From f2c17aabc917e1092eedb16fa2b8891e9379f7e6 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Mon, 7 Jan 2019 20:57:01 +0530 Subject: RISC-V: Implement compile-time fixed mappings This patch implements compile-time virtual to physical mappings. These compile-time fixed mappings can be used by earlycon, ACPI, and early ioremap for creating fixed mappings when FIX_EARLYCON_MEM=y. To start with, we have enabled compile-time fixed mappings for earlycon. Signed-off-by: Anup Patel Reviewed-by: Christoph Hellwig Reviewed-by: Palmer Dabbelt --- arch/riscv/include/asm/fixmap.h | 44 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 arch/riscv/include/asm/fixmap.h (limited to 'arch/riscv/include/asm/fixmap.h') diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h new file mode 100644 index 000000000000..57afe604b495 --- /dev/null +++ b/arch/riscv/include/asm/fixmap.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + */ + +#ifndef _ASM_RISCV_FIXMAP_H +#define _ASM_RISCV_FIXMAP_H + +#include +#include +#include +#include + +/* + * Here we define all the compile-time 'special' virtual addresses. + * The point is to have a constant address at compile time, but to + * set the physical address only in the boot process. + * + * These 'compile-time allocated' memory buffers are page-sized. Use + * set_fixmap(idx,phys) to associate physical memory with fixmap indices. + */ +enum fixed_addresses { + FIX_HOLE, + FIX_EARLYCON_MEM_BASE, + __end_of_fixed_addresses +}; + +#define FIXADDR_SIZE (__end_of_fixed_addresses * PAGE_SIZE) +#define FIXADDR_TOP (PAGE_OFFSET) +#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) + +#define FIXMAP_PAGE_IO PAGE_KERNEL + +#define __early_set_fixmap __set_fixmap + +#define __late_set_fixmap __set_fixmap +#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR) + +extern void __set_fixmap(enum fixed_addresses idx, + phys_addr_t phys, pgprot_t prot); + +#include + +#endif /* _ASM_RISCV_FIXMAP_H */ -- cgit v1.2.3