unicore32 core architecture: mm related: generic codes

This patch includes generic codes for memory management.
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

arch/unicore32/include/asm/cache.h

+/*
+ * linux/arch/unicore32/include/asm/cache.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __UNICORE_CACHE_H__
+#define __UNICORE_CACHE_H__
+
+#define L1_CACHE_SHIFT		(5)
+#define L1_CACHE_BYTES		(1 << L1_CACHE_SHIFT)
+
+/*
+ * Memory returned by kmalloc() may be used for DMA, so we must make
+ * sure that all such allocations are cache aligned. Otherwise,
+ * unrelated code may cause parts of the buffer to be read into the
+ * cache before the transfer is done, causing old data to be seen by
+ * the CPU.
+ */
+#define ARCH_DMA_MINALIGN	L1_CACHE_BYTES
+
+#endif

arch/unicore32/include/asm/memblock.h

+/*
+ * linux/arch/unicore32/include/asm/memblock.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __UNICORE_MEMBLOCK_H__
+#define __UNICORE_MEMBLOCK_H__
+
+/*
+ * Memory map description
+ */
+# define NR_BANKS 8
+
+struct membank {
+	unsigned long start;
+	unsigned long size;
+	unsigned int highmem;
+};
+
+struct meminfo {
+	int nr_banks;
+	struct membank bank[NR_BANKS];
+};
+
+extern struct meminfo meminfo;
+
+#define for_each_bank(iter, mi)				\
+	for (iter = 0; iter < (mi)->nr_banks; iter++)
+
+#define bank_pfn_start(bank)	__phys_to_pfn((bank)->start)
+#define bank_pfn_end(bank)	__phys_to_pfn((bank)->start + (bank)->size)
+#define bank_pfn_size(bank)	((bank)->size >> PAGE_SHIFT)
+#define bank_phys_start(bank)	((bank)->start)
+#define bank_phys_end(bank)	((bank)->start + (bank)->size)
+#define bank_phys_size(bank)	((bank)->size)
+
+extern void uc32_memblock_init(struct meminfo *);
+
+#endif

arch/unicore32/include/asm/memory.h

+/*
+ * linux/arch/unicore32/include/asm/memory.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  Note: this file should not be included by non-asm/.h files
+ */
+#ifndef __UNICORE_MEMORY_H__
+#define __UNICORE_MEMORY_H__
+
+#include <linux/compiler.h>
+#include <linux/const.h>
+#include <asm/sizes.h>
+#include <mach/memory.h>
+
+/*
+ * Allow for constants defined here to be used from assembly code
+ * by prepending the UL suffix only with actual C code compilation.
+ */
+#define UL(x) _AC(x, UL)
+
+/*
+ * PAGE_OFFSET - the virtual address of the start of the kernel image
+ * TASK_SIZE - the maximum size of a user space task.
+ * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area
+ */
+#define PAGE_OFFSET		UL(0xC0000000)
+#define TASK_SIZE		(PAGE_OFFSET - UL(0x41000000))
+#define TASK_UNMAPPED_BASE	(PAGE_OFFSET / 3)
+
+/*
+ * 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_VADDR		(PAGE_OFFSET - 16*1024*1024)
+#if TASK_SIZE > MODULES_VADDR
+#error Top of user space clashes with start of module space
+#endif
+
+#define MODULES_END		(PAGE_OFFSET)
+
+/*
+ * Allow 16MB-aligned ioremap pages
+ */
+#define IOREMAP_MAX_ORDER	24
+
+/*
+ * 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
+
+/*
+ * Convert a physical address to a Page Frame Number and back
+ */
+#define	__phys_to_pfn(paddr)	((paddr) >> PAGE_SHIFT)
+#define	__pfn_to_phys(pfn)	((pfn) << PAGE_SHIFT)
+
+/*
+ * Convert a page to/from a physical address
+ */
+#define page_to_phys(page)	(__pfn_to_phys(page_to_pfn(page)))
+#define phys_to_page(phys)	(pfn_to_page(__phys_to_pfn(phys)))
+
+#ifndef __ASSEMBLY__
+
+#ifndef arch_adjust_zones
+#define arch_adjust_zones(size, holes) do { } while (0)
+#endif
+
+/*
+ * 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)))
+#define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
+
+/*
+ * 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.
+ *
+ *  page_to_pfn(page)	convert a struct page * to a PFN number
+ *  pfn_to_page(pfn)	convert a _valid_ PFN number to struct page *
+ *
+ *  virt_to_page(k)	convert a _valid_ virtual address to struct page *
+ *  virt_addr_valid(k)	indicates whether a virtual address is valid
+ */
+#define ARCH_PFN_OFFSET		PHYS_PFN_OFFSET
+
+#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)
+
+#endif
+
+#include <asm-generic/memory_model.h>
+
+#endif

