/*
 * Copyright (C) 2009 Bahadir Bilgehan Balban
 */
#ifndef __ARM_UTCB_H__
#define __ARM_UTCB_H__

#define USER_UTCB_REF           0xFF000050
#define L4_KIP_ADDRESS		0xFF000000
#define UTCB_KIP_OFFSET		0x50

#ifndef __ASSEMBLY__
#include <l4lib/types.h>
#include <l4/macros.h>
#include INC_GLUE(message.h)
#include INC_GLUE(memory.h)
#include <string.h>
#include <stdio.h>

/* UTCB implementation */

/*
 * NOTE: In syslib.h the first few mrs are used by data frequently
 * needed for all ipcs. Those mrs are defined the kernel message.h
 */

struct utcb {
	u32 mr[MR_TOTAL];	/* MRs that are mapped to real registers */
	u32 saved_tag;		/* Saved tag field for stacked ipcs */
	u32 saved_sender;	/* Saved sender field for stacked ipcs */
	u32 mr_rest[MR_REST];	/* Complete the utcb for up to 64 words */
};

extern struct kip *kip;


/*
 * Pointer to Kernel Interface Page's UTCB pointer offset.
 */
extern struct utcb **kip_utcb_ref;

static inline struct utcb *l4_get_utcb()
{
 	/*
	 * By double dereferencing, we get the private TLS (aka UTCB). First
	 * reference is to the KIP's utcb offset, second is to the utcb itself,
	 * to which the KIP's utcb reference had been updated during context
	 * switch.
	 */
	return *kip_utcb_ref;
}

/* Functions to read/write utcb registers */
static inline unsigned int read_mr(int offset)
{
	if (offset < MR_TOTAL)
		return l4_get_utcb()->mr[offset];
	else
		return l4_get_utcb()->mr_rest[offset - MR_TOTAL];
}

static inline void write_mr(unsigned int offset, unsigned int val)
{
	if (offset < MR_TOTAL)
		l4_get_utcb()->mr[offset] = val;
	else
		l4_get_utcb()->mr_rest[offset - MR_TOTAL] = val;
}

#endif /* !__ASSEMBLY__ */

#endif /* __ARM_UTCB_H__ */