[mirror_ubuntu-artful-kernel.git] / arch / mips / kernel / rtlx.c

/*
 * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope 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, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <asm/mipsmtregs.h>
#include <asm/bitops.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/rtlx.h>
#include <asm/uaccess.h>

#define RTLX_TARG_VPE 1

static struct rtlx_info *rtlx;
static int major;
static char module_name[] = "rtlx";
static struct irqaction irq;
static int irq_num;

static inline int spacefree(int read, int write, int size)
{
	if (read == write) {
		/*
		 * never fill the buffer completely, so indexes are always
		 * equal if empty and only empty, or !equal if data available
		 */
		return size - 1;
	}

	return ((read + size - write) % size) - 1;
}

static struct chan_waitqueues {
	wait_queue_head_t rt_queue;
	wait_queue_head_t lx_queue;
} channel_wqs[RTLX_CHANNELS];

extern void *vpe_get_shared(int index);

static void rtlx_dispatch(struct pt_regs *regs)
{
	do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
}

static irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	int i;

	for (i = 0; i < RTLX_CHANNELS; i++) {
		struct rtlx_channel *chan = &rtlx->channel[i];

		if (chan->lx_read != chan->lx_write)
			wake_up_interruptible(&channel_wqs[i].lx_queue);
	}

	return IRQ_HANDLED;
}

/* call when we have the address of the shared structure from the SP side. */
static int rtlx_init(struct rtlx_info *rtlxi)
{
	int i;

	if (rtlxi->id != RTLX_ID) {
		printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
		return -ENOEXEC;
	}

	/* initialise the wait queues */
	for (i = 0; i < RTLX_CHANNELS; i++) {
		init_waitqueue_head(&channel_wqs[i].rt_queue);
		init_waitqueue_head(&channel_wqs[i].lx_queue);
	}

	/* set up for interrupt handling */
	memset(&irq, 0, sizeof(struct irqaction));

	if (cpu_has_vint)
		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);

	irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
	irq.handler = rtlx_interrupt;
	irq.flags = SA_INTERRUPT;
	irq.name = "RTLX";
	irq.dev_id = rtlx;
	setup_irq(irq_num, &irq);

	rtlx = rtlxi;

	return 0;
}

/* only allow one open process at a time to open each channel */
static int rtlx_open(struct inode *inode, struct file *filp)
{
	int minor, ret;
	struct rtlx_channel *chan;

	/* assume only 1 device at the mo. */
	minor = MINOR(inode->i_rdev);

	if (rtlx == NULL) {
		struct rtlx_info **p;
		if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
			printk(KERN_ERR "vpe_get_shared is NULL. "
			       "Has an SP program been loaded?\n");
			return -EFAULT;
		}

		if (*p == NULL) {
			printk(KERN_ERR "vpe_shared %p %p\n", p, *p);
			return -EFAULT;
		}

		if ((ret = rtlx_init(*p)) < 0)
			return ret;
	}

	chan = &rtlx->channel[minor];

	if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state))
		return -EBUSY;

	return 0;
}

static int rtlx_release(struct inode *inode, struct file *filp)
{
	int minor = MINOR(inode->i_rdev);

	clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state);
	smp_mb__after_clear_bit();

	return 0;
}

static unsigned int rtlx_poll(struct file *file, poll_table * wait)
{
	int minor;
	unsigned int mask = 0;
	struct rtlx_channel *chan;

	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	chan = &rtlx->channel[minor];

	poll_wait(file, &channel_wqs[minor].rt_queue, wait);
	poll_wait(file, &channel_wqs[minor].lx_queue, wait);

	/* data available to read? */
	if (chan->lx_read != chan->lx_write)
		mask |= POLLIN | POLLRDNORM;

	/* space to write */
	if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
		mask |= POLLOUT | POLLWRNORM;

	return mask;
}

static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
			 loff_t * ppos)
{
	unsigned long failed;
	size_t fl = 0L;
	int minor;
	struct rtlx_channel *lx;
	DECLARE_WAITQUEUE(wait, current);

	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	lx = &rtlx->channel[minor];

	/* data available? */
	if (lx->lx_write == lx->lx_read) {
		if (file->f_flags & O_NONBLOCK)
			return 0;	/* -EAGAIN makes cat whinge */

		/* go to sleep */
		add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		while (lx->lx_write == lx->lx_read)
			schedule();

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);

		/* back running */
	}

	/* find out how much in total */
	count = min(count,
		    (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size);

