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 <asm/system_info.h>
  20
  21 static struct gen_pool *tcm_pool;
  22 static bool dtcm_present;
  23 static bool itcm_present;
  24
  25 /* TCM section definitions from the linker */
  26 extern char __itcm_start, __sitcm_text, __eitcm_text;
  27 extern char __dtcm_start, __sdtcm_data, __edtcm_data;
  28
  29 /* These will be increased as we run */
  30 u32 dtcm_end = DTCM_OFFSET;
  31 u32 itcm_end = ITCM_OFFSET;
  32
  33 /*
  34  * TCM memory resources
  35  */
  36 static struct resource dtcm_res = {
  37         .name = "DTCM RAM",
  38         .start = DTCM_OFFSET,
  39         .end = DTCM_OFFSET,
  40         .flags = IORESOURCE_MEM
  41 };
  42
  43 static struct resource itcm_res = {
  44         .name = "ITCM RAM",
  45         .start = ITCM_OFFSET,
  46         .end = ITCM_OFFSET,
  47         .flags = IORESOURCE_MEM
  48 };
  49
  50 static struct map_desc dtcm_iomap[] __initdata = {
  51         {
  52                 .virtual        = DTCM_OFFSET,
  53                 .pfn            = __phys_to_pfn(DTCM_OFFSET),
  54                 .length         = 0,
  55                 .type           = MT_MEMORY_RW_DTCM
  56         }
  57 };
  58
  59 static struct map_desc itcm_iomap[] __initdata = {
  60         {
  61                 .virtual        = ITCM_OFFSET,
  62                 .pfn            = __phys_to_pfn(ITCM_OFFSET),
  63                 .length         = 0,
  64                 .type           = MT_MEMORY_RWX_ITCM,
  65         }
  66 };
  67
  68 /*
  69  * Allocate a chunk of TCM memory
  70  */
  71 void *tcm_alloc(size_t len)
  72 {
  73         unsigned long vaddr;
  74
  75         if (!tcm_pool)
  76                 return NULL;
  77
  78         vaddr = gen_pool_alloc(tcm_pool, len);
  79         if (!vaddr)
  80                 return NULL;
  81
  82         return (void *) vaddr;
  83 }
  84 EXPORT_SYMBOL(tcm_alloc);
  85
  86 /*
  87  * Free a chunk of TCM memory
  88  */
  89 void tcm_free(void *addr, size_t len)
  90 {
  91         gen_pool_free(tcm_pool, (unsigned long) addr, len);
  92 }
  93 EXPORT_SYMBOL(tcm_free);
  94
  95 bool tcm_dtcm_present(void)
  96 {
  97         return dtcm_present;
  98 }
  99 EXPORT_SYMBOL(tcm_dtcm_present);
 100
 101 bool tcm_itcm_present(void)
 102 {
 103         return itcm_present;
 104 }
 105 EXPORT_SYMBOL(tcm_itcm_present);
 106
 107 static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
 108                                   u32 *offset)
 109 {
 110         const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
 111                                     256, 512, 1024, -1, -1, -1, -1 };
 112         u32 tcm_region;
 113         int tcm_size;
 114
 115         /*
 116          * If there are more than one TCM bank of this type,
 117          * select the TCM bank to operate on in the TCM selection
 118          * register.
 119          */
 120         if (banks > 1)
 121                 asm("mcr        p15, 0, %0, c9, c2, 0"
 122                     : /* No output operands */
 123                     : "r" (bank));
 124
 125         /* Read the special TCM region register c9, 0 */
 126         if (!type)
 127                 asm("mrc        p15, 0, %0, c9, c1, 0"
 128                     : "=r" (tcm_region));
 129         else
 130                 asm("mrc        p15, 0, %0, c9, c1, 1"
 131                     : "=r" (tcm_region));
 132
 133         tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
 134         if (tcm_size < 0) {
 135                 pr_err("CPU: %sTCM%d of unknown size\n",
 136                        type ? "I" : "D", bank);
 137                 return -EINVAL;
 138         } else if (tcm_size > 32) {
 139                 pr_err("CPU: %sTCM%d larger than 32k found\n",
 140                        type ? "I" : "D", bank);
 141                 return -EINVAL;
 142         } else {
 143                 pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
 144                         type ? "I" : "D",
 145                         bank,
 146                         tcm_size,
 147                         (tcm_region & 0xfffff000U),
 148                         (tcm_region & 1) ? "" : "not ");
 149         }
 150
 151         /* Not much fun you can do with a size 0 bank */
 152         if (tcm_size == 0)
 153                 return 0;
 154
 155         /* Force move the TCM bank to where we want it, enable */
 156         tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
 157
 158         if (!type)
 159                 asm("mcr        p15, 0, %0, c9, c1, 0"
 160                     : /* No output operands */
 161                     : "r" (tcm_region));
 162         else
 163                 asm("mcr        p15, 0, %0, c9, c1, 1"
 164                     : /* No output operands */
 165                     : "r" (tcm_region));
 166
 167         /* Increase offset */
 168         *offset += (tcm_size << 10);
 169
 170         pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
 171                 type ? "I" : "D",
 172                 bank,
 173                 tcm_size,
 174                 (tcm_region & 0xfffff000U));
 175         return 0;
 176 }
 177
 178 /*
 179  * This initializes the TCM memory
 180  */
 181 void __init tcm_init(void)
 182 {
 183         u32 tcm_status;
 184         u8 dtcm_banks;
 185         u8 itcm_banks;
 186         size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
 187         size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
 188         char *start;
 189         char *end;
 190         char *ram;
 191         int ret;
 192         int i;
 193
 194         /*
 195          * Prior to ARMv5 there is no TCM, and trying to read the status
 196          * register will hang the processor.
