/*
 * The DSP56001 Device Driver, saviour of the Free World(tm)
 *
 * Authors: Fredrik Noring   <noring@nocrew.org>
 *          lars brinkhoff   <lars@nocrew.org>
 *          Tomas Berndtsson <tomas@nocrew.org>
 *
 * First version May 1996
 *
 * History:
 *  97-01-29   Tomas Berndtsson,
 *               Integrated with Linux 2.1.21 kernel sources.
 *  97-02-15   Tomas Berndtsson,
 *               Fixed for kernel 2.1.26
 *
 * BUGS:
 *  Hmm... there must be something here :)
 *
 * Copyright (C) 1996,1997 Fredrik Noring, lars brinkhoff & Tomas Berndtsson
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/version.h>
#include <linux/slab.h>	/* for kmalloc() and kfree() */
#include <linux/sched.h>	/* for struct wait_queue etc */
#include <linux/major.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/delay.h>	/* guess what */
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/smp_lock.h>

#include <asm/segment.h>
#include <asm/atarihw.h>
#include <asm/traps.h>
#include <asm/uaccess.h>	/* For put_user and get_user */

#include <asm/dsp56k.h>

/* minor devices */
#define DSP56K_DEV_56001        0    /* The only device so far */

#define TIMEOUT    10   /* Host port timeout in number of tries */
#define MAXIO    2048   /* Maximum number of words before sleep */
#define DSP56K_MAX_BINARY_LENGTH (3*64*1024)

#define DSP56K_TX_INT_ON	dsp56k_host_interface.icr |=  DSP56K_ICR_TREQ
#define DSP56K_RX_INT_ON	dsp56k_host_interface.icr |=  DSP56K_ICR_RREQ
#define DSP56K_TX_INT_OFF	dsp56k_host_interface.icr &= ~DSP56K_ICR_TREQ
#define DSP56K_RX_INT_OFF	dsp56k_host_interface.icr &= ~DSP56K_ICR_RREQ

#define DSP56K_TRANSMIT		(dsp56k_host_interface.isr & DSP56K_ISR_TXDE)
#define DSP56K_RECEIVE		(dsp56k_host_interface.isr & DSP56K_ISR_RXDF)

#define max(a,b) ((a) > (b) ? (a) : (b))
#define min(a,b) ((a) < (b) ? (a) : (b))

#define wait_some(n) \
{ \
	current->state = TASK_INTERRUPTIBLE; \
	schedule_timeout(n); \
}

#define handshake(count, maxio, timeout, ENABLE, f) \
{ \
	long i, t, m; \
	while (count > 0) { \
		m = min(count, maxio); \
		for (i = 0; i < m; i++) { \
			for (t = 0; t < timeout && !ENABLE; t++) \
				wait_some(HZ/50); \
			if(!ENABLE) \
				return -EIO; \
			f; \
		} \
		count -= m; \
		if (m == maxio) wait_some(HZ/50); \
	} \
}

#define tx_wait(n) \
{ \
	int t; \
	for(t = 0; t < n && !DSP56K_TRANSMIT; t++) \
		wait_some(HZ/100); \
	if(!DSP56K_TRANSMIT) { \
		return -EIO; \
	} \
}

#define rx_wait(n) \
{ \
	int t; \
	for(t = 0; t < n && !DSP56K_RECEIVE; t++) \
		wait_some(HZ/100); \
	if(!DSP56K_RECEIVE) { \
		return -EIO; \
	} \
}

