 0;
	u64 align;
	u32 ctag_offset;
	int err = 0;

	/*
	 * The kind used as part of the key for map caching. HW may
	 * actually be programmed with the fallback kind in case the
	 * key kind is compressible but we're out of comptags.
	 */
	s16 map_key_kind;

	binfo.flags = flags;
	binfo.size = dmabuf->size;
	binfo.compr_kind = compr_kind;
	binfo.incompr_kind = incompr_kind;

	if (compr_kind != NV_KIND_INVALID)
		map_key_kind = compr_kind;
	else
		map_key_kind = incompr_kind;

	if (map_key_kind == NV_KIND_INVALID) {
		nvgpu_err(g, "Valid kind must be supplied");
		return -EINVAL;
	}

	if (vm->userspace_managed &&
	    !(flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)) {
		nvgpu_err(g, "non-fixed-offset mapping not available on "
			  "userspace managed address spaces");
		return -EFAULT;
	}

	nvgpu_mutex_acquire(&vm->update_gmmu_lock);

	/* check if this buffer is already mapped */
	if (!vm->userspace_managed) {
		map_offset = __nvgpu_vm_find_mapping(
			vm, dmabuf, offset_align,
			flags, map_key_kind, rw_flag);
		if (map_offset) {
			nvgpu_mutex_release(&vm->update_gmmu_lock);
			*gpu_va = map_offset;
			return 0;
		}
	}

	sgt = gk20a_mm_pin(dev, dmabuf);
	if (IS_ERR(sgt)) {
		err = PTR_ERR(sgt);
		nvgpu_warn(g, "oom allocating tracking buffer");
		goto clean_up;
	}

	aperture = gk20a_dmabuf_aperture(g, dmabuf);
	if (aperture == APERTURE_INVALID) {
		err = -EINVAL;
		goto clean_up;
	}

	if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)
		map_offset = offset_align;

	align = nvgpu_get_buffer_alignment(g, sgt->sgl, aperture);
	if (g->mm.disable_bigpage)
		binfo.pgsz_idx = gmmu_page_size_small;
	else
		binfo.pgsz_idx = __get_pte_size(vm, map_offset,
						min_t(u64, binfo.size, align));
	mapping_size = mapping_size ? mapping_size : binfo.size;
	mapping_size = ALIGN(mapping_size, SZ_4K);

	if ((mapping_size > binfo.size) ||
	    (buffer_offset > (binfo.size - mapping_size))) {
		err = -EINVAL;
		goto clean_up;
	}

	/* Check if we should use a fixed offset for mapping this buffer */
	if (flags & NVGPU_AS_MAP_BUFFER_FLAGS_FIXED_OFFSET)  {
		err = nvgpu_vm_area_validate_buffer(vm,
						    offset_align,
						    mapping_size,
						    binfo.pgsz_idx,
						    &vm_area);
		if (err)
			goto clean_up;

		map_offset = offset_align;
		va_allocated = false;
	} else {
		va_allocated = true;
	}

	err = nvgpu_vm_compute_compression(vm, &binfo);
	if (err) {
		nvgpu_err(g, "failure setting up compression");
		goto clean_up;
	}

	/* bar1 and pmu vm don't need ctag */
	if (!vm->enable_ctag)
		binfo.ctag_lines = 0;

	gk20a_get_comptags(dev, dmabuf, &comptags);

	if (binfo.ctag_lines && !comptags.lines) {
		/* allocate compression resources if needed */
		err = gk20a_alloc_comptags(g, dev, dmabuf,
					   &g->gr.comp_tags,
					   binfo.ctag_lines);
		if (err) {
			/* TBD: we can partially alloc ctags as well... */

			/* prevent compression ... */
			binfo.compr_kind = NV_KIND_INVALID;

			/* ... and make sure we have the fallback */
			if (binfo.incompr_kind == NV_KIND_INVALID) {
				nvgpu_err(g, "comptag alloc failed and no fallback kind specified");
				goto clean_up;
			}
		} else {
			gk20a_get_comptags(dev,
					   dmabuf, &comptags);

			if (g->ops.ltc.cbc_ctrl)
				g->ops.ltc.cbc_ctrl(g, gk20a_cbc_op_clear,
						    comptags.offset,
						    comptags.offset +
							comptags.allocated_lines - 1);
			else
				clear_ctags = true;
		}
	}

	/*
	 * Calculate comptag index for this mapping. Differs in
	 * case of partial mapping.
	 */
	ctag_offset = comptags.offset;
	if (ctag_offset)
		ctag_offset += buffer_offset >>
			       ilog2(g->ops.fb.compression_page_size(g));

	nvgpu_sgt = nvgpu_linux_sgt_create(g, sgt);

