soc/intel/cannonlake: Use EBDA area to store cbmem_top address

This patch uses BIOS EBDA area to store relevent details
like cbmem top during romstage after MRC init is done.
Also provide provision to use the same EBDA data across
various stages without reexecuting memory map algorithm.

BRANCH=none
BUG=b:63974384
TEST=Ensures HW based memmap algorithm is executing once in romstage
and store required data into EBDA for other stage to avoid redundant
calculation and get cbmem_top start from EBDA area.

Change-Id: I763ad8181396ea8d8c0d5cf088264791ba62dceb
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/21985
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 51 insertions, 45 deletions

diff --git a/src/soc/intel/cannonlake/memmap.c b/src/soc/intel/cannonlake/memmap.c
index e5117ad81d..c14ccd712f 100644
--- a/src/soc/intel/cannonlake/memmap.c
+++ b/src/soc/intel/cannonlake/memmap.c
@@ -13,6 +13,8 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */
+
+#include <arch/ebda.h>
 #include <arch/io.h>
 #include <cbmem.h>
 #include <chip.h>
@@ -20,8 +22,8 @@
 #include <device/device.h>
 #include <device/pci.h>
 #include <fsp/util.h>
+#include <intelblocks/ebda.h>
 #include <intelblocks/systemagent.h>
-#include <soc/bootblock.h>
 #include <soc/pci_devs.h>
 #include <soc/smm.h>
 #include <soc/systemagent.h>
@@ -81,20 +83,6 @@ int smm_subregion(int sub, void **start, size_t *size)
 	return 0;
 }
 
-static void *top_of_ram_register(void)
-{
-	int num;
-	int offset;
-	num = (read32((uintptr_t *)HPET_BASE_ADDRESS) >> 8) & 0x1f;
-	offset = 0x100 + (0x20 * num) + 0x08;
-	return (void *)(uintptr_t)(HPET_BASE_ADDRESS + offset);
-}
-
-void clear_cbmem_top(void)
-{
-	write32(top_of_ram_register(), 0);
-}
-
 static bool is_ptt_enable(void)
 {
 	if ((read32((void *)PTT_TXT_BASE_ADDRESS) & PTT_PRESENT) ==
@@ -268,44 +256,62 @@ static uintptr_t calculate_dram_base(size_t *reserved_mem_size)
 	return dram_base;
 }
 
-void cbmem_top_init(void)
+/* Fill up memory layout information */
+void fill_soc_memmap_ebda(struct ebda_config *cfg)
 {
-	uintptr_t top;
 	size_t chipset_mem_size;
 
-	top = calculate_dram_base(&chipset_mem_size);
+	cfg->tolum_base = calculate_dram_base(&chipset_mem_size);
+}
 
-	write32(top_of_ram_register(), top);
+void cbmem_top_init(void)
+{
+	/* Fill up EBDA area */
+	fill_ebda_area();
 }
 
+/*
+ *     +-------------------------+  Top of RAM (aligned)
+ *     | System Management Mode  |
+ *     |      code and data      |  Length: CONFIG_TSEG_SIZE
+ *     |         (TSEG)          |
+ *     +-------------------------+  SMM base (aligned)
+ *     |                         |
+ *     | Chipset Reserved Memory |
+ *     |                         |
+ *     +-------------------------+  top_of_ram (aligned)
+ *     |                         |
+ *     |       CBMEM Root        |
+ *     |                         |
+ *     +-------------------------+
+ *     |                         |
+ *     |   FSP Reserved Memory   |
+ *     |                         |
+ *     +-------------------------+
+ *     |                         |
+ *     |  Various CBMEM Entries  |
+ *     |                         |
+ *     +-------------------------+  top_of_stack (8 byte aligned)
+ *     |                         |
+ *     |   stack (CBMEM Entry)   |
+ *     |                         |
+ *     +-------------------------+
+ */
 void *cbmem_top(void)
 {
+	struct ebda_config ebda_cfg;
+	struct ebda_config *cfg = &ebda_cfg;
+
 	/*
-	 *     +-------------------------+  Top of RAM (aligned)
-	 *     | System Management Mode  |
-	 *     |      code and data      |  Length: CONFIG_TSEG_SIZE
-	 *     |         (TSEG)          |
-	 *     +-------------------------+  SMM base (aligned)
-	 *     |                         |
-	 *     | Chipset Reserved Memory |
-	 *     |                         |
-	 *     +-------------------------+  top_of_ram (aligned)
-	 *     |                         |
-	 *     |       CBMEM Root        |
-	 *     |                         |
-	 *     +-------------------------+
-	 *     |                         |
-	 *     |   FSP Reserved Memory   |
-	 *     |                         |
-	 *     +-------------------------+
-	 *     |                         |
-	 *     |  Various CBMEM Entries  |
-	 *     |                         |
-	 *     +-------------------------+  top_of_stack (8 byte aligned)
-	 *     |                         |
-	 *     |   stack (CBMEM Entry)   |
-	 *     |                         |
-	 *     +-------------------------+
+	 * Check if Tseg has been initialized, we will use this as a flag
+	 * to check if the MRC is done, and only then continue to read the
+	 * PRMMR_BASE MSR. The system hangs if PRMRR_BASE MSR is read before
+	 * PRMRR_MASK MSR lock bit is set.
 	 */
-	return (void *)(uintptr_t)read32(top_of_ram_register());
+	if (sa_get_tseg_base() == 0)
+		return NULL;
+
+	retrieve_ebda_object(cfg);
+
+	return (void *)(uintptr_t)cfg->tolum_base;
 }