arch/unicore32/include/asm/page.h

+/*
+ * linux/arch/unicore32/include/asm/page.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __UNICORE_PAGE_H__
+#define __UNICORE_PAGE_H__
+
+/* PAGE_SHIFT determines the page size */
+#define PAGE_SHIFT		12
+#define PAGE_SIZE		(_AC(1, UL) << PAGE_SHIFT)
+#define PAGE_MASK		(~(PAGE_SIZE-1))
+
+#ifndef __ASSEMBLY__
+
+struct page;
+struct vm_area_struct;
+
+#define clear_page(page)	memset((void *)(page), 0, PAGE_SIZE)
+extern void copy_page(void *to, const void *from);
+
+#define clear_user_page(page, vaddr, pg)	clear_page(page)
+#define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
+
+#undef STRICT_MM_TYPECHECKS
+
+#ifdef STRICT_MM_TYPECHECKS
+/*
+ * These are used to make use of C type-checking..
+ */
+typedef struct { unsigned long pte; } pte_t;
+typedef struct { unsigned long pgd; } pgd_t;
+typedef struct { unsigned long pgprot; } pgprot_t;
+
+#define pte_val(x)      ((x).pte)
+#define pgd_val(x)	((x).pgd)
+#define pgprot_val(x)   ((x).pgprot)
+
+#define __pte(x)        ((pte_t) { (x) })
+#define __pgd(x)	((pgd_t) { (x) })
+#define __pgprot(x)     ((pgprot_t) { (x) })
+
+#else
+/*
+ * .. while these make it easier on the compiler
+ */
+typedef unsigned long pte_t;
+typedef unsigned long pgd_t;
+typedef unsigned long pgprot_t;
+
+#define pte_val(x)      (x)
+#define pgd_val(x)      (x)
+#define pgprot_val(x)   (x)
+
+#define __pte(x)        (x)
+#define __pgd(x)	(x)
+#define __pgprot(x)     (x)
+
+#endif /* STRICT_MM_TYPECHECKS */
+
+typedef struct page *pgtable_t;
+
+extern int pfn_valid(unsigned long);
+
+#include <asm/memory.h>
+
+#endif /* !__ASSEMBLY__ */
+
+#define VM_DATA_DEFAULT_FLAGS \
+	(VM_READ | VM_WRITE | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#include <asm-generic/getorder.h>
+
+#endif

