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