soc/intel/apollolake: Implement stage cache to improve resume time

This patch enables stage cache to save ~40ms during S3 resume.
It saves ramstage in the stage cache and restores it on resume
so that ramstage does not have to reinitialize during the
resume flow. Stage cache functionality is added to postcar stage
since ramstage is called from postcar.

BUG=chrome-os-partner:56941
BRANCH=none
TEST=built for Reef and tested ramstage being cached

Change-Id: I1551fd0faca536bd8c8656f0a8ec7f900aae1f72
Signed-off-by: Brandon Breitenstein <brandon.breitenstein@intel.com>
Reviewed-on: https://review.coreboot.org/16833
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

5 files changed, 59 insertions, 6 deletions

diff --git a/src/soc/intel/apollolake/Kconfig b/src/soc/intel/apollolake/Kconfig
index 3a23dbd0d2..6c178c31d4 100644
--- a/src/soc/intel/apollolake/Kconfig
+++ b/src/soc/intel/apollolake/Kconfig
@@ -26,6 +26,7 @@ config CPU_SPECIFIC_OPTIONS
 	select SOC_INTEL_COMMON_NHLT
 	# Misc options
 	select C_ENVIRONMENT_BOOTBLOCK
+	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM if RELOCATABLE_RAMSTAGE
 	select COLLECT_TIMESTAMPS
 	select COMMON_FADT
 	select GENERIC_GPIO_LIB
@@ -34,7 +35,6 @@ config CPU_SPECIFIC_OPTIONS
 	select MMCONF_SUPPORT
 	select MMCONF_SUPPORT_DEFAULT
 	select NO_FIXED_XIP_ROM_SIZE
-	select NO_STAGE_CACHE
 	select NO_XIP_EARLY_STAGES
 	select PARALLEL_MP
 	select PCIEXP_ASPM
@@ -254,4 +254,8 @@ config SPI_FLASH_INCLUDE_ALL_DRIVERS
 	bool
 	default n
 
+config SMM_RESERVED_SIZE
+	hex
+	default 0x100000
+
 endif
diff --git a/src/soc/intel/apollolake/cpu.c b/src/soc/intel/apollolake/cpu.c
index f3cf050415..e67842c369 100644
--- a/src/soc/intel/apollolake/cpu.c
+++ b/src/soc/intel/apollolake/cpu.c
@@ -102,19 +102,23 @@ static void get_smm_info(uintptr_t *perm_smbase, size_t *perm_smsize,
 {
 	void *smm_base;
 	size_t smm_size;
+	void *handler_base;
+	size_t handler_size;
 
 	/* All range registers are aligned to 4KiB */
 	const uint32_t rmask = ~((1 << 12) - 1);
 
 	/* Initialize global tracking state. */
 	smm_region(&smm_base, &smm_size);
+	smm_subregion(SMM_SUBREGION_HANDLER, &handler_base, &handler_size);
+
 	relo_attrs.smbase = (uint32_t)smm_base;
 	relo_attrs.smrr_base = relo_attrs.smbase | MTRR_TYPE_WRBACK;
 	relo_attrs.smrr_mask = ~(smm_size - 1) & rmask;
 	relo_attrs.smrr_mask |= MTRR_PHYS_MASK_VALID;
 
-	*perm_smbase = relo_attrs.smbase;
-	*perm_smsize = smm_size - CONFIG_SMM_RESERVED_SIZE;
+	*perm_smbase = (uintptr_t)handler_base;
+	*perm_smsize = handler_size;
 	*smm_save_state_size = sizeof(em64t100_smm_state_save_area_t);
 }
 
diff --git a/src/soc/intel/apollolake/include/soc/smm.h b/src/soc/intel/apollolake/include/soc/smm.h
index 7a9846eea2..740d02b114 100644
--- a/src/soc/intel/apollolake/include/soc/smm.h
+++ b/src/soc/intel/apollolake/include/soc/smm.h
@@ -20,6 +20,7 @@
 
 #include <stdint.h>
 #include <soc/gpio.h>
+#include <fsp/memmap.h>
 
 /* These helpers are for performing SMM relocation. */
 void southbridge_clear_smi_status(void);
@@ -35,7 +36,4 @@ void southbridge_smm_enable_smi(void);
 /* Mainboard handler for GPI SMIs*/
 void mainboard_smi_gpi_handler(const struct gpi_status *sts);
 
-/* Fills in the arguments for the entire SMM region covered by chipset
- * protections. e.g. TSEG. */
-void smm_region(void **start, size_t *size);
 #endif
diff --git a/src/soc/intel/apollolake/memmap.c b/src/soc/intel/apollolake/memmap.c
index ea6f447d43..cccbffd40d 100644
--- a/src/soc/intel/apollolake/memmap.c
+++ b/src/soc/intel/apollolake/memmap.c
@@ -24,6 +24,7 @@
 #define __SIMPLE_DEVICE__
 
 #include <arch/io.h>
+#include <assert.h>
 #include <cbmem.h>
 #include <device/pci.h>
 #include <soc/northbridge.h>
@@ -52,3 +53,34 @@ void smm_region(void **start, size_t *size)
 	*start = (void *)smm_region_start();
 	*size = smm_region_size();
 }
+
+int smm_subregion(int sub, void **start, size_t *size)
+{
+	uintptr_t sub_base;
+	size_t sub_size;
+	const size_t cache_size = CONFIG_SMM_RESERVED_SIZE;
+
+	sub_base = smm_region_start();
+	sub_size = smm_region_size();
+
+	assert(sub_size > CONFIG_SMM_RESERVED_SIZE);
+
+	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;
+}
diff --git a/src/soc/intel/apollolake/romstage.c b/src/soc/intel/apollolake/romstage.c
index b9733defa3..2384ceb1cf 100644
--- a/src/soc/intel/apollolake/romstage.c
+++ b/src/soc/intel/apollolake/romstage.c
@@ -29,6 +29,7 @@
 #include <device/pci_def.h>
 #include <device/resource.h>
 #include <fsp/api.h>
+#include <fsp/memmap.h>
 #include <fsp/util.h>
 #include <soc/iomap.h>
 #include <soc/northbridge.h>
@@ -105,6 +106,9 @@ asmlinkage void car_stage_entry(void)
 	uintptr_t top_of_ram;
 	bool s3wake;
 	struct chipset_power_state *ps = car_get_var_ptr(&power_state);
+	void *smm_base;
+	size_t smm_size;
+	uintptr_t tseg_base;
 
 	timestamp_add_now(TS_START_ROMSTAGE);
 
@@ -135,6 +139,17 @@ asmlinkage void car_stage_entry(void)
 		postcar_frame_add_mtrr(&pcf, -CONFIG_ROM_SIZE, CONFIG_ROM_SIZE,
 					MTRR_TYPE_WRPROT);
 
+	/*
+	* Cache the TSEG region at the top of ram. This region is
+	* not restricted to SMM mode until SMM has been relocated.
+	* By setting the region to cacheable it provides faster access
+	* when relocating the SMM handler as well as using the TSEG
+	* region for other purposes.
+	*/
+	smm_region(&smm_base, &smm_size);
+	tseg_base = (uintptr_t)smm_base;
+	postcar_frame_add_mtrr(&pcf, tseg_base, smm_size, MTRR_TYPE_WRBACK);
+
 	run_postcar_phase(&pcf);
 }