linux/drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c

// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
 * Copyright 2014-2022 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
#include "kfd_priv.h"
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/idr.h>

/*
 * This extension supports a kernel level doorbells management for the
 * kernel queues using the first doorbell page reserved for the kernel.
 */

/*
 * Each device exposes a doorbell aperture, a PCI MMIO aperture that
 * receives 32-bit writes that are passed to queues as wptr values.
 * The doorbells are intended to be written by applications as part
 * of queueing work on user-mode queues.
 * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
 * We map the doorbell address space into user-mode when a process creates
 * its first queue on each device.
 * Although the mapping is done by KFD, it is equivalent to an mmap of
 * the /dev/kfd with the particular device encoded in the mmap offset.
 * There will be other uses for mmap of /dev/kfd, so only a range of
 * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
 */

/* # of doorbell bytes allocated for each process. */
size_t kfd_doorbell_process_slice(struct kfd_dev *kfd)
{ … }

/* Doorbell calculations for device init. */
int kfd_doorbell_init(struct kfd_dev *kfd)
{ … }

void kfd_doorbell_fini(struct kfd_dev *kfd)
{ … }

int kfd_doorbell_mmap(struct kfd_node *dev, struct kfd_process *process,
		      struct vm_area_struct *vma)
{ … }


/* get kernel iomem pointer for a doorbell */
void __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
					unsigned int *doorbell_off)
{ … }

void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
{ … }

void write_kernel_doorbell(void __iomem *db, u32 value)
{ … }

void write_kernel_doorbell64(void __iomem *db, u64 value)
{ … }

static int init_doorbell_bitmap(struct qcm_process_device *qpd,
				struct kfd_dev *dev)
{ … }

phys_addr_t kfd_get_process_doorbells(struct kfd_process_device *pdd)
{ … }

int kfd_alloc_process_doorbells(struct kfd_dev *kfd, struct kfd_process_device *pdd)
{ … }

void kfd_free_process_doorbells(struct kfd_dev *kfd, struct kfd_process_device *pdd)
{ … }