/* DSP56001 bootstrap code */
static char bootstrap[] = {
	0x0c, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x60, 0xf4, 0x00, 0x00, 0x00, 0x4f, 0x61, 0xf4,
	0x00, 0x00, 0x7e, 0xa9, 0x06, 0x2e, 0x80, 0x00, 0x00, 0x47,
	0x07, 0xd8, 0x84, 0x07, 0x59, 0x84, 0x08, 0xf4, 0xa8, 0x00,
	0x00, 0x04, 0x08, 0xf4, 0xbf, 0x00, 0x0c, 0x00, 0x00, 0xfe,
	0xb8, 0x0a, 0xf0, 0x80, 0x00, 0x7e, 0xa9, 0x08, 0xf4, 0xa0,
	0x00, 0x00, 0x01, 0x08, 0xf4, 0xbe, 0x00, 0x00, 0x00, 0x0a,
	0xa9, 0x80, 0x00, 0x7e, 0xad, 0x08, 0x4e, 0x2b, 0x44, 0xf4,
	0x00, 0x00, 0x00, 0x03, 0x44, 0xf4, 0x45, 0x00, 0x00, 0x01,
	0x0e, 0xa0, 0x00, 0x0a, 0xa9, 0x80, 0x00, 0x7e, 0xb5, 0x08,
	0x50, 0x2b, 0x0a, 0xa9, 0x80, 0x00, 0x7e, 0xb8, 0x08, 0x46,
	0x2b, 0x44, 0xf4, 0x45, 0x00, 0x00, 0x02, 0x0a, 0xf0, 0xaa,
	0x00, 0x7e, 0xc9, 0x20, 0x00, 0x45, 0x0a, 0xf0, 0xaa, 0x00,
	0x7e, 0xd0, 0x06, 0xc6, 0x00, 0x00, 0x7e, 0xc6, 0x0a, 0xa9,
	0x80, 0x00, 0x7e, 0xc4, 0x08, 0x58, 0x6b, 0x0a, 0xf0, 0x80,
	0x00, 0x7e, 0xad, 0x06, 0xc6, 0x00, 0x00, 0x7e, 0xcd, 0x0a,
	0xa9, 0x80, 0x00, 0x7e, 0xcb, 0x08, 0x58, 0xab, 0x0a, 0xf0,
	0x80, 0x00, 0x7e, 0xad, 0x06, 0xc6, 0x00, 0x00, 0x7e, 0xd4,
	0x0a, 0xa9, 0x80, 0x00, 0x7e, 0xd2, 0x08, 0x58, 0xeb, 0x0a,
	0xf0, 0x80, 0x00, 0x7e, 0xad};
static int sizeof_bootstrap = 375;


static struct dsp56k_device {
	int in_use;
	long maxio, timeout;
	int tx_wsize, rx_wsize;
} dsp56k;

static int dsp56k_reset(void)
{
	u_char status;
	
	/* Power down the DSP */
	sound_ym.rd_data_reg_sel = 14;
	status = sound_ym.rd_data_reg_sel & 0xef;
	sound_ym.wd_data = status;
	sound_ym.wd_data = status | 0x10;
  
	udelay(10);
  
	/* Power up the DSP */
	sound_ym.rd_data_reg_sel = 14;
	sound_ym.wd_data = sound_ym.rd_data_reg_sel & 0xef;

	return 0;
}

static int dsp56k_upload(u_char *bin, int len)
{
	int i;
	u_char *p;
	
	dsp56k_reset();
  
	p = bootstrap;
	for (i = 0; i < sizeof_bootstrap/3; i++) {
		/* tx_wait(10); */
		dsp56k_host_interface.data.b[1] = *p++;
		dsp56k_host_interface.data.b[2] = *p++;
		dsp56k_host_interface.data.b[3] = *p++;
	}
	for (; i < 512; i++) {
		/* tx_wait(10); */
		dsp56k_host_interface.data.b[1] = 0;
		dsp56k_host_interface.data.b[2] = 0;
		dsp56k_host_interface.data.b[3] = 0;
	}
  
	for (i = 0; i < len; i++) {
		tx_wait(10);
		get_user(dsp56k_host_interface.data.b[1], bin++);
		get_user(dsp56k_host_interface.data.b[2], bin++);
		get_user(dsp56k_host_interface.data.b[3], bin++);
	}

	tx_wait(10);
	dsp56k_host_interface.data.l = 3;    /* Magic execute */

	return 0;
}

static ssize_t dsp56k_read(struct file *file, char *buf, size_t count,
			   loff_t *ppos)
{
	struct inode *inode = file->f_dentry->d_inode;
	int dev = MINOR(inode->i_rdev) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
	{

		long n;