arch/unicore32/include/asm/tlb.h

+/*
+ * linux/arch/unicore32/include/asm/tlb.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __UNICORE_TLB_H__
+#define __UNICORE_TLB_H__
+
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
+
+/*
+ * TLB handling.  This allows us to remove pages from the page
+ * tables, and efficiently handle the TLB issues.
+ */
+struct mmu_gather {
+	struct mm_struct	*mm;
+	unsigned int		fullmm;
+	unsigned long		range_start;
+	unsigned long		range_end;
+};
+
+DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+static inline struct mmu_gather *
+tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
+{
+	struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
+
+	tlb->mm = mm;
+	tlb->fullmm = full_mm_flush;
+
+	return tlb;
+}
+
+static inline void
+tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+	if (tlb->fullmm)
+		flush_tlb_mm(tlb->mm);
+
+	/* keep the page table cache within bounds */
+	check_pgt_cache();
+
+	put_cpu_var(mmu_gathers);
+}
+
+/*
+ * Memorize the range for the TLB flush.
+ */
+static inline void
+tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
+{
+	if (!tlb->fullmm) {
+		if (addr < tlb->range_start)
+			tlb->range_start = addr;
+		if (addr + PAGE_SIZE > tlb->range_end)
+			tlb->range_end = addr + PAGE_SIZE;
+	}
+}
+
+/*
+ * In the case of tlb vma handling, we can optimise these away in the
+ * case where we're doing a full MM flush.  When we're doing a munmap,
+ * the vmas are adjusted to only cover the region to be torn down.
+ */
+static inline void
+tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+	if (!tlb->fullmm) {
+		flush_cache_range(vma, vma->vm_start, vma->vm_end);
+		tlb->range_start = TASK_SIZE;
+		tlb->range_end = 0;
+	}
+}
+
+static inline void
+tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+	if (!tlb->fullmm && tlb->range_end > 0)
+		flush_tlb_range(vma, tlb->range_start, tlb->range_end);
+}
+
+#define tlb_remove_page(tlb, page)	free_page_and_swap_cache(page)
+#define pte_free_tlb(tlb, ptep, addr)	pte_free((tlb)->mm, ptep)
+#define pmd_free_tlb(tlb, pmdp, addr)	pmd_free((tlb)->mm, pmdp)
+#define pud_free_tlb(tlb, x, addr)      do { } while (0)
+
+#define tlb_migrate_finish(mm)		do { } while (0)
+
+#endif

arch/unicore32/include/mach/map.h

+/*
+ * linux/arch/unicore32/include/mach/map.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  Page table mapping constructs and function prototypes
+ */
+#define MT_DEVICE		0
+#define MT_DEVICE_CACHED	2
+#define MT_KUSER		7
+#define MT_HIGH_VECTORS		8
+#define MT_MEMORY		9
+#define MT_ROM			10
+

arch/unicore32/include/mach/memory.h

+/*
+ * linux/arch/unicore32/include/mach/memory.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __MACH_PUV3_MEMORY_H__
+#define __MACH_PUV3_MEMORY_H__
+
+#include <mach/hardware.h>
+
+/* Physical DRAM offset. */
+#define PHYS_OFFSET	UL(0x00000000)
+/* The base address of exception vectors. */
+#define VECTORS_BASE	UL(0xffff0000)
+/* The base address of kuser area. */
+#define KUSER_BASE	UL(0x80000000)
+
+#ifdef __ASSEMBLY__
+/* The byte offset of the kernel image in RAM from the start of RAM. */
+#define KERNEL_IMAGE_START	0x00408000
+#endif
+
+#if !defined(__ASSEMBLY__) && defined(CONFIG_PCI)
+
+void puv3_pci_adjust_zones(unsigned long *size, unsigned long *holes);
+
+#define arch_adjust_zones(size, holes) \
+	puv3_pci_adjust_zones(size, holes)
+
+#endif
+
+/*
+ * PCI controller in PKUnity-3 masks highest 5-bit for upstream channel,
+ * so we must limit the DMA allocation within 128M physical memory for
+ * supporting PCI devices.
+ */
+#define PCI_DMA_THRESHOLD	(PHYS_OFFSET + SZ_128M - 1)
+
+#define is_pcibus_device(dev)	(dev &&			\
+				(strncmp(dev->bus->name, "pci", 3) == 0))
+
+#define __virt_to_pcibus(x)     (__virt_to_phys(x) + PKUNITY_PCIAHB_BASE)
+#define __pcibus_to_virt(x)     __phys_to_virt((x) - PKUNITY_PCIAHB_BASE)
+
+/* kuser area */
+#define KUSER_VECPAGE_BASE	(KUSER_BASE + UL(0x3fff0000))
+#define KUSER_UNIGFX_BASE	(KUSER_BASE + PKUNITY_UNIGFX_MMAP_BASE)
+/* kuser_vecpage (0xbfff0000) is ro, and vectors page (0xffff0000) is rw */
+#define kuser_vecpage_to_vectors(x)	((x) - (KUSER_VECPAGE_BASE)	\
+					+ (VECTORS_BASE))
+
+#endif

