1/*
2 *  linux/arch/unicore32/kernel/hibernate.c
3 *
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
7 *	Copyright (C) 2001-2010 Guan Xuetao
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include <linux/gfp.h>
15#include <linux/suspend.h>
16#include <linux/bootmem.h>
17
18#include <asm/page.h>
19#include <asm/pgtable.h>
20#include <asm/pgalloc.h>
21#include <asm/sections.h>
22#include <asm/suspend.h>
23
24#include "mach/pm.h"
25
26/* Pointer to the temporary resume page tables */
27pgd_t *resume_pg_dir;
28
29struct swsusp_arch_regs swsusp_arch_regs_cpu0;
30
31/*
32 * Create a middle page table on a resume-safe page and put a pointer to it in
33 * the given global directory entry.  This only returns the gd entry
34 * in non-PAE compilation mode, since the middle layer is folded.
35 */
36static pmd_t *resume_one_md_table_init(pgd_t *pgd)
37{
38	pud_t *pud;
39	pmd_t *pmd_table;
40
41	pud = pud_offset(pgd, 0);
42	pmd_table = pmd_offset(pud, 0);
43
44	return pmd_table;
45}
46
47/*
48 * Create a page table on a resume-safe page and place a pointer to it in
49 * a middle page directory entry.
50 */
51static pte_t *resume_one_page_table_init(pmd_t *pmd)
52{
53	if (pmd_none(*pmd)) {
54		pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
55		if (!page_table)
56			return NULL;
57
58		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_KERNEL_TABLE));
59
60		BUG_ON(page_table != pte_offset_kernel(pmd, 0));
61
62		return page_table;
63	}
64
65	return pte_offset_kernel(pmd, 0);
66}
67
68/*
69 * This maps the physical memory to kernel virtual address space, a total
70 * of max_low_pfn pages, by creating page tables starting from address
71 * PAGE_OFFSET.  The page tables are allocated out of resume-safe pages.
72 */
73static int resume_physical_mapping_init(pgd_t *pgd_base)
74{
75	unsigned long pfn;
76	pgd_t *pgd;
77	pmd_t *pmd;
78	pte_t *pte;
79	int pgd_idx, pmd_idx;
80
81	pgd_idx = pgd_index(PAGE_OFFSET);
82	pgd = pgd_base + pgd_idx;
83	pfn = 0;
84
85	for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
86		pmd = resume_one_md_table_init(pgd);
87		if (!pmd)
88			return -ENOMEM;
89
90		if (pfn >= max_low_pfn)
91			continue;
92
93		for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
94			pte_t *max_pte;
95
96			if (pfn >= max_low_pfn)
97				break;
98
99			/* Map with normal page tables.
100			 * NOTE: We can mark everything as executable here
101			 */
102			pte = resume_one_page_table_init(pmd);
103			if (!pte)
104				return -ENOMEM;
105
106			max_pte = pte + PTRS_PER_PTE;
107			for (; pte < max_pte; pte++, pfn++) {
108				if (pfn >= max_low_pfn)
109					break;
110
111				set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
112			}
113		}
114	}
115
116	return 0;
117}
118
119static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
120{
121}
122
123int swsusp_arch_resume(void)
124{
125	int error;
126
127	resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
128	if (!resume_pg_dir)
129		return -ENOMEM;
130
131	resume_init_first_level_page_table(resume_pg_dir);
132	error = resume_physical_mapping_init(resume_pg_dir);
133	if (error)
134		return error;
135
136	/* We have got enough memory and from now on we cannot recover */
137	restore_image(resume_pg_dir, restore_pblist);
138	return 0;
139}
140
141/*
142 *	pfn_is_nosave - check if given pfn is in the 'nosave' section
143 */
144
145int pfn_is_nosave(unsigned long pfn)
146{
147	unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
148	unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
149
150	return (pfn >= begin_pfn) && (pfn < end_pfn);
151}
152
153void save_processor_state(void)
154{
155}
156
157void restore_processor_state(void)
158{
159	local_flush_tlb_all();
160}
161