uart401.c

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/*
 * sound/oss/uart401.c
 *
 * MPU-401 UART driver (formerly uart401_midi.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.
 *
 * Changes:
 *  Alan Cox        Reformatted, removed sound_mem usage, use normal Linux
 *              interrupt allocation. Protect against bogus unload
 *              Fixed to allow IRQ > 15
 *  Christoph Hellwig   Adapted to module_init/module_exit
 *  Arnaldo C. de Melo  got rid of check_region
 *
 * Status:
 *      Untested
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "sound_config.h"

#include "mpu401.h"

typedef struct uart401_devc
{
    int             base;
    int             irq;
    int            *osp;
    void            (*midi_input_intr) (int dev, unsigned char data);
    int             opened, disabled;
    volatile unsigned char input_byte;
    int             my_dev;
    int             share_irq;
    spinlock_t  lock;
}
uart401_devc;

#define DATAPORT   (devc->base)
#define COMDPORT   (devc->base+1)
#define STATPORT   (devc->base+1)

static int uart401_status(uart401_devc * devc)
{
    return inb(STATPORT);
}

#define input_avail(devc) (!(uart401_status(devc)&INPUT_AVAIL))
#define output_ready(devc)  (!(uart401_status(devc)&OUTPUT_READY))

static void uart401_cmd(uart401_devc * devc, unsigned char cmd)
{
    outb((cmd), COMDPORT);
}

static int uart401_read(uart401_devc * devc)
{
    return inb(DATAPORT);
}

static void uart401_write(uart401_devc * devc, unsigned char byte)
{
    outb((byte), DATAPORT);
}

#define OUTPUT_READY    0x40
#define INPUT_AVAIL 0x80
#define MPU_ACK     0xFE
#define MPU_RESET   0xFF
#define UART_MODE_ON    0x3F

static int      reset_uart401(uart401_devc * devc);
static void     enter_uart_mode(uart401_devc * devc);

static void uart401_input_loop(uart401_devc * devc)
{
    int work_limit=30000;
    
    while (input_avail(devc) && --work_limit)
    {
        unsigned char   c = uart401_read(devc);

        if (c == MPU_ACK)
            devc->input_byte = c;
        else if (devc->opened & OPEN_READ && devc->midi_input_intr)
            devc->midi_input_intr(devc->my_dev, c);
    }
    if(work_limit==0)
        printk(KERN_WARNING "Too much work in interrupt on uart401 (0x%X). UART jabbering ??\n", devc->base);
}

irqreturn_t uart401intr(int irq, void *dev_id)
{
    uart401_devc *devc = dev_id;

    if (devc == NULL)
    {
        printk(KERN_ERR "uart401: bad devc\n");
        return IRQ_NONE;
    }

    if (input_avail(devc))
        uart401_input_loop(devc);
    return IRQ_HANDLED;
}

static int
uart401_open(int dev, int mode,
         void            (*input) (int dev, unsigned char data),
         void            (*output) (int dev)
)
{
    uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;

    if (devc->opened)
        return -EBUSY;

    /* Flush the UART */
    
    while (input_avail(devc))
        uart401_read(devc);

    devc->midi_input_intr = input;
    devc->opened = mode;
    enter_uart_mode(devc);
    devc->disabled = 0;

    return 0;
}

static void uart401_close(int dev)
{
    uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;

    reset_uart401(devc);
    devc->opened = 0;
}

static int uart401_out(int dev, unsigned char midi_byte)
{
    int timeout;
    unsigned long flags;
    uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;

    if (devc->disabled)
        return 1;
    /*
     * Test for input since pending input seems to block the output.
     */

    spin_lock_irqsave(&devc->lock,flags);   
    if (input_avail(devc))
        uart401_input_loop(devc);

    spin_unlock_irqrestore(&devc->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(devc); timeout--);

    if (!output_ready(devc))
    {
          printk(KERN_WARNING "uart401: Timeout - Device not responding\n");
          devc->disabled = 1;
          reset_uart401(devc);
          enter_uart_mode(devc);
          return 1;
    }
    uart401_write(devc, midi_byte);
    return 1;
}