arch/unicore32/mm/Kconfig

+comment "Processor Type"
+
+# Select CPU types depending on the architecture selected.  This selects
+# which CPUs we support in the kernel image, and the compiler instruction
+# optimiser behaviour.
+
+config CPU_UCV2
+	def_bool y
+
+comment "Processor Features"
+
+config CPU_ICACHE_DISABLE
+	bool "Disable I-Cache (I-bit)"
+	help
+	  Say Y here to disable the processor instruction cache. Unless
+	  you have a reason not to or are unsure, say N.
+
+config CPU_DCACHE_DISABLE
+	bool "Disable D-Cache (D-bit)"
+	help
+	  Say Y here to disable the processor data cache. Unless
+	  you have a reason not to or are unsure, say N.
+
+config CPU_DCACHE_WRITETHROUGH
+	bool "Force write through D-cache"
+	help
+	  Say Y here to use the data cache in writethrough mode. Unless you
+	  specifically require this or are unsure, say N.
+
+config CPU_DCACHE_LINE_DISABLE
+	bool "Disable D-cache line ops"
+	default y
+	help
+	  Say Y here to disable the data cache line operations.
+
+config CPU_TLB_SINGLE_ENTRY_DISABLE
+	bool "Disable TLB single entry ops"
+	default y
+	help
+	  Say Y here to disable the TLB single entry operations.
+
+config SWIOTLB
+	def_bool y
+
+config IOMMU_HELPER
+	def_bool SWIOTLB
+
+config NEED_SG_DMA_LENGTH
+	def_bool SWIOTLB
+

arch/unicore32/mm/Makefile

+#
+# Makefile for the linux unicore-specific parts of the memory manager.
+#
+
+obj-y				:= extable.o fault.o init.o pgd.o mmu.o
+obj-y				+= iomap.o flush.o ioremap.o
+
+obj-$(CONFIG_SWIOTLB)		+= dma-swiotlb.o
+
+obj-$(CONFIG_MODULES)		+= proc-syms.o
+
+obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
+
+obj-$(CONFIG_CPU_UCV2)		+= cache-ucv2.o tlb-ucv2.o proc-ucv2.o
+

arch/unicore32/mm/iomap.c

+/*
+ * linux/arch/unicore32/mm/iomap.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Map IO port and PCI memory spaces so that {read,write}[bwl] can
+ * be used to access this memory.
+ */
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+
+#ifdef __io
+void __iomem *ioport_map(unsigned long port, unsigned int nr)
+{
+	/* we map PC lagcy 64K IO port to PCI IO space 0x80030000 */
+	return (void __iomem *) (unsigned long)
+			io_p2v((port & 0xffff) + PKUNITY_PCILIO_BASE);
+}
+EXPORT_SYMBOL(ioport_map);
+
+void ioport_unmap(void __iomem *addr)
+{
+}
+EXPORT_SYMBOL(ioport_unmap);
+#endif
+
+#ifdef CONFIG_PCI
+void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
+{
+	resource_size_t start = pci_resource_start(dev, bar);
+	resource_size_t len   = pci_resource_len(dev, bar);
+	unsigned long flags = pci_resource_flags(dev, bar);
+
+	if (!len || !start)
+		return NULL;
+	if (maxlen && len > maxlen)
+		len = maxlen;
+	if (flags & IORESOURCE_IO)
+		return ioport_map(start, len);
+	if (flags & IORESOURCE_MEM) {
+		if (flags & IORESOURCE_CACHEABLE)
+			return ioremap(start, len);
+		return ioremap_nocache(start, len);
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(pci_iomap);
+#endif

