/* * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved. * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org) * *  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/device.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/init.h>#include <asm/uaccess.h>#include <linux/list.h>#include <linux/vmalloc.h>#include <linux/elf.h>#include <linux/seq_file.h>#include <linux/syscalls.h>#include <linux/moduleloader.h>#include <linux/interrupt.h>#include <linux/poll.h>#include <linux/sched.h>#include <linux/wait.h>#include <asm/mipsmtregs.h>#include <asm/mips_mt.h>#include <asm/cacheflush.h>#include <linux/atomic.h>#include <asm/cpu.h>#include <asm/processor.h>#include <asm/vpe.h>#include <asm/rtlx.h>#include <asm/setup.h> static struct rtlx_info *rtlx;static int major;static char module_name[] = "rtlx"; static struct chan_waitqueues {	wait_queue_head_t rt_queue;	wait_queue_head_t lx_queue;	atomic_t in_open;	struct mutex mutex;} channel_wqs[RTLX_CHANNELS]; static struct vpe_notifications notify;static int sp_stopping; extern void *vpe_get_shared(int index); static void rtlx_dispatch(void){	do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);}  /* Interrupt handler may be called before rtlx_init has otherwise had   a chance to run.*/static irqreturn_t rtlx_interrupt(int irq, void *dev_id){	unsigned int vpeflags;	unsigned long flags;	int i; 	/* Ought not to be strictly necessary for SMTC builds */	local_irq_save(flags);	vpeflags = dvpe();	set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);	irq_enable_hazard();	evpe(vpeflags);	local_irq_restore(flags); 	for (i = 0; i < RTLX_CHANNELS; i++) {			wake_up(&channel_wqs[i].lx_queue);			wake_up(&channel_wqs[i].rt_queue);	} 	return IRQ_HANDLED;} static void __used dump_rtlx(void){	int i; 	printk("id 0x%lx state %d\n", rtlx->id, rtlx->state); 	for (i = 0; i < RTLX_CHANNELS; i++) {		struct rtlx_channel *chan = &rtlx->channel[i]; 		printk(" rt_state %d lx_state %d buffer_size %d\n",		       chan->rt_state, chan->lx_state, chan->buffer_size); 		printk(" rt_read %d rt_write %d\n",		       chan->rt_read, chan->rt_write); 		printk(" lx_read %d lx_write %d\n",		       chan->lx_read, chan->lx_write); 		printk(" rt_buffer <%s>\n", chan->rt_buffer);		printk(" lx_buffer <%s>\n", chan->lx_buffer);	}} /* call when we have the address of the shared structure from the SP side. */static int rtlx_init(struct rtlx_info *rtlxi){	if (rtlxi->id != RTLX_ID) {		printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n",			rtlxi, rtlxi->id);		return -ENOEXEC;	} 	rtlx = rtlxi; 	return 0;} /* notifications */static void starting(int vpe){	int i;	sp_stopping = 0; 	/* force a reload of rtlx */	rtlx=NULL; 	/* wake up any sleeping rtlx_open's */	for (i = 0; i < RTLX_CHANNELS; i++)		wake_up_interruptible(&channel_wqs[i].lx_queue);} static void stopping(int vpe){	int i; 	sp_stopping = 1;	for (i = 0; i < RTLX_CHANNELS; i++)		wake_up_interruptible(&channel_wqs[i].lx_queue);}  int rtlx_open(int index, int can_sleep){	struct rtlx_info **p;	struct rtlx_channel *chan;	enum rtlx_state state;	int ret = 0; 	if (index >= RTLX_CHANNELS) {		printk(KERN_DEBUG "rtlx_open index out of range\n");		return -ENOSYS;	} 	if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {		printk(KERN_DEBUG "rtlx_open channel %d already opened\n",		       index);		ret = -EBUSY;		goto out_fail;	} 	if (rtlx == NULL) {		if( (p = vpe_get_shared(tclimit)) == NULL) {		    if (can_sleep) {			ret = __wait_event_interruptible(					channel_wqs[index].lx_queue,					(p = vpe_get_shared(tclimit)));			if (ret)				goto out_fail;		    } else {			printk(KERN_DEBUG "No SP program loaded, and device "					"opened with O_NONBLOCK\n");			ret = -ENOSYS;			goto out_fail;		    }		} 		smp_rmb();		if (*p == NULL) {			if (can_sleep) {				DEFINE_WAIT(wait); 				for (;;) {					prepare_to_wait(						&channel_wqs[index].lx_queue,						&wait, TASK_INTERRUPTIBLE);					smp_rmb();					if (*p != NULL)						break;					if (!signal_pending(current)) {						schedule();						continue;					}					ret = -ERESTARTSYS;					goto out_fail;				}				finish_wait(&channel_wqs[index].lx_queue, &wait);			} else {				pr_err(" *vpe_get_shared is NULL. "				       "Has an SP program been loaded?