		/* Don't do anything if nothing is to be done */
		if (!count) return 0;

		n = 0;
		switch (dsp56k.rx_wsize) {
		case 1:  /* 8 bit */
		{
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.b[3], buf+n++));
			return n;
		}
		case 2:  /* 16 bit */
		{
			short *data;

			count /= 2;
			data = (short*) buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.w[1], data+n++));
			return 2*n;
		}
		case 3:  /* 24 bit */
		{
			count /= 3;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.b[1], buf+n++);
				  put_user(dsp56k_host_interface.data.b[2], buf+n++);
				  put_user(dsp56k_host_interface.data.b[3], buf+n++));
			return 3*n;
		}
		case 4:  /* 32 bit */
		{
			long *data;

			count /= 4;
			data = (long*) buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_RECEIVE,
				  put_user(dsp56k_host_interface.data.l, data+n++));
			return 4*n;
		}
		}
		return -EFAULT;
	}

	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}
}

static ssize_t dsp56k_write(struct file *file, const char *buf, size_t count,
			    loff_t *ppos)
{
	struct inode *inode = file->f_dentry->d_inode;
	int dev = MINOR(inode->i_rdev) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
	{
		long n;

		/* Don't do anything if nothing is to be done */
		if (!count) return 0;

		n = 0;
		switch (dsp56k.tx_wsize) {
		case 1:  /* 8 bit */
		{
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.b[3], buf+n++));
			return n;
		}
		case 2:  /* 16 bit */
		{
			short *data;

			count /= 2;
			data = (short*) buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.w[1], data+n++));
			return 2*n;
		}
		case 3:  /* 24 bit */
		{
			count /= 3;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.b[1], buf+n++);
				  get_user(dsp56k_host_interface.data.b[2], buf+n++);
				  get_user(dsp56k_host_interface.data.b[3], buf+n++));
			return 3*n;
		}
		case 4:  /* 32 bit */
		{
			long *data;

			count /= 4;
			data = (long*) buf;
			handshake(count, dsp56k.maxio, dsp56k.timeout, DSP56K_TRANSMIT,
				  get_user(dsp56k_host_interface.data.l, data+n++));
			return 4*n;
		}
		}

		return -EFAULT;
	}
	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}
}

static int dsp56k_ioctl(struct inode *inode, struct file *file,
			unsigned int cmd, unsigned long arg)
{
	int dev = MINOR(inode->i_rdev) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:

		switch(cmd) {
		case DSP56K_UPLOAD:
		{
			char *bin;
			int r, len;
			struct dsp56k_upload *binary = (struct dsp56k_upload *) arg;
    
			if(get_user(len, &binary->len) < 0)
				return -EFAULT;
			if(get_user(bin, &binary->bin) < 0)
				return -EFAULT;
		
			if (len == 0) {
				return -EINVAL;      /* nothing to upload?!? */
			}
			if (len > DSP56K_MAX_BINARY_LENGTH) {
				return -EINVAL;
			}
    
			r = dsp56k_upload(bin, len);
			if (r < 0) {
				return r;
			}
    
			break;
		}
		case DSP56K_SET_TX_WSIZE:
			if (arg > 4 || arg < 1)
				return -EINVAL;
			dsp56k.tx_wsize = (int) arg;
			break;
		case DSP56K_SET_RX_WSIZE:
			if (arg > 4 || arg < 1)
				return -EINVAL;
			dsp56k.rx_wsize = (int) arg;
			break;
		case DSP56K_HOST_FLAGS:
		{
			int dir, out, status;
			struct dsp56k_host_flags *hf = (struct dsp56k_host_flags*) arg;
    
			if(get_user(dir, &hf->dir) < 0)
				return -EFAULT;
			if(get_user(out, &hf->out) < 0)
				return -EFAULT;

			if ((dir & 0x1) && (out & 0x1))
				dsp56k_host_interface.icr |= DSP56K_ICR_HF0;
			else if (dir & 0x1)
				dsp56k_host_interface.icr &= ~DSP56K_ICR_HF0;
			if ((dir & 0x2) && (out & 0x2))
				dsp56k_host_interface.icr |= DSP56K_ICR_HF1;
			else if (dir & 0x2)
				dsp56k_host_interface.icr &= ~DSP56K_ICR_HF1;

