powerpc/pseries: Define papr-hvpipe ioctl

JIRA: https://issues.redhat.com/browse/RHEL-101849

Conflicts:
	backport upstream commit 043439a
	- 44bdcff ("Documentation: ioctl-number: Correct full path
	to papr-physical-attestation.h") needs more column width to
	include full path in the "Include file" column which affects
	the complete table format.
	- 15afd5d ("Documentation: ioctl-number: Extend
	"Include File" column width") changes the table width which
	needs so many patches that affect other source files.
	- Backport changes: powerpc/include/uapi/asm/papr-physical-attestation.h
	instead of arch/powerpc/include/uapi/asm/papr-physical-attestation.h

commit 043439a
Author: Haren Myneni <haren@linux.ibm.com>
Date:   Tue Sep 9 01:43:53 2025 -0700

    powerpc/pseries: Define papr-hvpipe ioctl

    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>
    Tested-by: Shashank MS <shashank.gowda@in.ibm.com>
    Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
    Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
    Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
    Link: https://patch.msgid.link/20250909084402.1488456-2-haren@linux.ibm.com

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

Author: Mamatha Inamdar

Documentation/userspace-api/ioctl/ioctl-number.rst

@@ -356,6 +356,8 @@ Code  Seq#    Include File                                           Comments
                                                                      <mailto:linuxppc-dev@lists.ozlabs.org>
 0xB2  08     powerpc/include/uapi/asm/papr-physical-attestation.h    powerpc/pseries Physical Attestation API
                                                                      <mailto:linuxppc-dev@lists.ozlabs.org>
+0xB2  09     arch/powerpc/include/uapi/asm/papr-hvpipe.h             powerpc/pseries HVPIPE API
+                                                                     <mailto:linuxppc-dev@lists.ozlabs.org>
 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>

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_ */