intel/common: fix stage_cache_external_region()

The stage_cache_external_region() calculation is actually
dependennt on the properties of the chipset. The reason
is that certain regions within the SMRAM are used for
chipset-specific features. Therefore, provide an API
for abstracting the querying of subregions within
the SMRAM.

The 3 subregions introduced are:

SMM_SUBREGION_HANDLER - SMM handler area
SMM_SUBREGION_CACHE - SMM cache region
SMM_SUBREGION_CHIPSET - Chipset specific area.

The subregions can be queried using the newly
added smm_subregion() function.

Now stage_cache_external_region() uses smm_subregion()
to query the external stage cache in SMRAM, and this
patch also eliminates 2 separate implementations of
stage_cache_external_region() between romstage and
ramstage.

BUG=chrome-os-partner:43636
BRANCH=None
TEST=Built, booted, suspended, resumed on glados.

Original-Change-Id: Id669326ba9647117193aa604038b38b364ff0f82
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/290833
Original-Reviewed-by: Leroy P Leahy <leroy.p.leahy@intel.com>
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

Change-Id: Idb1a75d93c9b87053a7dedb82e85afc7df6334e0
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11197
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

6 files changed, 124 insertions, 66 deletions

diff --git a/src/soc/intel/braswell/memmap.c b/src/soc/intel/braswell/memmap.c
index d1d784d73b..52bba3e96f 100644
--- a/src/soc/intel/braswell/memmap.c
+++ b/src/soc/intel/braswell/memmap.c
@@ -47,6 +47,45 @@ size_t mmap_region_granluarity(void)
 		: 8 << 20;
 }
 
+/*
+ *        Subregions within SMM
+ *     +-------------------------+ BUNIT_SMRRH
+ *     |  External Stage Cache   | SMM_RESERVED_SIZE
+ *     +-------------------------+
+ *     |      code and data      |
+ *     |         (TSEG)          |
+ *     +-------------------------+ BUNIT_SMRRL
+ */
+int smm_subregion(int sub, void **start, size_t *size)
+{
+	uintptr_t sub_base;
+	void *sub_ptr;
+	size_t sub_size;
+	const size_t cache_size = CONFIG_SMM_RESERVED_SIZE;
+
+	smm_region(&sub_ptr, &sub_size);
+	sub_base = (uintptr_t)sub_ptr;
+
+	switch (sub) {
+	case SMM_SUBREGION_HANDLER:
+		/* Handler starts at the base of TSEG. */
+		sub_size -= cache_size;
+		break;
+	case SMM_SUBREGION_CACHE:
+		/* External cache is in the middle of TSEG. */
+		sub_base += sub_size - cache_size;
+		sub_size = cache_size;
+		break;
+	default:
+		return -1;
+	}
+
+	*start = (void *)sub_base;
+	*size = sub_size;
+
+	return 0;
+}
+
 void *cbmem_top(void)
 {
 	char *smm_base;
diff --git a/src/soc/intel/common/Makefile.inc b/src/soc/intel/common/Makefile.inc
index 76854ad857..7c5bbbee48 100644
--- a/src/soc/intel/common/Makefile.inc
+++ b/src/soc/intel/common/Makefile.inc
@@ -13,6 +13,7 @@ ramstage-y += hda_verb.c
 ramstage-$(CONFIG_CACHE_MRC_SETTINGS) += mrc_cache.c
 ramstage-$(CONFIG_CACHE_MRC_SETTINGS) += nvm.c
 ramstage-$(CONFIG_SOC_INTEL_COMMON_RESET) += reset.c
+ramstage-$(CONFIG_SOC_INTEL_COMMON_STAGE_CACHE) += stage_cache.c
 ramstage-$(CONFIG_PLATFORM_USES_FSP1_1) += util.c
 ramstage-$(CONFIG_GOP_SUPPORT) += vbt.c
 
diff --git a/src/soc/intel/common/fsp_ramstage.c b/src/soc/intel/common/fsp_ramstage.c
index a5728b594d..c5916e3a47 100644
--- a/src/soc/intel/common/fsp_ramstage.c
+++ b/src/soc/intel/common/fsp_ramstage.c
@@ -36,63 +36,23 @@ __attribute__((weak)) void soc_after_silicon_init(void)
 	printk(BIOS_DEBUG, "WEAK: %s/%s called\n", __FILE__, __func__);
 }
 
