arch/sparc/include/asm/srmmu.h

/* SRMMU page table defines and code,
 * taken from the SPARC port of Linux
 *
 * Copyright (C) 2007 Daniel Hellstrom (daniel@gaisler.com)
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#ifndef __SPARC_SRMMU_H__
#define __SPARC_SRMMU_H__

#include <asm/asi.h>
#include <asm/page.h>

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

/* PMD_SHIFT determines the size of the area a second-level page table entry can map */
#define SRMMU_REAL_PMD_SHIFT		18
#define SRMMU_REAL_PMD_SIZE		(1UL << SRMMU_REAL_PMD_SHIFT)
#define SRMMU_REAL_PMD_MASK		(~(SRMMU_REAL_PMD_SIZE-1))
#define SRMMU_REAL_PMD_ALIGN(__addr)	(((__addr)+SRMMU_REAL_PMD_SIZE-1)&SRMMU_REAL_PMD_MASK)

/* PGDIR_SHIFT determines what a third-level page table entry can map */
#define SRMMU_PGDIR_SHIFT       24
#define SRMMU_PGDIR_SIZE        (1UL << SRMMU_PGDIR_SHIFT)
#define SRMMU_PGDIR_MASK        (~(SRMMU_PGDIR_SIZE-1))
#define SRMMU_PGDIR_ALIGN(addr) (((addr)+SRMMU_PGDIR_SIZE-1)&SRMMU_PGDIR_MASK)

#define SRMMU_REAL_PTRS_PER_PTE	64
#define SRMMU_REAL_PTRS_PER_PMD	64
#define SRMMU_PTRS_PER_PGD	256

#define SRMMU_REAL_PTE_TABLE_SIZE	(SRMMU_REAL_PTRS_PER_PTE*4)
#define SRMMU_PMD_TABLE_SIZE		(SRMMU_REAL_PTRS_PER_PMD*4)
#define SRMMU_PGD_TABLE_SIZE		(SRMMU_PTRS_PER_PGD*4)

/*
 * To support pagetables in highmem, Linux introduces APIs which
 * return struct page* and generally manipulate page tables when
 * they are not mapped into kernel space. Our hardware page tables
 * are smaller than pages. We lump hardware tabes into big, page sized
 * software tables.
 *
 * PMD_SHIFT determines the size of the area a second-level page table entry
 * can map, and our pmd_t is 16 times larger than normal.  The values which
 * were once defined here are now generic for 4c and srmmu, so they're
 * found in pgtable.h.
 */
#define SRMMU_PTRS_PER_PMD	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_FILE         0x40	/* Implemented in software */

#define SRMMU_PTE_FILE_SHIFT     8	/* == 32-PTE_FILE_MAX_BITS */

#define SRMMU_CHG_MASK    (0xffffff00 | SRMMU_REF | SRMMU_DIRTY)

/* SRMMU swap entry encoding
 *
 * We use 5 bits for the type and 19 for the offset.  This gives us
 * 32 swapfiles of 4GB each.  Encoding looks like:
 *
 * oooooooooooooooooootttttRRRRRRRR
 * fedcba9876543210fedcba9876543210
 *
 * The bottom 8 bits are reserved for protection and status bits, especially
 * FILE and PRESENT.
 */
#define SRMMU_SWP_TYPE_MASK	0x1f
#define SRMMU_SWP_TYPE_SHIFT	SRMMU_PTE_FILE_SHIFT
#define SRMMU_SWP_OFF_MASK	0x7ffff
#define SRMMU_SWP_OFF_SHIFT	(SRMMU_PTE_FILE_SHIFT + 5)

/* 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 __ASSEMBLY__

/* 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) __va(__nocache_pa(VADDR))

/* Accessing the MMU control register. */
extern __inline__ unsigned int srmmu_get_mmureg(void)
{
	unsigned int retval;
	__asm__ __volatile__("lda [%%g0] %1, %0\n\t":
			     "=r"(retval):"i"(ASI_M_MMUREGS));
	return retval;
}

extern __inline__ void srmmu_set_mmureg(unsigned long regval)
{
	__asm__ __volatile__("sta %0, [%%g0] %1\n\t"::"r"(regval),
			     "i"(ASI_M_MMUREGS):"memory");

