include/uapi/scsi/ufs/ioctl.h

#ifndef UAPI_UFS_IOCTL_H_
#define UAPI_UFS_IOCTL_H_

#include <linux/types.h>

/*
 *  IOCTL opcode for ufs queries has the following opcode after
 *  SCSI_IOCTL_GET_PCI
 */
#define UFS_IOCTL_QUERY			0x5388

/**
 * struct ufs_ioctl_query_data - used to transfer data to and from user via ioctl
 * @opcode: type of data to query (descriptor/attribute/flag)
 * @idn: id of the data structure
 * @buf_size: number of allocated bytes/data size on return
 * @buffer: data location
 *
 * Received: buffer and buf_size (available space for transfered data)
 * Submitted: opcode, idn, length, buf_size
 */
struct ufs_ioctl_query_data {
	/*
	 * User should select one of the opcode defined in "enum query_opcode".
	 * Please check include/uapi/scsi/ufs/ufs.h for the definition of it.
	 * Note that only UPIU_QUERY_OPCODE_READ_DESC,
	 * UPIU_QUERY_OPCODE_READ_ATTR & UPIU_QUERY_OPCODE_READ_FLAG are
	 * supported as of now. All other query_opcode would be considered
	 * invalid.
	 * As of now only read query operations are supported.
	 */
	__u32 opcode;
	/*
	 * User should select one of the idn from "enum flag_idn" or "enum
	 * attr_idn" or "enum desc_idn" based on whether opcode above is
	 * attribute, flag or descriptor.
	 * Please check include/uapi/scsi/ufs/ufs.h for the definition of it.
	 */
	__u8 idn;
	/*
	 * User should specify the size of the buffer (buffer[0] below) where
	 * it wants to read the query data (attribute/flag/descriptor).
	 * As we might end up reading less data then what is specified in
	 * buf_size. So we are updating buf_size to what exactly we have read.
	 */
	__u16 buf_size;
	/*
	 * placeholder for the start of the data buffer where kernel will copy
	 * the query data (attribute/flag/descriptor) read from the UFS device
	 * Note:
	 * For Read Attribute you will have to allocate 4 bytes
	 * For Read Flag you will have to allocate 1 byte
	 */
	__u8 buffer[0];
};

#endif /* UAPI_UFS_IOCTL_H_ */