Revert "mb/aopen/dxplplusu: Remove board"

This reverts commit eb76a455cd39ec59b7f2ba28baeec9538befd59e
and applies minor fixes to make it build again.

PARALLEL_MP was working prior to board removal and no
relevant SMI handlers were implemented. So NO_SMM choice
is now selected.

Change-Id: Ia1cd02278240d1b5d006fb2a7730d3d86390f85b
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69339
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

8 files changed, 1998 insertions, 0 deletions

diff --git a/src/northbridge/intel/e7505/Kconfig b/src/northbridge/intel/e7505/Kconfig
new file mode 100644
index 0000000000..4a54bc076d
--- /dev/null
+++ b/src/northbridge/intel/e7505/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config NORTHBRIDGE_INTEL_E7505
+	bool
+
+if NORTHBRIDGE_INTEL_E7505
+
+config NORTHBRIDGE_SPECIFIC_OPTIONS
+	def_bool y
+	select NO_ECAM_MMCONF_SUPPORT
+	select HAVE_DEBUG_RAM_SETUP
+	select NO_CBFS_MCACHE
+
+endif
diff --git a/src/northbridge/intel/e7505/Makefile.inc b/src/northbridge/intel/e7505/Makefile.inc
new file mode 100644
index 0000000000..29ac4379cf
--- /dev/null
+++ b/src/northbridge/intel/e7505/Makefile.inc
@@ -0,0 +1,10 @@
+ifeq ($(CONFIG_NORTHBRIDGE_INTEL_E7505),y)
+
+ramstage-y += northbridge.c
+ramstage-y += memmap.c
+
+romstage-y += romstage.c
+romstage-y += raminit.c
+romstage-y += memmap.c
+
+endif
diff --git a/src/northbridge/intel/e7505/e7505.h b/src/northbridge/intel/e7505/e7505.h
new file mode 100644
index 0000000000..b429c70ba4
--- /dev/null
+++ b/src/northbridge/intel/e7505/e7505.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/*
+ * e7505.h: PCI configuration space for the Intel E7501 memory controller
+ */
+
+#ifndef NORTHBRIDGE_INTEL_E7505_E7505_H
+#define NORTHBRIDGE_INTEL_E7505_E7505_H
+
+/************  D0:F0 ************/
+// Register offsets
+#define SMRBASE		0x14	/* System Memory RCOMP Base Address Register, 32 bit? */
+#define MCHCFGNS	0x52	/* MCH (scrubber) configuration register, 16 bit */
+
+#define PAM_0		0x59
+
+#define DRB_ROW_0	0x60	/* DRAM Row Boundary register, 8 bit */
+#define DRB_ROW_1	0x61
+#define DRB_ROW_2	0x62
+#define DRB_ROW_3	0x63
+#define DRB_ROW_4	0x64
+#define DRB_ROW_5	0x65
+#define DRB_ROW_6	0x66
+#define DRB_ROW_7	0x67
+
+#define DRA		0x70	/* DRAM Row Attributes registers, 4 x 8 bit */
+#define DRT		0x78	/* DRAM Timing register, 32 bit */
+#define DRC		0x7C	/* DRAM Controller Mode register, 32 bit */
+#define DRDCTL		0x80	/* DRAM Read Timing Control register, 16 bit? (if similar to 855PM) */
+#define CKDIS		0x8C	/* Clock disable register, 8 bit */
+#define SMRAMC		0x9D
+#define ESMRAMC		0x9E
+#define APSIZE		0xB4
+#define TOLM		0xC4	/* Top of Low Memory register, 16 bit */
+#define REMAPBASE	0xC6	/* Remap Base Address register, 16 bit */
+#define REMAPLIMIT	0xC8	/* Remap Limit Address register, 16 bit */
