src/arch/x86/cbmem.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <stdlib.h>
  15 #include <console/console.h>
  16 #include <cbmem.h>
  17 #include <arch/acpi.h>
  18
  19 #if IS_ENABLED(CONFIG_LATE_CBMEM_INIT)
  20
  21 void __attribute__((weak)) backup_top_of_low_cacheable(uintptr_t ramtop)
  22 {
  23         /* Do nothing. Chipset may have implementation to save ramtop in NVRAM.
  24          */
  25 }
  26
  27 uintptr_t __attribute__((weak)) restore_top_of_low_cacheable(void)
  28 {
  29         return 0;
  30 }
  31
  32 #endif /* LATE_CBMEM_INIT */
  33
  34 #if IS_ENABLED(CONFIG_CBMEM_TOP_BACKUP)
  35
  36 static void *cbmem_top_backup;
  37
  38 void set_late_cbmem_top(uintptr_t ramtop)
  39 {
  40         backup_top_of_low_cacheable(ramtop);
  41         if (ENV_RAMSTAGE)
  42                 cbmem_top_backup = (void *)ramtop;
  43 }
  44
  45 /* Top of CBMEM is at highest usable DRAM address below 4GiB. */
  46 uintptr_t __attribute__((weak)) restore_cbmem_top(void)
  47 {
  48         return restore_top_of_low_cacheable();
  49 }
  50
  51 void *cbmem_top(void)
  52 {
  53         uintptr_t top_backup;
  54
  55         if (ENV_RAMSTAGE && cbmem_top_backup != NULL)
  56                 return cbmem_top_backup;
  57
  58         top_backup = restore_cbmem_top();
  59
  60         if (ENV_RAMSTAGE)
  61                 cbmem_top_backup = (void *)top_backup;
  62
  63         return (void *)top_backup;
  64 }
  65
  66 #endif /* CBMEM_TOP_BACKUP */
  67
  68 /* Something went wrong, our high memory area got wiped */
  69 void cbmem_fail_resume(void)
  70 {
  71 #if !defined(__PRE_RAM__) && IS_ENABLED(CONFIG_HAVE_ACPI_RESUME)
  72         /* ACPI resume needs to be cleared in the fail-to-recover case, but that
  73          * condition is only handled during ramstage. */
  74         acpi_fail_wakeup();
  75 #endif
  76 }