smbios: Fix type 17 for Windows 10

The `GetPhysicallyInstalledSystemMemory` API call, at least on Windows
10, returns an error if SMBIOS tables are invalid. Various tools use
this API call and don't operate correctly if this fails. For example,
the "Intel Processor Diagnostic Tool" program is affected.

Windows then guesses the physical memory size by accumulating entries
from the firmware-provided memory map, which results in a total memory
size that is slightly lower than the actual installed memory capacity.

To fix this issue, add the handle to a type 16 entry to all type 17
entries.

Add new fields to struct memory_info and fill them in Intel common code.
Use the introduced variables to fill type 16 in smbios.c and provide
a handle to type 17 entries.

Besides keeping the current behaviour on intel/soc/common platforms, the
type 16 table is also emitted on platforms that don't explicitly fill
it, by using the existing fields of struct memory_info.

Tested on Windows 10:
The GetPhysicallyInstalledSystemMemory API call doesn't return an error
anymore and the installed memory is now being reported as 8192 MiB.

Change-Id: Idc3a363cbc3d0654dafd4176c4f4af9005210f42
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43969
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by:  Marcello Sylvester Bauer <sylv@sylv.io>
Reviewed-by: Christian Walter <christian.walter@9elements.com>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

3 files changed, 106 insertions, 57 deletions

diff --git a/src/arch/x86/smbios.c b/src/arch/x86/smbios.c
index d7e87470db..47b54aa116 100644
--- a/src/arch/x86/smbios.c
+++ b/src/arch/x86/smbios.c
@@ -310,7 +310,8 @@ static void smbios_fill_dimm_serial_number(const struct dimm_info *dimm,
 }
 
 static int create_smbios_type17_for_dimm(struct dimm_info *dimm,
-					 unsigned long *current, int *handle)
+					 unsigned long *current, int *handle,
+					 int type16_handle)
 {
 	struct smbios_type17 *t = (struct smbios_type17 *)*current;
 
@@ -365,6 +366,8 @@ static int create_smbios_type17_for_dimm(struct dimm_info *dimm,
 	t->memory_error_information_handle = 0xFFFE;
 	t->attributes = dimm->rank_per_dimm;
 	t->handle = *handle;
+	t->phys_memory_array_handle = type16_handle;
+
 	*handle += 1;
 	t->length = sizeof(struct smbios_type17) - 2;
 	return t->length + smbios_string_table_len(t->eos);
@@ -1063,7 +1066,53 @@ static int smbios_write_type11(unsigned long *current, int *handle)
 	return len;
 }
 
