1/*
2 * OpenRISC idle.c
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others.  All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 *      This program is free software; you can redistribute it and/or
13 *      modify it under the terms of the GNU General Public License
14 *      as published by the Free Software Foundation; either version
15 *      2 of the License, or (at your option) any later version.
16 */
17
18#include <linux/signal.h>
19#include <linux/sched.h>
20#include <linux/kernel.h>
21#include <linux/errno.h>
22#include <linux/string.h>
23#include <linux/types.h>
24#include <linux/ptrace.h>
25#include <linux/mman.h>
26#include <linux/mm.h>
27#include <linux/swap.h>
28#include <linux/smp.h>
29#include <linux/bootmem.h>
30#include <linux/init.h>
31#include <linux/delay.h>
32#include <linux/blkdev.h>	/* for initrd_* */
33#include <linux/pagemap.h>
34#include <linux/memblock.h>
35
36#include <asm/segment.h>
37#include <asm/pgalloc.h>
38#include <asm/pgtable.h>
39#include <asm/dma.h>
40#include <asm/io.h>
41#include <asm/tlb.h>
42#include <asm/mmu_context.h>
43#include <asm/kmap_types.h>
44#include <asm/fixmap.h>
45#include <asm/tlbflush.h>
46#include <asm/sections.h>
47
48int mem_init_done;
49
50DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
51
52static void __init zone_sizes_init(void)
53{
54	unsigned long zones_size[MAX_NR_ZONES];
55
56	/* Clear the zone sizes */
57	memset(zones_size, 0, sizeof(zones_size));
58
59	/*
60	 * We use only ZONE_NORMAL
61	 */
62	zones_size[ZONE_NORMAL] = max_low_pfn;
63
64	free_area_init(zones_size);
65}
66
67extern const char _s_kernel_ro[], _e_kernel_ro[];
68
69/*
70 * Map all physical memory into kernel's address space.
71 *
72 * This is explicitly coded for two-level page tables, so if you need
73 * something else then this needs to change.
74 */
75static void __init map_ram(void)
76{
77	unsigned long v, p, e;
78	pgprot_t prot;
79	pgd_t *pge;
80	pud_t *pue;
81	pmd_t *pme;
82	pte_t *pte;
83	/* These mark extents of read-only kernel pages...
84	 * ...from vmlinux.lds.S
85	 */
86	struct memblock_region *region;
87
88	v = PAGE_OFFSET;
89
90	for_each_memblock(memory, region) {
91		p = (u32) region->base & PAGE_MASK;
92		e = p + (u32) region->size;
93
94		v = (u32) __va(p);
95		pge = pgd_offset_k(v);
96
97		while (p < e) {
98			int j;
99			pue = pud_offset(pge, v);
100			pme = pmd_offset(pue, v);
101
102			if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
103				panic("%s: OR1K kernel hardcoded for "
104				      "two-level page tables",
105				     __func__);
106			}
107
108			/* Alloc one page for holding PTE's... */
109			pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
110			set_pmd(pme, __pmd(_KERNPG_TABLE + __pa(pte)));
111
112			/* Fill the newly allocated page with PTE'S */
113			for (j = 0; p < e && j < PTRS_PER_PGD;
114			     v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) {
115				if (v >= (u32) _e_kernel_ro ||
116				    v < (u32) _s_kernel_ro)
117					prot = PAGE_KERNEL;
118				else
119					prot = PAGE_KERNEL_RO;
120
121				set_pte(pte, mk_pte_phys(p, prot));
122			}
123
124			pge++;
125		}
126
127		printk(KERN_INFO "%s: Memory: 0x%x-0x%x\n", __func__,
128		       region->base, region->base + region->size);
129	}
130}
131
132void __init paging_init(void)
133{
134	extern void tlb_init(void);
135
136	unsigned long end;
137	int i;
138
139	printk(KERN_INFO "Setting up paging and PTEs.\n");
140
141	/* clear out the init_mm.pgd that will contain the kernel's mappings */
142
143	for (i = 0; i < PTRS_PER_PGD; i++)
144		swapper_pg_dir[i] = __pgd(0);
145
146	/* make sure the current pgd table points to something sane
147	 * (even if it is most probably not used until the next
148	 *  switch_mm)
149	 */
150	current_pgd = init_mm.pgd;
151
152	end = (unsigned long)__va(max_low_pfn * PAGE_SIZE);
153
154	map_ram();
155
156	zone_sizes_init();
157
158	/* self modifying code ;) */
159	/* Since the old TLB miss handler has been running up until now,
160	 * the kernel pages are still all RW, so we can still modify the
161	 * text directly... after this change and a TLB flush, the kernel
162	 * pages will become RO.
163	 */
164	{
165		extern unsigned long dtlb_miss_handler;
166		extern unsigned long itlb_miss_handler;
167
168		unsigned long *dtlb_vector = __va(0x900);
169		unsigned long *itlb_vector = __va(0xa00);
170
171		printk(KERN_INFO "itlb_miss_handler %p\n", &itlb_miss_handler);
172		*itlb_vector = ((unsigned long)&itlb_miss_handler -
173				(unsigned long)itlb_vector) >> 2;
174
175		/* Soft ordering constraint to ensure that dtlb_vector is
176		 * the last thing updated
177		 */
178		barrier();
179
180		printk(KERN_INFO "dtlb_miss_handler %p\n", &dtlb_miss_handler);
181		*dtlb_vector = ((unsigned long)&dtlb_miss_handler -
182				(unsigned long)dtlb_vector) >> 2;
183
184	}
185
186	/* Soft ordering constraint to ensure that cache invalidation and
187	 * TLB flush really happen _after_ code has been modified.
188	 */
189	barrier();
190
191	/* Invalidate instruction caches after code modification */
192	mtspr(SPR_ICBIR, 0x900);
193	mtspr(SPR_ICBIR, 0xa00);
194
195	/* New TLB miss handlers and kernel page tables are in now place.
196	 * Make sure that page flags get updated for all pages in TLB by
197	 * flushing the TLB and forcing all TLB entries to be recreated
198	 * from their page table flags.
199	 */
200	flush_tlb_all();
201}
202
203/* References to section boundaries */
204
205void __init mem_init(void)
206{
207	BUG_ON(!mem_map);
208
209	max_mapnr = max_low_pfn;
210	high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
211
212	/* clear the zero-page */
213	memset((void *)empty_zero_page, 0, PAGE_SIZE);
214
215	/* this will put all low memory onto the freelists */
216	free_all_bootmem();
217
218	mem_init_print_info(NULL);
219
220	printk("mem_init_done ...........................................\n");
221	mem_init_done = 1;
222	return;
223}
224
225#ifdef CONFIG_BLK_DEV_INITRD
226void free_initrd_mem(unsigned long start, unsigned long end)
227{
228	free_reserved_area((void *)start, (void *)end, -1, "initrd");
229}
230#endif
231
232void free_initmem(void)
233{
234	free_initmem_default(-1);
235}
236