ram: octeon: Add MIPS Octeon3 DDR4 support (part 3/3)

This Octeon 3 DDR driver is ported from the 2013 Cavium / Marvell U-Boot
repository. It currently supports DDR4 on Octeon 3. It can be later
extended to support also DDR3 and Octeon 2 platforms.

Part 3 includes the DIMM SPD handling code and the Kconfig / Makefile
integration.

Signed-off-by: Aaron Williams <awilliams@marvell.com>
Signed-off-by: Stefan Roese <sr@denx.de>

5 files changed, 435 insertions, 0 deletions

diff --git a/drivers/ram/Kconfig b/drivers/ram/Kconfig
index 7e6e9818971..a0e859afd6e 100644
--- a/drivers/ram/Kconfig
+++ b/drivers/ram/Kconfig
@@ -76,3 +76,4 @@ config IMXRT_SDRAM
 source "drivers/ram/rockchip/Kconfig"
 source "drivers/ram/sifive/Kconfig"
 source "drivers/ram/stm32mp1/Kconfig"
+source "drivers/ram/octeon/Kconfig"
diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
index 769c9d62187..d685a579a0f 100644
--- a/drivers/ram/Makefile
+++ b/drivers/ram/Makefile
@@ -19,3 +19,5 @@ obj-$(CONFIG_K3_J721E_DDRSS) += k3-j721e/
 obj-$(CONFIG_IMXRT_SDRAM) += imxrt_sdram.o
 
 obj-$(CONFIG_RAM_SIFIVE) += sifive/
+
+obj-$(CONFIG_ARCH_OCTEON) += octeon/
diff --git a/drivers/ram/octeon/Kconfig b/drivers/ram/octeon/Kconfig
new file mode 100644
index 00000000000..eb5a1208edf
--- /dev/null
+++ b/drivers/ram/octeon/Kconfig
@@ -0,0 +1,17 @@
+config RAM_OCTEON
+	bool "Ram drivers for Octeon SoCs"
+	depends on RAM && ARCH_OCTEON
+	default n
+	help
+	 This enables support for RAM drivers for Octeon SoCs.
+
+if RAM_OCTEON
+
+config RAM_OCTEON_DDR4
+	bool "Octeon III DDR4 RAM support"
+	default n
+	help
+	 This enables support for DDR4 RAM suppoort for Octeon III.  This does
+	 not include support for Octeon CN70XX.
+
+endif # RAM_OCTEON
diff --git a/drivers/ram/octeon/Makefile b/drivers/ram/octeon/Makefile
new file mode 100644
index 00000000000..27649d1e6f9
--- /dev/null
+++ b/drivers/ram/octeon/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2020 Marvell, Inc.
+#
+
+obj-$(CONFIG_RAM_OCTEON_DDR4) += octeon_ddr.o
+obj-$(CONFIG_RAM_OCTEON_DDR4) += octeon3_lmc.o
+obj-y += dimm_spd_eeprom.o
diff --git a/drivers/ram/octeon/dimm_spd_eeprom.c b/drivers/ram/octeon/dimm_spd_eeprom.c
new file mode 100644
index 00000000000..30db54804ca
--- /dev/null
+++ b/drivers/ram/octeon/dimm_spd_eeprom.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Marvell International Ltd.
