arch/mips/generic/yamon-dt.c

   1 /*
   2  * Copyright (C) 2016 Imagination Technologies
   3  * Author: Paul Burton <paul.burton@mips.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 #define pr_fmt(fmt) "yamon-dt: " fmt
  12
  13 #include <linux/bug.h>
  14 #include <linux/errno.h>
  15 #include <linux/kernel.h>
  16 #include <linux/libfdt.h>
  17 #include <linux/printk.h>
  18
  19 #include <asm/fw/fw.h>
  20 #include <asm/yamon-dt.h>
  21
  22 #define MAX_MEM_ARRAY_ENTRIES   2
  23
  24 __init int yamon_dt_append_cmdline(void *fdt)
  25 {
  26         int err, chosen_off;
  27
  28         /* find or add chosen node */
  29         chosen_off = fdt_path_offset(fdt, "/chosen");
  30         if (chosen_off == -FDT_ERR_NOTFOUND)
  31                 chosen_off = fdt_path_offset(fdt, "/chosen@0");
  32         if (chosen_off == -FDT_ERR_NOTFOUND)
  33                 chosen_off = fdt_add_subnode(fdt, 0, "chosen");
  34         if (chosen_off < 0) {
  35                 pr_err("Unable to find or add DT chosen node: %d\n",
  36                        chosen_off);
  37                 return chosen_off;
  38         }
  39
  40         err = fdt_setprop_string(fdt, chosen_off, "bootargs", fw_getcmdline());
  41         if (err) {
  42                 pr_err("Unable to set bootargs property: %d\n", err);
  43                 return err;
  44         }
  45
  46         return 0;
  47 }
  48
  49 static unsigned int __init gen_fdt_mem_array(
  50                                         const struct yamon_mem_region *regions,
  51                                         __be32 *mem_array,
  52                                         unsigned int max_entries,
  53                                         unsigned long memsize)
  54 {
  55         const struct yamon_mem_region *mr;
  56         unsigned long size;
  57         unsigned int entries = 0;
  58
  59         for (mr = regions; mr->size && memsize; ++mr) {
  60                 if (entries >= max_entries) {
  61                         pr_warn("Number of regions exceeds max %u\n",
  62                                 max_entries);
  63                         break;
  64                 }
  65
  66                 /* How much of the remaining RAM fits in the next region? */
  67                 size = min_t(unsigned long, memsize, mr->size);
  68                 memsize -= size;
  69
  70                 /* Emit a memory region */
  71                 *(mem_array++) = cpu_to_be32(mr->start);
  72                 *(mem_array++) = cpu_to_be32(size);
  73                 ++entries;
  74
  75                 /* Discard the next mr->discard bytes */
  76                 memsize -= min_t(unsigned long, memsize, mr->discard);
  77         }
  78         return entries;
  79 }
  80
  81 __init int yamon_dt_append_memory(void *fdt,
  82                                   const struct yamon_mem_region *regions)
  83 {
  84         unsigned long phys_memsize, memsize;
  85         __be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
  86         unsigned int mem_entries;
  87         int i, err, mem_off;
  88         char *var, param_name[10], *var_names[] = {
  89                 "ememsize", "memsize",
  90         };
  91
  92         /* find memory size from the bootloader environment */
  93         for (i = 0; i < ARRAY_SIZE(var_names); i++) {
  94                 var = fw_getenv(var_names[i]);
  95                 if (!var)
  96                         continue;
  97
  98                 err = kstrtoul(var, 0, &phys_memsize);
  99                 if (!err)
 100                         break;
 101
 102                 pr_warn("Failed to read the '%s' env variable '%s'\n",
 103                         var_names[i], var);
 104         }
 105
 106         if (!phys_memsize) {
 107                 pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
 108                 phys_memsize = 32 << 20;
 109         }
 110
 111         /* default to using all available RAM */
 112         memsize = phys_memsize;
 113
 114         /* allow the user to override the usable memory */
 115         for (i = 0; i < ARRAY_SIZE(var_names); i++) {
 116                 snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
 117                 var = strstr(arcs_cmdline, param_name);
 118                 if (!var)
 119                         continue;
 120
 121                 memsize = memparse(var + strlen(param_name), NULL);
 122         }
 123
 124         /* if the user says there's more RAM than we thought, believe them */
 125         phys_memsize = max_t(unsigned long, phys_memsize, memsize);
