/*
 * Copyright 2024 Advanced Micro Devices, Inc.
 *
 * SPDX-License-Identifier: MIT
 */

#include "drm-uapi/amdgpu_drm.h"

#include "amdgpu_virtio_private.h"
#include "ac_linux_drm.h"
#include "util/list.h"
#include "util/log.h"
#include "util/os_mman.h"
#include "util/os_time.h"
#include "util/u_math.h"
#include "sid.h"

#include <xf86drm.h>
#include <string.h>
#include <fcntl.h>

struct amdvgpu_host_blob {
   /* virtgpu properties */
   uint32_t handle;
   uint32_t res_id;
   uint64_t alloc_size;

   /* CPU mapping handling. */
   uint64_t offset;
   int map_count;
   void *cpu_addr;
   simple_mtx_t cpu_access_mutex;

   /* Allocation parameters. */
   uint32_t vm_flags;
   uint32_t preferred_heap;
   uint64_t phys_alignment;
   uint64_t flags;
};

static
void destroy_host_blob(amdvgpu_device_handle dev, struct amdvgpu_host_blob *hb);

static
struct amdvgpu_host_blob *create_host_blob(uint32_t kms_handle,
                                           uint32_t res_id,
                                           uint64_t size,
                                           struct amdgpu_ccmd_gem_new_req *req)
{
   struct amdvgpu_host_blob *hb = calloc(1, sizeof(*hb));
   hb->handle = kms_handle;
   hb->res_id = res_id;
   hb->alloc_size = size;

   if (req) {
      hb->phys_alignment = req->r.phys_alignment;
      hb->preferred_heap = req->r.preferred_heap;
      hb->flags = req->r.flags;
   }

   simple_mtx_init(&hb->cpu_access_mutex, mtx_plain);
   return hb;
}

static
void destroy_host_blob(amdvgpu_device_handle dev, struct amdvgpu_host_blob *hb) {
   simple_mtx_destroy(&hb->cpu_access_mutex);

   vdrm_bo_close(dev->vdev, hb->handle);
   free(hb);
}

static int
alloc_host_blob(amdvgpu_bo_handle bo,
                struct amdgpu_ccmd_gem_new_req *req,
                uint32_t blob_flags)
{
      uint32_t kms_handle, res_id;

      /* Create the host blob requires 2 steps. First create the host blob... */
      kms_handle = vdrm_bo_create(bo->dev->vdev, req->r.alloc_size, blob_flags,
                                  req->blob_id, &req->hdr);

      /* 0 is an invalid handle and is used by vdrm_bo_create to signal an error. */
      if (kms_handle == 0)
         return -1;

      /* ... and then retrieve its resource id (global id). */
      res_id = vdrm_handle_to_res_id(bo->dev->vdev, kms_handle);

      bo->host_blob = create_host_blob(kms_handle, res_id, req->r.alloc_size, req);

      simple_mtx_lock(&bo->dev->handle_to_vbo_mutex);
      _mesa_hash_table_insert(bo->dev->handle_to_vbo, (void*)(intptr_t)bo->host_blob->handle, bo);
      simple_mtx_unlock(&bo->dev->handle_to_vbo_mutex);

      return 0;
}

int amdvgpu_bo_export(amdvgpu_device_handle dev, amdvgpu_bo_handle bo,
                      enum amdgpu_bo_handle_type type,
                      uint32_t *shared_handle)
{
   switch (type) {
   case amdgpu_bo_handle_type_kms:
      /* Return the resource id as this handle is only going to be used
       * internally (AMDGPU_CHUNK_ID_BO_HANDLES mostly).
       */
      *shared_handle = amdvgpu_get_resource_id(bo);
      return 0;

   case amdgpu_bo_handle_type_dma_buf_fd:
      *shared_handle = vdrm_bo_export_dmabuf(dev->vdev, bo->host_blob->handle);
      return 0;

   case amdgpu_bo_handle_type_kms_noimport:
      /* Treat this deprecated type as _type_kms and return the GEM handle. */
      *shared_handle = bo->host_blob->handle;
      return 0;

   case amdgpu_bo_handle_type_gem_flink_name:
      break;
   }
   return -EINVAL;
}

int amdvgpu_bo_free(amdvgpu_device_handle dev, struct amdvgpu_bo *bo) {
   int refcnt = p_atomic_dec_return(&bo->refcount);

   if (refcnt == 0) {
      /* Flush pending ops. */
      vdrm_flush(dev->vdev);

