remoteproc: Add remoteproc character device interface

Add the character device interface into remoteproc framework.
This interface can be used in order to boot/shutdown remote
subsystems and provides a basic ioctl based interface to implement
supplementary functionality. An ioctl call is implemented to enable
the shutdown on release feature which will allow remote processors to
be shutdown when the controlling userspace application crashes or hangs.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>
Link: https://lore.kernel.org/r/1596044401-22083-2-git-send-email-sidgup@codeaurora.org
[bjorn: s/int32_t/s32/ per checkpatch]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/uapi/linux/remoteproc_cdev.h b/include/uapi/linux/remoteproc_cdev.h
new file mode 100644
index 000000000000..c43768e4b0dc
--- /dev/null
+++ b/include/uapi/linux/remoteproc_cdev.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * IOCTLs for Remoteproc's character device interface.
+ *
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#ifndef _UAPI_REMOTEPROC_CDEV_H_
+#define _UAPI_REMOTEPROC_CDEV_H_
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define RPROC_MAGIC	0xB7
+
+/*
+ * The RPROC_SET_SHUTDOWN_ON_RELEASE ioctl allows to enable/disable the shutdown of a remote
+ * processor automatically when the controlling userpsace closes the char device interface.
+ *
+ * input parameter: integer
+ *   0		: disable automatic shutdown
+ *   other	: enable automatic shutdown
+ */
+#define RPROC_SET_SHUTDOWN_ON_RELEASE _IOW(RPROC_MAGIC, 1, __s32)
+
+/*
+ * The RPROC_GET_SHUTDOWN_ON_RELEASE ioctl gets information about whether the automatic shutdown of
+ * a remote processor is enabled or disabled when the controlling userspace closes the char device
+ * interface.
+ *
+ * output parameter: integer
+ *   0		: automatic shutdown disable
+ *   other	: automatic shutdown enable
+ */
+#define RPROC_GET_SHUTDOWN_ON_RELEASE _IOR(RPROC_MAGIC, 2, __s32)
+
+#endif