+#define SKPD		0xDE	/* Scratchpad register, 16 bit */
+#define DVNP		0xE0	/* Device Not Present, 16 bit */
+#define MCHTST		0xF4	/* MCH Test Register, 32 bit? (if similar to 855PM) */
+
+// CAS# Latency bits in the DRAM Timing (DRT) register
+#define DRT_CAS_2_5		(0<<4)
+#define DRT_CAS_2_0		(1<<4)
+#define DRT_CAS_MASK		(3<<4)
+
+// Mode Select (SMS) bits in the DRAM Controller Mode (DRC) register
+#define RAM_COMMAND_NOP		(1<<4)
+#define RAM_COMMAND_PRECHARGE	(2<<4)
+#define RAM_COMMAND_MRS		(3<<4)
+#define RAM_COMMAND_EMRS	(4<<4)
+#define RAM_COMMAND_CBR		(6<<4)
+#define RAM_COMMAND_NORMAL	(7<<4)
+
+#define DRC_DONE		(1 << 29)
+
+// RCOMP Memory Map offsets
+// Conjecture based on apparent similarity between E7501 and 855PM
+// Intel doc. 252613-003 describes these for 855PM
+
+#define SMRCTL		0x20	/* System Memory RCOMP Control Register? */
+#define DQCMDSTR	0x30	/* Strength control for DQ and CMD signal groups? */
+#define CKESTR		0x31	/* Strength control for CKE signal group? */
+#define CSBSTR		0x32	/* Strength control for CS# signal group? */
+#define CKSTR		0x33	/* Strength control for CK signal group? */
+#define RCVENSTR	0x34	/* Strength control for RCVEnOut# signal group? */
+
+/************  D0:F1 ************/
+// Register offsets
+#define FERR_GLOBAL	0x40	/* First global error register, 32 bits */
+#define NERR_GLOBAL	0x44	/* Next global error register, 32 bits */
+#define DRAM_FERR	0x80	/* DRAM first error register, 8 bits */
+#define DRAM_NERR	0x82	/* DRAM next error register, 8 bits */
+
+/************  D1:F0 ************/
+
+#define APSIZE1		0x74
+
+#endif /* NORTHBRIDGE_INTEL_E7505_E7505_H */
diff --git a/src/northbridge/intel/e7505/memmap.c b/src/northbridge/intel/e7505/memmap.c
new file mode 100644
index 0000000000..b1ac3d1124
--- /dev/null
+++ b/src/northbridge/intel/e7505/memmap.c
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+// Use simple device model for this file even in ramstage
+#define __SIMPLE_DEVICE__
+
+#include <device/pci_ops.h>
+#include <arch/romstage.h>
+#include <cbmem.h>
+#include <cpu/x86/mtrr.h>
+#include <program_loading.h>
+#include "e7505.h"
+
+void *cbmem_top_chipset(void)
+{
+	const pci_devfn_t mch = PCI_DEV(0, 0, 0);
+	uintptr_t tolm;
+
+	/* This is at 128 MiB boundary. */
+	tolm = pci_read_config16(mch, TOLM) >> 11;
+	tolm <<= 27;
+
+	return (void *)tolm;
+}
+
+void northbridge_write_smram(u8 smram);
+
+void northbridge_write_smram(u8 smram)
+{
+	const pci_devfn_t mch = PCI_DEV(0, 0, 0);
+	pci_write_config8(mch, SMRAMC, smram);
+}
+
+void fill_postcar_frame(struct postcar_frame *pcf)
+{
+	uintptr_t top_of_ram;
+
+	/*
+	 * Choose to NOT set ROM as WP cacheable here.
+	 * Timestamps indicate the CPU this northbridge code is
+	 * connected to, performs better for memcpy() and un-lzma
+	 * operations when source is left as UC.
