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/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
* PAPR nvDimm Specific Methods (PDSM) and structs for libndctl
*
* (C) Copyright IBM 2020
*
* Author: Vaibhav Jain <vaibhav at linux.ibm.com>
*/
#ifndef _UAPI_ASM_POWERPC_PAPR_PDSM_H_
#define _UAPI_ASM_POWERPC_PAPR_PDSM_H_
#include <linux/types.h>
#include <linux/ndctl.h>
/*
* PDSM Envelope:
*
* The ioctl ND_CMD_CALL exchange data between user-space and kernel via
* envelope which consists of 2 headers sections and payload sections as
* illustrated below:
* +-----------------+---------------+---------------------------+
* | 64-Bytes | 8-Bytes | Max 184-Bytes |
* +-----------------+---------------+---------------------------+
* | ND-HEADER | PDSM-HEADER | PDSM-PAYLOAD |
* +-----------------+---------------+---------------------------+
* | nd_family | | |
* | nd_size_out | cmd_status | |
* | nd_size_in | reserved | nd_pdsm_payload |
* | nd_command | payload --> | |
* | nd_fw_size | | |
* | nd_payload ---> | | |
* +---------------+-----------------+---------------------------+
*
* ND Header:
* This is the generic libnvdimm header described as 'struct nd_cmd_pkg'
* which is interpreted by libnvdimm before passed on to papr_scm. Important
* member fields used are:
* 'nd_family' : (In) NVDIMM_FAMILY_PAPR_SCM
* 'nd_size_in' : (In) PDSM-HEADER + PDSM-IN-PAYLOAD (usually 0)
* 'nd_size_out' : (In) PDSM-HEADER + PDSM-RETURN-PAYLOAD
* 'nd_command' : (In) One of PAPR_PDSM_XXX
* 'nd_fw_size' : (Out) PDSM-HEADER + size of actual payload returned
*
* PDSM Header:
* This is papr-scm specific header that precedes the payload. This is defined
* as nd_cmd_pdsm_pkg. Following fields aare available in this header:
*
* 'cmd_status' : (Out) Errors if any encountered while servicing PDSM.
* 'reserved' : Not used, reserved for future and should be set to 0.
* 'payload' : A union of all the possible payload structs
*
* PDSM Payload:
*
* The layout of the PDSM Payload is defined by various structs shared between
* papr_scm and libndctl so that contents of payload can be interpreted. As such
* its defined as a union of all possible payload structs as
* 'union nd_pdsm_payload'. Based on the value of 'nd_cmd_pkg.nd_command'
* appropriate member of the union is accessed.
*/
/* Max payload size that we can handle */
#define ND_PDSM_PAYLOAD_MAX_SIZE 184
/* Max payload size that we can handle */
#define ND_PDSM_HDR_SIZE \
(sizeof(struct nd_pkg_pdsm) - ND_PDSM_PAYLOAD_MAX_SIZE)
/*
* Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
* via 'nd_cmd_pkg.nd_command' member of the ioctl struct
*/
enum papr_pdsm {
PAPR_PDSM_MIN = 0x0,
PAPR_PDSM_MAX,
};
/* Maximal union that can hold all possible payload types */
union nd_pdsm_payload {
__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
} __packed;
/*
* PDSM-header + payload expected with ND_CMD_CALL ioctl from libnvdimm
* Valid member of union 'payload' is identified via 'nd_cmd_pkg.nd_command'
* that should always precede this struct when sent to papr_scm via CMD_CALL
* interface.
*/
struct nd_pkg_pdsm {
__s32 cmd_status; /* Out: Sub-cmd status returned back */
__u16 reserved[2]; /* Ignored and to be set as '0' */
union nd_pdsm_payload payload;
} __packed;
#endif /* _UAPI_ASM_POWERPC_PAPR_PDSM_H_ */
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