/* $NetBSD: drm_gem_cma_helper.c,v 1.14 2022/07/02 00:26:07 riastradh Exp $ */

/*-
 * Copyright (c) 2015-2017 Jared McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: drm_gem_cma_helper.c,v 1.14 2022/07/02 00:26:07 riastradh Exp $");

#include <linux/err.h>

#include <drm/bus_dma_hacks.h>
#include <drm/drm_drv.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_prime.h>
#include <drm/drm_print.h>

#include <uvm/uvm_extern.h>

static struct drm_gem_cma_object *
drm_gem_cma_create_internal(struct drm_device *ddev, size_t size,
    struct sg_table *sgt)
{
	struct drm_gem_cma_object *obj;
	int error, nsegs;

	obj = kmem_zalloc(sizeof(*obj), KM_SLEEP);
	obj->dmat = ddev->dmat;
	obj->dmasize = size;

	if (sgt) {
		error = -drm_prime_sg_to_bus_dmamem(obj->dmat, obj->dmasegs, 1,
		    &nsegs, sgt);
	} else {
		if (ddev->cma_pool != NULL) {
			error = vmem_xalloc(ddev->cma_pool, obj->dmasize,
			    PAGE_SIZE, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
			    VM_BESTFIT | VM_NOSLEEP, &obj->vmem_addr);
			if (!error) {
				obj->vmem_pool = ddev->cma_pool;
				obj->dmasegs[0].ds_addr =
				    PHYS_TO_BUS_MEM(obj->dmat, obj->vmem_addr);
				obj->dmasegs[0].ds_len =
				    roundup(obj->dmasize, PAGE_SIZE);
				nsegs = 1;
			}
		}
		if (obj->vmem_pool == NULL) {
			error = bus_dmamem_alloc(obj->dmat, obj->dmasize,
			    PAGE_SIZE, 0, obj->dmasegs, 1, &nsegs,
			    BUS_DMA_WAITOK);
		}
	}
	if (error)
		goto failed;
	error = bus_dmamem_map(obj->dmat, obj->dmasegs, nsegs,
	    obj->dmasize, &obj->vaddr,
	    BUS_DMA_WAITOK | BUS_DMA_PREFETCHABLE);
	if (error)
		goto free;
	error = bus_dmamap_create(obj->dmat, obj->dmasize, 1,
	    obj->dmasize, 0, BUS_DMA_WAITOK, &obj->dmamap);
	if (error)
		goto unmap;
	error = bus_dmamap_load(obj->dmat, obj->dmamap, obj->vaddr,
	    obj->dmasize, NULL, BUS_DMA_WAITOK);
	if (error)
		goto destroy;

	if (!sgt)
		memset(obj->vaddr, 0, obj->dmasize);

	drm_gem_private_object_init(ddev, &obj->base, size);

	return obj;

destroy:
	bus_dmamap_destroy(obj->dmat, obj->dmamap);
unmap:
	bus_dmamem_unmap(obj->dmat, obj->vaddr, obj->dmasize);
free:
	if (obj->sgt)
		drm_prime_sg_free(obj->sgt);
	else if (obj->vmem_pool)
		vmem_xfree(obj->vmem_pool, obj->vmem_addr, obj->dmasize);
	else
		bus_dmamem_free(obj->dmat, obj->dmasegs, nsegs);
failed:
	kmem_free(obj, sizeof(*obj));

	return NULL;
}

struct drm_gem_cma_object *
drm_gem_cma_create(struct drm_device *ddev, size_t size)
{

	return drm_gem_cma_create_internal(ddev, size, NULL);
}

static void
drm_gem_cma_obj_free(struct drm_gem_cma_object *obj)
{

	bus_dmamap_unload(obj->dmat, obj->dmamap);
	bus_dmamap_destroy(obj->dmat, obj->dmamap);
	bus_dmamem_unmap(obj->dmat, obj->vaddr, obj->dmasize);
	if (obj->sgt)
		drm_prime_sg_free(obj->sgt);
	else if (obj->vmem_pool)
		vmem_xfree(obj->vmem_pool, obj->vmem_addr, obj->dmasize);
	else
		bus_dmamem_free(obj->dmat, obj->dmasegs, 1);
	kmem_free(obj, sizeof(*obj));
}

void
drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
{
	struct drm_gem_cma_object *obj = to_drm_gem_cma_obj(gem_obj);