-static int smbios_write_type17(unsigned long *current, int *handle)
+static int smbios_write_type16(unsigned long *current, int *handle)
+{
+	struct smbios_type16 *t = (struct smbios_type16 *)*current;
+
+	int len;
+	int i;
+
+	struct memory_info *meminfo;
+	meminfo = cbmem_find(CBMEM_ID_MEMINFO);
+	if (meminfo == NULL)
+		return 0;	/* can't find mem info in cbmem */
+
+	printk(BIOS_INFO, "Create SMBIOS type 16\n");
+
+	if (meminfo->max_capacity_mib == 0 || meminfo->number_of_devices == 0) {
+		/* Fill in defaults if not provided */
+		meminfo->number_of_devices = 0;
+		meminfo->max_capacity_mib = 0;
+		for (i = 0; i < meminfo->dimm_cnt && i < ARRAY_SIZE(meminfo->dimm); i++) {
+			meminfo->max_capacity_mib += meminfo->dimm[i].dimm_size;
+			meminfo->number_of_devices += !!meminfo->dimm[i].dimm_size;
+		}
+	}
+
+	memset(t, 0, sizeof(*t));
+	t->type = SMBIOS_PHYS_MEMORY_ARRAY;
+	t->handle = *handle;
+	t->length = len = sizeof(*t) - 2;
+
+	t->location = MEMORY_ARRAY_LOCATION_SYSTEM_BOARD;
+	t->use = MEMORY_ARRAY_USE_SYSTEM;
+	t->memory_error_correction = meminfo->ecc_capable ?
+				MEMORY_ARRAY_ECC_SINGLE_BIT : MEMORY_ARRAY_ECC_NONE;
+
+	/* no error information handle available */
+	t->memory_error_information_handle = 0xFFFE;
+	t->maximum_capacity = meminfo->max_capacity_mib * (MiB / KiB);
+	t->number_of_memory_devices = meminfo->number_of_devices;
+
+	len += smbios_string_table_len(t->eos);
+
+	*current += len;
+	(*handle)++;
+	return len;
+}
+
+static int smbios_write_type17(unsigned long *current, int *handle, int type16)
 {
 	int len = sizeof(struct smbios_type17);
 	int totallen = 0;
@@ -1079,7 +1128,13 @@ static int smbios_write_type17(unsigned long *current, int *handle)
 		i++) {
 		struct dimm_info *dimm;
 		dimm = &meminfo->dimm[i];
-		len = create_smbios_type17_for_dimm(dimm, current, handle);
+		/*
+		 * Windows 10 GetPhysicallyInstalledSystemMemory functions reads SMBIOS tables
+		 * type 16 and type 17. The type 17 tables need to point to a type 16 table.
+		 * Otherwise, the physical installed memory size is guessed from the system
+		 * memory map, which results in a slightly smaller value than the actual size.
+		 */
+		len = create_smbios_type17_for_dimm(dimm, current, handle, type16);
 		*current += len;
 		totallen += len;
 	}
@@ -1356,8 +1411,12 @@ unsigned long smbios_write_tables(unsigned long current)
 	if (CONFIG(ELOG))
 		update_max(len, max_struct_size,
 			elog_smbios_write_type15(&current,handle++));
-	update_max(len, max_struct_size, smbios_write_type17(&current,
+
+	const int type16 = handle;
+	update_max(len, max_struct_size, smbios_write_type16(&current,
 		&handle));
+	update_max(len, max_struct_size, smbios_write_type17(&current,
+		&handle, type16));
 	update_max(len, max_struct_size, smbios_write_type19(&current,
 		&handle));
 	update_max(len, max_struct_size, smbios_write_type32(&current,
diff --git a/src/include/memory_info.h b/src/include/memory_info.h
index a9891189d2..f4a200995c 100644
--- a/src/include/memory_info.h
+++ b/src/include/memory_info.h
@@ -5,6 +5,7 @@
 #define _MEMORY_INFO_H_
 
 #include <stdint.h>
+#include <stdbool.h>
 
 #define DIMM_INFO_SERIAL_SIZE		4
 #define DIMM_INFO_PART_NUMBER_SIZE	33
@@ -81,6 +82,14 @@ struct dimm_info {
 } __packed;
 
 struct memory_info {
+	/* controller specific */
+	bool ecc_capable;
+	/* Maximum capacity the DRAM controller/mainboard supports */
+	uint32_t max_capacity_mib;
+	/* Maximum number of DIMMs the DRAM controller/mainboard supports */
+	uint16_t number_of_devices;
+
+	/* active DIMM configuration */
 	uint8_t dimm_cnt;
 	struct dimm_info dimm[DIMM_INFO_TOTAL];
 } __packed;
diff --git a/src/soc/intel/common/block/systemagent/systemagent.c b/src/soc/intel/common/block/systemagent/systemagent.c
index e12e07c376..5da28007ee 100644
--- a/src/soc/intel/common/block/systemagent/systemagent.c
+++ b/src/soc/intel/common/block/systemagent/systemagent.c
@@ -13,6 +13,7 @@
 #include <soc/iomap.h>
 #include <soc/pci_devs.h>
 #include <soc/systemagent.h>
+#include <types.h>
 #include "systemagent_def.h"
 
 /* SoC override function */
@@ -46,6 +47,38 @@ __weak uint32_t soc_systemagent_max_chan_capacity_mib(u8 capid0_a_ddrsz)
 	return 32768;	/* 32 GiB per channel */
 }
 
