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 <mach/memory.h>
  19 #include "tcm.h"
  20
  21 /* Scream and warn about misuse */
  22 #if !defined(ITCM_OFFSET) || !defined(ITCM_END) || \
  23     !defined(DTCM_OFFSET) || !defined(DTCM_END)
  24 #error "TCM support selected but offsets not defined!"
  25 #endif
  26
  27 static struct gen_pool *tcm_pool;
  28
  29 /* TCM section definitions from the linker */
  30 extern char __itcm_start, __sitcm_text, __eitcm_text;
  31 extern char __dtcm_start, __sdtcm_data, __edtcm_data;
  32
  33 /*
  34  * TCM memory resources
  35  */
  36 static struct resource dtcm_res = {
  37         .name = "DTCM RAM",
  38         .start = DTCM_OFFSET,
  39         .end = DTCM_END,
  40         .flags = IORESOURCE_MEM
  41 };
  42
  43 static struct resource itcm_res = {
  44         .name = "ITCM RAM",
  45         .start = ITCM_OFFSET,
  46         .end = ITCM_END,
  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         = (DTCM_END - DTCM_OFFSET + 1),
  55                 .type           = MT_MEMORY_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         = (ITCM_END - ITCM_OFFSET + 1),
  64                 .type           = MT_MEMORY_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 static void __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
  96                                   u32 offset, u32 expected_size)
  97 {
  98         const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
  99                                     256, 512, 1024, -1, -1, -1, -1 };
 100         u32 tcm_region;
 101         int tcm_size;
 102
 103         /*
 104          * If there are more than one TCM bank of this type,
 105          * select the TCM bank to operate on in the TCM selection
 106          * register.
 107          */
 108         if (banks > 1)
 109                 asm("mcr        p15, 0, %0, c9, c2, 0"
 110                     : /* No output operands */
 111                     : "r" (bank));
 112
 113         /* Read the special TCM region register c9, 0 */
 114         if (!type)
 115                 asm("mrc        p15, 0, %0, c9, c1, 0"
 116                     : "=r" (tcm_region));
 117         else
 118                 asm("mrc        p15, 0, %0, c9, c1, 1"
 119                     : "=r" (tcm_region));
 120
 121         tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
 122         if (tcm_size < 0) {
 123                 pr_err("CPU: %sTCM%d of unknown size!\n",
 124                        type ? "I" : "D", bank);
 125         } else {
 126                 pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
 127                         type ? "I" : "D",
 128                         bank,
 129                         tcm_size,
 130                         (tcm_region & 0xfffff000U),
 131                         (tcm_region & 1) ? "" : "not ");
 132         }
 133
 134         if (tcm_size != (expected_size >> 10)) {
 135                 pr_crit("CPU: %sTCM%d was detected %dk but expected %dk!\n",
 136                         type ? "I" : "D",
 137                         bank,
 138                         tcm_size,
 139                         (expected_size >> 10));
 140                 /* Adjust to the expected size? what can we do... */
 141         }
 142
 143         /* Force move the TCM bank to where we want it, enable */
 144         tcm_region = offset | (tcm_region & 0x00000ffeU) | 1;
 145
 146         if (!type)
 147                 asm("mcr        p15, 0, %0, c9, c1, 0"
 148                     : /* No output operands */
 149                     : "r" (tcm_region));
 150         else
 151                 asm("mcr        p15, 0, %0, c9, c1, 1"
 152                     : /* No output operands */
 153                     : "r" (tcm_region));
 154
 155         pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
 156                 type ? "I" : "D",
 157                 bank,
 158                 tcm_size,
 159                 (tcm_region & 0xfffff000U));
 160 }
 161
 162 /* We expect to find what is configured for the platform */
 163 #define DTCM_EXPECTED (DTCM_END - DTCM_OFFSET + 1)
 164 #define ITCM_EXPECTED (ITCM_END - ITCM_OFFSET + 1)
 165
 166 /*
 167  * This initializes the TCM memory
 168  */
 169 void __init tcm_init(void)
 170 {
 171         u32 tcm_status = read_cpuid_tcmstatus();
 172         u8 dtcm_banks = (tcm_status >> 16) & 0x03;
