path: root/drivers/rpmsg/qcom_glink_native.c

/*
 * Copyright (c) 2016-2017, Linaro Ltd
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rpmsg.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/mailbox_client.h>

#include "rpmsg_internal.h"
#include "qcom_glink_native.h"

#define GLINK_NAME_SIZE		32
#define GLINK_VERSION_1		1

#define RPM_GLINK_CID_MIN	1
#define RPM_GLINK_CID_MAX	65536

struct glink_msg {
	__le16 cmd;
	__le16 param1;
	__le32 param2;
	u8 data[];
} __packed;

/**
 * struct glink_defer_cmd - deferred incoming control message
 * @node:	list node
 * @msg:	message header
 * data:	payload of the message
 *
 * Copy of a received control message, to be added to @rx_queue and processed
 * by @rx_work of @qcom_glink.
 */
struct glink_defer_cmd {
	struct list_head node;

	struct glink_msg msg;
	u8 data[];
};

/**
 * struct glink_core_rx_intent - RX intent
 * RX intent
 *
 * data: pointer to the data (may be NULL for zero-copy)
 * id: remote or local intent ID
 * size: size of the original intent (do not modify)
 * reuse: To mark if the intent can be reused after first use
 * in_use: To mark if intent is already in use for the channel
 * offset: next write offset (initially 0)
 */
struct glink_core_rx_intent {
	void *data;
	u32 id;
	size_t size;
	bool reuse;
	bool in_use;
	u32 offset;

	struct list_head node;
};

/**
 * struct qcom_glink - driver context, relates to one remote subsystem
 * @dev:	reference to the associated struct device
 * @mbox_client: mailbox client
 * @mbox_chan:  mailbox channel
 * @rx_pipe:	pipe object for receive FIFO
 * @tx_pipe:	pipe object for transmit FIFO
 * @irq:	IRQ for signaling incoming events
 * @rx_work:	worker for handling received control messages
 * @rx_lock:	protects the @rx_queue
 * @rx_queue:	queue of received control messages to be processed in @rx_work
 * @tx_lock:	synchronizes operations on the tx fifo
 * @idr_lock:	synchronizes @lcids and @rcids modifications
 * @lcids:	idr of all channels with a known local channel id
 * @rcids:	idr of all channels with a known remote channel id
 */
struct qcom_glink {
	struct device *dev;

	struct mbox_client mbox_client;
	struct mbox_chan *mbox_chan;

	struct qcom_glink_pipe *rx_pipe;
	struct qcom_glink_pipe *tx_pipe;

	int irq;

	struct work_struct rx_work;
	spinlock_t rx_lock;
	struct list_head rx_queue;

	struct mutex tx_lock;

	spinlock_t idr_lock;
	struct idr lcids;
	struct idr rcids;
	unsigned long features;

	bool intentless;
};

enum {
	GLINK_STATE_CLOSED,
	GLINK_STATE_OPENING,
	GLINK_STATE_OPEN,
	GLINK_STATE_CLOSING,
};

/**
 * struct glink_channel - internal representation of a channel
 * @rpdev:	rpdev reference, only used for primary endpoints
 * @ept:	rpmsg endpoint this channel is associated with
 * @glink:	qcom_glink context handle
 * @refcount:	refcount for the channel object
 * @recv_lock:	guard for @ept.cb
 * @name:	unique channel name/identifier
 * @lcid:	channel id, in local space
 * @rcid:	channel id, in remote space
 * @intent_lock: lock for protection of @liids, @riids
 * @liids:	idr of all local intents
 * @riids:	idr of all remote intents
 * @intent_work: worker responsible for transmitting rx_done packets
 * @done_intents: list of intents that needs to be announced rx_done
 * @buf:	receive buffer, for gathering fragments
 * @buf_offset:	write offset in @buf
 * @buf_size:	size of current @buf
 * @open_ack:	completed once remote has acked the open-request
 * @open_req:	com