+	 */
+
+	pcf->skip_common_mtrr = 1;
+
+	/* Cache RAM as WB from 0 -> CACHE_TMP_RAMTOP. */
+	postcar_frame_add_mtrr(pcf, 0, CACHE_TMP_RAMTOP, MTRR_TYPE_WRBACK);
+
+	/* Cache CBMEM region as WB. */
+	top_of_ram = (uintptr_t)cbmem_top();
+	postcar_frame_add_mtrr(pcf, top_of_ram - 8*MiB, 8*MiB,
+		MTRR_TYPE_WRBACK);
+}
diff --git a/src/northbridge/intel/e7505/northbridge.c b/src/northbridge/intel/e7505/northbridge.c
new file mode 100644
index 0000000000..08ac122243
--- /dev/null
+++ b/src/northbridge/intel/e7505/northbridge.c
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <assert.h>
+#include <console/console.h>
+#include <device/pci_ops.h>
+#include <device/device.h>
+#include <device/pci.h>
+#include <cpu/cpu.h>
+
+#include "e7505.h"
+
+static void mch_domain_read_resources(struct device *dev)
+{
+	int idx;
+	unsigned long tolmk;
+	uint64_t tom, remapbase, remaplimit;
+	struct device *mc_dev;
+
+	pci_domain_read_resources(dev);
+
+	mc_dev = pcidev_on_root(0, 0);
+	if (!mc_dev)
+		die("Could not find MCH device\n");
+
+	tolmk = pci_read_config16(mc_dev, TOLM) >> 11;
+	tolmk <<= 17;
+
+	tom = pci_read_config8(mc_dev, DRB_ROW_7);
+	tom <<= 26;
+
+	/* Remapped region with a 64 MiB granularity in register
+	   definition. Limit is inclusive, so add one. */
+	remapbase = pci_read_config16(mc_dev, REMAPBASE) & 0x3ff;
+	remapbase <<= 26;
+
+	remaplimit = pci_read_config16(mc_dev, REMAPLIMIT) & 0x3ff;
+	remaplimit += 1;
+	remaplimit <<= 26;
+
+	/* Report the memory regions */
+	idx = 10;
+	ram_resource_kb(dev, idx++, 0, tolmk);
+	mmio_resource_kb(dev, idx++, 0xa0000 / KiB, (0xc0000 - 0xa0000) / KiB);
+
+
+	ASSERT(tom == remapbase);
+	upper_ram_end(dev, idx++, remaplimit);
+}
+
+static void mch_domain_set_resources(struct device *dev)
+{
+	assign_resources(dev->link_list);
+}
+
+static struct device_operations pci_domain_ops = {
+	.read_resources   = mch_domain_read_resources,
+	.set_resources    = mch_domain_set_resources,
+	.scan_bus         = pci_domain_scan_bus,
+	.ops_pci          = &pci_dev_ops_pci,
+};
+
+
+static struct device_operations cpu_bus_ops = {
+	.read_resources   = noop_read_resources,
+	.set_resources    = noop_set_resources,
+	.init             = mp_cpu_bus_init,
+};
+
+static void enable_dev(struct device *dev)
+{
+	/* Set the operations if it is a special bus type */
+	if (dev->path.type == DEVICE_PATH_DOMAIN) {
+		dev->ops = &pci_domain_ops;
+	} else if (dev->path.type == DEVICE_PATH_CPU_CLUSTER) {
+		dev->ops = &cpu_bus_ops;
+	}
+}
+
+struct chip_operations northbridge_intel_e7505_ops = {
+	CHIP_NAME("Intel E7505 Northbridge")
+	.enable_dev = enable_dev,
+};
diff --git a/src/northbridge/intel/e7505/raminit.c b/src/northbridge/intel/e7505/raminit.c
new file mode 100644
index 0000000000..5387d4df04
--- /dev/null
+++ b/src/northbridge/intel/e7505/raminit.c
@@ -0,0 +1,1718 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/* This was originally for the e7500, modified for e7501
+ * The primary differences are that 7501 apparently can
+ * support single channel RAM (i haven't tested),
+ * CAS1.5 is no longer supported, The ECC scrubber
+ * now supports a mode to zero RAM and init ECC in one step
+ * and the undocumented registers at 0x80 require new
+ * (undocumented) values determined by guesswork and
+ * comparison w/ OEM BIOS values.
