/* SPDX-License-Identifier: GPL-2.0 */
/*
 * pgtsrmmu.h:  SRMMU page table defines and code.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 */

#ifndef _SPARC_PGTSRMMU_H
#define _SPARC_PGTSRMMU_H

#include <asm/page.h>

#ifdef __ASSEMBLER__
#include <asm/thread_info.h>    /* TI_UWINMASK for WINDOW_FLUSH */
#endif

/* Number of contexts is implementation-dependent; 64k is the most we support */
#define SRMMU_MAX_CONTEXTS      65536

#define SRMMU_PTE_TABLE_SIZE            (PTRS_PER_PTE*4)
#define SRMMU_PMD_TABLE_SIZE            (PTRS_PER_PMD*4)
#define SRMMU_PGD_TABLE_SIZE            (PTRS_PER_PGD*4)

/* Definition of the values in the ET field of PTD's and PTE's */
#define SRMMU_ET_MASK         0x3
#define SRMMU_ET_INVALID      0x0
#define SRMMU_ET_PTD          0x1
#define SRMMU_ET_PTE          0x2
#define SRMMU_ET_REPTE        0x3 /* AIEEE, SuperSparc II reverse endian page! */

/* Physical page extraction from PTP's and PTE's. */
#define SRMMU_CTX_PMASK    0xfffffff0
#define SRMMU_PTD_PMASK    0xfffffff0
#define SRMMU_PTE_PMASK    0xffffff00

/* The pte non-page bits.  Some notes:
 * 1) cache, dirty, valid, and ref are frobbable
 *    for both supervisor and user pages.
 * 2) exec and write will only give the desired effect
 *    on user pages
 * 3) use priv and priv_readonly for changing the
 *    characteristics of supervisor ptes
 */
#define SRMMU_CACHE        0x80
#define SRMMU_DIRTY        0x40
#define SRMMU_REF          0x20
#define SRMMU_NOREAD       0x10
#define SRMMU_EXEC         0x08
#define SRMMU_WRITE        0x04
#define SRMMU_VALID        0x02 /* SRMMU_ET_PTE */
#define SRMMU_PRIV         0x1c
#define SRMMU_PRIV_RDONLY  0x18

#define SRMMU_CHG_MASK    (0xffffff00 | SRMMU_REF | SRMMU_DIRTY)

/* SRMMU swap entry encoding */
#define SRMMU_SWP_TYPE_MASK     0x1f
#define SRMMU_SWP_TYPE_SHIFT    7
#define SRMMU_SWP_OFF_MASK      0xfffff
#define SRMMU_SWP_OFF_SHIFT     (SRMMU_SWP_TYPE_SHIFT + 5)
/* We borrow bit 6 to store the exclusive marker in swap PTEs. */
#define SRMMU_SWP_EXCLUSIVE     SRMMU_DIRTY

/* Some day I will implement true fine grained access bits for
 * user pages because the SRMMU gives us the capabilities to
 * enforce all the protection levels that vma's can have.
 * XXX But for now...
 */
#define SRMMU_PAGE_NONE    __pgprot(SRMMU_CACHE | \
                                    SRMMU_PRIV | SRMMU_REF)
#define SRMMU_PAGE_SHARED  __pgprot(SRMMU_VALID | SRMMU_CACHE | \
                                    SRMMU_EXEC | SRMMU_WRITE | SRMMU_REF)
#define SRMMU_PAGE_COPY    __pgprot(SRMMU_VALID | SRMMU_CACHE | \
                                    SRMMU_EXEC | SRMMU_REF)
#define SRMMU_PAGE_RDONLY  __pgprot(SRMMU_VALID | SRMMU_CACHE | \
                                    SRMMU_EXEC | SRMMU_REF)
#define SRMMU_PAGE_KERNEL  __pgprot(SRMMU_VALID | SRMMU_CACHE | SRMMU_PRIV | \
                                    SRMMU_DIRTY | SRMMU_REF)

/* SRMMU Register addresses in ASI 0x4.  These are valid for all
 * current SRMMU implementations that exist.
 */
#define SRMMU_CTRL_REG           0x00000000
#define SRMMU_CTXTBL_PTR         0x00000100
#define SRMMU_CTX_REG            0x00000200
#define SRMMU_FAULT_STATUS       0x00000300
#define SRMMU_FAULT_ADDR         0x00000400

#define WINDOW_FLUSH(tmp1, tmp2)                                        \
        mov     0, tmp1;                                                \
98:     ld      [%g6 + TI_UWINMASK], tmp2;                              \
        orcc    %g0, tmp2, %g0;                                         \
        add     tmp1, 1, tmp1;                                          \
        bne     98b;                                                    \
         save   %sp, -64, %sp;                                          \
99:     subcc   tmp1, 1, tmp1;                                          \
        bne     99b;                                                    \
         restore %g0, %g0, %g0;

#ifndef __ASSEMBLER__
extern unsigned long last_valid_pfn;

/* This makes sense. Honest it does - Anton */
/* XXX Yes but it's ugly as sin.  FIXME. -KMW */
extern void *srmmu_nocache_pool;
#define __nocache_pa(VADDR) (((unsigned long)VADDR) - SRMMU_NOCACHE_VADDR + __pa((unsigned long)srmmu_nocache_pool))
#define __nocache_va(PADDR) (__va((unsigned long)PADDR) - (unsigned long)srmmu_nocache_pool + SRMMU_NOCACHE_VADDR)
#define __nocache_fix(VADDR) ((__typeof__(VADDR))__va(__nocache_pa(VADDR)))

/* Accessing the MMU control register. */
unsigned int srmmu_get_mmureg(void);
void srmmu_set_mmureg(unsigned long regval);
void srmmu_set_ctable_ptr(unsigned long paddr);
void srmmu_set_context(int context);
int srmmu_get_context(void);
unsigned int srmmu_get_fstatus(void);
unsigned int srmmu_get_faddr(void);

/* This is guaranteed on all SRMMU's. */
static inline void srmmu_flush_whole_tlb(void)
{
        __asm__ __volatile__("sta %%g0, [%0] %1\n\t": :
                             "r" (0x400),        /* Flush entire TLB!! */
                             "i" (ASI_M_FLUSH_PROBE) : "memory");

}

static inline int
srmmu_get_pte (unsigned long addr)
{
        register unsigned long entry;
        
        __asm__ __volatile__("\n\tlda [%1] %2,%0\n\t" :
                                "=r" (entry):
                                "r" ((addr & 0xfffff000) | 0x400), "i" (ASI_M_FLUSH_PROBE));
        return entry;
}

#endif /* !(__ASSEMBLER__) */

#endif /* !(_SPARC_PGTSRMMU_H) */