+ */
+
+#include <i2c.h>
+#include <ram.h>
+
+#include <mach/octeon_ddr.h>
+
+#define DEVICE_TYPE	DDR4_SPD_KEY_BYTE_DEVICE_TYPE // same for DDR3 and DDR4
+#define MODULE_TYPE	DDR4_SPD_KEY_BYTE_MODULE_TYPE // same for DDR3 and DDR4
+#define BUS_WIDTH(t)	(((t) == DDR4_DRAM) ?		    \
+			 DDR4_SPD_MODULE_MEMORY_BUS_WIDTH : \
+			 DDR3_SPD_MEMORY_BUS_WIDTH)
+
+/*
+ * Allow legacy code to encode bus number in the upper bits of the address
+ * These are only supported in read_spd()
+ */
+#define OCTEON_TWSI_BUS_IN_ADDR_BIT       12
+#define OCTEON_TWSI_BUS_IN_ADDR_MASK      (15 << OCTEON_TWSI_BUS_IN_ADDR_BIT)
+#define OCTEON_TWSI_GET_BUS(addr)			\
+	(((addr) >> OCTEON_TWSI_BUS_IN_ADDR_BIT) & 0xf)
+
+const char *ddr3_dimm_types[] = {
+	/* 0000 */ "Undefined",
+	/* 0001 */ "RDIMM",
+	/* 0010 */ "UDIMM",
+	/* 0011 */ "SO-DIMM",
+	/* 0100 */ "Micro-DIMM",
+	/* 0101 */ "Mini-RDIMM",
+	/* 0110 */ "Mini-UDIMM",
+	/* 0111 */ "Mini-CDIMM",
+	/* 1000 */ "72b-SO-UDIMM",
+	/* 1001 */ "72b-SO-RDIMM",
+	/* 1010 */ "72b-SO-CDIMM"
+	/* 1011 */ "LRDIMM",
+	/* 1100 */ "16b-SO-DIMM",
+	/* 1101 */ "32b-SO-DIMM",
+	/* 1110 */ "Reserved",
+	/* 1111 */ "Reserved"
+};
+
+const char *ddr4_dimm_types[] = {
+	/* 0000 */ "Extended",
+	/* 0001 */ "RDIMM",
+	/* 0010 */ "UDIMM",
+	/* 0011 */ "SO-DIMM",
+	/* 0100 */ "LRDIMM",
+	/* 0101 */ "Mini-RDIMM",
+	/* 0110 */ "Mini-UDIMM",
+	/* 0111 */ "Reserved",
+	/* 1000 */ "72b-SO-RDIMM",
+	/* 1001 */ "72b-SO-UDIMM",
+	/* 1010 */ "Reserved",
+	/* 1011 */ "Reserved",
+	/* 1100 */ "16b-SO-DIMM",
+	/* 1101 */ "32b-SO-DIMM",
+	/* 1110 */ "Reserved",
+	/* 1111 */ "Reserved"
+};
+
+static u16 ddr3_crc16(u8 *ptr, int count)
+{
+	/* From DDR3 SPD specification */
+	int crc, i;
+
+	crc = 0;
+	while (--count >= 0) {
+		crc = crc ^ (int)*ptr++ << 8;
+		for (i = 0; i < 8; ++i) {
+			if (crc & 0x8000)
+				crc = crc << 1 ^ 0x1021;
+			else
+				crc = crc << 1;
+		}
+	}
+
+	return (crc & 0xFFFF);
+}
+
+static int validate_spd_checksum_ddr4(struct dimm_config *dimm_config,
+				      int dimm_index, int twsi_addr, int silent)
+{
+	u8 *spd_data = dimm_config->spd_data[dimm_index];
+	int crc_bytes = 126;
+	u16 crc_comp;
+
+	/* Check byte 0 to see how many bytes checksum is over */
+	if (spd_data[0] & 0x80)
+		crc_bytes = 117;
+
+	crc_comp = ddr3_crc16(spd_data, crc_bytes);
+
+	if (spd_data[126] == (crc_comp & 0xff) &&
+	    spd_data[127] == (crc_comp >> 8))
+		return 1;
+
+	if (!silent) {
+		printf("DDR4 SPD CRC error, spd addr: 0x%x, calculated crc: 0x%04x, read crc: 0x%02x%02x\n",
+		       twsi_addr, crc_comp, spd_data[127], spd_data[126]);
+	}
+
+	return 0;
+}
+
+static int validate_spd_checksum(struct ddr_priv *priv,
+				 struct dimm_config *dimm_config,
+				 int dimm_index, int twsi_addr,
+				 int silent, u8 rv)
+{
+	if (ddr_verbose(priv))
+		debug("Validating DIMM at address 0x%x\n", twsi_addr);
+
+	if (rv >= 0x8 && rv <= 0xA)
+		printf("%s: Error: DDR2 support disabled\n", __func__);
+
+	if (rv == 0xB)
+		printf("%s: Error: DDR3 support disabled\n", __func__);
+
+	if (rv == 0xC) {
+		return validate_spd_checksum_ddr4(dimm_config, dimm_index,
+						  twsi_addr, silent);
+	}
+
+	if (!silent) {
+		printf("Unrecognized DIMM type: 0x%x at spd address: 0x%x\n",
+		       rv, twsi_addr);
+	}
+
+	return 0;
+}
+
+/*
+ * Read an DIMM SPD value, either using TWSI to read it from the DIMM, or
+ * from a provided array.
