path: root/drivers/platform/mellanox/mlxbf-tmfifo.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Mellanox BlueField SoC TmFifo driver
 *
 * Copyright (C) 2019 Mellanox Technologies
 */

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/circ_buf.h>
#include <linux/efi.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/types.h>

#include <linux/virtio_config.h>
#include <linux/virtio_console.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_net.h>
#include <linux/virtio_ring.h>

#include "mlxbf-tmfifo-regs.h"

/* Vring size. */
#define MLXBF_TMFIFO_VRING_SIZE			SZ_1K

/* Console Tx buffer size. */
#define MLXBF_TMFIFO_CON_TX_BUF_SIZE		SZ_32K

/* Console Tx buffer reserved space. */
#define MLXBF_TMFIFO_CON_TX_BUF_RSV_SIZE	8

/* House-keeping timer interval. */
#define MLXBF_TMFIFO_TIMER_INTERVAL		(HZ / 10)

/* Virtual devices sharing the TM FIFO. */
#define MLXBF_TMFIFO_VDEV_MAX		(VIRTIO_ID_CONSOLE + 1)

/*
 * Reserve 1/16 of TmFifo space, so console messages are not starved by
 * the networking traffic.
 */
#define MLXBF_TMFIFO_RESERVE_RATIO		16

/* Message with data needs at least two words (for header & data). */
#define MLXBF_TMFIFO_DATA_MIN_WORDS		2

/* Tx timeout in milliseconds. */
#define TMFIFO_TX_TIMEOUT			2000

/* ACPI UID for BlueField-3. */
#define TMFIFO_BF3_UID				1

struct mlxbf_tmfifo;

/**
 * struct mlxbf_tmfifo_vring - Structure of the TmFifo virtual ring
 * @va: virtual address of the ring
 * @dma: dma address of the ring
 * @vq: pointer to the virtio virtqueue
 * @desc: current descriptor of the pending packet
 * @desc_head: head descriptor of the pending packet
 * @drop_desc: dummy desc for packet dropping
 * @cur_len: processed length of the current descriptor
 * @rem_len: remaining length of the pending packet
 * @rem_padding: remaining bytes to send as paddings
 * @pkt_len: total length of the pending packet
 * @next_avail: next avail descriptor id
 * @num: vring size (number of descriptors)
 * @align: vring alignment size
 * @index: vring index
 * @vdev_id: vring virtio id (VIRTIO_ID_xxx)
 * @tx_timeout: expire time of last tx packet
 * @fifo: pointer to the tmfifo structure
 */
struct mlxbf_tmfifo_vring {
	void *va;
	dma_addr_t dma;
	struct virtqueue *vq;
	struct vring_desc *desc;
	struct vring_desc *desc_head;
	struct vring_desc drop_desc;
	int cur_len;
	int rem_len;
	int rem_padding;
	u32 pkt_len;
	u16 next_avail;
	int num;