[ARM] nommu: adjust headers for !MMU ARM systems

Majorily based on Hyok Choi's patches, this fixes up the asm-arm
header files for mmuless systems.  Over and above Hyok's patches:

- nommu.h merged into mmu.h (it's only a structure)
- nommu_context.h is essentially the same as mmu_context.h, but
  without the MM switching code.

so there's no point having separate files.  Also, in memory.h,
there's no point #ifndef'ing PHYS_OFFSET and END_MEM - both
CONFIG_DRAM_BASE and CONFIG_DRAM_SIZE will always be set by the
configuration scripts.

Other files have minor formatting changes, but are essentially
the same.  Hyok's original patches were signed off thusly:
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/bugs.h

@@ -10,8 +10,12 @@
 #ifndef __ASM_BUGS_H
 #define __ASM_BUGS_H
 
+#ifdef CONFIG_MMU
 extern void check_writebuffer_bugs(void);
 
 #define check_bugs() check_writebuffer_bugs()
+#else
+#define check_bugs() do { } while (0)
+#endif
 
 #endif

include/asm-arm/domain.h

@@ -50,6 +50,8 @@
 #define domain_val(dom,type)	((type) << (2*(dom)))
 
 #ifndef __ASSEMBLY__
+
+#ifdef CONFIG_MMU
 #define set_domain(x)					\
 	do {						\
 	__asm__ __volatile__(				\
@@ -66,5 +68,10 @@
 	set_domain(thread->cpu_domain);				\
 	} while (0)
 
+#else
+#define set_domain(x)		do { } while (0)
+#define modify_domain(dom,type)	do { } while (0)
+#endif
+
 #endif
 #endif /* !__ASSEMBLY__ */

include/asm-arm/memory.h

@@ -2,6 +2,7 @@
  *  linux/include/asm-arm/memory.h
  *
  *  Copyright (C) 2000-2002 Russell King
+ *  modification for nommu, Hyok S. Choi, 2004
  *
  * 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
@@ -26,6 +27,8 @@
 #include <asm/arch/memory.h>
 #include <asm/sizes.h>
 
+#ifdef CONFIG_MMU
+
 #ifndef TASK_SIZE
 /*
  * TASK_SIZE - the maximum size of a user space task.
@@ -47,6 +50,60 @@
 #define PAGE_OFFSET		UL(0xc0000000)
 #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 MODULE_END		(PAGE_OFFSET)
+#define MODULE_START		(MODULE_END - 16*1048576)
+
+#if TASK_SIZE > MODULE_START
+#error Top of user space clashes with start of module space
+#endif
+
+/*
+ * The XIP kernel gets mapped at the bottom of the module vm area.
+ * Since we use sections to map it, this macro replaces the physical address
+ * with its virtual address while keeping offset from the base section.
+ */
+#define XIP_VIRT_ADDR(physaddr)  (MODULE_START + ((physaddr) & 0x000fffff))
+
+#else /* CONFIG_MMU */
+
+/*
+ * The limitation of user task size can grow up to the end of free ram region.
+ * It is difficult to define and perhaps will never meet the original meaning
+ * of this define that was meant to.
+ * Fortunately, there is no reference for this in noMMU mode, for now.
+ */
+#ifndef TASK_SIZE
+#define TASK_SIZE		(CONFIG_DRAM_SIZE)
+#endif
+
+#ifndef TASK_UNMAPPED_BASE
+#define TASK_UNMAPPED_BASE	UL(0x00000000)
+#endif
+
+#ifndef PHYS_OFFSET
+#define PHYS_OFFSET 		(CONFIG_DRAM_BASE)
+#endif
+
+#ifndef END_MEM
+#define END_MEM     		(CONFIG_DRAM_BASE + CONFIG_DRAM_SIZE)
+#endif
+
+#ifndef PAGE_OFFSET
+#define PAGE_OFFSET		(PHYS_OFFSET)
+#endif
+
+/*
+ * The module can be at any place in ram in nommu mode.
+ */
+#define MODULE_END		(END_MEM)
+#define MODULE_START		(PHYS_OFFSET)
+
+#endif /* !CONFIG_MMU */
+
 /*
  * Size of DMA-consistent memory region.  Must be multiple of 2M,
  * between 2MB and 14MB inclusive.
@@ -71,24 +128,6 @@
 #define	__phys_to_pfn(paddr)	((paddr) >> PAGE_SHIFT)
 #define	__pfn_to_phys(pfn)	((pfn) << PAGE_SHIFT)
 
-/*
- * The module space lives between the addresses given by TASK_SIZE
- * and PAGE_OFFSET - it must be within 32MB of the kernel text.
- */
-#define MODULE_END	(PAGE_OFFSET)
-#define MODULE_START	(MODULE_END - 16*1048576)
-
-#if TASK_SIZE > MODULE_START
-#error Top of user space clashes with start of module space
-#endif
-
-/*
- * The XIP kernel gets mapped at the bottom of the module vm area.
- * Since we use sections to map it, this macro replaces the physical address
- * with its virtual address while keeping offset from the base section.
- */
-#define XIP_VIRT_ADDR(physaddr)  (MODULE_START + ((physaddr) & 0x000fffff))
-
 #ifndef __ASSEMBLY__
 