      /* Remove it from the bo table. */
      if (bo->host_blob->handle > 0) {
         simple_mtx_lock(&dev->handle_to_vbo_mutex);
         struct hash_entry *entry = _mesa_hash_table_search(dev->handle_to_vbo,
                                                            (void*)(intptr_t)bo->host_blob->handle);
         if (entry) {
            /* entry can be NULL for the shmem buffer. */
            _mesa_hash_table_remove(dev->handle_to_vbo, entry);
         }
         simple_mtx_unlock(&dev->handle_to_vbo_mutex);
      }

      if (bo->host_blob)
         destroy_host_blob(dev, bo->host_blob);

      free(bo);
   }

   return 0;
}

int amdvgpu_bo_alloc(amdvgpu_device_handle dev,
                     struct amdgpu_bo_alloc_request *request,
                     amdvgpu_bo_handle *bo)
{
   int r;
   uint32_t blob_flags = 0;

   struct amdgpu_ccmd_gem_new_req req = {
         .hdr = AMDGPU_CCMD(GEM_NEW, sizeof(req)),
         .blob_id = p_atomic_inc_return(&dev->next_blob_id),
   };
   req.r.alloc_size = request->alloc_size;
   req.r.phys_alignment = request->phys_alignment;
   req.r.preferred_heap = request->preferred_heap;
   req.r.__pad = 0;
   req.r.flags = request->flags;

   if (!(request->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS))
      blob_flags |= VIRTGPU_BLOB_FLAG_USE_MAPPABLE;

   if (request->flags & AMDGPU_GEM_CREATE_VIRTIO_SHARED) {
      blob_flags |= VIRTGPU_BLOB_FLAG_USE_SHAREABLE;
      req.r.flags &= ~AMDGPU_GEM_CREATE_VIRTIO_SHARED;
   }

   /* blob_id 0 is reserved for the shared memory buffer. */
   assert(req.blob_id > 0);

   amdvgpu_bo_handle out = calloc(1, sizeof(struct amdvgpu_bo));
   out->dev = dev;
   out->size = request->alloc_size;

   r = alloc_host_blob(out, &req, blob_flags);

   if (r < 0) {
      free(out);
      return r;
   }

   p_atomic_set(&out->refcount, 1);
   *bo = out;

   return 0;
}

int amdvgpu_bo_va_op_raw(amdvgpu_device_handle dev,
                         uint32_t res_id,
                         uint64_t offset,
                         uint64_t size,
                         uint64_t addr,
                         uint64_t flags,
                         uint32_t ops)
{
   int r;

   /* Fill base structure fields. */
   struct amdgpu_ccmd_bo_va_op_req req = {
      .hdr = AMDGPU_CCMD(BO_VA_OP, sizeof(req)),
      .va = addr,
      .res_id = res_id,
      .offset = offset,
      .vm_map_size = size,
      .flags = flags,
      .op = ops,
      .flags2 = res_id == 0 ? AMDGPU_CCMD_BO_VA_OP_SPARSE_BO : 0,
   };
   struct amdgpu_ccmd_rsp *rsp =
      vdrm_alloc_rsp(dev->vdev, &req.hdr, sizeof(*rsp));

   r = vdrm_send_req_wrapper(dev, &req.hdr, rsp, false);

   return r;
}

int amdvgpu_bo_import(amdvgpu_device_handle dev, enum amdgpu_bo_handle_type type,
                      uint32_t handle, struct amdvgpu_bo_import_result *result)
{
   if (type != amdgpu_bo_handle_type_dma_buf_fd)
      return -1;

   uint32_t kms_handle;
   kms_handle = vdrm_dmabuf_to_handle(dev->vdev, handle);
   if (kms_handle == 0) {
      mesa_loge("drmPrimeFDToHandle failed for dmabuf fd: %u\n", handle);
      return -1;
   }

