xref: /openbmc/linux/arch/arc/mm/init.c (revision ff4a7481c3898ffc3cc271d6aca431d190c37247)
1 /*
2  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/mm.h>
11 #include <linux/memblock.h>
12 #ifdef CONFIG_BLK_DEV_INITRD
13 #include <linux/initrd.h>
14 #endif
15 #include <linux/of_fdt.h>
16 #include <linux/swap.h>
17 #include <linux/module.h>
18 #include <linux/highmem.h>
19 #include <asm/page.h>
20 #include <asm/pgalloc.h>
21 #include <asm/sections.h>
22 #include <asm/arcregs.h>
23 
24 pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
25 char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
26 EXPORT_SYMBOL(empty_zero_page);
27 
28 static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
29 static unsigned long low_mem_sz;
30 
31 #ifdef CONFIG_HIGHMEM
32 static unsigned long min_high_pfn, max_high_pfn;
33 static u64 high_mem_start;
34 static u64 high_mem_sz;
35 #endif
36 
37 #ifdef CONFIG_DISCONTIGMEM
38 struct pglist_data node_data[MAX_NUMNODES] __read_mostly;
39 EXPORT_SYMBOL(node_data);
40 #endif
41 
42 long __init arc_get_mem_sz(void)
43 {
44 	return low_mem_sz;
45 }
46 
47 /* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
48 static int __init setup_mem_sz(char *str)
49 {
50 	low_mem_sz = memparse(str, NULL) & PAGE_MASK;
51 
52 	/* early console might not be setup yet - it will show up later */
53 	pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(low_mem_sz));
54 
55 	return 0;
56 }
57 early_param("mem", setup_mem_sz);
58 
59 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
60 {
61 	int in_use = 0;
62 
63 	if (!low_mem_sz) {
64 		if (base != low_mem_start)
65 			panic("CONFIG_LINUX_RAM_BASE != DT memory { }");
66 
67 		low_mem_sz = size;
68 		in_use = 1;
69 	} else {
70 #ifdef CONFIG_HIGHMEM
71 		high_mem_start = base;
72 		high_mem_sz = size;
73 		in_use = 1;
74 #endif
75 	}
76 
77 	pr_info("Memory @ %llx [%lldM] %s\n",
78 		base, TO_MB(size), !in_use ? "Not used":"");
79 }
80 
81 #ifdef CONFIG_BLK_DEV_INITRD
82 static int __init early_initrd(char *p)
83 {
84 	unsigned long start, size;
85 	char *endp;
86 
87 	start = memparse(p, &endp);
88 	if (*endp == ',') {
89 		size = memparse(endp + 1, NULL);
90 
91 		initrd_start = (unsigned long)__va(start);
92 		initrd_end = (unsigned long)__va(start + size);
93 	}
94 	return 0;
95 }
96 early_param("initrd", early_initrd);
97 #endif
98 
99 /*
100  * First memory setup routine called from setup_arch()
101  * 1. setup swapper's mm @init_mm
102  * 2. Count the pages we have and setup bootmem allocator
103  * 3. zone setup
104  */
105 void __init setup_arch_memory(void)
106 {
107 	unsigned long zones_size[MAX_NR_ZONES];
108 	unsigned long zones_holes[MAX_NR_ZONES];
109 
110 	init_mm.start_code = (unsigned long)_text;
111 	init_mm.end_code = (unsigned long)_etext;
112 	init_mm.end_data = (unsigned long)_edata;
113 	init_mm.brk = (unsigned long)_end;
114 
115 	/* first page of system - kernel .vector starts here */
116 	min_low_pfn = ARCH_PFN_OFFSET;
117 
118 	/* Last usable page of low mem */
119 	max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);
120 
121 #ifdef CONFIG_FLATMEM
122 	/* pfn_valid() uses this */
123 	max_mapnr = max_low_pfn - min_low_pfn;
124 #endif
125 
126 	/*------------- bootmem allocator setup -----------------------*/
127 
128 	/*
129 	 * seed the bootmem allocator after any DT memory node parsing or
130 	 * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz
