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 <[email protected]>
   7  * Author: Rickard Andersson <[email protected]>
   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 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         /* Force move the TCM bank to where we want it, enable */
 138         tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
 139
 140         if (!type)
 141                 asm("mcr        p15, 0, %0, c9, c1, 0"
 142                     : /* No output operands */
 143                     : "r" (tcm_region));
 144         else
 145                 asm("mcr        p15, 0, %0, c9, c1, 1"
 146                     : /* No output operands */
 147                     : "r" (tcm_region));
 148
 149         /* Increase offset */
 150         *offset += (tcm_size << 10);
 151
 152         pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
 153                 type ? "I" : "D",
 154                 bank,
 155                 tcm_size,
 156                 (tcm_region & 0xfffff000U));
 157         return 0;
 158 }
 159
 160 /*
 161  * This initializes the TCM memory
 162  */
 163 void __init tcm_init(void)
 164 {
 165         u32 tcm_status = read_cpuid_tcmstatus();
 166         u8 dtcm_banks = (tcm_status >> 16) & 0x03;
 167         u8 itcm_banks = (tcm_status & 0x03);
 168         char *start;
 169         char *end;
 170         char *ram;
 171         int ret;
 172         int i;
 173
 174         /* Setup DTCM if present */
 175         if (dtcm_banks > 0) {
 176                 for (i = 0; i < dtcm_banks; i++) {
 177                         ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
 178                         if (ret)
 179                                 return;
 180                 }
 181                 dtcm_res.end = dtcm_end - 1;
 182                 request_resource(&iomem_resource, &dtcm_res);
 183                 dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
 184                 iotable_init(dtcm_iomap, 1);
 185                 /* Copy data from RAM to DTCM */
 186                 start = &__sdtcm_data;
 187                 end   = &__edtcm_data;
 188                 ram   = &__dtcm_start;
 189                 /* This means you compiled more code than fits into DTCM */
 190                 BUG_ON((end - start) > (dtcm_end - DTCM_OFFSET));
 191                 memcpy(start, ram, (end-start));
 192                 pr_debug("CPU DTCM: copied data from %p - %p\n", start, end);
 193         }
 194
 195         /* Setup ITCM if present */
 196         if (itcm_banks > 0) {
 197                 for (i = 0; i < itcm_banks; i++) {
 198                         ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
 199                         if (ret)
 200                                 return;
 201                 }
 202                 itcm_res.end = itcm_end - 1;
 203                 request_resource(&iomem_resource, &itcm_res);
 204                 itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
 205                 iotable_init(itcm_iomap, 1);
 206                 /* Copy code from RAM to ITCM */
 207                 start = &__sitcm_text;
 208                 end   = &__eitcm_text;
 209                 ram   = &__itcm_start;
 210                 /* This means you compiled more code than fits into ITCM */
 211                 BUG_ON((end - start) > (itcm_end - ITCM_OFFSET));
 212                 memcpy(start, ram, (end-start));
 213                 pr_debug("CPU ITCM: copied code from %p - %p\n", start, end);
 214         }
 215 }
 216
 217 /*
 218  * This creates the TCM memory pool and has to be done later,
 219  * during the core_initicalls, since the allocator is not yet
 220  * up and running when the first initialization runs.
 221  */
 222 static int __init setup_tcm_pool(void)
 223 {
 224         u32 tcm_status = read_cpuid_tcmstatus();
 225         u32 dtcm_pool_start = (u32) &__edtcm_data;
 226         u32 itcm_pool_start = (u32) &__eitcm_text;
 227         int ret;
 228
 229         /*
 230          * Set up malloc pool, 2^2 = 4 bytes granularity since
 231          * the TCM is sometimes just 4 KiB. NB: pages and cache
 232          * line alignments does not matter in TCM!
 233          */
 234         tcm_pool = gen_pool_create(2, -1);
 235
 236         pr_debug("Setting up TCM memory pool\n");
 237
 238         /* Add the rest of DTCM to the TCM pool */
 239         if (tcm_status & (0x03 << 16)) {
 240                 if (dtcm_pool_start < dtcm_end) {
 241                         ret = gen_pool_add(tcm_pool, dtcm_pool_start,
 242                                            dtcm_end - dtcm_pool_start, -1);
 243                         if (ret) {
 244                                 pr_err("CPU DTCM: could not add DTCM " \
 245                                        "remainder to pool!\n");
 246                                 return ret;
 247                         }
 248                         pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
 249                                  "the TCM memory pool\n",
 250                                  dtcm_end - dtcm_pool_start,
 251                                  dtcm_pool_start);
 252                 }
 253         }
 254
 255         /* Add the rest of ITCM to the TCM pool */
 256         if (tcm_status & 0x03) {
 257                 if (itcm_pool_start < itcm_end) {
 258                         ret = gen_pool_add(tcm_pool, itcm_pool_start,
 259                                            itcm_end - itcm_pool_start, -1);
 260                         if (ret) {
 261                                 pr_err("CPU ITCM: could not add ITCM " \
 262                                        "remainder to pool!\n");
 263                                 return ret;
 264                         }
 265                         pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
 266                                  "the TCM memory pool\n",
 267                                  itcm_end - itcm_pool_start,
 268                                  itcm_pool_start);
 269                 }
 270         }
 271         return 0;
 272 }
 273
 274 core_initcall(setup_tcm_pool);