cpu/intel/sandybridge: Put stage cache into TSEG

TSEG is not accessible in ring 0 after it is locked in ramstage, in
contrast with cbmem which remains accessible. Assuming SMM does not
touch the cache this is a good region to cache stages.

The code is mostly copied from src/cpu/intel/haswell.

TESTED on Thinkpad X220: on a cold boot the stage cache gets created
and on S3 the cached ramstage gets properly used.

Change-Id: Ifd8f939416b1712f6e5c74f544a5828745f8c2f2
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/23592
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/cpu/intel/model_206ax/model_206ax.h b/src/cpu/intel/model_206ax/model_206ax.h
index 594dde143c..962b8302eb 100644
--- a/src/cpu/intel/model_206ax/model_206ax.h
+++ b/src/cpu/intel/model_206ax/model_206ax.h
@@ -92,6 +92,28 @@
 #define PSS_LATENCY_TRANSITION		10
 #define PSS_LATENCY_BUSMASTER		10
 
+/*
+ * Region of SMM space is reserved for multipurpose use. It falls below
+ * the IED region and above the SMM handler.
+ */
+#define RESERVED_SMM_SIZE CONFIG_SMM_RESERVED_SIZE
+#define RESERVED_SMM_OFFSET \
+	(CONFIG_SMM_TSEG_SIZE - CONFIG_IED_REGION_SIZE - RESERVED_SMM_SIZE)
+
+/* Sanity check config options. */
+#if (CONFIG_SMM_TSEG_SIZE <= (CONFIG_IED_REGION_SIZE + RESERVED_SMM_SIZE))
+# error "CONFIG_SMM_TSEG_SIZE <= (CONFIG_IED_REGION_SIZE + RESERVED_SMM_SIZE)"
+#endif
+#if (CONFIG_SMM_TSEG_SIZE < 0x800000)
+# error "CONFIG_SMM_TSEG_SIZE must at least be 8MiB"
+#endif
+#if ((CONFIG_SMM_TSEG_SIZE & (CONFIG_SMM_TSEG_SIZE - 1)) != 0)
+# error "CONFIG_SMM_TSEG_SIZE is not a power of 2"
+#endif
+#if ((CONFIG_IED_REGION_SIZE & (CONFIG_IED_REGION_SIZE - 1)) != 0)
+# error "CONFIG_IED_REGION_SIZE is not a power of 2"
+#endif
+
 #ifdef __SMM__
 /* Lock MSRs */
 void intel_model_206ax_finalize_smm(void);