/* * 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. * * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved. * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org) * Copyright (C) 2013 Imagination Technologies Ltd. */#include <linux/kernel.h>#include <linux/fs.h>#include <linux/syscalls.h>#include <linux/moduleloader.h>#include <linux/atomic.h>#include <linux/sched/signal.h> #include <asm/mipsmtregs.h>#include <asm/mips_mt.h>#include <asm/processor.h>#include <asm/rtlx.h>#include <asm/setup.h>#include <asm/vpe.h> static int sp_stopping;struct rtlx_info *rtlx;struct chan_waitqueues channel_wqs[RTLX_CHANNELS];struct vpe_notifications rtlx_notify;void (*aprp_hook)(void) = NULL;EXPORT_SYMBOL(aprp_hook); static void __used dump_rtlx(void){	int i; 	pr_info("id 0x%lx state %d\n", rtlx->id, rtlx->state); 	for (i = 0; i < RTLX_CHANNELS; i++) {		struct rtlx_channel *chan = &rtlx->channel[i]; 		pr_info(" rt_state %d lx_state %d buffer_size %d\n",			chan->rt_state, chan->lx_state, chan->buffer_size); 		pr_info(" rt_read %d rt_write %d\n",			chan->rt_read, chan->rt_write); 		pr_info(" lx_read %d lx_write %d\n",			chan->lx_read, chan->lx_write); 		pr_info(" rt_buffer <%s>\n", chan->rt_buffer);		pr_info(" 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) {		pr_err("no valid RTLX id at 0x%p 0x%lx\n", rtlxi, rtlxi->id);		return -ENOEXEC;	} 	rtlx = rtlxi; 	return 0;} /* notifications */void rtlx_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);} void rtlx_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) {		pr_debug("rtlx_open index out of range\n");		return -ENOSYS;	} 	if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {		pr_debug("rtlx_open channel %d already opened\n", index);		ret = -EBUSY;		goto out_fail;	} 	if (rtlx == NULL) {		p = vpe_get_shared(aprp_cpu_index());		if (p == NULL) {			if (can_sleep) {				ret = __wait_event_interruptible(					channel_wqs[index].lx_queue,					(p = vpe_get_shared(aprp_cpu_index())));				if (ret)					goto out_fail;			} else {				pr_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) {			pr_warn("vpe_get_shared returned an invalid pointer maybe an error code %d\n",				(int)*p);			ret = -ENOSYS;			goto out_fail;		} 		ret = rtlx_init(*p);		if (ret < 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_t(size_t, count, 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); 	_interrupt_sp(); 	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 __poll_t file_poll(struct file *file, poll_table *wait){	int minor = iminor(file_inode(file));	__poll_t 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 |= EPOLLIN | EPOLLRDNORM; 	/* space to write */	if (rtlx_write_poll(minor))		mask |= EPOLLOUT | EPOLLWRNORM; 	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' whine */ 	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);} 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,}; module_init(rtlx_module_init);module_exit(rtlx_module_exit); MODULE_DESCRIPTION("MIPS RTLX");MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");MODULE_LICENSE("GPL");