uart6850.c

Go to the documentation of this file.

/*
 * 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 [email protected]:
 *      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");