Paul Burton | e81a8c7d | 2015-09-22 11:56:38 -0700 | [diff] [blame] | 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 | } |