commit 63fac81fc80d701a785ed61a3b5738ea0a821169
author Kyösti Mälkki <kyosti.malkki@gmail.com> Sat Sep 02 16:41:43 2017 +0300
committer Kyösti Mälkki <kyosti.malkki@gmail.com> Tue Sep 26 10:05:48 2017 +0000
tree 7b50798c95fc1e3ec309351157197784e04131f8
parent 8bf978c2aa92aa194d74e6588344f579de5828de

AGESA: Implement POSTCAR_STAGE

Move all boards that have moved away from AGESA_LEGACY_WRAPPER
or BINARYPI_LEGACY_WRAPPER to use POSTCAR_STAGE.

We use POSTCAR_STAGE as a conditional in CAR teardown to tell
our MTRR setup is prepared such that invalidation without
writeback is a valid operation.

Change-Id: I3f4e2170054bdb84c72d2f7c956f8d51a6d7f0ca
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/21384
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/amd/agesa/cache_as_ram.S

diff --git a/src/cpu/amd/agesa/cache_as_ram.S b/src/cpu/amd/agesa/cache_as_ram.S
index b96a5e7..50242f7 100644
--- a/src/cpu/amd/agesa/cache_as_ram.S
+++ b/src/cpu/amd/agesa/cache_as_ram.S
@@ -29,6 +29,7 @@
 
 .code32
 .globl _cache_as_ram_setup, _cache_as_ram_setup_end
+.globl chipset_teardown_car
 
 _cache_as_ram_setup:
 
@@ -105,20 +106,44 @@
   movd  %mm0, %eax		/* bist */
   pushl %eax
   call  romstage_main
+
+#if IS_ENABLED(CONFIG_POSTCAR_STAGE)
+
+/* We do not return. Execution continues with run_postcar_phase()
+ * calling to chipset_teardown_car below.
+ */
+  jmp postcar_entry_failure
+
+chipset_teardown_car:
+
+/*
+ * Retrieve return address from stack as it will get trashed below if
+ * execution is utilizing the cache-as-ram stack.
+ */
+  pop %esp
+
+#else
+
   movl  %eax, %esp
 
-/* Register %esp is new stacktop for remaining of romstage.
- * It is the only register preserved in AMD_DISABLE_STACK.
- */
+/* Register %esp is new stacktop for remaining of romstage. */
 
-disable_cache_as_ram:
+#endif
+
   /* Disable cache */
   movl	%cr0, %eax
   orl	$CR0_CacheDisable, %eax
   movl	%eax, %cr0
 
+/* Register %esp is preserved in AMD_DISABLE_STACK. */
   AMD_DISABLE_STACK
 
+#if IS_ENABLED(CONFIG_POSTCAR_STAGE)
+
+  jmp *%esp
+
+#else
+
   /* enable cache */
   movl %cr0, %eax
   andl $0x9fffffff, %eax
@@ -126,9 +151,22 @@
 
   call  romstage_after_car
 
+#endif
+
   /* Should never see this postcode */
   post_code(0xaf)
+
 stop:
+  hlt
+  jmp stop
+
+/* These are here for linking purposes. */
+.weak early_all_cores, romstage_main
+early_all_cores:
+romstage_main:
+postcar_entry_failure:
+  /* Should never see this postcode */
+  post_code(0xae)
   jmp stop
 
 _cache_as_ram_setup_end: