/*
 * Intel Wireless WiMAX Connection 2400m
 * SDIO TX transaction backends
 *
 *
 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * 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.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 COPYRIGHT
 * OWNER OR CONTRIBUTORS 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.
 *
 *
 * Intel Corporation <linux-wimax@intel.com>
 * Dirk Brandewie <dirk.j.brandewie@intel.com>
 *  - Initial implementation
 *
 *
 * Takes the TX messages in the i2400m's driver TX FIFO and sends them
 * to the device until there are no more.
 *
 * If we fail sending the message, we just drop it. There isn't much
 * we can do at this point. Most of the traffic is network, which has
 * recovery methods for dropped packets.
 *
 * The SDIO functions are not atomic, so we can't run from the context
 * where i2400m->bus_tx_kick() [i2400ms_bus_tx_kick()] is being called
 * (some times atomic). Thus, the actual TX work is deferred to a
 * workqueue.
 *
 * ROADMAP
 *
 * i2400ms_bus_tx_kick()
 *   i2400ms_tx_submit()     [through workqueue]
 *
 * i2400m_tx_setup()
 *
 * i2400m_tx_release()
 */
#include <linux/mmc/sdio_func.h>
#include "i2400m-sdio.h"

#define D_SUBMODULE tx
#include "sdio-debug-levels.h"


/*
 * Pull TX transations from the TX FIFO and send them to the device
 * until there are no more.
 */
static
void i2400ms_tx_submit(struct work_struct *ws)
{
	int result;
	struct i2400ms *i2400ms = container_of(ws, struct i2400ms, tx_worker);
	struct i2400m *i2400m = &i2400ms->i2400m;
	struct sdio_func *func = i2400ms->func;
	struct device *dev = &func->dev;
	struct i2400m_msg_hdr *tx_msg;
	size_t tx_msg_size;

	d_fnstart(4, dev, "(i2400ms %p, i2400m %p)\n", i2400ms, i2400ms);

	while (NULL != (tx_msg = i2400m_tx_msg_get(i2400m, &tx_msg_size))) {
		d_printf(2, dev, "TX: submitting %zu bytes\n", tx_msg_size);
		d_dump(5, dev, tx_msg, tx_msg_size);

		sdio_claim_host(func);
		result = sdio_memcpy_toio(func, 0, tx_msg, tx_msg_size);
		sdio_release_host(func);

		i2400m_tx_msg_sent(i2400m);

		if (result < 0) {
			dev_err(dev, "TX: cannot submit TX; tx_msg @%zu %zu B:"
				" %d\n", (void *) tx_msg - i2400m->tx_buf,
				tx_msg_size, result);
		}

		d_printf(2, dev, "TX: %zub submitted\n", tx_msg_size);
	}

	d_fnend(4, dev, "(i2400ms %p) = void\n", i2400ms);
}


/*
 * The generic driver notifies us that there is data ready for TX
 *
 * Schedule a run of i2400ms_tx_submit() to handle it.
 */
void i2400ms_bus_tx_kick(struct i2400m *i2400m)
{
	struct i2400ms *i2400ms = container_of(i2400m, struct i2400ms, i2400m);
	struct device *dev = &i2400ms->func->dev;

	d_fnstart(3, dev, "(i2400m %p) = void\n", i2400m);

	/* schedule tx work, this is because tx may block, therefore
	 * it has to run in a thread context.
	 */
	queue_work(i2400ms->tx_workqueue, &i2400ms->tx_worker);

	d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
}

int i2400ms_tx_setup(struct i2400ms *i2400ms)
{
	int result;
	struct device *dev = &i2400ms->func->dev;
	struct i2400m *i2400m = &i2400ms->i2400m;

	d_fnstart(5, dev, "(i2400ms %p)\n", i2400ms);

	INIT_WORK(&i2400ms->tx_worker, i2400ms_tx_submit);
	snprintf(i2400ms->tx_wq_name, sizeof(i2400ms->tx_wq_name),
		 "%s-tx", i2400m->wimax_dev.name);
	i2400ms->tx_workqueue =
		create_singlethread_workqueue(i2400ms->tx_wq_name);
	if (NULL == i2400ms->tx_workqueue) {
		dev_err(dev, "TX: failed to create workqueue\n");
		result = -ENOMEM;
	} else
		result = 0;
	d_fnend(5, dev, "(i2400ms %p) = %d\n", i2400ms, result);
	return result;
}

void i2400ms_tx_release(struct i2400ms *i2400ms)
{
	if (i2400ms->tx_workqueue) {
		destroy_workqueue(i2400ms->tx_workqueue);
		i2400ms->tx_workqueue = NULL;
	}
}