 /*

include/asm-arm/mmu.h

 #ifndef __ARM_MMU_H
 #define __ARM_MMU_H
 
+#ifdef CONFIG_MMU
+
 typedef struct {
 #if __LINUX_ARM_ARCH__ >= 6
 	unsigned int id;
@@ -13,4 +15,18 @@ typedef struct {
 #define ASID(mm)	(0)
 #endif
 
+#else
+
+/*
+ * From nommu.h:
+ *  Copyright (C) 2002, David McCullough <davidm@snapgear.com>
+ *  modified for 2.6 by Hyok S. Choi <hyok.choi@samsung.com>
+ */
+typedef struct {
+	struct vm_list_struct	*vmlist;
+	unsigned long		end_brk;
+} mm_context_t;
+
+#endif
+
 #endif

include/asm-arm/mmu_context.h

@@ -82,6 +82,7 @@ static inline void
 switch_mm(struct mm_struct *prev, struct mm_struct *next,
 	  struct task_struct *tsk)
 {
+#ifdef CONFIG_MMU
 	unsigned int cpu = smp_processor_id();
 
 	if (prev != next) {
@@ -91,6 +92,7 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
 		if (cache_is_vivt())
 			cpu_clear(cpu, prev->cpu_vm_mask);
 	}
+#endif
 }
 
 #define deactivate_mm(tsk,mm)	do { } while (0)

include/asm-arm/page-nommu.h

+/*
+ *  linux/include/asm-arm/page-nommu.h
+ *
+ *  Copyright (C) 2004 Hyok S. Choi
+ *
+ * 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 _ASMARM_PAGE_NOMMU_H
+#define _ASMARM_PAGE_NOMMU_H
+
+#if !defined(CONFIG_SMALL_TASKS) && PAGE_SHIFT < 13
+#define KTHREAD_SIZE (8192)
+#else
+#define KTHREAD_SIZE PAGE_SIZE
+#endif
+ 
+#define get_user_page(vaddr)		__get_free_page(GFP_KERNEL)
+#define free_user_page(page, addr)	free_page(addr)
+
+#define clear_page(page)	memset((page), 0, PAGE_SIZE)
+#define copy_page(to,from)	memcpy((to), (from), PAGE_SIZE)
+
+#define clear_user_page(page, vaddr, pg)	clear_page(page)
+#define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
+
+/*
+ * These are used to make use of C type-checking..
+ */
+typedef unsigned long pte_t;
+typedef unsigned long pmd_t;
+typedef unsigned long pgd_t[2];
+typedef unsigned long pgprot_t;
+
+#define pte_val(x)      (x)
+#define pmd_val(x)      (x)
+#define pgd_val(x)	((x)[0])
+#define pgprot_val(x)   (x)
+
+#define __pte(x)        (x)
+#define __pmd(x)        (x)
+#define __pgprot(x)     (x)
+
+/* to align the pointer to the (next) page boundary */
+#define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)
+
+extern unsigned long memory_start;
+extern unsigned long memory_end;
+
+#endif

include/asm-arm/page.h

@@ -23,6 +23,12 @@
 
 #ifndef __ASSEMBLY__
 
+#ifndef CONFIG_MMU
+
+#include "page-nommu.h"
+
+#else
+
 #include <asm/glue.h>
 
 /*
@@ -171,6 +177,8 @@ typedef unsigned long pgprot_t;
 /* the upper-most page table pointer */
 extern pmd_t *top_pmd;
 
+#endif /* CONFIG_MMU */
+
 #include <asm/memory.h>
 
 #endif /* !__ASSEMBLY__ */

include/asm-arm/pgalloc.h

@@ -16,6 +16,10 @@
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 
+#define check_pgt_cache()		do { } while (0)
+
+#ifdef CONFIG_MMU
+
 #define _PAGE_USER_TABLE	(PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_USER))
 #define _PAGE_KERNEL_TABLE	(PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_KERNEL))
 
@@ -32,8 +36,6 @@ extern void free_pgd_slow(pgd_t *pgd);
 #define pgd_alloc(mm)			get_pgd_slow(mm)
 #define pgd_free(pgd)			free_pgd_slow(pgd)
 
-#define check_pgt_cache()		do { } while (0)
-
 /*
  * Allocate one PTE table.
  *
@@ -126,4 +128,6 @@ pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *ptep)
 	__pmd_populate(pmdp, page_to_pfn(ptep) << PAGE_SHIFT | _PAGE_USER_TABLE);
 }
 
