linux/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.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.
 */

/*
 * KFD Interrupts.
 *
 * AMD GPUs deliver interrupts by pushing an interrupt description onto the
 * interrupt ring and then sending an interrupt. KGD receives the interrupt
 * in ISR and sends us a pointer to each new entry on the interrupt ring.
 *
 * We generally can't process interrupt-signaled events from ISR, so we call
 * out to each interrupt client module (currently only the scheduler) to ask if
 * each interrupt is interesting. If they return true, then it requires further
 * processing so we copy it to an internal interrupt ring and call each
 * interrupt client again from a work-queue.
 *
 * There's no acknowledgment for the interrupts we use. The hardware simply
 * queues a new interrupt each time without waiting.
 *
 * The fixed-size internal queue means that it's possible for us to lose
 * interrupts because we have no back-pressure to the hardware.
 */

#include <linux/slab.h>
#include <linux/device.h>
#include <linux/kfifo.h>
#include "kfd_priv.h"

#define KFD_IH_NUM_ENTRIES …

static void interrupt_wq(struct work_struct *);

int kfd_interrupt_init(struct kfd_node *node)
{ … }

void kfd_interrupt_exit(struct kfd_node *node)
{ … }

/*
 * Assumption: single reader/writer. This function is not re-entrant
 */
bool enqueue_ih_ring_entry(struct kfd_node *node, const void *ih_ring_entry)
{ … }

/*
 * Assumption: single reader/writer. This function is not re-entrant
 */
static bool dequeue_ih_ring_entry(struct kfd_node *node, void *ih_ring_entry)
{ … }

static void interrupt_wq(struct work_struct *work)
{ … }

bool interrupt_is_wanted(struct kfd_node *dev,
			const uint32_t *ih_ring_entry,
			uint32_t *patched_ihre, bool *flag)
{ … }