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1 | /* |
2 | * Copyright (C) 2015 Imagination Technologies | |
3 | * Author: Paul Burton <paul.burton@imgtec.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by the | |
7 | * Free Software Foundation; either version 2 of the License, or (at your | |
8 | * option) any later version. | |
9 | */ | |
10 | ||
11 | #include <linux/bug.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/libfdt.h> | |
14 | #include <linux/of_fdt.h> | |
15 | #include <linux/sizes.h> | |
16 | #include <asm/bootinfo.h> | |
17 | #include <asm/fw/fw.h> | |
18 | #include <asm/page.h> | |
19 | ||
20 | static unsigned char fdt_buf[16 << 10] __initdata; | |
21 | ||
22 | /* determined physical memory size, not overridden by command line args */ | |
23 | extern unsigned long physical_memsize; | |
24 | ||
25 | #define MAX_MEM_ARRAY_ENTRIES 1 | |
26 | ||
27 | static unsigned __init gen_fdt_mem_array(__be32 *mem_array, unsigned long size) | |
28 | { | |
29 | unsigned long size_preio; | |
30 | unsigned entries; | |
31 | ||
32 | entries = 1; | |
33 | mem_array[0] = cpu_to_be32(PHYS_OFFSET); | |
34 | if (config_enabled(CONFIG_EVA)) { | |
35 | /* | |
36 | * The current Malta EVA configuration is "special" in that it | |
37 | * always makes use of addresses in the upper half of the 32 bit | |
38 | * physical address map, which gives it a contiguous region of | |
39 | * DDR but limits it to 2GB. | |
40 | */ | |
41 | mem_array[1] = cpu_to_be32(size); | |
42 | } else { | |
43 | size_preio = min_t(unsigned long, size, SZ_256M); | |
44 | mem_array[1] = cpu_to_be32(size_preio); | |
45 | } | |
46 | ||
47 | BUG_ON(entries > MAX_MEM_ARRAY_ENTRIES); | |
48 | return entries; | |
49 | } | |
50 | ||
51 | static void __init append_memory(void *fdt, int root_off) | |
52 | { | |
53 | __be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES]; | |
54 | unsigned long memsize; | |
55 | unsigned mem_entries; | |
56 | int i, err, mem_off; | |
57 | char *var, param_name[10], *var_names[] = { | |
58 | "ememsize", "memsize", | |
59 | }; | |
60 | ||
61 | /* if a memory node already exists, leave it alone */ | |
62 | mem_off = fdt_path_offset(fdt, "/memory"); | |
63 | if (mem_off >= 0) | |
64 | return; | |
65 | ||
66 | /* find memory size from the bootloader environment */ | |
67 | for (i = 0; i < ARRAY_SIZE(var_names); i++) { | |
68 | var = fw_getenv(var_names[i]); | |
69 | if (!var) | |
70 | continue; | |
71 | ||
72 | err = kstrtoul(var, 0, &physical_memsize); | |
73 | if (!err) | |
74 | break; | |
75 | ||
76 | pr_warn("Failed to read the '%s' env variable '%s'\n", | |
77 | var_names[i], var); | |
78 | } | |
79 | ||
80 | if (!physical_memsize) { | |
81 | pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n"); | |
82 | physical_memsize = 32 << 20; | |
83 | } | |
84 | ||
85 | if (config_enabled(CONFIG_CPU_BIG_ENDIAN)) { | |
86 | /* | |
87 | * SOC-it swaps, or perhaps doesn't swap, when DMA'ing | |
88 | * the last word of physical memory. | |
89 | */ | |
90 | physical_memsize -= PAGE_SIZE; | |
91 | } | |
92 | ||
93 | /* default to using all available RAM */ | |
94 | memsize = physical_memsize; | |
95 | ||
96 | /* allow the user to override the usable memory */ | |
97 | for (i = 0; i < ARRAY_SIZE(var_names); i++) { | |
98 | snprintf(param_name, sizeof(param_name), "%s=", var_names[i]); | |
99 | var = strstr(arcs_cmdline, param_name); | |
100 | if (!var) | |
101 | continue; | |
102 | ||
103 | memsize = memparse(var + strlen(param_name), NULL); | |
104 | } | |
105 | ||
106 | /* if the user says there's more RAM than we thought, believe them */ | |
107 | physical_memsize = max_t(unsigned long, physical_memsize, memsize); | |
108 | ||
109 | /* append memory to the DT */ | |
110 | mem_off = fdt_add_subnode(fdt, root_off, "memory"); | |
111 | if (mem_off < 0) | |
112 | panic("Unable to add memory node to DT: %d", mem_off); | |
113 | ||
114 | err = fdt_setprop_string(fdt, mem_off, "device_type", "memory"); | |
115 | if (err) | |
116 | panic("Unable to set memory node device_type: %d", err); | |
117 | ||
118 | mem_entries = gen_fdt_mem_array(mem_array, physical_memsize); | |
119 | err = fdt_setprop(fdt, mem_off, "reg", mem_array, | |
120 | mem_entries * 2 * sizeof(mem_array[0])); | |
121 | if (err) | |
122 | panic("Unable to set memory regs property: %d", err); | |
123 | ||
124 | mem_entries = gen_fdt_mem_array(mem_array, memsize); | |
125 | err = fdt_setprop(fdt, mem_off, "linux,usable-memory", mem_array, | |
126 | mem_entries * 2 * sizeof(mem_array[0])); | |
127 | if (err) | |
128 | panic("Unable to set linux,usable-memory property: %d", err); | |
129 | } | |
130 | ||
131 | void __init *malta_dt_shim(void *fdt) | |
132 | { | |
133 | int root_off, len, err; | |
134 | const char *compat; | |
135 | ||
136 | if (fdt_check_header(fdt)) | |
137 | panic("Corrupt DT"); | |
138 | ||
139 | err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf)); | |
140 | if (err) | |
141 | panic("Unable to open FDT: %d", err); | |
142 | ||
143 | root_off = fdt_path_offset(fdt_buf, "/"); | |
144 | if (root_off < 0) | |
145 | panic("No / node in DT"); | |
146 | ||
147 | compat = fdt_getprop(fdt_buf, root_off, "compatible", &len); | |
148 | if (!compat) | |
149 | panic("No root compatible property in DT: %d", len); | |
150 | ||
151 | /* if this isn't Malta, leave the DT alone */ | |
152 | if (strncmp(compat, "mti,malta", len)) | |
153 | return fdt; | |
154 | ||
155 | append_memory(fdt_buf, root_off); | |
156 | ||
157 | err = fdt_pack(fdt_buf); | |
158 | if (err) | |
159 | panic("Unable to pack FDT: %d\n", err); | |
160 | ||
161 | return fdt_buf; | |
162 | } |