+ * Steven James 02/06/2003
+ */
+
+#include <stdint.h>
+#include <device/pci_def.h>
+#include <arch/io.h>
+#include <device/mmio.h>
+#include <device/pci_ops.h>
+#include <device/smbus_host.h>
+#include <lib.h>
+#include <commonlib/helpers.h>
+#include <console/console.h>
+#include <assert.h>
+#include <spd.h>
+#include <sdram_mode.h>
+#include <timestamp.h>
+
+#include "raminit.h"
+#include "e7505.h"
+
+/*-----------------------------------------------------------------------------
+Definitions:
+-----------------------------------------------------------------------------*/
+
+#if CONFIG(DEBUG_RAM_SETUP)
+#define RAM_DEBUG_MESSAGE(x)	printk(BIOS_DEBUG, x)
+#define RAM_DEBUG_HEX32(x)	printk(BIOS_DEBUG, "%08x", x)
+#define RAM_DEBUG_HEX8(x)	printk(BIOS_DEBUG, "%02x", x)
+#else
+#define RAM_DEBUG_MESSAGE(x)
+#define RAM_DEBUG_HEX32(x)
+#define RAM_DEBUG_HEX8(x)
+#endif
+
+#define E7501_SDRAM_MODE	(SDRAM_BURST_INTERLEAVED | SDRAM_BURST_4)
+#define SPD_ERROR		"Error reading SPD info\n"
+
+#define MCHDEV		PCI_DEV(0, 0, 0)
+#define RASDEV		PCI_DEV(0, 0, 1)
+#define AGPDEV		PCI_DEV(0, 1, 0)
+#define D060DEV		PCI_DEV(0, 6, 0)
+
+// NOTE: This used to be 0x100000.
+//       That doesn't work on systems where A20M# is asserted, because
+//       attempts to access 0x1000NN end up accessing 0x0000NN.
+#define RCOMP_MMIO ((u8 *)0x200000)
+
+struct dimm_size {
+	unsigned long side1;
+	unsigned long side2;
+};
+
+static const uint32_t refresh_frequency[] = {
+	/* Relative frequency (array value) of each E7501 Refresh Mode Select
+	 * (RMS) value (array index)
+	 * 0 == least frequent refresh (longest interval between refreshes)
+	 * [0] disabled  -> 0
+	 * [1] 15.6 usec -> 2
+	 * [2]  7.8 usec -> 3
+	 * [3] 64   usec -> 1
+	 * [4] reserved  -> 0
+	 * [5] reserved  -> 0
+	 * [6] reserved  -> 0
+	 * [7] 64 clocks -> 4
+	 */
+	0, 2, 3, 1, 0, 0, 0, 4
+};
+
+static const uint32_t refresh_rate_map[] = {
+	/* Map the JEDEC spd refresh rates (array index) to E7501 Refresh Mode
+	 * Select values (array value)
+	 * These are all the rates defined by JESD21-C Appendix D, Rev. 1.0
+	 * The E7501 supports only 15.6 us (1), 7.8 us (2), 64 us (3), and
+	 * 64 clock (481 ns) (7) refresh.
+	 * [0] ==  15.625 us -> 15.6 us
+	 * [1] ==   3.9   us -> 481  ns
+	 * [2] ==   7.8   us ->  7.8 us
+	 * [3] ==  31.3   us -> 15.6 us
+	 * [4] ==  62.5   us -> 15.6 us
+	 * [5] == 125     us -> 64   us
+	 */
+	1, 7, 2, 1, 1, 3
+};
+
+#define MAX_SPD_REFRESH_RATE (ARRAY_SIZE(refresh_rate_map) - 1)
+
+// SPD parameters that must match for dual-channel operation
+static const uint8_t dual_channel_parameters[] = {
+	SPD_MEMORY_TYPE,
+	SPD_MODULE_VOLTAGE,
+	SPD_NUM_COLUMNS,
+	SPD_NUM_ROWS,
+	SPD_NUM_DIMM_BANKS,
+	SPD_PRIMARY_SDRAM_WIDTH,
+	SPD_NUM_BANKS_PER_SDRAM
+};
+
+	/* Comments here are remains of e7501 or even 855PM.
+	 * They might be partially (in)correct for e7505.
+	 */
+
+	/* (DRAM Read Timing Control, if similar to 855PM?)
