arch/arm/kernel/tcm.c

   1 /*
   2  * Copyright (C) 2008-2009 ST-Ericsson AB
   3  * License terms: GNU General Public License (GPL) version 2
   4  * TCM memory handling for ARM systems
   5  *
   6  * Author: Linus Walleij <linus.walleij@stericsson.com>
   7  * Author: Rickard Andersson <rickard.andersson@stericsson.com>
   8  */
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/stddef.h>
  13 #include <linux/ioport.h>
  14 #include <linux/genalloc.h>
  15 #include <linux/string.h> /* memcpy */
  16 #include <asm/cputype.h>
  17 #include <asm/mach/map.h>
  18 #include <asm/memory.h>
  19 #include "tcm.h"
  20
  21 static struct gen_pool *tcm_pool;
  22
  23 /* TCM section definitions from the linker */
  24 extern char __itcm_start, __sitcm_text, __eitcm_text;
  25 extern char __dtcm_start, __sdtcm_data, __edtcm_data;
  26
  27 /* These will be increased as we run */
  28 u32 dtcm_end = DTCM_OFFSET;
  29 u32 itcm_end = ITCM_OFFSET;
  30
  31 /*
  32  * TCM memory resources
  33  */
  34 static struct resource dtcm_res = {
  35         .name = "DTCM RAM",
  36         .start = DTCM_OFFSET,
  37         .end = DTCM_OFFSET,
  38         .flags = IORESOURCE_MEM
  39 };
  40
  41 static struct resource itcm_res = {
  42         .name = "ITCM RAM",
  43         .start = ITCM_OFFSET,
  44         .end = ITCM_OFFSET,
  45         .flags = IORESOURCE_MEM
  46 };
  47
  48 static struct map_desc dtcm_iomap[] __initdata = {
  49         {
  50                 .virtual        = DTCM_OFFSET,
  51                 .pfn            = __phys_to_pfn(DTCM_OFFSET),
  52                 .length         = 0,
  53                 .type           = MT_MEMORY_DTCM
  54         }
  55 };
  56
  57 static struct map_desc itcm_iomap[] __initdata = {
  58         {
  59                 .virtual        = ITCM_OFFSET,
  60                 .pfn            = __phys_to_pfn(ITCM_OFFSET),
  61                 .length         = 0,
  62                 .type           = MT_MEMORY_ITCM
  63         }
  64 };
  65
  66 /*
  67  * Allocate a chunk of TCM memory
  68  */
  69 void *tcm_alloc(size_t len)
  70 {
  71         unsigned long vaddr;
  72
  73         if (!tcm_pool)
  74                 return NULL;
  75
  76         vaddr = gen_pool_alloc(tcm_pool, len);
  77         if (!vaddr)
  78                 return NULL;
  79
  80         return (void *) vaddr;
  81 }
  82 EXPORT_SYMBOL(tcm_alloc);
  83
  84 /*
  85  * Free a chunk of TCM memory
  86  */
  87 void tcm_free(void *addr, size_t len)
  88 {
  89         gen_pool_free(tcm_pool, (unsigned long) addr, len);
  90 }
  91 EXPORT_SYMBOL(tcm_free);
  92
  93 static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
  94                                   u32 *offset)
  95 {
  96         const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
  97                                     256, 512, 1024, -1, -1, -1, -1 };
  98         u32 tcm_region;
  99         int tcm_size;
 100
 101         /*
 102          * If there are more than one TCM bank of this type,
 103          * select the TCM bank to operate on in the TCM selection
 104          * register.
 105          */
 106         if (banks > 1)
 107                 asm("mcr        p15, 0, %0, c9, c2, 0"
 108                     : /* No output operands */
 109                     : "r" (bank));
 110
 111         /* Read the special TCM region register c9, 0 */
 112         if (!type)
 113                 asm("mrc        p15, 0, %0, c9, c1, 0"
 114                     : "=r" (tcm_region));
 115         else
 116                 asm("mrc        p15, 0, %0, c9, c1, 1"
 117                     : "=r" (tcm_region));
 118
 119         tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
 120         if (tcm_size < 0) {
 121                 pr_err("CPU: %sTCM%d of unknown size\n",
 122                        type ? "I" : "D", bank);
 123                 return -EINVAL;
 124         } else if (tcm_size > 32) {
 125                 pr_err("CPU: %sTCM%d larger than 32k found\n",
 126                        type ? "I" : "D", bank);
 127                 return -EINVAL;
 128         } else {
 129                 pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
 130                         type ? "I" : "D",
 131                         bank,
 132                         tcm_size,
 133                         (tcm_region & 0xfffff000U),
 134                         (tcm_region & 1) ? "" : "not ");
 135         }
 136
 137         /* Not much fun you can do with a size 0 bank */
 138         if (tcm_size == 0)
 139                 return 0;
 140
 141         /* Force move the TCM bank to where we want it, enable */
 142         tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
 143
 144         if (!type)
 145                 asm("mcr        p15, 0, %0, c9, c1, 0"
 146                     : /* No output operands */
 147                     : "r" (tcm_region));
 148         else
 149                 asm("mcr        p15, 0, %0, c9, c1, 1"
 150                     : /* No output operands */
 151                     : "r" (tcm_region));
 152
 153         /* Increase offset */
 154         *offset += (tcm_size << 10);
 155
 156         pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
 157                 type ? "I" : "D",
 158                 bank,
 159                 tcm_size,
 160                 (tcm_region & 0xfffff000U));
 161         return 0;
 162 }
 163
 164 /*
 165  * This initializes the TCM memory
 166  */
 167 void __init tcm_init(void)
 168 {
 169         u32 tcm_status = read_cpuid_tcmstatus();
 170         u8 dtcm_banks = (tcm_status >> 16) & 0x03;
 171         u8 itcm_banks = (tcm_status & 0x03);
 172         size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
 173         size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
 174         char *start;
 175         char *end;
 176         char *ram;
 177         int ret;
 178         int i;
 179
 180         /* Values greater than 2 for D/ITCM banks are "reserved" */
