/*
 * sound/oss/uart6850.c
 *
 *
 * Copyright (C) by Hannu Savolainen 1993-1997
 *
 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
 * Version 2 (June 1991). See the "COPYING" file distributed with this software
 * for more info.
 * Extended by Alan Cox for Red Hat Software. Now a loadable MIDI driver.
 * 28/4/97 - (C) Copyright Alan Cox. Released under the GPL version 2.
 *
 * Alan Cox:            Updated for new modular code. Removed snd_* irq handling. Now
 *                      uses native linux resources
 * Christoph Hellwig:   Adapted to module_init/module_exit
 * Jeff Garzik:         Made it work again, in theory
 *                      FIXME: If the request_irq() succeeds, the probe succeeds. Ug.
 *
 *      Status: Testing required (no shit -jgarzik)
 *
 *
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/spinlock.h>
/* Mon Nov 22 22:38:35 MET 1993 marco@driq.home.usn.nl:
 *      added 6850 support, used with COVOX SoundMaster II and custom cards.
 */

#include "sound_config.h"

static int uart6850_base = 0x330;

static int *uart6850_osp;

#define DATAPORT   (uart6850_base)
#define COMDPORT   (uart6850_base+1)
#define STATPORT   (uart6850_base+1)

static int uart6850_status(void)
{
        return inb(STATPORT);
}

#define input_avail()           (uart6850_status()&INPUT_AVAIL)
#define output_ready()          (uart6850_status()&OUTPUT_READY)

static void uart6850_cmd(unsigned char cmd)
{
        outb(cmd, COMDPORT);
}

static int uart6850_read(void)
{
        return inb(DATAPORT);
}

static void uart6850_write(unsigned char byte)
{
        outb(byte, DATAPORT);
}

#define OUTPUT_READY    0x02    /* Mask for data ready Bit */
#define INPUT_AVAIL     0x01    /* Mask for Data Send Ready Bit */

#define UART_RESET      0x95
#define UART_MODE_ON    0x03

static int uart6850_opened;
static int uart6850_irq;
static int uart6850_detected;
static int my_dev;
static DEFINE_SPINLOCK(lock);

static void (*midi_input_intr) (int dev, unsigned char data);
static void poll_uart6850(unsigned long dummy);


static DEFINE_TIMER(uart6850_timer, poll_uart6850, 0, 0);

static void uart6850_input_loop(void)
{
        int count = 10;

        while (count)
        {
                /*
                 * Not timed out
                 */
                if (input_avail())
                {
                        unsigned char c = uart6850_read();
                        count = 100;
                        if (uart6850_opened & OPEN_READ)
                                midi_input_intr(my_dev, c);
                }
                else
                {
                        while (!input_avail() && count)
                                count--;
                }
        }
}

static irqreturn_t m6850intr(int irq, void *dev_id)
{
        if (input_avail())
                uart6850_input_loop();
        return IRQ_HANDLED;
}

/*
 *      It looks like there is no input interrupts in the UART mode. Let's try
 *      polling.
 */

static void poll_uart6850(unsigned long dummy)
{
        unsigned long flags;

        if (!(uart6850_opened & OPEN_READ))
                return;         /* Device has been closed */

        spin_lock_irqsave(&lock,flags);
        if (input_avail())
                uart6850_input_loop();

        uart6850_timer.expires = 1 + jiffies;
        add_timer(&uart6850_timer);
        
        /*
         *      Come back later
         */

        spin_unlock_irqrestore(&lock,flags);
}

static int uart6850_open(int dev, int mode,
              void            (*input) (int dev, unsigned char data),
              void            (*output) (int dev)
)
{
        if (uart6850_opened)
        {
/*                printk("Midi6850: Midi busy\n");*/
                  return -EBUSY;
        };

        uart6850_cmd(UART_RESET);
        uart6850_input_loop();
        midi_input_intr = input;
        uart6850_opened = mode;
        poll_uart6850(0);       /*
                                 * Enable input polling
                                 */

        return 0;
}

static void uart6850_close(int dev)
{
        uart6850_cmd(UART_MODE_ON);
        del_timer(&uart6850_timer);
        uart6850_opened = 0;
}

static int uart6850_out(int dev, unsigned char midi_byte)
{
        int timeout;
        unsigned long flags;

        /*
         * Test for input since pending input seems to block the output.
         */

        spin_lock_irqsave(&lock,flags);

        if (input_avail())
                uart6850_input_loop();

        spin_unlock_irqrestore(&lock,flags);