arch/unicore32/mm/ioremap.c

+/*
+ * linux/arch/unicore32/mm/ioremap.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *
+ * Re-map IO memory to kernel address space so that we can access it.
+ *
+ * This allows a driver to remap an arbitrary region of bus memory into
+ * virtual space.  One should *only* use readl, writel, memcpy_toio and
+ * so on with such remapped areas.
+ *
+ * Because UniCore only has a 32-bit address space we can't address the
+ * whole of the (physical) PCI space at once.  PCI huge-mode addressing
+ * allows us to circumvent this restriction by splitting PCI space into
+ * two 2GB chunks and mapping only one at a time into processor memory.
+ * We use MMU protection domains to trap any attempt to access the bank
+ * that is not currently mapped.  (This isn't fully implemented yet.)
+ */
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/io.h>
+
+#include <asm/cputype.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/sizes.h>
+
+#include <mach/map.h>
+#include "mm.h"
+
+/*
+ * Used by ioremap() and iounmap() code to mark (super)section-mapped
+ * I/O regions in vm_struct->flags field.
+ */
+#define VM_UNICORE_SECTION_MAPPING	0x80000000
+
+int ioremap_page(unsigned long virt, unsigned long phys,
+		 const struct mem_type *mtype)
+{
+	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
+				  __pgprot(mtype->prot_pte));
+}
+EXPORT_SYMBOL(ioremap_page);
+
+/*
+ * Section support is unsafe on SMP - If you iounmap and ioremap a region,
+ * the other CPUs will not see this change until their next context switch.
+ * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
+ * which requires the new ioremap'd region to be referenced, the CPU will
+ * reference the _old_ region.
+ *
+ * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
+ * mask the size back to 4MB aligned or we will overflow in the loop below.
+ */
+static void unmap_area_sections(unsigned long virt, unsigned long size)
+{
+	unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
+	pgd_t *pgd;
+
+	flush_cache_vunmap(addr, end);
+	pgd = pgd_offset_k(addr);
+	do {
+		pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr);
+
+		pmd = *pmdp;
+		if (!pmd_none(pmd)) {
+			/*
+			 * Clear the PMD from the page table, and
+			 * increment the kvm sequence so others
+			 * notice this change.
+			 *
+			 * Note: this is still racy on SMP machines.
+			 */
+			pmd_clear(pmdp);
+
+			/*
+			 * Free the page table, if there was one.
+			 */
+			if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
+				pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
+		}
+
+		addr += PGDIR_SIZE;
+		pgd++;
+	} while (addr < end);
+
+	flush_tlb_kernel_range(virt, end);
+}
+
+static int
+remap_area_sections(unsigned long virt, unsigned long pfn,
+		    size_t size, const struct mem_type *type)
+{
+	unsigned long addr = virt, end = virt + size;
+	pgd_t *pgd;
+
+	/*
+	 * Remove and free any PTE-based mapping, and
+	 * sync the current kernel mapping.
+	 */
+	unmap_area_sections(virt, size);
+
+	pgd = pgd_offset_k(addr);
+	do {
+		pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
+
+		set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect));
+		pfn += SZ_4M >> PAGE_SHIFT;
+		flush_pmd_entry(pmd);
+
+		addr += PGDIR_SIZE;
+		pgd++;
+	} while (addr < end);
+
+	return 0;
+}
+
+void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
+	unsigned long offset, size_t size, unsigned int mtype, void *caller)
+{
+	const struct mem_type *type;
+	int err;
+	unsigned long addr;
+	struct vm_struct *area;
+
+	/*
+	 * High mappings must be section aligned
+	 */
+	if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
+		return NULL;
+
+	/*
+	 * Don't allow RAM to be mapped
+	 */
+	if (pfn_valid(pfn)) {
+		printk(KERN_WARNING "BUG: Your driver calls ioremap() on\n"
+			"system memory.  This leads to architecturally\n"