+static bool sa_supports_ecc(const uint32_t capid0_a)
+{
+	return !(capid0_a & CAPID_ECCDIS);
+}
+
+static size_t sa_slots_per_channel(const uint32_t capid0_a)
+{
+	return !(capid0_a & CAPID_DDPCD) + 1;
+}
+
+static size_t sa_number_of_channels(const uint32_t capid0_a)
+{
+	return !(capid0_a & CAPID_PDCD) + 1;
+}
+
+static void sa_soc_systemagent_init(struct device *dev)
+{
+	soc_systemagent_init(dev);
+
+	struct memory_info *m = cbmem_find(CBMEM_ID_MEMINFO);
+	if (m == NULL)
+		return;
+
+	const uint32_t capid0_a = pci_read_config32(dev, CAPID0_A);
+
+	m->ecc_capable = sa_supports_ecc(capid0_a);
+	m->max_capacity_mib = soc_systemagent_max_chan_capacity_mib(CAPID_DDRSZ(capid0_a)) *
+			      sa_number_of_channels(capid0_a);
+	m->number_of_devices = sa_slots_per_channel(capid0_a) *
+			       sa_number_of_channels(capid0_a);
+}
+
 /*
  * Add all known fixed MMIO ranges that hang off the host bridge/memory
  * controller device.
@@ -262,55 +295,6 @@ static void systemagent_read_resources(struct device *dev)
 		sa_add_imr_resources(dev, &index);
 }
 
-#if CONFIG(GENERATE_SMBIOS_TABLES)
-static bool sa_supports_ecc(const uint32_t capida)
-{
-	return !(capida & CAPID_ECCDIS);
-}
-
-static size_t sa_slots_per_channel(const uint32_t capida)
-{
-	return !(capida & CAPID_DDPCD) + 1;
-}
-
-static size_t sa_number_of_channels(const uint32_t capida)
-{
-	return !(capida & CAPID_PDCD) + 1;
-}
-
-static int sa_smbios_write_type_16(struct device *dev, int *handle,
-		unsigned long *current)
-{
-	struct smbios_type16 *t = (struct smbios_type16 *)*current;
-	int len = sizeof(struct smbios_type16);
-	const uint32_t capida = pci_read_config32(dev, CAPID0_A);
-
-	struct memory_info *meminfo;
-	meminfo = cbmem_find(CBMEM_ID_MEMINFO);
-	if (meminfo == NULL)
-		return 0;	/* can't find mem info in cbmem */
-
-	memset(t, 0, sizeof(struct smbios_type16));
-	t->type = SMBIOS_PHYS_MEMORY_ARRAY;
-	t->handle = *handle;
-	t->length = len - 2;
-	t->location = MEMORY_ARRAY_LOCATION_SYSTEM_BOARD;
-	t->use = MEMORY_ARRAY_USE_SYSTEM;
-	t->memory_error_correction = sa_supports_ecc(capida) ? MEMORY_ARRAY_ECC_SINGLE_BIT :
-		MEMORY_ARRAY_ECC_NONE;
-	/* no error information handle available */
-	t->memory_error_information_handle = 0xFFFE;
-	t->maximum_capacity = soc_systemagent_max_chan_capacity_mib(CAPID_DDRSZ(capida)) *
-			      sa_number_of_channels(capida) * (MiB / KiB);
-	t->number_of_memory_devices = sa_slots_per_channel(capida) *
-				      sa_number_of_channels(capida);
-
-	*current += len;
-	*handle += 1;
-	return len;
-}
-#endif
-
 void enable_power_aware_intr(void)
 {
 	uint8_t pair;
@@ -326,14 +310,11 @@ static struct device_operations systemagent_ops = {
 	.read_resources   = systemagent_read_resources,
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_dev_enable_resources,
-	.init             = soc_systemagent_init,
+	.init             = sa_soc_systemagent_init,
 	.ops_pci          = &pci_dev_ops_pci,
 #if CONFIG(HAVE_ACPI_TABLES)
 	.write_acpi_tables = sa_write_acpi_tables,
 #endif
-#if CONFIG(GENERATE_SMBIOS_TABLES)
-	.get_smbios_data = sa_smbios_write_type_16,
-#endif
 };
 
 static const unsigned short systemagent_ids[] = {