[PATCH RFC 1/9] powerpc/pseries: Define papr-hvpipe ioctl

[Haren Myneni <haren@linux.ibm.com>]

PowerPC FW introduced HVPIPE RTAS calls such as
ibm,send-hvpipe-msg and ibm,receive-hvpipe-msg for the user space
to exchange information with different sources such as Hardware
Management Consoles (HMC).

HVPIPE_IOC_CREATE_HANDLE is defined to use /dev/papr-hvpipe
interface for ibm,send-hvpipe-msg and ibm,receive-hvpipe-msg
RTAS calls.

Also defined papr_hvpipe_hdr which will added in the payload
that is passed between the kernel and the user space.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 .../userspace-api/ioctl/ioctl-number.rst      |  2 ++
 arch/powerpc/include/uapi/asm/papr-hvpipe.h   | 33 +++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 arch/powerpc/include/uapi/asm/papr-hvpipe.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index bc91756bde73..8ed8eb54cb7d 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -371,6 +371,8 @@ Code  Seq#    Include File                                           Comments
                                                                      <mailto:linuxppc-dev>
 0xB2  08     powerpc/include/uapi/asm/papr-physical-attestation.h    powerpc/pseries Physical Attestation API
                                                                      <mailto:linuxppc-dev>
+0xB2  09     arch/powerpc/include/uapi/asm/papr-hvpipe.h             powerpc/pseries HVPIPE API
+                                                                     <mailto:linuxppc-dev>
 0xB3  00     linux/mmc/ioctl.h
 0xB4  00-0F  linux/gpio.h                                            <mailto:linux-gpio@vger.kernel.org>
 0xB5  00-0F  uapi/linux/rpmsg.h                                      <mailto:linux-remoteproc@vger.kernel.org>
diff --git a/arch/powerpc/include/uapi/asm/papr-hvpipe.h b/arch/powerpc/include/uapi/asm/papr-hvpipe.h
new file mode 100644
index 000000000000..459a7bb0e6c9
--- /dev/null
+++ b/arch/powerpc/include/uapi/asm/papr-hvpipe.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PAPR_HVPIPE_H_
+#define _UAPI_PAPR_HVPIPE_H_
+
+#include <linux/types.h>
+#include <asm/ioctl.h>
+#include <asm/papr-miscdev.h>
+
+/*
+ * This header is included in payload between OS and the user
+ * space.
+ * flags: OS notifies the user space whether the hvpipe is
+ *        closed or the buffer has the payload.
+ */
+struct papr_hvpipe_hdr {
+	u8 version;
+	u8 reserved[3];
+	u32 flags;
+	u8 reserved2[40];
+};
+
+/*
+ * ioctl for /dev/papr-hvpipe
+ */
+#define PAPR_HVPIPE_IOC_CREATE_HANDLE	_IOW(PAPR_MISCDEV_IOC_ID, 9, __u32)
+
+/*
+ * hvpipe_hdr flags used for read()
+ */
+#define HVPIPE_MSG_AVAILABLE	0x01 /* Payload is available */
+#define HVPIPE_LOST_CONNECTION	0x02 /* Pipe connection is closed/unavailable */
+
+#endif /* _UAPI_PAPR_HVPIPE_H_ */
-- 
2.43.5