	/* update gmmu ptes */
	map_offset = g->ops.mm.gmmu_map(vm,
					map_offset,
					nvgpu_sgt,
					buffer_offset, /* sg offset */
					mapping_size,
					binfo.pgsz_idx,
					(binfo.compr_kind != NV_KIND_INVALID ?
					 binfo.compr_kind : binfo.incompr_kind),
					ctag_offset,
					flags, rw_flag,
					clear_ctags,
					false,
					false,
					batch,
					aperture);
	if (!map_offset)
		goto clean_up;

	nvgpu_sgt_free(nvgpu_sgt, g);

	mapped_buffer = nvgpu_kzalloc(g, sizeof(*mapped_buffer));
	if (!mapped_buffer) {
		nvgpu_warn(g, "oom allocating tracking buffer");
		goto clean_up;
	}
	mapped_buffer->dmabuf      = dmabuf;
	mapped_buffer->sgt         = sgt;
	mapped_buffer->addr        = map_offset;
	mapped_buffer->size        = mapping_size;
	mapped_buffer->pgsz_idx    = binfo.pgsz_idx;
	mapped_buffer->ctag_offset = ctag_offset;
	mapped_buffer->ctag_lines  = binfo.ctag_lines;
	mapped_buffer->ctag_allocated_lines = comptags.allocated_lines;
	mapped_buffer->vm          = vm;
	mapped_buffer->flags       = flags;
	mapped_buffer->kind        = map_key_kind;
	mapped_buffer->va_allocated = va_allocated;
	nvgpu_init_list_node(&mapped_buffer->buffer_list);
	nvgpu_ref_init(&mapped_buffer->ref);

	err = nvgpu_insert_mapped_buf(vm, mapped_buffer);
	if (err) {
		nvgpu_err(g, "failed to insert into mapped buffer tree");
		goto clean_up;
	}

	vm->num_user_mapped_buffers++;

	if (vm_area) {
		nvgpu_list_add_tail(&mapped_buffer->buffer_list,
			      &vm_area->buffer_list_head);
		mapped_buffer->vm_area = vm_area;
	}

	nvgpu_mutex_release(&vm->update_gmmu_lock);

	*gpu_va = map_offset;
	return 0;

clean_up:
	nvgpu_kfree(g, mapped_buffer);
	if (va_allocated)
		__nvgpu_vm_free_va(vm, map_offset, binfo.pgsz_idx);
	if (!IS_ERR(sgt))
		gk20a_mm_unpin(dev, dmabuf, sgt);

	nvgpu_mutex_release(&vm->update_gmmu_lock);
	nvgpu_log_info(g, "err=%d", err);
	return err;
}

int nvgpu_vm_map_buffer(struct vm_gk20a *vm,
			int dmabuf_fd,
			u64 *offset_align,
			u32 flags, /*NVGPU_AS_MAP_BUFFER_FLAGS_*/
			s16 compr_kind,
			s16 incompr_kind,
			u64 buffer_offset,
			u64 mapping_size,
			struct vm_gk20a_mapping_batch *batch)
{
	int err = 0;
	struct dma_buf *dmabuf;
	u64 ret_va;

	gk20a_dbg_fn("");

	/* get ref to the mem handle (released on unmap_locked) */
	dmabuf = dma_buf_get(dmabuf_fd);
	if (IS_ERR(dmabuf)) {
		nvgpu_warn(gk20a_from_vm(vm), "%s: fd %d is not a dmabuf",
			 __func__, dmabuf_fd);
		return PTR_ERR(dmabuf);
	}

	/* verify that we're not overflowing the buffer, i.e.
	 * (buffer_offset + mapping_size)> dmabuf->size.
	 *
	 * Since buffer_offset + mapping_size could overflow, first check
	 * that mapping size < dmabuf_size, at which point we can subtract
	 * mapping_size from both sides for the final comparison.
	 */
	if ((mapping_size > dmabuf->size) ||
			(buffer_offset > (dmabuf->size - mapping_size))) {
		nvgpu_err(gk20a_from_vm(vm),
			"buf size %llx < (offset(%llx) + map_size(%llx))\n",
			(u64)dmabuf->size, buffer_offset, mapping_size);
		return -EINVAL;
	}

	err = gk20a_dmabuf_alloc_drvdata(dmabuf, dev_from_vm(vm));
	if (err) {
		dma_buf_put(dmabuf);
		return err;
	}

	err = nvgpu_vm_map_linux(vm, dmabuf, *offset_align,
				 flags, compr_kind, incompr_kind,
				 gk20a_mem_flag_none,
				 buffer_offset,
				 mapping_size,
				 batch,
				 &ret_va);

	if (!err)
		*offset_align = ret_va;
	else
		dma_buf_put(dmabuf);

	return err;
}

/*
 * This is the function call-back for freeing OS specific components of an
 * nvgpu_mapped_buf. This should most likely never be called outside of the
 * core MM framework!
 *
 * Note: the VM lock will be held.
 */
void nvgpu_vm_unmap_system(struct nvgpu_mapped_buf *mapped_buffer)
{
	struct vm_gk20a *vm = mapped_buffer->vm;

	gk20a_mm_unpin(dev_from_vm(vm), mapped_buffer->dmabuf,
		       mapped_buffer->sgt);

	dma_buf_put(mapped_buffer->dmabuf);
}