mainboard/asus/kgpe-d16: Set DDR3 memory voltage based on SPD data

Change-Id: I21777283ce0fd3c607951204a63ff67dc656c8cc
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/11956
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/mainboard/asus/kgpe-d16/Kconfig

@@ -6,6 +6,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select DIMM_DDR3
 	select DIMM_REGISTERED
 	# select QRANK_DIMM_SUPPORT
+	select DIMM_VOLTAGE_SET_SUPPORT
 	select NORTHBRIDGE_AMD_AMDFAM10
 	select SOUTHBRIDGE_AMD_SR5650
 	select SOUTHBRIDGE_AMD_SB700

src/mainboard/asus/kgpe-d16/cmos.default

@@ -6,6 +6,7 @@ iommu = Disable
 nmi = Disable
 hypertransport_speed_limit = Auto
 max_mem_clock = DDR3-1600
+minimum_memory_voltage = 1.5V
 ECC_memory = Enable
 ECC_redirection = Disable
 ecc_scrub_rate = 1.28us

src/mainboard/asus/kgpe-d16/cmos.layout

@@ -37,6 +37,7 @@ entries
 456          1       e       1        ECC_memory
 457          1       e       1        ECC_redirection
 458          4       e       11       hypertransport_speed_limit
+462          2       e       12       minimum_memory_voltage
 477          1       e       1        ieee1394_controller
 728        256       h       0        user_data
 984         16       h       0        check_sum
@@ -125,6 +126,10 @@ enumerations
 11    13    400MHz
 11    14    300MHz
 11    15    200MHz
+12    0     1.5V
+12    1     1.35V
+12    2     1.25V
+12    3     1.15V
 
 checksums
 

src/mainboard/asus/kgpe-d16/romstage.c

@@ -131,7 +131,7 @@ static void activate_spd_rom(const struct mem_controller *ctrl) {
  */
 static void set_ddr3_voltage(uint8_t node, uint8_t index) {
 	uint8_t byte;
-	uint8_t value;
+	uint8_t value = 0;
 
 	if (index == 0)
 		value = 0x0;
@@ -157,6 +157,82 @@ static void set_ddr3_voltage(uint8_t node, uint8_t index) {
 	byte = pci_read_config8(PCI_DEV(0, 0x14, 3), 0xd0);
 	byte &= 0x0f;
 	pci_write_config8(PCI_DEV(0, 0x14, 3), 0xd0, byte);
+
+	printk(BIOS_DEBUG, "Node %02d DIMM voltage set to index %02x\n", node, index);
+}
+
+void DIMMSetVoltages(struct MCTStatStruc *pMCTstat,
+				struct DCTStatStruc *pDCTstatA) {
+	/* This mainboard allows the DIMM voltage to be set per-socket.
+	 * Therefore, for each socket, iterate over all DIMMs to find the
+	 * lowest supported voltage common to all DIMMs on that socket.
+	 */
+	uint8_t nvram;
+	uint8_t dimm;
+	uint8_t node;
+	uint8_t socket;
+	uint8_t allowed_voltages = 0xf;	/* The mainboard VRMs allow 1.15V, 1.25V, 1.35V, and 1.5V */
+	uint8_t node_allowed_voltages;
+	uint32_t set_voltage = 0;
+
+	if (get_option(&nvram, "minimum_memory_voltage") == CB_SUCCESS) {
+		switch (nvram) {
+		case 2:
+			allowed_voltages = 0x7;	/* Allow 1.25V, 1.35V, and 1.5V */
+			break;
+		case 1:
+			allowed_voltages = 0x3;	/* Allow 1.35V and 1.5V */
+			break;
+		case 0:
+		default:
+			allowed_voltages = 0x1;	/* Allow 1.5V only */
+			break;
+		}
+	}
+
+	for (node = 0; node < MAX_NODES_SUPPORTED; node++) {
+		socket = node / 2;
+		node_allowed_voltages = allowed_voltages;
+		struct DCTStatStruc *pDCTstat;
+		pDCTstat = pDCTstatA + node;
+		if (pDCTstat->NodePresent) {
+			for (dimm = 0; dimm < MAX_DIMMS_SUPPORTED; dimm++) {
+				if (pDCTstat->DIMMValid & (1 << dimm)) {
+					node_allowed_voltages &= pDCTstat->DimmSupportedVoltages[dimm];
+				}
+			}
+		}
+
+		if (pDCTstat->NodePresent && (node % 2)) {
+			/* Set voltages */
+			if (node_allowed_voltages & 0x8) {
+				set_voltage = 1150;
+				set_ddr3_voltage(socket, 3);
+			} else if (node_allowed_voltages & 0x4) {
+				set_voltage = 1250;
+				set_ddr3_voltage(socket, 2);
+			} else if (node_allowed_voltages & 0x2) {
+				set_voltage = 1350;
+				set_ddr3_voltage(socket, 1);
+			} else {
+				set_voltage = 1500;
+				set_ddr3_voltage(socket, 0);
+			}
+
+			/* Save final DIMM voltages for SMBIOS use */
+			if (pDCTstat->NodePresent) {
+				for (dimm = 0; dimm < MAX_DIMMS_SUPPORTED; dimm++) {
+					pDCTstat->DimmConfiguredVoltage[dimm] = set_voltage;
+				}
+			}
+			pDCTstat = pDCTstatA + (node - 1);
+			if (pDCTstat->NodePresent) {
+				for (dimm = 0; dimm < MAX_DIMMS_SUPPORTED; dimm++) {
+					pDCTstat->DimmConfiguredVoltage[dimm] = set_voltage;
+				}
+			}
+		}
+	}
 }
 
 static void set_peripheral_control_lines(void) {
@@ -351,10 +427,8 @@ void cache_as_ram_main(unsigned long bist, unsigned long cpu_init_detectedx)
 		die("After soft_reset_x - shouldn't see this message!!!\n");
 	}
 
-	/* Set DDR memory voltage
+	/* Set default DDR memory voltage
-	 * FIXME
+	 * This will be overridden later during RAM initialization
-	 * This should be set based on the output of the DIMM SPDs
-	 * For now it is locked to 1.5V
 	 */
 	set_lpc_sticky_ctl(1);	/* Retain LPC/IMC GPIO configuration during S3 sleep */
 	if (!s3resume) {	/* Avoid supply voltage glitches while the DIMMs are retaining data */