CBMEM: Clarify CBMEM_TOP_BACKUP function usage

The deprecated LATE_CBMEM_INIT function is renamed:
  set_top_of_ram -> set_late_cbmem_top

Obscure term top_of_ram is replaced:
  backup_top_of_ram -> backup_top_of_low_cacheable
  get_top_of_ram -> restore_top_of_low_cacheable

New function that always resolves to CBMEM top boundary, with
or without SMM, is named restore_cbmem_top().

Change-Id: I61d20f94840ad61e9fd55976e5aa8c27040b8fb7
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/19377
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>

1 files changed, 18 insertions, 13 deletions

diff --git a/src/arch/x86/cbmem.c b/src/arch/x86/cbmem.c
index e35d43cecb..57ed83b5ca 100644
--- a/src/arch/x86/cbmem.c
+++ b/src/arch/x86/cbmem.c
@@ -18,13 +18,13 @@
 
 #if IS_ENABLED(CONFIG_LATE_CBMEM_INIT)
 
-void __attribute__((weak)) backup_top_of_ram(uint64_t ramtop)
+void __attribute__((weak)) backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	/* Do nothing. Chipset may have implementation to save ramtop in NVRAM.
 	 */
 }
 
-unsigned long __attribute__((weak)) get_top_of_ram(void)
+uintptr_t __attribute__((weak)) restore_top_of_low_cacheable(void)
 {
 	return 0;
 }
@@ -33,29 +33,34 @@ unsigned long __attribute__((weak)) get_top_of_ram(void)
 
 #if IS_ENABLED(CONFIG_CBMEM_TOP_BACKUP)
 
-static void *ramtop_pointer;
+static void *cbmem_top_backup;
 
-void set_top_of_ram(uint64_t ramtop)
+void set_late_cbmem_top(uintptr_t ramtop)
 {
-	backup_top_of_ram(ramtop);
+	backup_top_of_low_cacheable(ramtop);
 	if (ENV_RAMSTAGE)
-		ramtop_pointer = (void *)(uintptr_t)ramtop;
+		cbmem_top_backup = (void *)ramtop;
+}
+
+/* Top of CBMEM is at highest usable DRAM address below 4GiB. */
+uintptr_t __attribute__((weak)) restore_cbmem_top(void)
+{
+	return restore_top_of_low_cacheable();
 }
 
 void *cbmem_top(void)
 {
-	/* Top of cbmem is at lowest usable DRAM address below 4GiB. */
-	uintptr_t ramtop;
+	uintptr_t top_backup;
 
-	if (ENV_RAMSTAGE && ramtop_pointer != NULL)
-		return ramtop_pointer;
+	if (ENV_RAMSTAGE && cbmem_top_backup != NULL)
+		return cbmem_top_backup;
 
-	ramtop = get_top_of_ram();
+	top_backup = restore_cbmem_top();
 
 	if (ENV_RAMSTAGE)
-		ramtop_pointer = (void *)ramtop;
+		cbmem_top_backup = (void *)top_backup;
 
-	return (void *)ramtop;
+	return (void *)top_backup;
 }
 
 #endif /* CBMEM_TOP_BACKUP */