}

extern __inline__ void srmmu_set_ctable_ptr(unsigned long paddr)
{
	paddr = ((paddr >> 4) & SRMMU_CTX_PMASK);
	__asm__ __volatile__("sta %0, [%1] %2\n\t"::"r"(paddr),
			     "r"(SRMMU_CTXTBL_PTR),
			     "i"(ASI_M_MMUREGS):"memory");
}

extern __inline__ unsigned long srmmu_get_ctable_ptr(void)
{
	unsigned int retval;

	__asm__ __volatile__("lda [%1] %2, %0\n\t":
			     "=r"(retval):
			     "r"(SRMMU_CTXTBL_PTR), "i"(ASI_M_MMUREGS));
	return (retval & SRMMU_CTX_PMASK) << 4;
}

extern __inline__ void srmmu_set_context(int context)
{
	__asm__ __volatile__("sta %0, [%1] %2\n\t"::"r"(context),
			     "r"(SRMMU_CTX_REG), "i"(ASI_M_MMUREGS):"memory");
}

extern __inline__ int srmmu_get_context(void)
{
	register int retval;
	__asm__ __volatile__("lda [%1] %2, %0\n\t":
			     "=r"(retval):
			     "r"(SRMMU_CTX_REG), "i"(ASI_M_MMUREGS));
	return retval;
}

extern __inline__ unsigned int srmmu_get_fstatus(void)
{
	unsigned int retval;

	__asm__ __volatile__("lda [%1] %2, %0\n\t":
			     "=r"(retval):
			     "r"(SRMMU_FAULT_STATUS), "i"(ASI_M_MMUREGS));
	return retval;
}

extern __inline__ unsigned int srmmu_get_faddr(void)
{
	unsigned int retval;

	__asm__ __volatile__("lda [%1] %2, %0\n\t":
			     "=r"(retval):
			     "r"(SRMMU_FAULT_ADDR), "i"(ASI_M_MMUREGS));
	return retval;
}

/* This is guaranteed on all SRMMU's. */
extern __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");

}

/* These flush types are not available on all chips... */
extern __inline__ void srmmu_flush_tlb_ctx(void)
{
	__asm__ __volatile__("sta %%g0, [%0] %1\n\t"::"r"(0x300),	/* Flush TLB ctx.. */
			     "i"(ASI_M_FLUSH_PROBE):"memory");

}

extern __inline__ void srmmu_flush_tlb_region(unsigned long addr)
{
	addr &= SRMMU_PGDIR_MASK;
	__asm__ __volatile__("sta %%g0, [%0] %1\n\t"::"r"(addr | 0x200),	/* Flush TLB region.. */
			     "i"(ASI_M_FLUSH_PROBE):"memory");

}

extern __inline__ void srmmu_flush_tlb_segment(unsigned long addr)
{
	addr &= SRMMU_REAL_PMD_MASK;
	__asm__ __volatile__("sta %%g0, [%0] %1\n\t"::"r"(addr | 0x100),	/* Flush TLB segment.. */
			     "i"(ASI_M_FLUSH_PROBE):"memory");

}

extern __inline__ void srmmu_flush_tlb_page(unsigned long page)
{
	page &= PAGE_MASK;
	__asm__ __volatile__("sta %%g0, [%0] %1\n\t"::"r"(page),	/* Flush TLB page.. */
			     "i"(ASI_M_FLUSH_PROBE):"memory");

}

extern __inline__ unsigned long srmmu_hwprobe(unsigned long vaddr)
{
	unsigned long retval;

	vaddr &= PAGE_MASK;
	__asm__ __volatile__("lda [%1] %2, %0\n\t":
			     "=r"(retval):
			     "r"(vaddr | 0x400), "i"(ASI_M_FLUSH_PROBE));

	return retval;
}

extern __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;
}

extern unsigned long (*srmmu_read_physical) (unsigned long paddr);
extern void (*srmmu_write_physical) (unsigned long paddr, unsigned long word);

#endif				/* !(__ASSEMBLY__) */

#endif				/* !(__SPARC_SRMMU_H__) */