	drm_gem_free_mmap_offset(gem_obj);
	drm_gem_object_release(gem_obj);
	drm_gem_cma_obj_free(obj);
}

int
drm_gem_cma_dumb_create(struct drm_file *file_priv, struct drm_device *ddev,
    struct drm_mode_create_dumb *args)
{
	struct drm_gem_cma_object *obj;
	uint32_t handle;
	int error;

	args->pitch = args->width * ((args->bpp + 7) / 8);
	args->size = args->pitch * args->height;
	args->size = roundup(args->size, PAGE_SIZE);
	args->handle = 0;

	obj = drm_gem_cma_create(ddev, args->size);
	if (obj == NULL)
		return -ENOMEM;

	error = drm_gem_handle_create(file_priv, &obj->base, &handle);
	drm_gem_object_put_unlocked(&obj->base);
	if (error) {
		drm_gem_cma_obj_free(obj);
		return error;
	}

	args->handle = handle;

	return 0;
}

static int
drm_gem_cma_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr,
    struct vm_page **pps, int npages, int centeridx, vm_prot_t access_type,
    int flags)
{
	struct vm_map_entry *entry = ufi->entry;
	struct uvm_object *uobj = entry->object.uvm_obj;
	struct drm_gem_object *gem_obj =
	    container_of(uobj, struct drm_gem_object, gemo_uvmobj);
	struct drm_gem_cma_object *obj = to_drm_gem_cma_obj(gem_obj);
	off_t curr_offset;
	vaddr_t curr_va;
	paddr_t paddr, mdpgno;
	u_int mmapflags;
	int lcv, retval;
	vm_prot_t mapprot;

	if (UVM_ET_ISCOPYONWRITE(entry))
		return EIO;

	curr_offset = entry->offset + (vaddr - entry->start);
	curr_va = vaddr;

	retval = 0;
	for (lcv = 0; lcv < npages; lcv++, curr_offset += PAGE_SIZE,
	    curr_va += PAGE_SIZE) {
		if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx)
			continue;
		if (pps[lcv] == PGO_DONTCARE)
			continue;

		mdpgno = bus_dmamem_mmap(obj->dmat, obj->dmasegs, 1,
		    curr_offset, access_type, BUS_DMA_PREFETCHABLE);
		if (mdpgno == -1) {
			retval = EIO;
			break;
		}
		paddr = pmap_phys_address(mdpgno);
		mmapflags = pmap_mmap_flags(mdpgno);
		mapprot = ufi->entry->protection;

		if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, mapprot,
		    PMAP_CANFAIL | mapprot | mmapflags) != 0) {
			pmap_update(ufi->orig_map->pmap);
			uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);
			return ENOMEM;
		}
	}

	pmap_update(ufi->orig_map->pmap);
	uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj);

	return retval;
}

const struct uvm_pagerops drm_gem_cma_uvm_ops = {
	.pgo_reference = drm_gem_pager_reference,
	.pgo_detach = drm_gem_pager_detach,
	.pgo_fault = drm_gem_cma_fault,
};

struct sg_table *
drm_gem_cma_prime_get_sg_table(struct drm_gem_object *gem_obj)
{
	struct drm_gem_cma_object *obj = to_drm_gem_cma_obj(gem_obj);

	return drm_prime_bus_dmamem_to_sg(obj->dmat, obj->dmasegs, 1);
}

struct drm_gem_object *
drm_gem_cma_prime_import_sg_table(struct drm_device *ddev,
    struct dma_buf_attachment *attach, struct sg_table *sgt)
{
	size_t size = drm_prime_sg_size(sgt);
	struct drm_gem_cma_object *obj;

	obj = drm_gem_cma_create_internal(ddev, size, sgt);
	if (obj == NULL)
		return ERR_PTR(-ENOMEM);

	return &obj->base;
}

void *
drm_gem_cma_prime_vmap(struct drm_gem_object *gem_obj)
{
	struct drm_gem_cma_object *obj = to_drm_gem_cma_obj(gem_obj);

	return obj->vaddr;
}

void
drm_gem_cma_prime_vunmap(struct drm_gem_object *gem_obj, void *vaddr)
{
	struct drm_gem_cma_object *obj __diagused =
	    to_drm_gem_cma_obj(gem_obj);

	KASSERT(vaddr == obj->vaddr);
}