static inline int uart401_start_read(int dev)
{
    return 0;
}

static inline int uart401_end_read(int dev)
{
    return 0;
}

static inline void uart401_kick(int dev)
{
}

static inline int uart401_buffer_status(int dev)
{
    return 0;
}

#define MIDI_SYNTH_NAME "MPU-401 UART"
#define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
#include "midi_synth.h"

static const struct midi_operations uart401_operations =
{
    .owner      = THIS_MODULE,
    .info       = {"MPU-401 (UART) MIDI", 0, 0, SNDCARD_MPU401},
    .converter  = &std_midi_synth,
    .in_info    = {0},
    .open       = uart401_open,
    .close      = uart401_close,
    .outputc    = uart401_out,
    .start_read = uart401_start_read,
    .end_read   = uart401_end_read,
    .kick       = uart401_kick,
    .buffer_status  = uart401_buffer_status,
};

static void enter_uart_mode(uart401_devc * devc)
{
    int ok, timeout;
    unsigned long flags;

    spin_lock_irqsave(&devc->lock,flags);   
    for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);

    devc->input_byte = 0;
    uart401_cmd(devc, UART_MODE_ON);

    ok = 0;
    for (timeout = 50000; timeout > 0 && !ok; timeout--)
        if (devc->input_byte == MPU_ACK)
            ok = 1;
        else if (input_avail(devc))
            if (uart401_read(devc) == MPU_ACK)
                ok = 1;

    spin_unlock_irqrestore(&devc->lock,flags);
}

static int reset_uart401(uart401_devc * devc)
{
    int ok, timeout, n;

    /*
     * Send the RESET command. Try again if no success at the first time.
     */

    ok = 0;

    for (n = 0; n < 2 && !ok; n++)
    {
        for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);
        devc->input_byte = 0;
        uart401_cmd(devc, MPU_RESET);

        /*
         * Wait at least 25 msec. This method is not accurate so let's make the
         * loop bit longer. Cannot sleep since this is called during boot.
         */

        for (timeout = 50000; timeout > 0 && !ok; timeout--)
        {
            if (devc->input_byte == MPU_ACK)    /* Interrupt */
                ok = 1;
            else if (input_avail(devc))
            {
                if (uart401_read(devc) == MPU_ACK)
                    ok = 1;
            }
        }
    }


    if (ok)
    {
        DEB(printk("Reset UART401 OK\n"));
    }
    else
        DDB(printk("Reset UART401 failed - No hardware detected.\n"));

    if (ok)
        uart401_input_loop(devc);   /*
                         * Flush input before enabling interrupts
                         */

    return ok;
}

int probe_uart401(struct address_info *hw_config, struct module *owner)
{
    uart401_devc *devc;
    char *name = "MPU-401 (UART) MIDI";
    int ok = 0;
    unsigned long flags;

    DDB(printk("Entered probe_uart401()\n"));

    /* Default to "not found" */
    hw_config->slots[4] = -1;

    if (!request_region(hw_config->io_base, 4, "MPU-401 UART")) {
        printk(KERN_INFO "uart401: could not request_region(%d, 4)\n", hw_config->io_base);
        return 0;
    }

    devc = kmalloc(sizeof(uart401_devc), GFP_KERNEL);
    if (!devc) {
        printk(KERN_WARNING "uart401: Can't allocate memory\n");
        goto cleanup_region;
    }

    devc->base = hw_config->io_base;
    devc->irq = hw_config->irq;
    devc->osp = hw_config->osp;
    devc->midi_input_intr = NULL;
    devc->opened = 0;
    devc->input_byte = 0;
    devc->my_dev = 0;
    devc->share_irq = 0;
    spin_lock_init(&devc->lock);

    spin_lock_irqsave(&devc->lock,flags);   
    ok = reset_uart401(devc);
    spin_unlock_irqrestore(&devc->lock,flags);

    if (!ok)
        goto cleanup_devc;

    if (hw_config->name)
        name = hw_config->name;

    if (devc->irq < 0) {
        devc->share_irq = 1;
        devc->irq *= -1;
    } else
        devc->share_irq = 0;

    if (!devc->share_irq)
        if (request_irq(devc->irq, uart401intr, 0, "MPU-401 UART", devc) < 0) {
            printk(KERN_WARNING "uart401: Failed to allocate IRQ%d\n", devc->irq);
            devc->share_irq = 1;
        }
    devc->my_dev = sound_alloc_mididev();
    enter_uart_mode(devc);