+ */
+int read_spd(struct dimm_config *dimm_config, int dimm_index, int spd_field)
+{
+	dimm_index = !!dimm_index;
+
+	if (spd_field >= SPD_EEPROM_SIZE) {
+		printf("ERROR: Trying to read unsupported SPD EEPROM value %d\n",
+		       spd_field);
+	}
+
+	/*
+	 * If pointer to data is provided, use it, otherwise read from SPD
+	 * over twsi
+	 */
+	if (dimm_config->spd_ptrs[dimm_index])
+		return dimm_config->spd_ptrs[dimm_index][spd_field];
+	else if (dimm_config->spd_addrs[dimm_index])
+		return dimm_config->spd_data[dimm_index][spd_field];
+
+	return -1;
+}
+
+int read_spd_init(struct dimm_config *dimm_config, int dimm_index)
+{
+	u8 busno = OCTEON_TWSI_GET_BUS(dimm_config->spd_addrs[dimm_index]);
+	u8 cmdno = dimm_config->spd_addrs[dimm_index];
+	struct udevice *dev_i2c;
+	u8 *spd_data;
+	int ret;
+
+	if (dimm_config->spd_cached[dimm_index])
+		return 0;
+
+	dimm_config->spd_cached[dimm_index] = 1;
+	spd_data = dimm_config->spd_data[dimm_index];
+
+	ret = i2c_get_chip_for_busnum(busno, cmdno, 2, &dev_i2c);
+	if (ret) {
+		debug("Cannot find SPL EEPROM: %d\n", ret);
+		return -ENODEV;
+	}
+
+	ret = dm_i2c_read(dev_i2c, 0, spd_data, SPD_EEPROM_SIZE);
+
+	return ret;
+}
+
+int validate_dimm(struct ddr_priv *priv, struct dimm_config *dimm_config,
+		  int dimm_index)
+{
+	int spd_addr;
+
+	dimm_index = !!dimm_index;  /* Normalize to 0/1 */
+	spd_addr = dimm_config->spd_addrs[dimm_index];
+
+	debug("Validating dimm %d, spd addr: 0x%02x spd ptr: %p\n",
+	      dimm_index,
+	      dimm_config->spd_addrs[dimm_index],
+	      dimm_config->spd_ptrs[dimm_index]);
+
+	/* Only validate 'real' dimms, assume compiled in values are OK */
+	if (!dimm_config->spd_ptrs[dimm_index]) {
+		int val0, val1;
+		int dimm_type;
+		int ret;
+
+		ret = read_spd_init(dimm_config, dimm_index);
+		if (ret)
+			return 0;
+
+		dimm_type = read_spd(dimm_config, dimm_index,
+				     DDR2_SPD_MEM_TYPE) & 0xff;
+		switch (dimm_type) {
+		case 0x0B:              /* DDR3 */
+			if (ddr_verbose(priv))
+				printf("Validating DDR3 DIMM %d\n", dimm_index);
+			val0 = read_spd(dimm_config, dimm_index,
+					DDR3_SPD_DENSITY_BANKS);
+			val1 = read_spd(dimm_config, dimm_index,
+					DDR3_SPD_ADDRESSING_ROW_COL_BITS);
+			if (val0 < 0 && val1 < 0) {
+				if (ddr_verbose(priv))
+					printf("Error reading SPD for DIMM %d\n",
+					       dimm_index);
+				return 0; /* Failed to read dimm */
+			}
+			if (val0 == 0xff && val1 == 0xff) {
+				if (ddr_verbose(priv))
+					printf("Blank or unreadable SPD for DIMM %d\n",
+					       dimm_index);
+				/* Blank SPD or otherwise unreadable device */
+				return 0;
+			}
