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