        /*
         * Sometimes it takes about 13000 loops before the output becomes ready
         * (After reset). Normally it takes just about 10 loops.
         */

        for (timeout = 30000; timeout > 0 && !output_ready(); timeout--);       /*
                                                                                 * Wait
                                                                                 */
        if (!output_ready())
        {
                printk(KERN_WARNING "Midi6850: Timeout\n");
                return 0;
        }
        uart6850_write(midi_byte);
        return 1;
}

static inline int uart6850_command(int dev, unsigned char *midi_byte)
{
        return 1;
}

static inline int uart6850_start_read(int dev)
{
        return 0;
}

static inline int uart6850_end_read(int dev)
{
        return 0;
}

static inline void uart6850_kick(int dev)
{
}

static inline int uart6850_buffer_status(int dev)
{
        return 0;               /*
                                 * No data in buffers
                                 */
}

#define MIDI_SYNTH_NAME "6850 UART Midi"
#define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
#include "midi_synth.h"

static struct midi_operations uart6850_operations =
{
        .owner          = THIS_MODULE,
        .info           = {"6850 UART", 0, 0, SNDCARD_UART6850},
        .converter      = &std_midi_synth,
        .in_info        = {0},
        .open           = uart6850_open,
        .close          = uart6850_close,
        .outputc        = uart6850_out,
        .start_read     = uart6850_start_read,
        .end_read       = uart6850_end_read,
        .kick           = uart6850_kick,
        .command        = uart6850_command,
        .buffer_status  = uart6850_buffer_status
};


static void __init attach_uart6850(struct address_info *hw_config)
{
        int ok, timeout;
        unsigned long   flags;

        if (!uart6850_detected)
                return;

        if ((my_dev = sound_alloc_mididev()) == -1)
        {
                printk(KERN_INFO "uart6850: Too many midi devices detected\n");
                return;
        }
        uart6850_base = hw_config->io_base;
        uart6850_osp = hw_config->osp;
        uart6850_irq = hw_config->irq;

        spin_lock_irqsave(&lock,flags);

        for (timeout = 30000; timeout > 0 && !output_ready(); timeout--);       /*
                                                                                 * Wait
                                                                                 */
        uart6850_cmd(UART_MODE_ON);
        ok = 1;
        spin_unlock_irqrestore(&lock,flags);

        conf_printf("6850 Midi Interface", hw_config);

        std_midi_synth.midi_dev = my_dev;
        hw_config->slots[4] = my_dev;
        midi_devs[my_dev] = &uart6850_operations;
        sequencer_init();
}

static inline int reset_uart6850(void)
{
        uart6850_read();
        return 1;               /*
                                 * OK
                                 */
}

static int __init probe_uart6850(struct address_info *hw_config)
{
        int ok;

        uart6850_osp = hw_config->osp;
        uart6850_base = hw_config->io_base;
        uart6850_irq = hw_config->irq;

        if (request_irq(uart6850_irq, m6850intr, 0, "MIDI6850", NULL) < 0)
                return 0;

        ok = reset_uart6850();
        uart6850_detected = ok;
        return ok;
}

static void __exit unload_uart6850(struct address_info *hw_config)
{
        free_irq(hw_config->irq, NULL);
        sound_unload_mididev(hw_config->slots[4]);
}

static struct address_info cfg_mpu;

static int __initdata io = -1;
static int __initdata irq = -1;

module_param(io, int, 0);
module_param(irq, int, 0);

static int __init init_uart6850(void)
{
        cfg_mpu.io_base = io;
        cfg_mpu.irq = irq;

        if (cfg_mpu.io_base == -1 || cfg_mpu.irq == -1) {
                printk(KERN_INFO "uart6850: irq and io must be set.\n");
                return -EINVAL;
        }

        if (probe_uart6850(&cfg_mpu))
                return -ENODEV;
        attach_uart6850(&cfg_mpu);

        return 0;
}

static void __exit cleanup_uart6850(void)
{
        unload_uart6850(&cfg_mpu);
}

module_init(init_uart6850);
module_exit(cleanup_uart6850);

#ifndef MODULE
static int __init setup_uart6850(char *str)
{
        /* io, irq */
        int ints[3];
        
        str = get_options(str, ARRAY_SIZE(ints), ints);
        
        io = ints[1];
        irq = ints[2];

        return 1;
}
__setup("uart6850=", setup_uart6850);
#endif
MODULE_LICENSE("GPL");