v4.19.13 snapshot.
diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
new file mode 100644
index 0000000..18c509c
--- /dev/null
+++ b/arch/mips/kernel/rtlx.c
@@ -0,0 +1,409 @@
+/*
+ * 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");