-/*
- * SMM Memory Map:
- *
- * +--------------------------+ smm_region_size() ----.
- * |     FSP Cache            |                       |
- * +--------------------------+                       |
- * |     SMM Stage Cache      |                       + CONFIG_SMM_RESERVED_SIZE
- * +--------------------------+  ---------------------'
- * |     SMM Code             |
- * +--------------------------+ smm_base
- *
- */
-
-void stage_cache_external_region(void **base, size_t *size)
-{
-	size_t cache_size;
-	u8 *cache_base;
-
-	/* Determine the location of the ramstage cache */
-	smm_region((void **)&cache_base, &cache_size);
-	*size = CONFIG_SMM_RESERVED_SIZE;
-	*base = &cache_base[cache_size - CONFIG_SMM_RESERVED_SIZE];
-}
-
 /* Display SMM memory map */
 static void smm_memory_map(void)
 {
-	u8 *smm_base;
-	size_t smm_bytes;
-	size_t smm_code_bytes;
-	u8 *ext_cache;
-	size_t ext_cache_bytes;
-	u8 *smm_reserved;
-	size_t smm_reserved_bytes;
-
-	/* Locate the SMM regions */
-	smm_region((void **)&smm_base, &smm_bytes);
-	stage_cache_external_region((void **)&ext_cache, &ext_cache_bytes);
-	smm_code_bytes = ext_cache - smm_base;
-	smm_reserved_bytes = smm_bytes - ext_cache_bytes - smm_code_bytes;
-	smm_reserved = smm_base + smm_bytes - smm_reserved_bytes;
-
-	/* Display the SMM regions */
-	printk(BIOS_SPEW, "\nLocation          SMM Memory Map        Offset\n");
-	if (smm_reserved_bytes) {
-		printk(BIOS_SPEW, "0x%p +--------------------------+ 0x%08x\n",
-			&smm_reserved[smm_reserved_bytes], (u32)smm_bytes);
-		printk(BIOS_SPEW, "           |   Other reserved region  |\n");
+	void *base;
+	size_t size;
+	int i;
+
+	printk(BIOS_SPEW, "SMM Memory Map\n");
+
+	smm_region(&base, &size);
+	printk(BIOS_SPEW, "SMRAM       : %p 0x%zx\n", base, size);
+
+	for (i = 0; i < SMM_SUBREGION_NUM; i++) {
+		if (smm_subregion(i, &base, &size))
+			continue;
+		printk(BIOS_SPEW, " Subregion %d: %p 0x%zx\n", i, base, size);
 	}
-	printk(BIOS_SPEW, "0x%p +--------------------------+ 0x%08x\n",
-		smm_reserved, (u32)(smm_reserved - smm_base));
-	printk(BIOS_SPEW, "           |   external cache         |\n");
-	printk(BIOS_SPEW, "0x%p +--------------------------+ 0x%08x\n",
-		ext_cache, (u32)(ext_cache - smm_base));
-	printk(BIOS_SPEW, "           |   SMM code               |\n");
-	printk(BIOS_SPEW, "0x%p +--------------------------+ 0x%08x\n",
-		smm_base, 0);
 }
 
 static void fsp_run_silicon_init(int is_s3_wakeup)
diff --git a/src/soc/intel/common/memmap.h b/src/soc/intel/common/memmap.h
index d94f0add7f..3d51539f55 100644
--- a/src/soc/intel/common/memmap.h
+++ b/src/soc/intel/common/memmap.h
@@ -28,6 +28,24 @@
  * this value should be set to 8 MiB.
  */
 size_t mmap_region_granluarity(void);
+
+/* Fills in the arguments for the entire SMM region covered by chipset
+ * protections. e.g. TSEG. */
 void smm_region(void **start, size_t *size);
 