 181         if (dtcm_banks > 2)
 182                 dtcm_banks = 0;
 183         if (itcm_banks > 2)
 184                 itcm_banks = 0;
 185
 186         /* Setup DTCM if present */
 187         if (dtcm_banks > 0) {
 188                 for (i = 0; i < dtcm_banks; i++) {
 189                         ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
 190                         if (ret)
 191                                 return;
 192                 }
 193                 /* This means you compiled more code than fits into DTCM */
 194                 if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
 195                         pr_info("CPU DTCM: %u bytes of code compiled to "
 196                                 "DTCM but only %lu bytes of DTCM present\n",
 197                                 dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
 198                         goto no_dtcm;
 199                 }
 200                 dtcm_res.end = dtcm_end - 1;
 201                 request_resource(&iomem_resource, &dtcm_res);
 202                 dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
 203                 iotable_init(dtcm_iomap, 1);
 204                 /* Copy data from RAM to DTCM */
 205                 start = &__sdtcm_data;
 206                 end   = &__edtcm_data;
 207                 ram   = &__dtcm_start;
 208                 memcpy(start, ram, dtcm_code_sz);
 209                 pr_debug("CPU DTCM: copied data from %p - %p\n",
 210                          start, end);
 211         } else if (dtcm_code_sz) {
 212                 pr_info("CPU DTCM: %u bytes of code compiled to DTCM but no "
 213                         "DTCM banks present in CPU\n", dtcm_code_sz);
 214         }
 215
 216 no_dtcm:
 217         /* Setup ITCM if present */
 218         if (itcm_banks > 0) {
 219                 for (i = 0; i < itcm_banks; i++) {
 220                         ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
 221                         if (ret)
 222                                 return;
 223                 }
 224                 /* This means you compiled more code than fits into ITCM */
 225                 if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
 226                         pr_info("CPU ITCM: %u bytes of code compiled to "
 227                                 "ITCM but only %lu bytes of ITCM present\n",
 228                                 itcm_code_sz, (itcm_end - ITCM_OFFSET));
 229                         return;
 230                 }
 231                 itcm_res.end = itcm_end - 1;
 232                 request_resource(&iomem_resource, &itcm_res);
 233                 itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
 234                 iotable_init(itcm_iomap, 1);
 235                 /* Copy code from RAM to ITCM */
 236                 start = &__sitcm_text;
 237                 end   = &__eitcm_text;
 238                 ram   = &__itcm_start;
 239                 memcpy(start, ram, itcm_code_sz);
 240                 pr_debug("CPU ITCM: copied code from %p - %p\n",
 241                          start, end);
 242         } else if (itcm_code_sz) {
 243                 pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
 244                         "ITCM banks present in CPU\n", itcm_code_sz);
 245         }
 246 }
 247
 248 /*
 249  * This creates the TCM memory pool and has to be done later,
 250  * during the core_initicalls, since the allocator is not yet
 251  * up and running when the first initialization runs.
 252  */
 253 static int __init setup_tcm_pool(void)
 254 {
 255         u32 tcm_status = read_cpuid_tcmstatus();
 256         u32 dtcm_pool_start = (u32) &__edtcm_data;
 257         u32 itcm_pool_start = (u32) &__eitcm_text;
 258         int ret;
 259
 260         /*
 261          * Set up malloc pool, 2^2 = 4 bytes granularity since
 262          * the TCM is sometimes just 4 KiB. NB: pages and cache
 263          * line alignments does not matter in TCM!
 264          */
 265         tcm_pool = gen_pool_create(2, -1);
 266
 267         pr_debug("Setting up TCM memory pool\n");
 268
 269         /* Add the rest of DTCM to the TCM pool */
 270         if (tcm_status & (0x03 << 16)) {
 271                 if (dtcm_pool_start < dtcm_end) {
 272                         ret = gen_pool_add(tcm_pool, dtcm_pool_start,
 273                                            dtcm_end - dtcm_pool_start, -1);
 274                         if (ret) {
 275                                 pr_err("CPU DTCM: could not add DTCM " \
 276                                        "remainder to pool!\n");
 277                                 return ret;
 278                         }
 279                         pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
 280                                  "the TCM memory pool\n",
 281                                  dtcm_end - dtcm_pool_start,
 282                                  dtcm_pool_start);
 283                 }
 284         }
 285
 286         /* Add the rest of ITCM to the TCM pool */
 287         if (tcm_status & 0x03) {
 288                 if (itcm_pool_start < itcm_end) {
 289                         ret = gen_pool_add(tcm_pool, itcm_pool_start,
 290                                            itcm_end - itcm_pool_start, -1);
 291                         if (ret) {
 292                                 pr_err("CPU ITCM: could not add ITCM " \
 293                                        "remainder to pool!\n");
 294                                 return ret;
 295                         }
 296                         pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
 297                                  "the TCM memory pool\n",
 298                                  itcm_end - itcm_pool_start,
 299                                  itcm_pool_start);
 300                 }
 301         }
 302         return 0;
 303 }
 304
 305 core_initcall(setup_tcm_pool);