\n");				ret = -ENOSYS;				goto out_fail;			}		} 		if ((unsigned int)*p < KSEG0) {			printk(KERN_WARNING "vpe_get_shared returned an "			       "invalid pointer maybe an error code %d\n",			       (int)*p);			ret = -ENOSYS;			goto out_fail;		} 		if ((ret = rtlx_init(*p)) < 0)			goto out_ret;	} 	chan = &rtlx->channel[index]; 	state = xchg(&chan->lx_state, RTLX_STATE_OPENED);	if (state == RTLX_STATE_OPENED) {		ret = -EBUSY;		goto out_fail;	} out_fail:	smp_mb();	atomic_dec(&channel_wqs[index].in_open);	smp_mb(); out_ret:	return ret;} int rtlx_release(int index){	if (rtlx == NULL) {		pr_err("rtlx_release() with null rtlx\n");		return 0;	}	rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;	return 0;} unsigned int rtlx_read_poll(int index, int can_sleep){	struct rtlx_channel *chan; 	if (rtlx == NULL)		return 0; 	chan = &rtlx->channel[index]; 	/* data available to read? */	if (chan->lx_read == chan->lx_write) {		if (can_sleep) {			int ret = __wait_event_interruptible(				channel_wqs[index].lx_queue,				(chan->lx_read != chan->lx_write) ||				sp_stopping);			if (ret)				return ret; 			if (sp_stopping)				return 0;		} else			return 0;	} 	return (chan->lx_write + chan->buffer_size - chan->lx_read)	       % chan->buffer_size;} static inline int write_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;} unsigned int rtlx_write_poll(int index){	struct rtlx_channel *chan = &rtlx->channel[index]; 	return write_spacefree(chan->rt_read, chan->rt_write,				chan->buffer_size);} ssize_t rtlx_read(int index, void __user *buff, size_t count){	size_t lx_write, fl = 0L;	struct rtlx_channel *lx;	unsigned long failed; 	if (rtlx == NULL)		return -ENOSYS; 	lx = &rtlx->channel[index]; 	mutex_lock(&channel_wqs[index].mutex);	smp_rmb();	lx_write = lx->lx_write; 	/* find out how much in total */	count = min(count,		     (size_t)(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(buff, lx->lx_buffer + lx->lx_read, fl);	if (failed)		goto out; 	/* and if there is anything left at the beginning of the buffer */	if (count - fl)		failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl); out:	count -= failed; 	smp_wmb();	lx->lx_read = (lx->lx_read + count) % lx->buffer_size;	smp_wmb();	mutex_unlock(&channel_wqs[index].mutex); 	return count;} ssize_t rtlx_write(int index, const void __user *buffer, size_t count){	struct rtlx_channel *rt;	unsigned long failed;	size_t rt_read;	size_t fl; 	if (rtlx == NULL)		return(-ENOSYS); 	rt = &rtlx->channel[index]; 	mutex_lock(&channel_wqs[index].mutex);	smp_rmb();	rt_read = rt->rt_read; 	/* total number of bytes to copy */	count = min(count, (size_t)write_spacefree(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)		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);	} out:	count -= failed; 	smp_wmb();	rt->rt_write = (rt->rt_write + count) % rt->buffer_size;	smp_wmb();	mutex_unlock(&channel_wqs[index].mutex); 	return count;}  static int file_open(struct inode *inode, struct file *filp){	return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1);} static int file_release(struct inode *inode, struct file *filp){	return rtlx_release(iminor(inode));} static unsigned int file_poll(struct file *file, poll_table * wait){	int minor = iminor(file_inode(file));	unsigned int mask = 0; 	poll_wait(file, &channel_wqs[minor].rt_queue, wait);	poll_wait(file, &channel_wqs[minor].lx_queue, wait); 	if (rtlx == NULL)		return 0; 	/* data available to read? */	if (rtlx_read_poll(minor, 0))		mask |= POLLIN | POLLRDNORM; 	/* space to write */	if (rtlx_write_poll(minor))		mask |= POLLOUT | POLLWRNORM; 	return mask;} static ssize_t file_read(struct file *file, char __user * buffer, size_t count,			 loff_t * ppos){	int minor = iminor(file_inode(file)); 	/* data available? */	if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {		return 0;	// -EAGAIN makes cat whinge	} 	return rtlx_read(minor, buffer, count);} static ssize_t file_write(struct file *file, const char __user * buffer,			  size_t count, loff_t * ppos){	int minor = iminor(file_inode(file)); 	/* any space left... */	if (!rtlx_write_poll(minor)) {		int ret; 		if (file->f_flags & O_NONBLOCK)			return -EAGAIN; 		ret = __wait_event_interruptible(channel_wqs[minor].rt_queue,					   rtlx_write_poll(minor));		if (ret)			return ret;	} 	return rtlx_write(minor, buffer, count);} static const struct file_operations rtlx_fops = {	.owner =   THIS_MODULE,	.open =	   file_open,	.release = file_release,	.write =   file_write,	.read =	   file_read,	.poll =	   file_poll,	.llseek =  noop_llseek,}; static struct irqaction rtlx_irq = {	.handler	= rtlx_interrupt,	.name		= "RTLX",}; static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ; static char register_chrdev_failed[] __initdata =	KERN_ERR "rtlx_module_init: unable to register device\n"; static int __init rtlx_module_init(void){	struct device *dev;	int i, err; 	if (!cpu_has_mipsmt) {		printk("VPE loader: not a MIPS MT capable processor\n");		return -ENODEV;	} 	if (tclimit == 0) {		printk(KERN_WARNING "No TCs reserved for AP/SP, not "		       "initializing RTLX.\nPass maxtcs=<n> argument as kernel "		       "argument\n"); 		return -ENODEV;	} 	major = register_chrdev(0, module_name, &rtlx_fops);	if (major < 0) {		printk(register_chrdev_failed);		return major;	} 

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