 173         u32 dtcm_banksize = DTCM_EXPECTED / dtcm_banks;
 174         u8 itcm_banks = (tcm_status & 0x03);
 175         u32 itcm_banksize = ITCM_EXPECTED / itcm_banks;
 176         char *start;
 177         char *end;
 178         char *ram;
 179         int i;
 180
 181         /* Setup DTCM if present */
 182         for (i = 0; i < dtcm_banks; i++) {
 183                 setup_tcm_bank(0, i, dtcm_banks,
 184                                DTCM_OFFSET + (i * dtcm_banksize),
 185                                dtcm_banksize);
 186                 request_resource(&iomem_resource, &dtcm_res);
 187                 iotable_init(dtcm_iomap, 1);
 188                 /* Copy data from RAM to DTCM */
 189                 start = &__sdtcm_data;
 190                 end   = &__edtcm_data;
 191                 ram   = &__dtcm_start;
 192                 memcpy(start, ram, (end-start));
 193                 pr_debug("CPU DTCM: copied data from %p - %p\n", start, end);
 194         }
 195
 196         /* Setup ITCM if present */
 197         for (i = 0; i < itcm_banks; i++) {
 198                 setup_tcm_bank(1, i, itcm_banks,
 199                                ITCM_OFFSET + (i * itcm_banksize),
 200                                itcm_banksize);
 201                 request_resource(&iomem_resource, &itcm_res);
 202                 iotable_init(itcm_iomap, 1);
 203                 /* Copy code from RAM to ITCM */
 204                 start = &__sitcm_text;
 205                 end   = &__eitcm_text;
 206                 ram   = &__itcm_start;
 207                 memcpy(start, ram, (end-start));
 208                 pr_debug("CPU ITCM: copied code from %p - %p\n", start, end);
 209         }
 210 }
 211
 212 /*
 213  * This creates the TCM memory pool and has to be done later,
 214  * during the core_initicalls, since the allocator is not yet
 215  * up and running when the first initialization runs.
 216  */
 217 static int __init setup_tcm_pool(void)
 218 {
 219         u32 tcm_status = read_cpuid_tcmstatus();
 220         u32 dtcm_pool_start = (u32) &__edtcm_data;
 221         u32 itcm_pool_start = (u32) &__eitcm_text;
 222         int ret;
 223
 224         /*
 225          * Set up malloc pool, 2^2 = 4 bytes granularity since
 226          * the TCM is sometimes just 4 KiB. NB: pages and cache
 227          * line alignments does not matter in TCM!
 228          */
 229         tcm_pool = gen_pool_create(2, -1);
 230
 231         pr_debug("Setting up TCM memory pool\n");
 232
 233         /* Add the rest of DTCM to the TCM pool */
 234         if (tcm_status & (0x03 << 16)) {
 235                 if (dtcm_pool_start < DTCM_END) {
 236                         ret = gen_pool_add(tcm_pool, dtcm_pool_start,
 237                                            DTCM_END - dtcm_pool_start + 1, -1);
 238                         if (ret) {
 239                                 pr_err("CPU DTCM: could not add DTCM " \
 240                                        "remainder to pool!\n");
 241                                 return ret;
 242                         }
 243                         pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
 244                                  "the TCM memory pool\n",
 245                                  DTCM_END - dtcm_pool_start + 1,
 246                                  dtcm_pool_start);
 247                 }
 248         }
 249
 250         /* Add the rest of ITCM to the TCM pool */
 251         if (tcm_status & 0x03) {
 252                 if (itcm_pool_start < ITCM_END) {
 253                         ret = gen_pool_add(tcm_pool, itcm_pool_start,
 254                                            ITCM_END - itcm_pool_start + 1, -1);
 255                         if (ret) {
 256                                 pr_err("CPU ITCM: could not add ITCM " \
 257                                        "remainder to pool!\n");
 258                                 return ret;
 259                         }
 260                         pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
 261                                  "the TCM memory pool\n",
 262                                  ITCM_END - itcm_pool_start + 1,
 263                                  itcm_pool_start);
 264                 }
 265         }
 266         return 0;
 267 }
 268
 269 core_initcall(setup_tcm_pool);