+enum {
+	/* SMM handler area. */
+	SMM_SUBREGION_HANDLER,
+	/* SMM cache region. */
+	SMM_SUBREGION_CACHE,
+	/* Chipset specific area. */
+	SMM_SUBREGION_CHIPSET,
+	/* Total sub regions supported. */
+	SMM_SUBREGION_NUM,
+};
+
+/* Fills in the start and size for the requested SMM subregion. Returns
+ * 0 on susccess, < 0 on failure. */
+int smm_subregion(int sub, void **start, size_t *size);
+
 #endif /* _COMMON_MEMMAP_H_ */
diff --git a/src/soc/intel/common/stage_cache.c b/src/soc/intel/common/stage_cache.c
index 8e96d73179..5bb83c9499 100644
--- a/src/soc/intel/common/stage_cache.c
+++ b/src/soc/intel/common/stage_cache.c
@@ -18,22 +18,15 @@
  * Foundation, Inc.
  */
 
-#include <cbmem.h>
+#include <console/console.h>
 #include <soc/intel/common/memmap.h>
-#include <soc/smm.h>
 #include <stage_cache.h>
 
 void stage_cache_external_region(void **base, size_t *size)
 {
-	char *smm_base;
-	size_t smm_size;
-	const size_t cache_size = CONFIG_SMM_RESERVED_SIZE;
-
-	/*
-	 * The ramstage cache lives in the TSEG region.
-	 * The top of ram is defined to be the TSEG base address.
-	 */
-	smm_region((void **)&smm_base, &smm_size);
-	*size = cache_size;
-	*base = (void *)(&smm_base[smm_size - cache_size]);
+	if (smm_subregion(SMM_SUBREGION_CACHE, base, size)) {
+		printk(BIOS_ERR, "ERROR: No cache SMM subregion.\n");
+		*base = NULL;
+		*size = 0;
+	}
 }
diff --git a/src/soc/intel/skylake/memmap.c b/src/soc/intel/skylake/memmap.c
index 81ec89d95d..494b259455 100644
--- a/src/soc/intel/skylake/memmap.c
+++ b/src/soc/intel/skylake/memmap.c
@@ -61,6 +61,53 @@ void smm_region(void **start, size_t *size)
 	*size = smm_region_size();
 }
 
+/*
+ *        Subregions within SMM
+ *     +-------------------------+ BGSM
+ *     |          IED            | IED_REGION_SIZE
+ *     +-------------------------+
+ *     |  External Stage Cache   | SMM_RESERVED_SIZE
+ *     +-------------------------+
+ *     |      code and data      |
+ *     |         (TSEG)          |
+ *     +-------------------------+ TSEG
+ */
+int smm_subregion(int sub, void **start, size_t *size)
+{
+	uintptr_t sub_base;
+	size_t sub_size;
+	const size_t ied_size = CONFIG_IED_REGION_SIZE;
+	const size_t cache_size = CONFIG_SMM_RESERVED_SIZE;
+
+	sub_base = smm_region_start();
+	sub_size = smm_region_size();
+
+	switch (sub) {
+	case SMM_SUBREGION_HANDLER:
+		/* Handler starts at the base of TSEG. */
+		sub_size -= ied_size;
+		sub_size -= cache_size;
+		break;
+	case SMM_SUBREGION_CACHE:
+		/* External cache is in the middle of TSEG. */
+		sub_base += sub_size - (ied_size + cache_size);
+		sub_size = cache_size;
+		break;
+	case SMM_SUBREGION_CHIPSET:
+		/* IED is at the top. */
+		sub_base += sub_size - ied_size;
+		sub_size = ied_size;
+		break;
+	default:
+		return -1;
+	}
+
+	*start = (void *)sub_base;
+	*size = sub_size;
+
+	return 0;
+}
+
 void *cbmem_top(void)
 {
 	/*