			status = 0;
			if (dsp56k_host_interface.icr & DSP56K_ICR_HF0) status |= 0x1;
			if (dsp56k_host_interface.icr & DSP56K_ICR_HF1) status |= 0x2;
			if (dsp56k_host_interface.isr & DSP56K_ISR_HF2) status |= 0x4;
			if (dsp56k_host_interface.isr & DSP56K_ISR_HF3) status |= 0x8;

			return put_user(status, &hf->status);
		}
		case DSP56K_HOST_CMD:
			if (arg > 31 || arg < 0)
				return -EINVAL;
			dsp56k_host_interface.cvr = (u_char)((arg & DSP56K_CVR_HV_MASK) |
							     DSP56K_CVR_HC);
			break;
		default:
			return -EINVAL;
		}
		return 0;

	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}
}

/* As of 2.1.26 this should be dsp56k_poll,
 * but how do I then check device minor number?
 * Do I need this function at all???
 */
#if 0
static unsigned int dsp56k_poll(struct file *file, poll_table *wait)
{
	int dev = MINOR(file->f_dentry->d_inode->i_rdev) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:
		/* poll_wait(file, ???, wait); */
		return POLLIN | POLLRDNORM | POLLOUT;

	default:
		printk("DSP56k driver: Unknown minor device: %d\n", dev);
		return 0;
	}
}
#endif

static int dsp56k_open(struct inode *inode, struct file *file)
{
	int dev = MINOR(inode->i_rdev) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:

		if (dsp56k.in_use)
			return -EBUSY;

		dsp56k.in_use = 1;
		dsp56k.timeout = TIMEOUT;
		dsp56k.maxio = MAXIO;
		dsp56k.rx_wsize = dsp56k.tx_wsize = 4; 

		DSP56K_TX_INT_OFF;
		DSP56K_RX_INT_OFF;

		/* Zero host flags */
		dsp56k_host_interface.icr &= ~DSP56K_ICR_HF0;
		dsp56k_host_interface.icr &= ~DSP56K_ICR_HF1;

		break;

	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}

	return 0;
}

static int dsp56k_release(struct inode *inode, struct file *file)
{
	int dev = MINOR(inode->i_rdev) & 0x0f;

	switch(dev)
	{
	case DSP56K_DEV_56001:

		lock_kernel();
		dsp56k.in_use = 0;
		unlock_kernel();

		break;
	default:
		printk(KERN_ERR "DSP56k driver: Unknown minor device: %d\n", dev);
		return -ENXIO;
	}

	return 0;
}

static struct file_operations dsp56k_fops = {
	owner:		THIS_MODULE,
	read:		dsp56k_read,
	write:		dsp56k_write,
	ioctl:		dsp56k_ioctl,
	open:		dsp56k_open,
	release:	dsp56k_release,
};


/****** Init and module functions ******/

static devfs_handle_t devfs_handle;

static const char banner[] __initdata = KERN_INFO "DSP56k driver installed\n";

static int __init dsp56k_init_driver(void)
{
	if(!MACH_IS_ATARI || !ATARIHW_PRESENT(DSP56K)) {
		printk("DSP56k driver: Hardware not present\n");
		return -ENODEV;
	}

	if(devfs_register_chrdev(DSP56K_MAJOR, "dsp56k", &dsp56k_fops)) {
		printk("DSP56k driver: Unable to register driver\n");
		return -ENODEV;
	}
	devfs_handle = devfs_register(NULL, "dsp56k", DEVFS_FL_DEFAULT,
				      DSP56K_MAJOR, 0,
				      S_IFCHR | S_IRUSR | S_IWUSR,
				      &dsp56k_fops, NULL);

	printk(banner);
	return 0;
}
module_init(dsp56k_init_driver);

static void __exit dsp56k_cleanup_driver(void)
{
	devfs_unregister_chrdev(DSP56K_MAJOR, "dsp56k");
	devfs_unregister(devfs_handle);
}
module_exit(dsp56k_cleanup_driver);