	/* then how much from the read pointer onwards */
	fl = min(count, (size_t)lx->buffer_size - lx->lx_read);

	failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
	if (failed) {
		count = fl - failed;
		goto out;
	}

	/* and if there is anything left at the beginning of the buffer */
	if (count - fl) {
		failed = copy_to_user (buffer + fl, lx->lx_buffer, count - fl);
		if (failed) {
			count -= failed;
			goto out;
		}
	}

out:
	/* update the index */
	lx->lx_read += count;
	lx->lx_read %= lx->buffer_size;

	return count;
}

static ssize_t rtlx_write(struct file *file, const char __user * buffer,
			  size_t count, loff_t * ppos)
{
	unsigned long failed;
	int minor;
	struct rtlx_channel *rt;
	size_t fl;
	DECLARE_WAITQUEUE(wait, current);

	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	rt = &rtlx->channel[minor];

	/* any space left... */
	if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {

		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size))
			schedule();

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
	}

	/* total number of bytes to copy */
	count = min(count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) );

	/* first bit from write pointer to the end of the buffer, or count */
	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);

	failed = copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl);
	if (failed) {
		count = fl - failed;
		goto out;
	}

	/* if there's any left copy to the beginning of the buffer */
	if (count - fl) {
		failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
		if (failed) {
			count -= failed;
			goto out;
		}
	}

out:
	rt->rt_write += count;
	rt->rt_write %= rt->buffer_size;

	return count;
}

static struct file_operations rtlx_fops = {
	.owner		= THIS_MODULE,
	.open		= rtlx_open,
	.release	= rtlx_release,
	.write		= rtlx_write,
	.read		= rtlx_read,
	.poll		= rtlx_poll
};

static char register_chrdev_failed[] __initdata =
	KERN_ERR "rtlx_module_init: unable to register device\n";

static int __init rtlx_module_init(void)
{
	major = register_chrdev(0, module_name, &rtlx_fops);
	if (major < 0) {
		printk(register_chrdev_failed);
		return major;
	}

	return 0;
}

static void __exit rtlx_module_exit(void)
{
	unregister_chrdev(major, module_name);
}

module_init(rtlx_module_init);
module_exit(rtlx_module_exit);