+
+			/* Don't treat bad checksums as fatal */
+			validate_spd_checksum(priv, dimm_config, dimm_index,
+					      spd_addr, 0, dimm_type);
+			break;
+
+		case 0x0C:              /* DDR4 */
+			if (ddr_verbose(priv))
+				printf("Validating DDR4 DIMM %d\n", dimm_index);
+			val0 = read_spd(dimm_config, dimm_index,
+					DDR4_SPD_DENSITY_BANKS);
+			val1 = read_spd(dimm_config, dimm_index,
+					DDR4_SPD_ADDRESSING_ROW_COL_BITS);
+			if (val0 < 0 && val1 < 0) {
+				if (ddr_verbose(priv))
+					printf("Error reading SPD for DIMM %d\n",
+					       dimm_index);
+				return 0; /* Failed to read dimm */
+			}
+			if (val0 == 0xff && val1 == 0xff) {
+				if (ddr_verbose(priv)) {
+					printf("Blank or unreadable SPD for DIMM %d\n",
+					       dimm_index);
+				}
+				/* Blank SPD or otherwise unreadable device */
+				return 0;
+			}
+
+			/* Don't treat bad checksums as fatal */
+			validate_spd_checksum(priv, dimm_config, dimm_index,
+					      spd_addr, 0, dimm_type);
+			break;
+
+		case 0x00:
+			/* Terminator detected. Fail silently. */
+			return 0;
+
+		default:
+			debug("Unknown DIMM type 0x%x for DIMM %d @ 0x%x\n",
+			      dimm_type, dimm_index,
+			      dimm_config->spd_addrs[dimm_index]);
+			return 0;      /* Failed to read dimm */
+		}
+	}
+
+	return 1;
+}
+
+int get_ddr_type(struct dimm_config *dimm_config, int upper_dimm)
+{
+	int spd_ddr_type;
+
+	spd_ddr_type = read_spd(dimm_config, upper_dimm, DEVICE_TYPE);
+
+	debug("%s:%d spd_ddr_type=0x%02x\n", __func__, __LINE__,
+	      spd_ddr_type);
+
+	/* we return only DDR4 or DDR3 */
+	return (spd_ddr_type == 0x0C) ? DDR4_DRAM : DDR3_DRAM;
+}
+
+static int get_dimm_ecc(struct dimm_config *dimm_config, int upper_dimm,
+			int ddr_type)
+{
+	return !!(read_spd(dimm_config, upper_dimm, BUS_WIDTH(ddr_type)) & 8);
+}
+
+int get_dimm_module_type(struct dimm_config *dimm_config, int upper_dimm,
+			 int ddr_type)
+{
+	return read_spd(dimm_config, upper_dimm, MODULE_TYPE) & 0x0f;
+}
+
+char *printable_rank_spec(char *buffer, int num_ranks, int dram_width,
+			  int spd_package)
+{
+	int die_count = ((spd_package >> 4) & 7) + 1;
+
+	if (spd_package & 0x80) { // non-monolithic
+		if ((spd_package & 3) == 2) { // 3DS
+			sprintf(buffer, "%dS%dRx%d", num_ranks, die_count,
+				dram_width);
+		} else { // MLS
+			char hchar = (die_count == 2) ? 'D' : 'Q';
+
+			sprintf(buffer, "%d%cRx%d", num_ranks, hchar,
+				dram_width);
+		}
+	} else {
+		sprintf(buffer, "%dRx%d", num_ranks, dram_width);
+	}
+
+	return buffer;
+}
+
+static void report_common_dimm(struct dimm_config *dimm_config, int upper_dimm,