 126
 127         /* find or add a memory node */
 128         mem_off = fdt_path_offset(fdt, "/memory");
 129         if (mem_off == -FDT_ERR_NOTFOUND)
 130                 mem_off = fdt_add_subnode(fdt, 0, "memory");
 131         if (mem_off < 0) {
 132                 pr_err("Unable to find or add memory DT node: %d\n", mem_off);
 133                 return mem_off;
 134         }
 135
 136         err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
 137         if (err) {
 138                 pr_err("Unable to set memory node device_type: %d\n", err);
 139                 return err;
 140         }
 141
 142         mem_entries = gen_fdt_mem_array(regions, mem_array,
 143                                         MAX_MEM_ARRAY_ENTRIES, phys_memsize);
 144         err = fdt_setprop(fdt, mem_off, "reg",
 145                           mem_array, mem_entries * 2 * sizeof(mem_array[0]));
 146         if (err) {
 147                 pr_err("Unable to set memory regs property: %d\n", err);
 148                 return err;
 149         }
 150
 151         mem_entries = gen_fdt_mem_array(regions, mem_array,
 152                                         MAX_MEM_ARRAY_ENTRIES, memsize);
 153         err = fdt_setprop(fdt, mem_off, "linux,usable-memory",
 154                           mem_array, mem_entries * 2 * sizeof(mem_array[0]));
 155         if (err) {
 156                 pr_err("Unable to set linux,usable-memory property: %d\n", err);
 157                 return err;
 158         }
 159
 160         return 0;
 161 }
 162
 163 __init int yamon_dt_serial_config(void *fdt)
 164 {
 165         const char *yamontty, *mode_var;
 166         char mode_var_name[9], path[20], parity;
 167         unsigned int uart, baud, stop_bits;
 168         bool hw_flow;
 169         int chosen_off, err;
 170
 171         yamontty = fw_getenv("yamontty");
 172         if (!yamontty || !strcmp(yamontty, "tty0")) {
 173                 uart = 0;
 174         } else if (!strcmp(yamontty, "tty1")) {
 175                 uart = 1;
 176         } else {
 177                 pr_warn("yamontty environment variable '%s' invalid\n",
 178                         yamontty);
 179                 uart = 0;
 180         }
 181
 182         baud = stop_bits = 0;
 183         parity = 0;
 184         hw_flow = false;
 185
 186         snprintf(mode_var_name, sizeof(mode_var_name), "modetty%u", uart);
 187         mode_var = fw_getenv(mode_var_name);
 188         if (mode_var) {
 189                 while (mode_var[0] >= '0' && mode_var[0] <= '9') {
 190                         baud *= 10;
 191                         baud += mode_var[0] - '0';
 192                         mode_var++;
 193                 }
 194                 if (mode_var[0] == ',')
 195                         mode_var++;
 196                 if (mode_var[0])
 197                         parity = mode_var[0];
 198                 if (mode_var[0] == ',')
 199                         mode_var++;
 200                 if (mode_var[0])
 201                         stop_bits = mode_var[0] - '0';
 202                 if (mode_var[0] == ',')
 203                         mode_var++;
 204                 if (!strcmp(mode_var, "hw"))
 205                         hw_flow = true;
 206         }
 207
 208         if (!baud)
 209                 baud = 38400;
 210
 211         if (parity != 'e' && parity != 'n' && parity != 'o')
 212                 parity = 'n';
 213
 214         if (stop_bits != 7 && stop_bits != 8)
 215                 stop_bits = 8;
 216
 217         WARN_ON(snprintf(path, sizeof(path), "serial%u:%u%c%u%s",
 218                          uart, baud, parity, stop_bits,
 219                          hw_flow ? "r" : "") >= sizeof(path));
 220
 221         /* find or add chosen node */
 222         chosen_off = fdt_path_offset(fdt, "/chosen");
 223         if (chosen_off == -FDT_ERR_NOTFOUND)
 224                 chosen_off = fdt_path_offset(fdt, "/chosen@0");
 225         if (chosen_off == -FDT_ERR_NOTFOUND)
 226                 chosen_off = fdt_add_subnode(fdt, 0, "chosen");
 227         if (chosen_off < 0) {
 228                 pr_err("Unable to find or add DT chosen node: %d\n",
 229                        chosen_off);
 230                 return chosen_off;
 231         }
 232
 233         err = fdt_setprop_string(fdt, chosen_off, "stdout-path", path);
 234         if (err) {
 235                 pr_err("Unable to set stdout-path property: %d\n", err);
 236                 return err;
 237         }
 238
 239         return 0;
 240 }