/*
 * include/asm-mips/processor.h
 *
 * Copyright (C) 1994  Waldorf Electronics
 * written by Ralf Baechle
 */

#ifndef __ASM_MIPS_PROCESSOR_H
#define __ASM_MIPS_PROCESSOR_H

#if !defined (__LANGUAGE_ASSEMBLY__)
#include <asm/cachectl.h>
#include <asm/mipsregs.h>
#include <asm/reg.h>
#include <asm/system.h>

/*
 * System setup and hardware bug flags..
 */
extern char wait_available;		/* only available on R4[26]00 */

extern unsigned long intr_count;
extern unsigned long event;

/*
 * Bus types (default is ISA, but people can check others with these..)
 * MCA_bus hardcoded to 0 for now.
 *
 * This needs to be extended since MIPS systems are being delivered with
 * numerous different types of bus systems.
 */
extern int EISA_bus;
#define MCA_bus 0
#define MCA_bus__is_a_macro /* for versions in ksyms.c */

/*
 * MIPS has no problems with write protection
 */
#define wp_works_ok 1
#define wp_works_ok__is_a_macro /* for versions in ksyms.c */

/*
 * User space process size: 2GB. This is hardcoded into a few places,
 * so don't change it unless you know what you are doing.
 */
#define TASK_SIZE	(0x80000000UL)

/*
 * Size of io_bitmap in longwords: 32 is ports 0-0x3ff.
 */
#define IO_BITMAP_SIZE	32

#define NUM_FPU_REGS	32

struct mips_fpu_hard_struct {
	double fp_regs[NUM_FPU_REGS];
	unsigned int control;
};

/*
 * FIXME: no fpu emulator yet (but who cares anyway?)
 */
struct mips_fpu_soft_struct {
	long	dummy;
	};

union mips_fpu_union {
        struct mips_fpu_hard_struct hard;
        struct mips_fpu_soft_struct soft;
};

#define INIT_FPU { \
	{{0,},} \
}

/*
 * If you change thread_struct remember to change the #defines below too!
 */
struct thread_struct {
        /*
         * saved main processor registers
         */
        unsigned long   reg16, reg17, reg18, reg19, reg20, reg21, reg22, reg23;
        unsigned long                               reg28, reg29, reg30, reg31;
	/*
	 * saved cp0 stuff
	 */
	unsigned long cp0_status;
	/*
	 * saved fpu/fpu emulator stuff
	 */
	union mips_fpu_union fpu;
	/*
	 * Other stuff associated with the thread
	 */
	unsigned long cp0_badvaddr;
	unsigned long error_code;
	unsigned long trap_no;
	unsigned long ksp;		/* Top of kernel stack   */
	unsigned long pg_dir;		/* L1 page table pointer */
#define MF_FIXADE 1
	unsigned long mflags;
};

#endif /* !defined (__LANGUAGE_ASSEMBLY__) */

/*
 * If you change the #defines remember to change thread_struct above too!
 */
#define TOFF_REG16		0
#define TOFF_REG17		(TOFF_REG16+4)
#define TOFF_REG18		(TOFF_REG17+4)
#define TOFF_REG19		(TOFF_REG18+4)
#define TOFF_REG20		(TOFF_REG19+4)
#define TOFF_REG21		(TOFF_REG20+4)
#define TOFF_REG22		(TOFF_REG21+4)
#define TOFF_REG23		(TOFF_REG22+4)
#define TOFF_REG28		(TOFF_REG23+4)
#define TOFF_REG29		(TOFF_REG28+4)
#define TOFF_REG30		(TOFF_REG29+4)
#define TOFF_REG31		(TOFF_REG30+4)
#define TOFF_CP0_STATUS		(TOFF_REG31+4)
/*
 * Pad for 8 byte boundary!
 */
#define TOFF_FPU		(((TOFF_CP0_STATUS+4)+(8-1))&~(8-1))
#define TOFF_CP0_BADVADDR	(TOFF_FPU+264)
#define TOFF_ERROR_CODE		(TOFF_CP0_BADVADDR+4)
#define TOFF_TRAP_NO		(TOFF_ERROR_CODE+4)
#define TOFF_KSP		(TOFF_TRAP_NO+4)
#define TOFF_PG_DIR		(TOFF_KSP+4)
#define TOFF_MFLAGS		(TOFF_PG_DIR+4)

#if !defined (__LANGUAGE_ASSEMBLY__)

#define INIT_MMAP { &init_mm, KSEG0, KSEG1, PAGE_SHARED, \
                    VM_READ | VM_WRITE | VM_EXEC }

#define INIT_TSS  { \
        /* \
         * saved main processor registers \
         */ \
	0, 0, 0, 0, 0, 0, 0, 0, \
	            0, 0, 0, 0, \
	/* \
	 * saved cp0 stuff \
	 */ \
	0, \
	/* \
	 * saved fpu/fpu emulator stuff \
	 */ \
	INIT_FPU, \
	/* \
	 * Other stuff associated with the process\
	 */ \
	0, 0, 0, sizeof(init_kernel_stack) + (unsigned long)init_kernel_stack - 8, \
	(unsigned long) swapper_pg_dir - PT_OFFSET, 0 \
}

/*
 * Return saved PC of a blocked thread.
 */
extern inline unsigned long thread_saved_pc(struct thread_struct *t)
{
	return ((unsigned long *)t->reg29)[EF_CP0_EPC];
}

/*
 * Do necessary setup to start up a newly executed thread.
 */
static __inline__
void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
{
	/*
	 * Pure paranoia; probably not needed.
	 */
	sys_cacheflush(0, ~0, BCACHE);
	sync_mem();
	regs->cp0_epc = pc;
	/*
	 * New thread loses kernel privileges.
	 */
	regs->cp0_status = (regs->cp0_status & ~(ST0_CU0|ST0_KSU)) | KSU_USER;
	/*
	 * Reserve argument save space for registers a0 - a3.
	regs->reg29 = sp - 4 * sizeof(unsigned long);
	 */
	regs->reg29 = sp;
}

#ifdef __KERNEL__

/*
 * switch_to(n) should switch tasks to task nr n, first
 * checking that n isn't the current task, in which case it does nothing.
 */
asmlinkage void resume(struct task_struct *tsk, int offset);

#define switch_to(n) \
	resume(n, ((int)(&((struct task_struct *)0)->tss)))

/*
 * Does the process account for user or for system time?
 */
#if defined (__R4000__)

#define USES_USER_TIME(regs) (!((regs)->cp0_status & 0x18))

#else /* !defined (__R4000__) */

#define USES_USER_TIME(regs) (!((regs)->cp0_status & 0x4))

#endif /* !defined (__R4000__) */

#endif /* __KERNEL__ */

#endif /* !defined (__LANGUAGE_ASSEMBLY__) */

/*
 * ELF support
 *
 * Using EM_MIPS is actually wrong - this one is reserved for big endian
 * machines only
 */
#define INCOMPATIBLE_MACHINE(m) ((m) != EM_MIPS && (m) != EM_MIPS_RS4_BE)
#define ELF_EM_CPU EM_MIPS

#endif /* __ASM_MIPS_PROCESSOR_H */