 197          */
 198         if (cpu_architecture() < CPU_ARCH_ARMv5) {
 199                 if (dtcm_code_sz || itcm_code_sz)
 200                         pr_info("CPU TCM: %u bytes of DTCM and %u bytes of "
 201                                 "ITCM code compiled in, but no TCM present "
 202                                 "in pre-v5 CPU\n", dtcm_code_sz, itcm_code_sz);
 203                 return;
 204         }
 205
 206         tcm_status = read_cpuid_tcmstatus();
 207         dtcm_banks = (tcm_status >> 16) & 0x03;
 208         itcm_banks = (tcm_status & 0x03);
 209
 210         /* Values greater than 2 for D/ITCM banks are "reserved" */
 211         if (dtcm_banks > 2)
 212                 dtcm_banks = 0;
 213         if (itcm_banks > 2)
 214                 itcm_banks = 0;
 215
 216         /* Setup DTCM if present */
 217         if (dtcm_banks > 0) {
 218                 for (i = 0; i < dtcm_banks; i++) {
 219                         ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
 220                         if (ret)
 221                                 return;
 222                 }
 223                 /* This means you compiled more code than fits into DTCM */
 224                 if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
 225                         pr_info("CPU DTCM: %u bytes of code compiled to "
 226                                 "DTCM but only %lu bytes of DTCM present\n",
 227                                 dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
 228                         goto no_dtcm;
 229                 }
 230                 dtcm_res.end = dtcm_end - 1;
 231                 request_resource(&iomem_resource, &dtcm_res);
 232                 dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
 233                 iotable_init(dtcm_iomap, 1);
 234                 /* Copy data from RAM to DTCM */
 235                 start = &__sdtcm_data;
 236                 end   = &__edtcm_data;
 237                 ram   = &__dtcm_start;
 238                 memcpy(start, ram, dtcm_code_sz);
 239                 pr_debug("CPU DTCM: copied data from %p - %p\n",
 240                          start, end);
 241                 dtcm_present = true;
 242         } else if (dtcm_code_sz) {
 243                 pr_info("CPU DTCM: %u bytes of code compiled to DTCM but no "
 244                         "DTCM banks present in CPU\n", dtcm_code_sz);
 245         }
 246
 247 no_dtcm:
 248         /* Setup ITCM if present */
 249         if (itcm_banks > 0) {
 250                 for (i = 0; i < itcm_banks; i++) {
 251                         ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
 252                         if (ret)
 253                                 return;
 254                 }
 255                 /* This means you compiled more code than fits into ITCM */
 256                 if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
 257                         pr_info("CPU ITCM: %u bytes of code compiled to "
 258                                 "ITCM but only %lu bytes of ITCM present\n",
 259                                 itcm_code_sz, (itcm_end - ITCM_OFFSET));
 260                         return;
 261                 }
 262                 itcm_res.end = itcm_end - 1;
 263                 request_resource(&iomem_resource, &itcm_res);
 264                 itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
 265                 iotable_init(itcm_iomap, 1);
 266                 /* Copy code from RAM to ITCM */
 267                 start = &__sitcm_text;
 268                 end   = &__eitcm_text;
 269                 ram   = &__itcm_start;
 270                 memcpy(start, ram, itcm_code_sz);
 271                 pr_debug("CPU ITCM: copied code from %p - %p\n",
 272                          start, end);
 273                 itcm_present = true;
 274         } else if (itcm_code_sz) {
 275                 pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
 276                         "ITCM banks present in CPU\n", itcm_code_sz);
 277         }
 278 }
 279
 280 /*
 281  * This creates the TCM memory pool and has to be done later,
 282  * during the core_initicalls, since the allocator is not yet
 283  * up and running when the first initialization runs.
 284  */
 285 static int __init setup_tcm_pool(void)
 286 {
 287         u32 dtcm_pool_start = (u32) &__edtcm_data;
 288         u32 itcm_pool_start = (u32) &__eitcm_text;
 289         int ret;
 290
 291         /*
 292          * Set up malloc pool, 2^2 = 4 bytes granularity since
 293          * the TCM is sometimes just 4 KiB. NB: pages and cache
 294          * line alignments does not matter in TCM!
 295          */
 296         tcm_pool = gen_pool_create(2, -1);
 297
 298         pr_debug("Setting up TCM memory pool\n");
 299
 300         /* Add the rest of DTCM to the TCM pool */
 301         if (dtcm_present) {
 302                 if (dtcm_pool_start < dtcm_end) {
 303                         ret = gen_pool_add(tcm_pool, dtcm_pool_start,
 304                                            dtcm_end - dtcm_pool_start, -1);
 305                         if (ret) {
 306                                 pr_err("CPU DTCM: could not add DTCM " \
 307                                        "remainder to pool!\n");
 308                                 return ret;
 309                         }
 310                         pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
 311                                  "the TCM memory pool\n",
 312                                  dtcm_end - dtcm_pool_start,
 313                                  dtcm_pool_start);
 314                 }
 315         }
 316
 317         /* Add the rest of ITCM to the TCM pool */
 318         if (itcm_present) {
 319                 if (itcm_pool_start < itcm_end) {
 320                         ret = gen_pool_add(tcm_pool, itcm_pool_start,
 321                                            itcm_end - itcm_pool_start, -1);
 322                         if (ret) {
 323                                 pr_err("CPU ITCM: could not add ITCM " \
 324                                        "remainder to pool!\n");
 325                                 return ret;
 326                         }
 327                         pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
 328                                  "the TCM memory pool\n",
 329                                  itcm_end - itcm_pool_start,
 330                                  itcm_pool_start);
 331                 }
 332         }
 333         return 0;
 334 }
 335
 336 core_initcall(setup_tcm_pool);