+static inline int spufs_switch_log_used(struct spu_context *ctx)
+{
+ return (ctx->switch_log->head - ctx->switch_log->tail) %
+ SWITCH_LOG_BUFSIZE;
+}
+
+static inline int spufs_switch_log_avail(struct spu_context *ctx)
+{
+ return SWITCH_LOG_BUFSIZE - spufs_switch_log_used(ctx);
+}
+
+static int spufs_switch_log_open(struct inode *inode, struct file *file)
+{
+ struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
+ int rc;
+
+ rc = spu_acquire(ctx);
+ if (rc)
+ return rc;
+
+ if (ctx->switch_log) {
+ rc = -EBUSY;
+ goto out;
+ }
+
+ ctx->switch_log = kmalloc(sizeof(struct switch_log) +
+ SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
+ GFP_KERNEL);
+
+ if (!ctx->switch_log) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ ctx->switch_log->head = ctx->switch_log->tail = 0;
+ init_waitqueue_head(&ctx->switch_log->wait);
+ rc = 0;
+
+out:
+ spu_release(ctx);
+ return rc;
+}
+
+static int spufs_switch_log_release(struct inode *inode, struct file *file)
+{
+ struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
+ int rc;
+
+ rc = spu_acquire(ctx);
+ if (rc)
+ return rc;
+
+ kfree(ctx->switch_log);
+ ctx->switch_log = NULL;
+ spu_release(ctx);
+
+ return 0;
+}
+
+static int switch_log_sprint(struct spu_context *ctx, char *tbuf, int n)
+{
+ struct switch_log_entry *p;
+
+ p = ctx->switch_log->log + ctx->switch_log->tail % SWITCH_LOG_BUFSIZE;
+
+ return snprintf(tbuf, n, "%u.%09u %d %u %u %llu\n",
+ (unsigned int) p->tstamp.tv_sec,
+ (unsigned int) p->tstamp.tv_nsec,
+ p->spu_id,
+ (unsigned int) p->type,
+ (unsigned int) p->val,
+ (unsigned long long) p->timebase);
+}
+
+static ssize_t spufs_switch_log_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
+ int error = 0, cnt = 0;
+
+ if (!buf)
+ return -EINVAL;
+
+ error = spu_acquire(ctx);
+ if (error)
+ return error;
+
+ while (cnt < len) {
+ char tbuf[128];
+ int width;
+
+ if (spufs_switch_log_used(ctx) == 0) {
+ if (cnt > 0) {
+ /* If there's data ready to go, we can
+ * just return straight away */
+ break;
+
+ } else if (file->f_flags & O_NONBLOCK) {
+ error = -EAGAIN;
+ break;
+
+ } else {
+ /* spufs_wait will drop the mutex and
+ * re-acquire, but since we're in read(), the
+ * file cannot be _released (and so
+ * ctx->switch_log is stable).
+ */
+ error = spufs_wait(ctx->switch_log->wait,
+ spufs_switch_log_used(ctx) > 0);
+
+ /* On error, spufs_wait returns without the
+ * state mutex held */
+ if (error)
+ return error;
+
+ /* We may have had entries read from underneath
+ * us while we dropped the mutex in spufs_wait,
+ * so re-check */
+ if (spufs_switch_log_used(ctx) == 0)
+ continue;
+ }
+ }
+
+ width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
+ if (width < len)
+ ctx->switch_log->tail =
+ (ctx->switch_log->tail + 1) %
+ SWITCH_LOG_BUFSIZE;
+ else
+ /* If the record is greater than space available return
+ * partial buffer (so far) */
+ break;
+
+ error = copy_to_user(buf + cnt, tbuf, width);
+ if (error)
+ break;
+ cnt += width;
+ }
+
+ spu_release(ctx);
+
+ return cnt == 0 ? error : cnt;
+}
+
+static unsigned int spufs_switch_log_poll(struct file *file, poll_table *wait)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
+ unsigned int mask = 0;
+ int rc;
+
+ poll_wait(file, &ctx->switch_log->wait, wait);
+
+ rc = spu_acquire(ctx);
+ if (rc)
+ return rc;
+
+ if (spufs_switch_log_used(ctx) > 0)
+ mask |= POLLIN;
+
+ spu_release(ctx);
+
+ return mask;
+}
+
+static const struct file_operations spufs_switch_log_fops = {
+ .owner = THIS_MODULE,
+ .open = spufs_switch_log_open,
+ .read = spufs_switch_log_read,
+ .poll = spufs_switch_log_poll,
+ .release = spufs_switch_log_release,
+};
+
+/**
+ * Log a context switch event to a switch log reader.
+ *
+ * Must be called with ctx->state_mutex held.
+ */
+void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
+ u32 type, u32 val)
+{
+ if (!ctx->switch_log)
+ return;
+
+ if (spufs_switch_log_avail(ctx) > 1) {
+ struct switch_log_entry *p;
+
+ p = ctx->switch_log->log + ctx->switch_log->head;
+ ktime_get_ts(&p->tstamp);
+ p->timebase = get_tb();
+ p->spu_id = spu ? spu->number : -1;
+ p->type = type;
+ p->val = val;
+
+ ctx->switch_log->head =
+ (ctx->switch_log->head + 1) % SWITCH_LOG_BUFSIZE;
+ }
+
+ wake_up(&ctx->switch_log->wait);
+}
+
+static int spufs_show_ctx(struct seq_file *s, void *private)
+{
+ struct spu_context *ctx = s->private;
+ u64 mfc_control_RW;
+
+ mutex_lock(&ctx->state_mutex);
+ if (ctx->spu) {
+ struct spu *spu = ctx->spu;
+ struct spu_priv2 __iomem *priv2 = spu->priv2;