+			       int dimm, const char **dimm_types, int ddr_type,
+			       char *volt_str, int if_num,
+			       int num_ranks, int dram_width, int spd_package)
+{
+	unsigned int spd_module_type;
+	char rank_spec[8];
+	int spd_ecc;
+
+	spd_module_type = get_dimm_module_type(dimm_config, upper_dimm,
+					       ddr_type);
+	spd_ecc = get_dimm_ecc(dimm_config, upper_dimm, ddr_type);
+
+	printable_rank_spec(rank_spec, num_ranks, dram_width, spd_package);
+	printf("LMC%d.DIMM%d: DDR%d %s %s %s, %s\n",
+	       if_num, dimm, ddr_type, dimm_types[spd_module_type],
+	       rank_spec, spd_ecc ? "ECC" : "non-ECC", volt_str);
+}
+
+static void report_ddr3_dimm(struct dimm_config *dimm_config, int upper_dimm,
+			     int dimm, int if_num)
+{
+	int spd_voltage;
+	char *volt_str;
+	int spd_org = read_spd(dimm_config, upper_dimm,
+			       DDR3_SPD_MODULE_ORGANIZATION);
+	int num_ranks = 1 +  ((spd_org >> 3) & 0x7);
+	int dram_width = 4 << ((spd_org >> 0) & 0x7);
+
+	spd_voltage = read_spd(dimm_config, upper_dimm,
+			       DDR3_SPD_NOMINAL_VOLTAGE);
+	if (spd_voltage == 0 || spd_voltage & 3)
+		volt_str = "1.5V";
+	if (spd_voltage & 2)
+		volt_str = "1.35V";
+	if (spd_voltage & 4)
+		volt_str = "1.2xV";
+
+	report_common_dimm(dimm_config, upper_dimm, dimm, ddr3_dimm_types,
+			   DDR3_DRAM, volt_str, if_num,
+			   num_ranks, dram_width, /*spd_package*/0);
+}
+
+static void report_ddr4_dimm(struct dimm_config *dimm_config, int upper_dimm,
+			     int dimm, int if_num)
+{
+	int spd_voltage;
+	char *volt_str;
+	int spd_package = 0xff & read_spd(dimm_config, upper_dimm,
+					  DDR4_SPD_PACKAGE_TYPE);
+	int spd_org     = 0xff & read_spd(dimm_config, upper_dimm,
+					  DDR4_SPD_MODULE_ORGANIZATION);
+	int num_ranks   = 1 +  ((spd_org >> 3) & 0x7);
+	int dram_width  = 4 << ((spd_org >> 0) & 0x7);
+
+	spd_voltage = read_spd(dimm_config, upper_dimm,
+			       DDR4_SPD_MODULE_NOMINAL_VOLTAGE);
+	if (spd_voltage == 0x01 || spd_voltage & 0x02)
+		volt_str = "1.2V";
+	if (spd_voltage == 0x04 || spd_voltage & 0x08)
+		volt_str = "TBD1 V";
+	if (spd_voltage == 0x10 || spd_voltage & 0x20)
+		volt_str = "TBD2 V";
+
+	report_common_dimm(dimm_config, upper_dimm, dimm, ddr4_dimm_types,
+			   DDR4_DRAM, volt_str, if_num,
+			   num_ranks, dram_width, spd_package);
+}
+
+void report_dimm(struct dimm_config *dimm_config, int upper_dimm,
+		 int dimm, int if_num)
+{
+	int ddr_type;
+
+	/* ddr_type only indicates DDR4 or DDR3 */
+	ddr_type = get_ddr_type(dimm_config, upper_dimm);
+
+	if (ddr_type == DDR4_DRAM)
+		report_ddr4_dimm(dimm_config, 0, dimm, if_num);
+	else
+		report_ddr3_dimm(dimm_config, 0, dimm, if_num);
+}