+	 * 0x80 - 0x81   documented differently for e7505
+	 * This register has something to do with CAS latencies,
+	 * possibly this is the real chipset control.
+	 * At 0x00 CAS latency 1.5 works.
+	 * At 0x06 CAS latency 2.5 works.
+	 * At 0x01 CAS latency 2.0 works.
+	 *
+	 * This is still undocumented in e7501, but with different values
+	 * CAS 2.0 values taken from Intel BIOS settings, others are a guess
+	 * and may be terribly wrong. Old values preserved as comments until I
+	 * figure this out for sure.
+	 * e7501 docs claim that CAS1.5 is unsupported, so it may or may not
+	 * work at all.
+	 * Steven James 02/06/2003
+	 *
+	 * NOTE: values now configured in configure_e7501_cas_latency() based
+	 *       on SPD info and total number of DIMMs (per Intel)
+	 */
+
+	/* FDHC - Fixed DRAM Hole Control  ???
+	 * 0x58  undocumented for e7505, memory hole in southbridge configuration?
+	 * [7:7] Hole_Enable
+	 *       0 == No memory Hole
+	 *       1 == Memory Hole from 15MB to 16MB
+	 * [6:0] Reserved
+	 */
+
+	/* Another Intel undocumented register
+	 * 0x88 - 0x8B
+	 * [31:31]      Purpose unknown
+	 * [26:26]      Master DLL Reset?
+	 *                      0 == Normal operation?
+	 *                      1 == Reset?
+	 * [07:07]      Periodic memory recalibration?
+	 *                      0 == Disabled?
+	 *                      1 == Enabled?
+	 * [04:04]      Receive FIFO RE-Sync?
+	 *                      0 == Normal operation?
+	 *                      1 == Reset?
+	 */
+
+/* DDR RECOMP tables */
+// Slew table for 2x drive?
+static const uint32_t slew_2x[] = {
+	0x00000000, 0x76543210, 0xffffeca8, 0xffffffff,
+	0x21000000, 0xa8765432, 0xffffffec, 0xffffffff,
+};
+
+// Pull Up / Pull Down offset table, if analogous to IXP2800?
+static const uint32_t pull_updown_offset_table[] = {
+	0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff,
+	0x88888888, 0x88888888, 0x88888888, 0x88888888,
+};
+
+/*-----------------------------------------------------------------------------
+Delay functions:
+-----------------------------------------------------------------------------*/
+
+/* Estimate that SLOW_DOWN_IO takes about 1 us */
+#define SLOW_DOWN_IO inb(0x80)
+static void local_udelay(int i)
+{
+	while (i--) {
+		SLOW_DOWN_IO;
+	}
+}
+
+/* delay for 200us */
+#define DO_DELAY local_udelay(200)
+#define EXTRA_DELAY DO_DELAY
+
+/*-----------------------------------------------------------------------------
+Handle (undocumented) control bits MCHTST and PCI_DEV(0,6,0)
+-----------------------------------------------------------------------------*/
+typedef enum {
+	MCHTST_CMD_0,
+	D060_ENABLE,
+	D060_DISABLE,
+	RCOMP_BAR_ENABLE,
+	RCOMP_BAR_DISABLE,
+} mchtst_cc;
+
+typedef enum {
+	D060_CMD_0,
+	D060_CMD_1,
+} d060_cc;
+
+typedef enum {
+	RCOMP_HOLD,
+	RCOMP_RELEASE,
+	RCOMP_SMR_00,
+	RCOMP_SMR_01,
+} rcomp_smr_cc;
+
+/**
+ * MCHTST - 0xF4 - 0xF7     --   Based on similarity to 855PM
+ *
+ * [31:31] Purpose unknown
+ * [30:30] Purpose unknown
+ * [29:23] Unknown - not used?
+ * [22:22] System Memory MMR Enable
+ *         0 == Disable: mem space and BAR at 0x14 are not accessible
+ *         1 == Enable: mem space and BAR at 0x14 are accessible
+ * [21:20] Purpose unknown
+ * [19:02] Unknown - not used?