   /* Look up existing bo. */
   simple_mtx_lock(&dev->handle_to_vbo_mutex);
   struct hash_entry *entry = _mesa_hash_table_search(dev->handle_to_vbo, (void*)(intptr_t)kms_handle);

   if (entry) {
      struct amdvgpu_bo *bo = entry->data;
      p_atomic_inc(&bo->refcount);
      simple_mtx_unlock(&dev->handle_to_vbo_mutex);
      result->buf_handle = (void*)bo;
      result->alloc_size = bo->size;
      assert(bo->host_blob);
      return 0;
   }
   simple_mtx_unlock(&dev->handle_to_vbo_mutex);

   uint32_t res_id = vdrm_handle_to_res_id(dev->vdev, kms_handle);
   if (res_id == 0)
      return -1;

   off_t size = lseek(handle, 0, SEEK_END);
   if (size == (off_t) -1) {
      mesa_loge("lseek failed (%s)\n", strerror(errno));
      return -1;
   }
   lseek(handle, 0, SEEK_CUR);

   struct amdvgpu_bo *bo = calloc(1, sizeof(struct amdvgpu_bo));
   bo->dev = dev;
   bo->size = size;
   bo->host_blob = create_host_blob(kms_handle, res_id, size, NULL);
   p_atomic_set(&bo->refcount, 1);

   result->buf_handle = bo;
   result->alloc_size = bo->size;

   simple_mtx_lock(&dev->handle_to_vbo_mutex);
   _mesa_hash_table_insert(dev->handle_to_vbo, (void*)(intptr_t)bo->host_blob->handle, bo);
   simple_mtx_unlock(&dev->handle_to_vbo_mutex);

   return 0;
}

int amdvgpu_bo_cpu_map(amdvgpu_device_handle dev, amdvgpu_bo_handle bo_handle,
                       void **cpu) {
   simple_mtx_lock(&bo_handle->host_blob->cpu_access_mutex);

   if (bo_handle->host_blob->cpu_addr == NULL) {
      assert(bo_handle->host_blob->cpu_addr == NULL);
      /* Use *cpu as a fixed address hint from the caller. */
      bo_handle->host_blob->cpu_addr = vdrm_bo_map(dev->vdev, bo_handle->host_blob->handle,
                                                   bo_handle->host_blob->alloc_size, *cpu);
   }

   assert(bo_handle->host_blob->cpu_addr != NULL);
   *cpu = bo_handle->host_blob->cpu_addr;
   p_atomic_inc(&bo_handle->host_blob->map_count);

   simple_mtx_unlock(&bo_handle->host_blob->cpu_access_mutex);

   return *cpu == NULL;
}

int amdvgpu_bo_cpu_unmap(amdvgpu_device_handle dev, amdvgpu_bo_handle bo) {
   int r = 0;

   simple_mtx_lock(&bo->host_blob->cpu_access_mutex);
   if (bo->host_blob->map_count == 0) {
      simple_mtx_unlock(&bo->host_blob->cpu_access_mutex);
      return 0;
   }
   assert(bo->host_blob->cpu_addr);
   if (p_atomic_dec_zero(&bo->host_blob->map_count)) {
      r = os_munmap(bo->host_blob->cpu_addr, bo->host_blob->alloc_size);
      bo->host_blob->cpu_addr = NULL;
   }
   simple_mtx_unlock(&bo->host_blob->cpu_access_mutex);

   return r;
}

uint32_t amdvgpu_get_resource_id(amdvgpu_bo_handle bo) {
   return bo->host_blob->res_id;
}

int amdvgpu_bo_wait_for_idle(amdvgpu_device_handle dev,
                             amdvgpu_bo_handle bo,
                             uint64_t abs_timeout_ns) {
   /* TODO: add a wait for idle command? */
   return vdrm_bo_wait(dev->vdev, bo->host_blob->handle);
}