131 	 *
132 	 * Only low mem is added, otherwise we have crashes when allocating
133 	 * mem_map[] itself. NO_BOOTMEM allocates mem_map[] at the end of
134 	 * avail memory, ending in highmem with a > 32-bit address. However
135 	 * it then tries to memset it with a truncaed 32-bit handle, causing
136 	 * the crash
137 	 */
138 
139 	memblock_add_node(low_mem_start, low_mem_sz, 0);
140 	memblock_reserve(low_mem_start, __pa(_end) - low_mem_start);
141 
142 #ifdef CONFIG_BLK_DEV_INITRD
143 	if (initrd_start)
144 		memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
145 #endif
146 
147 	early_init_fdt_reserve_self();
148 	early_init_fdt_scan_reserved_mem();
149 
150 	memblock_dump_all();
151 
152 	/*----------------- node/zones setup --------------------------*/
153 	memset(zones_size, 0, sizeof(zones_size));
154 	memset(zones_holes, 0, sizeof(zones_holes));
155 
156 	zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
157 	zones_holes[ZONE_NORMAL] = 0;
158 
159 	/*
160 	 * We can't use the helper free_area_init(zones[]) because it uses
161 	 * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
162 	 * when our kernel doesn't start at PAGE_OFFSET, i.e.
163 	 * PAGE_OFFSET != CONFIG_LINUX_RAM_BASE
164 	 */
165 	free_area_init_node(0,			/* node-id */
166 			    zones_size,		/* num pages per zone */
167 			    min_low_pfn,	/* first pfn of node */
168 			    zones_holes);	/* holes */
169 
170 #ifdef CONFIG_HIGHMEM
171 	/*
172 	 * Populate a new node with highmem
173 	 *
174 	 * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based)
175 	 * than addresses in normal ala low memory (0x8000_0000 based).
176 	 * Even with PAE, the huge peripheral space hole would waste a lot of
177 	 * mem with single mem_map[]. This warrants a mem_map per region design.
178 	 * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM.
179 	 *
180 	 * DISCONTIGMEM in turns requires multiple nodes. node 0 above is
181 	 * populated with normal memory zone while node 1 only has highmem
182 	 */
183 	node_set_online(1);
184 
185 	min_high_pfn = PFN_DOWN(high_mem_start);
186 	max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
187 
188 	zones_size[ZONE_NORMAL] = 0;
189 	zones_holes[ZONE_NORMAL] = 0;
190 
191 	zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn;
192 	zones_holes[ZONE_HIGHMEM] = 0;
193 
194 	free_area_init_node(1,			/* node-id */
195 			    zones_size,		/* num pages per zone */
196 			    min_high_pfn,	/* first pfn of node */
197 			    zones_holes);	/* holes */
198 
199 	high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
200 	kmap_init();
201 #endif
202 }
203 
204 /*
205  * mem_init - initializes memory
206  *
207  * Frees up bootmem
208  * Calculates and displays memory available/used
209  */
210 void __init mem_init(void)
211 {
212 #ifdef CONFIG_HIGHMEM
213 	unsigned long tmp;
214 
215 	reset_all_zones_managed_pages();
216 	for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++)
217 		free_highmem_page(pfn_to_page(tmp));
218 #endif
219 
220 	memblock_free_all();
221 	mem_init_print_info(NULL);
222 }
223 
224 /*
225  * free_initmem: Free all the __init memory.
226  */
227 void __ref free_initmem(void)
228 {
229 	free_initmem_default(-1);
230 }
231 
232 #ifdef CONFIG_BLK_DEV_INITRD
233 void __init free_initrd_mem(unsigned long start, unsigned long end)
234 {
235 	free_reserved_area((void *)start, (void *)end, -1, "initrd");
236 }
237 #endif
238