+ * [01:01] D6EN (Device #6 enable)
+ *         0 == Disable
+ *         1 == Enable
+ * [00:00] Unknown - not used?
+ */
+static void mchtest_control(mchtst_cc cmd)
+{
+	uint32_t dword = pci_read_config32(MCHDEV, MCHTST);
+	switch (cmd) {
+	case MCHTST_CMD_0:
+		dword &= ~(3 << 30);
+		break;
+	case RCOMP_BAR_ENABLE:
+		dword |= (1 << 22);
+		break;
+	case RCOMP_BAR_DISABLE:
+		dword &= ~(1 << 22);
+		break;
+	case D060_ENABLE:
+		dword |= (1 << 1);
+		break;
+	case D060_DISABLE:
+		dword &= ~(1 << 1);
+		break;
+	};
+	pci_write_config32(MCHDEV, MCHTST, dword);
+}
+
+/**
+ *
+ */
+static void d060_control(d060_cc cmd)
+{
+	mchtest_control(D060_ENABLE);
+	uint32_t dword = pci_read_config32(D060DEV, 0xf0);
+	switch (cmd) {
+	case D060_CMD_0:
+		dword |= (1 << 2);
+		break;
+	case D060_CMD_1:
+		dword |= (3 << 27);
+		break;
+	}
+	pci_write_config32(D060DEV, 0xf0, dword);
+	mchtest_control(D060_DISABLE);
+}
+
+/**
+ *
+ */
+static void rcomp_smr_control(rcomp_smr_cc cmd)
+{
+	uint32_t dword = read32(RCOMP_MMIO + SMRCTL);
+	switch (cmd) {
+	case RCOMP_HOLD:
+		dword |= (1 << 9);
+		break;
+	case RCOMP_RELEASE:
+		dword &= ~((1 << 9) | (3 << 0));
+		dword |= (1 << 10) | (1 << 0);
+		break;
+	case RCOMP_SMR_00:
+		dword &= ~(1 << 8);
+		break;
+	case RCOMP_SMR_01:
+		dword |= (1 << 10) | (1 << 8);
+		break;
+	}
+	write32(RCOMP_MMIO + SMRCTL, dword);
+}
+
+/*-----------------------------------------------------------------------------
+Serial presence detect (SPD) functions:
+-----------------------------------------------------------------------------*/
+
+static void die_on_spd_error(int spd_return_value)
+{
+	if (spd_return_value < 0)
+		die("Error reading SPD info\n");
+}
+
+/**
+ * Calculate the page size for each physical bank of the DIMM:
+ *   log2(page size) = (# columns) + log2(data width)
+ *
+ * NOTE: Page size is the total number of data bits in a row.
+ *
+ * @param dimm_socket_address SMBus address of DIMM socket to interrogate.
+ * @return log2(page size) for each side of the DIMM.
+ */
+static struct dimm_size sdram_spd_get_page_size(uint16_t dimm_socket_address)
+{
+	uint16_t module_data_width;
+	int value;
+	struct dimm_size pgsz;
+
+	pgsz.side1 = 0;
+	pgsz.side2 = 0;
+
+	// Side 1
+	value = smbus_read_byte(dimm_socket_address, SPD_NUM_COLUMNS);
+	if (value < 0)
+		goto hw_err;
+	pgsz.side1 = value & 0xf;	// # columns in bank 1
+
+	/* Get the module data width and convert it to a power of two */
+	value = smbus_read_byte(dimm_socket_address, SPD_MODULE_DATA_WIDTH_MSB);
+	if (value < 0)
+		goto hw_err;
+	module_data_width = (value & 0xff) << 8;
+
+	value = smbus_read_byte(dimm_socket_address, SPD_MODULE_DATA_WIDTH_LSB);
+	if (value < 0)
+		goto hw_err;
+	module_data_width |= (value & 0xff);
+
+	pgsz.side1 += log2(module_data_width);
+
+	/* side two */
+	value = smbus_read_byte(dimm_socket_address, SPD_NUM_DIMM_BANKS);
+	if (value < 0)
+		goto hw_err;
+	if (value > 2)
+		die("Bad SPD value\n");
+	if (value == 2) {
+
+		pgsz.side2 = pgsz.side1;	// Assume symmetric banks until we know differently
+		value = smbus_read_byte(dimm_socket_address, SPD_NUM_COLUMNS);
+		if (value < 0)
+			goto hw_err;
+		if ((value & 0xf0) != 0) {
+			// Asymmetric banks
+			pgsz.side2 -= value & 0xf;	/* Subtract out columns on side 1 */
+			pgsz.side2 += (value >> 4) & 0xf;	/* Add in columns on side 2 */
+		}
+	}
+
+	return pgsz;
+
+hw_err:
+	die(SPD_ERROR);
+	return pgsz;		// Never reached
+}
+
+/**
+ * Read the width in bits of each DIMM side's DRAMs via SPD (i.e. 4, 8, 16).
