--- /dev/null
+/*
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <asm/uaccess.h>
+#include <linux/slab.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/cacheflush.h>
+#include <asm/atomic.h>
+#include <asm/cpu.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/vpe.h>
+#include <asm/rtlx.h>
+
+#define RTLX_TARG_VPE 1
+
+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;
+ int in_open;
+} channel_wqs[RTLX_CHANNELS];
+
+static struct irqaction irq;
+static int irq_num;
+static struct vpe_notifications notify;
+static int sp_stopping = 0;
+
+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);
+}
+
+
+/* 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, struct pt_regs *regs)
+{
+ int i;
+
+ 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 __attribute_used__ void 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%x\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)
+{
+ int ret;
+ struct rtlx_channel *chan;
+ volatile struct rtlx_info **p;
+
+ if (index >= RTLX_CHANNELS) {
+ printk(KERN_DEBUG "rtlx_open index out of range\n");
+ return -ENOSYS;
+ }
+
+ if (channel_wqs[index].in_open) {
+ printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
+ return -EBUSY;
+ }
+
+ channel_wqs[index].in_open++;
+
+ if (rtlx == NULL) {
+ if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
+ if (can_sleep) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ /* go to sleep */
+ add_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ while ((p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
+ schedule();
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+ /* back running */
+ } else {
+ printk( KERN_DEBUG "No SP program loaded, and device "
+ "opened with O_NONBLOCK\n");
+ channel_wqs[index].in_open = 0;
+ return -ENOSYS;
+ }
+ }
+
+ if (*p == NULL) {
+ if (can_sleep) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ /* go to sleep */
+ add_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ while (*p == NULL) {
+ schedule();
+
+ /* reset task state to interruptable otherwise
+ we'll whizz round here like a very fast loopy
+ thing. schedule() appears to return with state
+ set to TASK_RUNNING.
+
+ If the loaded SP program, for whatever reason,
+ doesn't set up the shared structure *p will never
+ become true. So whoever connected to either /dev/rt?
+ or if it was kspd, will then take up rather a lot of
+ processor cycles.
+ */
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+ /* back running */
+ }
+ else {
+ printk(" *vpe_get_shared is NULL. "
+ "Has an SP program been loaded?\n");
+ channel_wqs[index].in_open = 0;
+ return -ENOSYS;
+ }
+ }
+
+ if ((unsigned int)*p < KSEG0) {
+ printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
+ "maybe an error code %d\n", (int)*p);
+ channel_wqs[index].in_open = 0;
+ return -ENOSYS;
+ }
+
+ if ((ret = rtlx_init(*p)) < 0) {
+ channel_wqs[index].in_open = 0;
+ return ret;
+ }
+ }
+
+ chan = &rtlx->channel[index];
+
+ if (chan->lx_state == RTLX_STATE_OPENED) {
+ channel_wqs[index].in_open = 0;
+ return -EBUSY;
+ }
+
+ chan->lx_state = RTLX_STATE_OPENED;
+ channel_wqs[index].in_open = 0;
+ return 0;
+}
+
+int rtlx_release(int index)
+{
+ 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) {
+ DECLARE_WAITQUEUE(wait, current);
+
+ /* go to sleep */
+ add_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ while (chan->lx_read == chan->lx_write) {
+ schedule();
+
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (sp_stopping) {
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+ return 0;
+ }
+ }
+
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+ /* back running */
+ }
+ 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);
+}
+
+static inline void copy_to(void *dst, void *src, size_t count, int user)
+{
+ if (user)
+ copy_to_user(dst, src, count);
+ else
+ memcpy(dst, src, count);
+}
+
+static inline void copy_from(void *dst, void *src, size_t count, int user)
+{
+ if (user)
+ copy_from_user(dst, src, count);
+ else
+ memcpy(dst, src, count);
+}
+
+ssize_t rtlx_read(int index, void *buff, size_t count, int user)
+{
+ size_t fl = 0L;
+ struct rtlx_channel *lx;
+
+ if (rtlx == NULL)
+ return -ENOSYS;
+
+ lx = &rtlx->channel[index];
+
+ /* 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);
+
+ copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
+
+ /* and if there is anything left at the beginning of the buffer */
+ if ( count - fl )
+ copy_to (buff + fl, lx->lx_buffer, count - fl, user);
+
+ /* update the index */
+ lx->lx_read += count;
+ lx->lx_read %= lx->buffer_size;
+
+ return count;
+}
+
+ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
+{
+ struct rtlx_channel *rt;
+ size_t fl;
+
+ if (rtlx == NULL)
+ return(-ENOSYS);
+
+ rt = &rtlx->channel[index];
+
+ /* total number of bytes to copy */
+ count = min(count,
+ (size_t)write_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);
+
+ copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
+
+ /* if there's any left copy to the beginning of the buffer */
+ if( count - fl )
+ copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
+
+ rt->rt_write += count;
+ rt->rt_write %= rt->buffer_size;
+
+ return(count);
+}
+
+
+static int file_open(struct inode *inode, struct file *filp)
+{
+ int minor = iminor(inode);
+
+ return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
+}
+
+static int file_release(struct inode *inode, struct file *filp)
+{
+ int minor = iminor(inode);
+
+ return rtlx_release(minor);
+}
+
+static unsigned int file_poll(struct file *file, poll_table * wait)
+{
+ int minor;
+ unsigned int mask = 0;
+
+ minor = iminor(file->f_dentry->d_inode);
+
+ 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->f_dentry->d_inode);
+
+ /* 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, 1);
+}
+
+static ssize_t file_write(struct file *file, const char __user * buffer,
+ size_t count, loff_t * ppos)
+{
+ int minor;
+ struct rtlx_channel *rt;
+ DECLARE_WAITQUEUE(wait, current);
+
+ minor = iminor(file->f_dentry->d_inode);
+ rt = &rtlx->channel[minor];
+
+ /* any space left... */
+ if (!rtlx_write_poll(minor)) {
+
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ while (!rtlx_write_poll(minor))
+ schedule();
+
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
+ }
+
+ return rtlx_write(minor, (void *)buffer, count, 1);
+}
+
+static struct file_operations rtlx_fops = {
+ .owner = THIS_MODULE,
+ .open = file_open,
+ .release = file_release,
+ .write = file_write,
+ .read = file_read,
+ .poll = file_poll
+};
+
+static struct irqaction rtlx_irq = {
+ .handler = rtlx_interrupt,
+ .flags = SA_INTERRUPT,
+ .name = "RTLX",
+};
+
+static int rtlx_irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
+
+static char register_chrdev_failed[] __initdata =
+ KERN_ERR "rtlx_module_init: unable to register device\n";
+
+static int rtlx_module_init(void)
+{
+ int i;
+
+ major = register_chrdev(0, module_name, &rtlx_fops);
+ if (major < 0) {
+ printk(register_chrdev_failed);
+ return major;
+ }
+
+ /* 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);
+ channel_wqs[i].in_open = 0;
+ }
+
+ /* set up notifiers */
+ notify.start = starting;
+ notify.stop = stopping;
+ vpe_notify(RTLX_TARG_VPE, ¬ify);
+
+ if (cpu_has_vint)
+ set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
+
+ rtlx_irq.dev_id = rtlx;
+ setup_irq(rtlx_irq_num, &rtlx_irq);
+
+ 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 Oldham, MIPS Technologies, Inc.");
+MODULE_LICENSE("GPL");