MODULE_DESCRIPTION("MIPS RTLX");
MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc.");
MODULE_LICENSE("GPL");
Commit	Line	Data
e01402b1 RB	1	/*
	2	* Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
	3	*
	4	* This program is free software; you can distribute it and/or modify it
	5	* under the terms of the GNU General Public License (Version 2) as
	6	* published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	11	* for more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along
	14	* with this program; if not, write to the Free Software Foundation, Inc.,
	15	* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
	16	*
	17	*/
	18
	19	#include <linux/kernel.h>
	20	#include <linux/module.h>
	21	#include <linux/fs.h>
	22	#include <linux/init.h>
e01402b1 RB	23	#include <linux/poll.h>
	24	#include <linux/sched.h>
	25	#include <linux/wait.h>
	26	#include <asm/mipsmtregs.h>
afc4841d	27	#include <asm/bitops.h>
e01402b1 RB	28	#include <asm/cpu.h>
e01402b1 RB	29	#include <asm/processor.h>
e01402b1	30	#include <asm/rtlx.h>
afc4841d	31	#include <asm/uaccess.h>
e01402b1	32
e01402b1 RB	33	#define RTLX_TARG_VPE 1
e01402b1 RB	34
afc4841d	35	static struct rtlx_info *rtlx;
e01402b1 RB	36	static int major;
e01402b1 RB	37	static char module_name[] = "rtlx";
afc4841d RB	38	static struct irqaction irq;
	39	static int irq_num;
	40
	41	static inline int spacefree(int read, int write, int size)
	42	{
	43	if (read == write) {
	44	/*
	45	* never fill the buffer completely, so indexes are always
	46	* equal if empty and only empty, or !equal if data available
	47	*/
	48	return size - 1;
	49	}
	50
	51	return ((read + size - write) % size) - 1;
	52	}
e01402b1 RB	53
	54	static struct chan_waitqueues {
	55	wait_queue_head_t rt_queue;
	56	wait_queue_head_t lx_queue;
	57	} channel_wqs[RTLX_CHANNELS];
	58
e01402b1 RB	59	extern void *vpe_get_shared(int index);
	60
	61	static void rtlx_dispatch(struct pt_regs *regs)
	62	{
	63	do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
	64	}
	65
afc4841d	66	static irqreturn_t rtlx_interrupt(int irq, void dev_id, struct pt_regs regs)
e01402b1	67	{
e01402b1 RB	68	int i;
	69
	70	for (i = 0; i < RTLX_CHANNELS; i++) {
	71	struct rtlx_channel *chan = &rtlx->channel[i];
	72
	73	if (chan->lx_read != chan->lx_write)
	74	wake_up_interruptible(&channel_wqs[i].lx_queue);
	75	}
	76
afc4841d	77	return IRQ_HANDLED;
e01402b1 RB	78	}
	79
	80	/* call when we have the address of the shared structure from the SP side. */
	81	static int rtlx_init(struct rtlx_info *rtlxi)
	82	{
	83	int i;
	84
	85	if (rtlxi->id != RTLX_ID) {
	86	printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
afc4841d	87	return -ENOEXEC;
e01402b1 RB	88	}
	89
	90	/* initialise the wait queues */
	91	for (i = 0; i < RTLX_CHANNELS; i++) {
	92	init_waitqueue_head(&channel_wqs[i].rt_queue);
	93	init_waitqueue_head(&channel_wqs[i].lx_queue);
	94	}
	95
	96	/* set up for interrupt handling */
	97	memset(&irq, 0, sizeof(struct irqaction));
	98
afc4841d	99	if (cpu_has_vint)
e01402b1	100	set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
e01402b1 RB	101
	102	irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
	103	irq.handler = rtlx_interrupt;
	104	irq.flags = SA_INTERRUPT;
	105	irq.name = "RTLX";
	106	irq.dev_id = rtlx;
	107	setup_irq(irq_num, &irq);
	108
	109	rtlx = rtlxi;
afc4841d RB	110
afc4841d RB	111	return 0;
e01402b1 RB	112	}
	113
	114	/* only allow one open process at a time to open each channel */
	115	static int rtlx_open(struct inode inode, struct file filp)
	116	{
	117	int minor, ret;
	118	struct rtlx_channel *chan;
	119
	120	/* assume only 1 device at the mo. */
	121	minor = MINOR(inode->i_rdev);
	122
	123	if (rtlx == NULL) {
	124	struct rtlx_info **p;
	125	if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
afc4841d RB	126	printk(KERN_ERR "vpe_get_shared is NULL. "
	127	"Has an SP program been loaded?\n");
	128	return -EFAULT;
e01402b1 RB	129	}
	130
	131	if (*p == NULL) {
afc4841d RB	132	printk(KERN_ERR "vpe_shared %p %p\n", p, *p);
afc4841d RB	133	return -EFAULT;
e01402b1 RB	134	}
	135
	136	if ((ret = rtlx_init(*p)) < 0)
afc4841d	137	return ret;
e01402b1 RB	138	}
	139
	140	chan = &rtlx->channel[minor];
	141
afc4841d RB	142	if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state))
afc4841d RB	143	return -EBUSY;
e01402b1	144
afc4841d	145	return 0;
e01402b1 RB	146	}
	147
	148	static int rtlx_release(struct inode inode, struct file filp)
	149	{
afc4841d	150	int minor = MINOR(inode->i_rdev);
e01402b1	151
afc4841d RB	152	clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state);
	153	smp_mb__after_clear_bit();
	154
	155	return 0;
e01402b1 RB	156	}
	157
	158	static unsigned int rtlx_poll(struct file file, poll_table wait)
	159	{
	160	int minor;
	161	unsigned int mask = 0;
	162	struct rtlx_channel *chan;
	163
	164	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	165	chan = &rtlx->channel[minor];
	166
	167	poll_wait(file, &channel_wqs[minor].rt_queue, wait);
