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authorAnup Patel <anup.patel@wdc.com>2019-01-07 18:27:01 +0300
committerAnup Patel <anup@brainfault.org>2019-02-21 08:56:42 +0300
commitf2c17aabc917e1092eedb16fa2b8891e9379f7e6 (patch)
tree263b4020a36643cbc07ede2630e67f60801550bd /arch/riscv/include/asm/fixmap.h
parent6f1e9e946f0bc32cf55a7d7c36f80cb365e1877a (diff)
downloadlinux-f2c17aabc917e1092eedb16fa2b8891e9379f7e6.tar.xz
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 <anup.patel@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/include/asm/fixmap.h')
-rw-r--r--arch/riscv/include/asm/fixmap.h44
1 files changed, 44 insertions, 0 deletions
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 <linux/kernel.h>
+#include <linux/sizes.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+/*
+ * 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 <asm-generic/fixmap.h>
+
+#endif /* _ASM_RISCV_FIXMAP_H */