+#endif /* CONFIG_MMU */
+
 #endif

include/asm-arm/pgtable-nommu.h

+/*
+ *  linux/include/asm-arm/pgtable-nommu.h
+ *
+ *  Copyright (C) 1995-2002 Russell King
+ *  Copyright (C) 2004  Hyok S. Choi
+ *
+ * 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 _ASMARM_PGTABLE_NOMMU_H
+#define _ASMARM_PGTABLE_NOMMU_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/io.h>
+
+/*
+ * Trivial page table functions.
+ */
+#define pgd_present(pgd)	(1)
+#define pgd_none(pgd)		(0)
+#define pgd_bad(pgd)		(0)
+#define pgd_clear(pgdp)
+#define kern_addr_valid(addr)	(1)
+#define	pmd_offset(a, b)	((void *)0)
+/* FIXME */
+/*
+ * PMD_SHIFT determines the size of the area a second-level page table can map
+ * PGDIR_SHIFT determines what a third-level page table entry can map
+ */
+#define PGDIR_SHIFT		21
+
+#define PGDIR_SIZE		(1UL << PGDIR_SHIFT)
+#define PGDIR_MASK		(~(PGDIR_SIZE-1))
+/* FIXME */
+
+#define PAGE_NONE	__pgprot(0)
+#define PAGE_SHARED	__pgprot(0)
+#define PAGE_COPY	__pgprot(0)
+#define PAGE_READONLY	__pgprot(0)
+#define PAGE_KERNEL	__pgprot(0)
+
+//extern void paging_init(struct meminfo *, struct machine_desc *);
+#define swapper_pg_dir ((pgd_t *) 0)
+
+#define __swp_type(x)		(0)
+#define __swp_offset(x)		(0)
+#define __swp_entry(typ,off)	((swp_entry_t) { ((typ) | ((off) << 7)) })
+#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
+#define __swp_entry_to_pte(x)	((pte_t) { (x).val })
+
+
+typedef pte_t *pte_addr_t;
+
+static inline int pte_file(pte_t pte) { return 0; }
+
+/*
+ * ZERO_PAGE is a global shared page that is always zero: used
+ * for zero-mapped memory areas etc..
+ */
+#define ZERO_PAGE(vaddr)	(virt_to_page(0))
+
+/*
+ * Mark the prot value as uncacheable and unbufferable.
+ */
+#define pgprot_noncached(prot)	__pgprot(0)
+#define pgprot_writecombine(prot) __pgprot(0)
+
+
+/*
+ * These would be in other places but having them here reduces the diffs.
+ */
+extern unsigned int kobjsize(const void *objp);
+extern int is_in_rom(unsigned long);
+
+/*
+ * No page table caches to initialise.
+ */
+#define pgtable_cache_init()	do { } while (0)
+#define io_remap_page_range	remap_page_range
+#define io_remap_pfn_range	remap_pfn_range
+
+#define MK_IOSPACE_PFN(space, pfn)	(pfn)
+#define GET_IOSPACE(pfn)		0
+#define GET_PFN(pfn)			(pfn)
+
+
+/*
+ * All 32bit addresses are effectively valid for vmalloc...
+ * Sort of meaningless for non-VM targets.
+ */
+#define	VMALLOC_START	0
+#define	VMALLOC_END	0xffffffff
+
+#define FIRST_USER_ADDRESS      (0)
+
+#else 
+
+/*
+ * dummy tlb and user structures.
+ */
+#define v3_tlb_fns	(0)
+#define v4_tlb_fns	(0)
+#define v4wb_tlb_fns	(0)
+#define v4wbi_tlb_fns	(0)
+#define v6_tlb_fns	(0)
+
+#define v3_user_fns	(0)
+#define v4_user_fns	(0)
+#define v4_mc_user_fns	(0)
+#define v4wb_user_fns	(0)
+#define v4wt_user_fns	(0)
+#define v6_user_fns	(0)
+#define xscale_mc_user_fns (0)
+
+#endif /*__ASSEMBLY__*/
+
+#endif /* _ASMARM_PGTABLE_H */

include/asm-arm/pgtable.h

@@ -11,9 +11,15 @@
 #define _ASMARM_PGTABLE_H
 
 #include <asm-generic/4level-fixup.h>
+#include <asm/proc-fns.h>
+
+#ifndef CONFIG_MMU
+
+#include "pgtable-nommu.h"
+
+#else
 
 #include <asm/memory.h>
-#include <asm/proc-fns.h>
 #include <asm/arch/vmalloc.h>
 
 /*
@@ -378,4 +384,6 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 
 #endif /* !__ASSEMBLY__ */
 
+#endif /* CONFIG_MMU */
+
 #endif /* _ASMARM_PGTABLE_H */

include/asm-arm/proc-fns.h

@@ -165,6 +165,8 @@
 
 #include <asm/memory.h>
 
+#ifdef CONFIG_MMU
+
 #define cpu_switch_mm(pgd,mm) cpu_do_switch_mm(virt_to_phys(pgd),mm)
 
 #define cpu_get_pgd()	\
@@ -176,6 +178,8 @@
 		(pgd_t *)phys_to_virt(pg);		\
 	})
 
+#endif
+
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* __ASM_PROCFNS_H */