nds32: MMU definitions

This patch includes virtual memory layout, PHYS_OFFSET is defined as 0x0. It
also includes the 4KB/8KB page size configurations and pte operations.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 105 insertions, 0 deletions

diff --git a/arch/nds32/include/asm/memory.h b/arch/nds32/include/asm/memory.h
new file mode 100644
index 000000000000..60efc726b56e
--- /dev/null
+++ b/arch/nds32/include/asm/memory.h
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __ASM_NDS32_MEMORY_H
+#define __ASM_NDS32_MEMORY_H
+
+#include <linux/compiler.h>
+#include <linux/sizes.h>
+
+#ifndef __ASSEMBLY__
+#include <asm/page.h>
+#endif
+
+#ifndef PHYS_OFFSET
+#define PHYS_OFFSET     (0x0)
+#endif
+
+#ifndef __virt_to_bus
+#define __virt_to_bus	__virt_to_phys
+#endif
+
+#ifndef __bus_to_virt
+#define __bus_to_virt	__phys_to_virt
+#endif
+
+/*
+ * TASK_SIZE - the maximum size of a user space task.
+ * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area
+ */
+#define TASK_SIZE		((CONFIG_PAGE_OFFSET) - (SZ_32M))
+#define TASK_UNMAPPED_BASE	ALIGN(TASK_SIZE / 3, SZ_32M)
+#define PAGE_OFFSET		(CONFIG_PAGE_OFFSET)
+
+/*
+ * Physical vs virtual RAM address space conversion.  These are
+ * private definitions which should NOT be used outside memory.h
+ * files.  Use virt_to_phys/phys_to_virt/__pa/__va instead.
+ */
+#ifndef __virt_to_phys
+#define __virt_to_phys(x)	((x) - PAGE_OFFSET + PHYS_OFFSET)
+#define __phys_to_virt(x)	((x) - PHYS_OFFSET + PAGE_OFFSET)
+#endif
+
+/*
+ * The module space lives between the addresses given by TASK_SIZE
+ * and PAGE_OFFSET - it must be within 32MB of the kernel text.
+ */
+#define MODULES_END	(PAGE_OFFSET)
+#define MODULES_VADDR	(MODULES_END - SZ_32M)
+
+#if TASK_SIZE > MODULES_VADDR
+#error Top of user space clashes with start of module space
+#endif
+
+#ifndef __ASSEMBLY__
+
+/*
+ * PFNs are used to describe any physical page; this means
+ * PFN 0 == physical address 0.
+ *
+ * This is the PFN of the first RAM page in the kernel
+ * direct-mapped view.  We assume this is the first page
+ * of RAM in the mem_map as well.
+ */
+#define PHYS_PFN_OFFSET	(PHYS_OFFSET >> PAGE_SHIFT)
+
+/*
+ * Drivers should NOT use these either.
+ */
+#define __pa(x)			__virt_to_phys((unsigned long)(x))
+#define __va(x)			((void *)__phys_to_virt((unsigned long)(x)))
+
+/*
+ * Conversion between a struct page and a physical address.
+ *
+ * Note: when converting an unknown physical address to a
+ * struct page, the resulting pointer must be validated
+ * using VALID_PAGE().  It must return an invalid struct page
+ * for any physical address not corresponding to a system
+ * RAM address.
+ *
+ *  pfn_valid(pfn)	indicates whether a PFN number is valid
+ *
+ *  virt_to_page(k)	convert a _valid_ virtual address to struct page *
+ *  virt_addr_valid(k)	indicates whether a virtual address is valid
+ */
+#ifndef CONFIG_DISCONTIGMEM
+
+#define ARCH_PFN_OFFSET		PHYS_PFN_OFFSET
+#define pfn_valid(pfn)		((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
+
+#define virt_to_page(kaddr)	(pfn_to_page(__pa(kaddr) >> PAGE_SHIFT))
+#define virt_addr_valid(kaddr)	((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
+
+#else /* CONFIG_DISCONTIGMEM */
+#error CONFIG_DISCONTIGMEM is not supported yet.
+#endif /* !CONFIG_DISCONTIGMEM */
+
+#define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
+
+#endif
+
+#include <asm-generic/memory_model.h>
+
+#endif