	168	poll_wait(file, &channel_wqs[minor].lx_queue, wait);
	169
	170	/* data available to read? */
	171	if (chan->lx_read != chan->lx_write)
	172	mask \|= POLLIN \| POLLRDNORM;
	173
	174	/* space to write */
	175	if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
	176	mask \|= POLLOUT \| POLLWRNORM;
	177
afc4841d	178	return mask;
e01402b1 RB	179	}
	180
	181	static ssize_t rtlx_read(struct file file, char __user buffer, size_t count,
	182	loff_t * ppos)
	183	{
afc4841d	184	unsigned long failed;
e01402b1 RB	185	size_t fl = 0L;
	186	int minor;
	187	struct rtlx_channel *lx;
	188	DECLARE_WAITQUEUE(wait, current);
	189
	190	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	191	lx = &rtlx->channel[minor];
	192
	193	/* data available? */
	194	if (lx->lx_write == lx->lx_read) {
	195	if (file->f_flags & O_NONBLOCK)
afc4841d	196	return 0; /* -EAGAIN makes cat whinge */
e01402b1 RB	197
	198	/* go to sleep */
	199	add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
	200	set_current_state(TASK_INTERRUPTIBLE);
	201
	202	while (lx->lx_write == lx->lx_read)
	203	schedule();
	204
	205	set_current_state(TASK_RUNNING);
	206	remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);
	207
	208	/* back running */
	209	}
	210
	211	/* find out how much in total */
afc4841d RB	212	count = min(count,
afc4841d RB	213	(size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size);
e01402b1 RB	214
e01402b1 RB	215	/* then how much from the read pointer onwards */
afc4841d	216	fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
e01402b1	217
afc4841d RB	218	failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
	219	if (failed) {
	220	count = fl - failed;
	221	goto out;
	222	}
e01402b1 RB	223
e01402b1 RB	224	/* and if there is anything left at the beginning of the buffer */
afc4841d RB	225	if (count - fl) {
	226	failed = copy_to_user (buffer + fl, lx->lx_buffer, count - fl);
	227	if (failed) {
	228	count -= failed;
	229	goto out;
	230	}
	231	}
e01402b1	232
afc4841d	233	out:
e01402b1 RB	234	/* update the index */
	235	lx->lx_read += count;
	236	lx->lx_read %= lx->buffer_size;
	237
afc4841d	238	return count;
e01402b1 RB	239	}
	240
	241	static ssize_t rtlx_write(struct file file, const char __user buffer,
	242	size_t count, loff_t * ppos)
	243	{
afc4841d	244	unsigned long failed;
e01402b1 RB	245	int minor;
	246	struct rtlx_channel *rt;
	247	size_t fl;
	248	DECLARE_WAITQUEUE(wait, current);
	249
	250	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	251	rt = &rtlx->channel[minor];
	252
	253	/* any space left... */
	254	if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {
	255
	256	if (file->f_flags & O_NONBLOCK)
afc4841d	257	return -EAGAIN;
e01402b1 RB	258
	259	add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
	260	set_current_state(TASK_INTERRUPTIBLE);
	261
	262	while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size))
	263	schedule();
	264
	265	set_current_state(TASK_RUNNING);
	266	remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
	267	}
	268
	269	/* total number of bytes to copy */
afc4841d	270	count = min(count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) );
e01402b1 RB	271
	272	/* first bit from write pointer to the end of the buffer, or count */
	273	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
	274
afc4841d RB	275	failed = copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl);
	276	if (failed) {
	277	count = fl - failed;
	278	goto out;
	279	}
e01402b1 RB	280
e01402b1 RB	281	/* if there's any left copy to the beginning of the buffer */
afc4841d RB	282	if (count - fl) {
	283	failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
	284	if (failed) {
	285	count -= failed;
	286	goto out;
	287	}
	288	}
e01402b1	289
afc4841d	290	out:
e01402b1 RB	291	rt->rt_write += count;
	292	rt->rt_write %= rt->buffer_size;
	293
afc4841d	294	return count;
e01402b1 RB	295	}
	296
	297	static struct file_operations rtlx_fops = {
afc4841d RB	298	.owner = THIS_MODULE,
	299	.open = rtlx_open,
	300	.release = rtlx_release,
	301	.write = rtlx_write,
	302	.read = rtlx_read,
	303	.poll = rtlx_poll
e01402b1 RB	304	};
e01402b1 RB	305
afc4841d RB	306	static char register_chrdev_failed[] __initdata =
	307	KERN_ERR "rtlx_module_init: unable to register device\n";
	308
	309	static int __init rtlx_module_init(void)
e01402b1	310	{
afc4841d RB	311	major = register_chrdev(0, module_name, &rtlx_fops);
	312	if (major < 0) {
	313	printk(register_chrdev_failed);
	314	return major;
e01402b1 RB	315	}
e01402b1 RB	316
afc4841d	317	return 0;
e01402b1 RB	318	}
e01402b1 RB	319
afc4841d	320	static void __exit rtlx_module_exit(void)
e01402b1 RB	321	{
	322	unregister_chrdev(major, module_name);
	323	}
	324
	325	module_init(rtlx_module_init);
	326	module_exit(rtlx_module_exit);
afc4841d	327
e01402b1	328	MODULE_DESCRIPTION("MIPS RTLX");
afc4841d	329	MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc.");
e01402b1	330	MODULE_LICENSE("GPL");