    if (devc->my_dev == -1) {
        printk(KERN_INFO "uart401: Too many midi devices detected\n");
        goto cleanup_irq;
    }
    conf_printf(name, hw_config);
    midi_devs[devc->my_dev] = kmalloc(sizeof(struct midi_operations), GFP_KERNEL);
    if (!midi_devs[devc->my_dev]) {
        printk(KERN_ERR "uart401: Failed to allocate memory\n");
        goto cleanup_unload_mididev;
    }
    memcpy(midi_devs[devc->my_dev], &uart401_operations, sizeof(struct midi_operations));

    if (owner)
        midi_devs[devc->my_dev]->owner = owner;
    
    midi_devs[devc->my_dev]->devc = devc;
    midi_devs[devc->my_dev]->converter = kmalloc(sizeof(struct synth_operations), GFP_KERNEL);
    if (!midi_devs[devc->my_dev]->converter) {
        printk(KERN_WARNING "uart401: Failed to allocate memory\n");
        goto cleanup_midi_devs;
    }
    memcpy(midi_devs[devc->my_dev]->converter, &std_midi_synth, sizeof(struct synth_operations));
    strcpy(midi_devs[devc->my_dev]->info.name, name);
    midi_devs[devc->my_dev]->converter->id = "UART401";
    midi_devs[devc->my_dev]->converter->midi_dev = devc->my_dev;

    if (owner)
        midi_devs[devc->my_dev]->converter->owner = owner;

    hw_config->slots[4] = devc->my_dev;
    sequencer_init();
    devc->opened = 0;
    return 1;
cleanup_midi_devs:
    kfree(midi_devs[devc->my_dev]);
cleanup_unload_mididev:
    sound_unload_mididev(devc->my_dev);
cleanup_irq:
    if (!devc->share_irq)
        free_irq(devc->irq, devc);
cleanup_devc:
    kfree(devc);
cleanup_region:
    release_region(hw_config->io_base, 4);
    return 0;
}

void unload_uart401(struct address_info *hw_config)
{
    uart401_devc *devc;
    int n=hw_config->slots[4];
    
    /* Not set up */
    if(n==-1 || midi_devs[n]==NULL)
        return;
        
    /* Not allocated (erm ??) */
    
    devc = midi_devs[hw_config->slots[4]]->devc;
    if (devc == NULL)
        return;

    reset_uart401(devc);
    release_region(hw_config->io_base, 4);

    if (!devc->share_irq)
        free_irq(devc->irq, devc);
    if (devc)
    {
        kfree(midi_devs[devc->my_dev]->converter);
        kfree(midi_devs[devc->my_dev]);
        kfree(devc);
        devc = NULL;
    }
    /* This kills midi_devs[x] */
    sound_unload_mididev(hw_config->slots[4]);
}

EXPORT_SYMBOL(probe_uart401);
EXPORT_SYMBOL(unload_uart401);
EXPORT_SYMBOL(uart401intr);

static struct address_info cfg_mpu;

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

module_param(io, int, 0444);
module_param(irq, int, 0444);


static int __init init_uart401(void)
{
    cfg_mpu.irq = irq;
    cfg_mpu.io_base = io;

    /* Can be loaded either for module use or to provide functions
       to others */
    if (cfg_mpu.io_base != -1 && cfg_mpu.irq != -1) {
        printk(KERN_INFO "MPU-401 UART driver Copyright (C) Hannu Savolainen 1993-1997");
        if (!probe_uart401(&cfg_mpu, THIS_MODULE))
            return -ENODEV;
    }

    return 0;
}

static void __exit cleanup_uart401(void)
{
    if (cfg_mpu.io_base != -1 && cfg_mpu.irq != -1)
        unload_uart401(&cfg_mpu);
}

module_init(init_uart401);
module_exit(cleanup_uart401);

#ifndef MODULE
static int __init setup_uart401(char *str)
{
    /* io, irq */
    int ints[3];
    
    str = get_options(str, ARRAY_SIZE(ints), ints);

    io = ints[1];
    irq = ints[2];
    
    return 1;
}

__setup("uart401=", setup_uart401);
#endif
MODULE_LICENSE("GPL");