+			"unpredictable behaviour, and ioremap() will fail in\n"
+			"the next kernel release. Please fix your driver.\n");
+		WARN_ON(1);
+	}
+
+	type = get_mem_type(mtype);
+	if (!type)
+		return NULL;
+
+	/*
+	 * Page align the mapping size, taking account of any offset.
+	 */
+	size = PAGE_ALIGN(offset + size);
+
+	area = get_vm_area_caller(size, VM_IOREMAP, caller);
+	if (!area)
+		return NULL;
+	addr = (unsigned long)area->addr;
+
+	if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
+		area->flags |= VM_UNICORE_SECTION_MAPPING;
+		err = remap_area_sections(addr, pfn, size, type);
+	} else
+		err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
+					 __pgprot(type->prot_pte));
+
+	if (err) {
+		vunmap((void *)addr);
+		return NULL;
+	}
+
+	flush_cache_vmap(addr, addr + size);
+	return (void __iomem *) (offset + addr);
+}
+
+void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
+	unsigned int mtype, void *caller)
+{
+	unsigned long last_addr;
+	unsigned long offset = phys_addr & ~PAGE_MASK;
+	unsigned long pfn = __phys_to_pfn(phys_addr);
+
+	/*
+	 * Don't allow wraparound or zero size
+	 */
+	last_addr = phys_addr + size - 1;
+	if (!size || last_addr < phys_addr)
+		return NULL;
+
+	return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
+}
+
+/*
+ * Remap an arbitrary physical address space into the kernel virtual
+ * address space. Needed when the kernel wants to access high addresses
+ * directly.
+ *
+ * NOTE! We need to allow non-page-aligned mappings too: we will obviously
+ * have to convert them into an offset in a page-aligned mapping, but the
+ * caller shouldn't need to know that small detail.
+ */
+void __iomem *
+__uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
+		  unsigned int mtype)
+{
+	return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
+			__builtin_return_address(0));
+}
+EXPORT_SYMBOL(__uc32_ioremap_pfn);
+
+void __iomem *
+__uc32_ioremap(unsigned long phys_addr, size_t size)
+{
+	return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
+			__builtin_return_address(0));
+}
+EXPORT_SYMBOL(__uc32_ioremap);
+
+void __iomem *
+__uc32_ioremap_cached(unsigned long phys_addr, size_t size)
+{
+	return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED,
+			__builtin_return_address(0));
+}
+EXPORT_SYMBOL(__uc32_ioremap_cached);
+
+void __uc32_iounmap(volatile void __iomem *io_addr)
+{
+	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
+	struct vm_struct **p, *tmp;
+
+	/*
+	 * If this is a section based mapping we need to handle it
+	 * specially as the VM subsystem does not know how to handle
+	 * such a beast. We need the lock here b/c we need to clear
+	 * all the mappings before the area can be reclaimed
+	 * by someone else.
+	 */
+	write_lock(&vmlist_lock);
+	for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
+		if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
+			if (tmp->flags & VM_UNICORE_SECTION_MAPPING) {
+				unmap_area_sections((unsigned long)tmp->addr,
+						    tmp->size);
+			}
+			break;
+		}
+	}
+	write_unlock(&vmlist_lock);
+
+	vunmap(addr);
+}
+EXPORT_SYMBOL(__uc32_iounmap);

arch/unicore32/mm/mm.h

+/*
+ * linux/arch/unicore32/mm/mm.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+/* the upper-most page table pointer */
+extern pmd_t *top_pmd;
+extern int sysctl_overcommit_memory;
+
+#define TOP_PTE(x)	pte_offset_kernel(top_pmd, x)
+
+static inline pmd_t *pmd_off(pgd_t *pgd, unsigned long virt)
+{
+	return pmd_offset((pud_t *)pgd, virt);
+}
+
+static inline pmd_t *pmd_off_k(unsigned long virt)
+{
+	return pmd_off(pgd_offset_k(virt), virt);
+}
+
+struct mem_type {
+	unsigned int prot_pte;
+	unsigned int prot_l1;
+	unsigned int prot_sect;
+};
+
+const struct mem_type *get_mem_type(unsigned int type);
+
+extern void __flush_dcache_page(struct address_space *, struct page *);
+
+void __init bootmem_init(void);
+void uc32_mm_memblock_reserve(void);