/*
        Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
        <http://rt2x00.serialmonkey.com>

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        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.

        You should have received a copy of the GNU General Public License
        along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

/*
        Module: rt2x00mmio
        Abstract: rt2x00 generic mmio device routines.
 */

#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "rt2x00.h"
#include "rt2x00mmio.h"

/*
 * Register access.
 */
int rt2x00mmio_regbusy_read(struct rt2x00_dev *rt2x00dev,
                            const unsigned int offset,
                            const struct rt2x00_field32 field,
                            u32 *reg)
{
        unsigned int i;

        if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
                return 0;

        for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
                rt2x00mmio_register_read(rt2x00dev, offset, reg);
                if (!rt2x00_get_field32(*reg, field))
                        return 1;
                udelay(REGISTER_BUSY_DELAY);
        }

        printk_once(KERN_ERR "%s() Indirect register access failed: "
              "offset=0x%.08x, value=0x%.08x\n", __func__, offset, *reg);
        *reg = ~0;

        return 0;
}
EXPORT_SYMBOL_GPL(rt2x00mmio_regbusy_read);

bool rt2x00mmio_rxdone(struct rt2x00_dev *rt2x00dev)
{
        struct data_queue *queue = rt2x00dev->rx;
        struct queue_entry *entry;
        struct queue_entry_priv_mmio *entry_priv;
        struct skb_frame_desc *skbdesc;
        int max_rx = 16;

        while (--max_rx) {
                entry = rt2x00queue_get_entry(queue, Q_INDEX);
                entry_priv = entry->priv_data;

                if (rt2x00dev->ops->lib->get_entry_state(entry))
                        break;

                /*
                 * Fill in desc fields of the skb descriptor
                 */
                skbdesc = get_skb_frame_desc(entry->skb);
                skbdesc->desc = entry_priv->desc;
                skbdesc->desc_len = entry->queue->desc_size;

                /*
                 * DMA is already done, notify rt2x00lib that
                 * it finished successfully.
                 */
                rt2x00lib_dmastart(entry);
                rt2x00lib_dmadone(entry);

                /*
                 * Send the frame to rt2x00lib for further processing.
                 */
                rt2x00lib_rxdone(entry, GFP_ATOMIC);
        }

        return !max_rx;
}
EXPORT_SYMBOL_GPL(rt2x00mmio_rxdone);

void rt2x00mmio_flush_queue(struct data_queue *queue, bool drop)
{
        unsigned int i;

        for (i = 0; !rt2x00queue_empty(queue) && i < 10; i++)
                msleep(10);
}
EXPORT_SYMBOL_GPL(rt2x00mmio_flush_queue);

/*
 * Device initialization handlers.
 */
static int rt2x00mmio_alloc_queue_dma(struct rt2x00_dev *rt2x00dev,
                                      struct data_queue *queue)
{
        struct queue_entry_priv_mmio *entry_priv;
        void *addr;
        dma_addr_t dma;
        unsigned int i;

        /*
         * Allocate DMA memory for descriptor and buffer.
         */
        addr = dma_zalloc_coherent(rt2x00dev->dev,
                                   queue->limit * queue->desc_size, &dma,
                                   GFP_KERNEL);
        if (!addr)
                return -ENOMEM;

        /*
         * Initialize all queue entries to contain valid addresses.
         */
        for (i = 0; i < queue->limit; i++) {
                entry_priv = queue->entries[i].priv_data;
                entry_priv->desc = addr + i * queue->desc_size;
                entry_priv->desc_dma = dma + i * queue->desc_size;
        }

        return 0;
}

static void rt2x00mmio_free_queue_dma(struct rt2x00_dev *rt2x00dev,
                                      struct data_queue *queue)
{
        struct queue_entry_priv_mmio *entry_priv =
            queue->entries[0].priv_data;

        if (entry_priv->desc)
                dma_free_coherent(rt2x00dev->dev,
                                  queue->limit * queue->desc_size,
                                  entry_priv->desc, entry_priv->desc_dma);
        entry_priv->desc = NULL;
}

int rt2x00mmio_initialize(struct rt2x00_dev *rt2x00dev)
{
        struct data_queue *queue;
        int status;

        /*
         * Allocate DMA
         */
        queue_for_each(rt2x00dev, queue) {
                status = rt2x00mmio_alloc_queue_dma(rt2x00dev, queue);
                if (status)
                        goto exit;
        }

        /*
         * Register interrupt handler.
         */
        status = request_irq(rt2x00dev->irq,
                             rt2x00dev->ops->lib->irq_handler,
                             IRQF_SHARED, rt2x00dev->name, rt2x00dev);
        if (status) {
                rt2x00_err(rt2x00dev, "IRQ %d allocation failed (error %d)\n",
                           rt2x00dev->irq, status);
                goto exit;
        }

        return 0;

exit:
        queue_for_each(rt2x00dev, queue)
                rt2x00mmio_free_queue_dma(rt2x00dev, queue);

        return status;
}
EXPORT_SYMBOL_GPL(rt2x00mmio_initialize);

void rt2x00mmio_uninitialize(struct rt2x00_dev *rt2x00dev)
{
        struct data_queue *queue;

        /*
         * Free irq line.
         */
        free_irq(rt2x00dev->irq, rt2x00dev);

        /*
         * Free DMA
         */
        queue_for_each(rt2x00dev, queue)
                rt2x00mmio_free_queue_dma(rt2x00dev, queue);
}
EXPORT_SYMBOL_GPL(rt2x00mmio_uninitialize);

/*
 * rt2x00mmio module information.
 */
MODULE_AUTHOR(DRV_PROJECT);
MODULE_VERSION(DRV_VERSION);
MODULE_DESCRIPTION("rt2x00 mmio library");
MODULE_LICENSE("GPL");