/* $Id: marshal.h,v 1.1 2003/08/19 13:37:07 mikpe Exp $

 * Performance-monitoring counters driver.

 * Structure marshalling support.

 *

 * Copyright (C) 2003  Mikael Pettersson

 */

/*

 * Each encoded datum starts with a 32-bit header word, containing

 * the datum's type (1 bit: UINT32 or UINT64), the target's field

 * tag (16 bits), and the target field's array index (15 bits).

 *

 * After the header follows the datum's value, in one (for UINT32)

 * or two (for UINT64) words. Multi-word values are emitted in

 * native word order.

 *

 * To encode a struct, encode each field with a non-zero value,

 * and place the encodings in sequence. The field order is arbitrary.

 *

 * To decode an encoded struct, first memset() the target struct

 * to zero. Then decode each encoded field in the sequence and

 * update the corresponding field in the target struct.

 */

#define PERFCTR_HEADER(TYPE,TAG,ITEMNR) (((TAG)<<16)|((ITEMNR)<<1)|(TYPE))

#define PERFCTR_HEADER_TYPE(H)		((H) & 0x1)

#define PERFCTR_HEADER_ITEMNR(H)	(((H) >> 1) & 0x7FFF)

#define PERFCTR_HEADER_TAG(H)		((H) >> 16)

#define PERFCTR_HEADER_UINT32		0

#define PERFCTR_HEADER_UINT64		1

/*

 * A field descriptor describes a struct field to the

 * encoding and decoding procedures.

 *

 * To keep the descriptors small, field tags and array sizes

 * are currently restricted to 8 and 7 bits, respectively.

 * This does not change the encoded format.

 */

struct perfctr_field_desc {

	unsigned short offset;	/* offsetof() for this field */

	unsigned char tag;	/* identifying tag in encoded format */

	unsigned char type;	/* base type (1 bit), array size - 1 (7 bits) */

};

#define PERFCTR_TYPE_ARRAY(N,T)	((((N) - 1) << 1) | (T))

#define PERFCTR_TYPE_BASE(T)	((T) & 0x1)

#define PERFCTR_TYPE_NRITEMS(T)	(((T) >> 1) + 1)

#define PERFCTR_TYPE_BYTES4	0	/* uint32 or char[4] */

#define PERFCTR_TYPE_UINT64	1	/* long long */

struct perfctr_struct_desc {

	unsigned short total_sizeof;	/* for buffer allocation and decode memset() */

	unsigned short total_nrfields;	/* for buffer allocation */

	unsigned short nrfields;

	unsigned short nrsubs;

	/* Note: the fields must be in ascending tag order */

	const struct perfctr_field_desc *fields;

	const struct perfctr_sub_struct_desc {

		unsigned short offset;

		const struct perfctr_struct_desc *sdesc;

	} *subs;

};

struct perfctr_marshal_stream {

	unsigned int size;

	unsigned int *buffer;

	unsigned int pos;

	unsigned int error;

};

extern void perfctr_encode_struct(const void *address,

				  const struct perfctr_struct_desc *sdesc,

				  struct perfctr_marshal_stream *stream);

extern int perfctr_decode_struct(void *address,

				 const struct perfctr_struct_desc *sdesc,

				 struct perfctr_marshal_stream *stream);

extern const struct perfctr_struct_desc perfctr_sum_ctrs_sdesc;

extern const struct perfctr_struct_desc perfctr_cpu_control_sdesc;

extern const struct perfctr_struct_desc perfctr_info_sdesc;

extern const struct perfctr_struct_desc vperfctr_control_sdesc;

extern const struct perfctr_struct_desc gperfctr_cpu_control_sdesc;

extern const struct perfctr_struct_desc gperfctr_cpu_state_only_cpu_sdesc;

extern const struct perfctr_struct_desc gperfctr_cpu_state_sdesc;

#ifdef __KERNEL__

extern int perfctr_copy_to_user(struct perfctr_struct_buf *argp,

				void *struct_address,

				const struct perfctr_struct_desc *sdesc);

extern int perfctr_copy_from_user(void *struct_address,

				  struct perfctr_struct_buf *argp,

				  const struct perfctr_struct_desc *sdesc);

#else

extern int perfctr_ioctl_w(int fd, unsigned int cmd, const void *arg,

			   const struct perfctr_struct_desc *sdesc);

extern int perfctr_ioctl_r(int fd, unsigned int cmd, void *res,

			   const struct perfctr_struct_desc *sdesc);

extern int perfctr_ioctl_wr(int fd, unsigned int cmd, void *argres,

			    const struct perfctr_struct_desc *arg_sdesc,

			    const struct perfctr_struct_desc *res_sdesc);

#endif /* __KERNEL__ */