linux-brain/arch/mips/include/asm/mach-generic/spaces.h
Paul Burton 3ffc17d876 MIPS: Adjust MIPS64 CAC_BASE to reflect Config.K0
On MIPS64 we define the default CAC_BASE as one of the xkphys regions of
the virtual address space. Since the CCA is encoded in bits 61:59 of
xkphys addresses, fixing CAC_BASE to any particular one prevents us from
dynamically changing the CCA as we do for MIPS32 where CAC_BASE is
placed within kseg0. In order to make the kernel more generic, drop the
current kludge that gives CAC_BASE CCA=3 if CONFIG_DMA_NONCOHERENT is
selected (disregarding CONFIG_DMA_MAYBE_COHERENT) & CCA=5 (which is not
standardised by the architecture) otherwise. Instead read Config.K0 and
generate the appropriate offset into xkphys, presuming that either the
bootloader or early kernel code will have configured Config.K0
appropriately. This seems like the best option for a generic
implementation.

The ip27 spaces.h is adjusted to set its former value of CAC_BASE, since
it's the only user of CAC_BASE from assembly (in its smp_slave_setup
macro). This allows the generic case to focus solely on C code without
breaking ip27.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14351/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06 18:02:35 +02:00

103 lines
2.2 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 - 1999, 2000, 03, 04 Ralf Baechle
* Copyright (C) 2000, 2002 Maciej W. Rozycki
* Copyright (C) 1990, 1999, 2000 Silicon Graphics, Inc.
*/
#ifndef _ASM_MACH_GENERIC_SPACES_H
#define _ASM_MACH_GENERIC_SPACES_H
#include <linux/const.h>
#include <asm/mipsregs.h>
/*
* This gives the physical RAM offset.
*/
#ifndef PHYS_OFFSET
#define PHYS_OFFSET _AC(0, UL)
#endif
#ifdef CONFIG_32BIT
#ifdef CONFIG_KVM_GUEST
#define CAC_BASE _AC(0x40000000, UL)
#else
#define CAC_BASE _AC(0x80000000, UL)
#endif
#ifndef IO_BASE
#define IO_BASE _AC(0xa0000000, UL)
#endif
#ifndef UNCAC_BASE
#define UNCAC_BASE _AC(0xa0000000, UL)
#endif
#ifndef MAP_BASE
#ifdef CONFIG_KVM_GUEST
#define MAP_BASE _AC(0x60000000, UL)
#else
#define MAP_BASE _AC(0xc0000000, UL)
#endif
#endif
/*
* Memory above this physical address will be considered highmem.
*/
#ifndef HIGHMEM_START
#define HIGHMEM_START _AC(0x20000000, UL)
#endif
#endif /* CONFIG_32BIT */
#ifdef CONFIG_64BIT
#ifndef CAC_BASE
#define CAC_BASE PHYS_TO_XKPHYS(read_c0_config() & CONF_CM_CMASK, 0)
#endif
#ifndef IO_BASE
#define IO_BASE _AC(0x9000000000000000, UL)
#endif
#ifndef UNCAC_BASE
#define UNCAC_BASE _AC(0x9000000000000000, UL)
#endif
#ifndef MAP_BASE
#define MAP_BASE _AC(0xc000000000000000, UL)
#endif
/*
* Memory above this physical address will be considered highmem.
* Fixme: 59 bits is a fictive number and makes assumptions about processors
* in the distant future. Nobody will care for a few years :-)
*/
#ifndef HIGHMEM_START
#define HIGHMEM_START (_AC(1, UL) << _AC(59, UL))
#endif
#define TO_PHYS(x) ( ((x) & TO_PHYS_MASK))
#define TO_CAC(x) (CAC_BASE | ((x) & TO_PHYS_MASK))
#define TO_UNCAC(x) (UNCAC_BASE | ((x) & TO_PHYS_MASK))
#endif /* CONFIG_64BIT */
/*
* This handles the memory map.
*/
#ifndef PAGE_OFFSET
#define PAGE_OFFSET (CAC_BASE + PHYS_OFFSET)
#endif
#ifndef FIXADDR_TOP
#ifdef CONFIG_KVM_GUEST
#define FIXADDR_TOP ((unsigned long)(long)(int)0x7ffe0000)
#else
#define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000)
#endif
#endif
#endif /* __ASM_MACH_GENERIC_SPACES_H */