+ *
+ * @param dimm_socket_address SMBus address of DIMM socket to interrogate.
+ * @return Width in bits of each DIMM side's DRAMs.
+ */
+static struct dimm_size sdram_spd_get_width(uint16_t dimm_socket_address)
+{
+	int value;
+	struct dimm_size width;
+
+	width.side1 = 0;
+	width.side2 = 0;
+
+	value = smbus_read_byte(dimm_socket_address, SPD_PRIMARY_SDRAM_WIDTH);
+	die_on_spd_error(value);
+
+	width.side1 = value & 0x7f;	// Mask off bank 2 flag
+
+	if (value & 0x80) {
+		width.side2 = width.side1 << 1;	// Bank 2 exists and is double-width
+	} else {
+		// If bank 2 exists, it's the same width as bank 1
+		value = smbus_read_byte(dimm_socket_address, SPD_NUM_DIMM_BANKS);
+		die_on_spd_error(value);
+
+		if (value == 2)
+			width.side2 = width.side1;
+	}
+
+	return width;
+}
+
+/**
+ * Calculate the log base 2 size in bits of both DIMM sides.
+ *
+ * log2(# bits) = (# columns) + log2(data width) +
+ *                (# rows) + log2(banks per SDRAM)
+ *
+ * Note that it might be easier to use SPD byte 31 here, it has the DIMM size
+ * as a multiple of 4MB. The way we do it now we can size both sides of an
+ * asymmetric DIMM.
+ *
+ * @param dimm_socket_address SMBus address of DIMM socket to interrogate.
+ * @return log2(number of bits) for each side of the DIMM.
+ */
+static struct dimm_size spd_get_dimm_size(unsigned int dimm_socket_address)
+{
+	int value;
+
+	// Start with log2(page size)
+	struct dimm_size sz = sdram_spd_get_page_size(dimm_socket_address);
+
+	if (sz.side1 > 0) {
+
+		value = smbus_read_byte(dimm_socket_address, SPD_NUM_ROWS);
+		die_on_spd_error(value);
+
+		sz.side1 += value & 0xf;
+
+		if (sz.side2 > 0) {
+
+			// Double-sided DIMM
+			if (value & 0xF0)
+				sz.side2 += value >> 4;	// Asymmetric
+			else
+				sz.side2 += value;	// Symmetric
+		}
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_NUM_BANKS_PER_SDRAM);
+		die_on_spd_error(value);
+
+		value = log2(value);
+		sz.side1 += value;
+		if (sz.side2 > 0)
+			sz.side2 += value;
+	}
+
+	return sz;
+}
+
+/**
+ * Determine whether two DIMMs have the same value for an SPD parameter.
+ *
+ * @param spd_byte_number The SPD byte number to compare in both DIMMs.
+ * @param dimm0_address SMBus address of the 1st DIMM socket to interrogate.
+ * @param dimm1_address SMBus address of the 2nd DIMM socket to interrogate.
+ * @return 1 if both DIMM sockets report the same value for the specified
+ *         SPD parameter, 0 if the values differed or an error occurred.
+ */
+static uint8_t are_spd_values_equal(uint8_t spd_byte_number,
+				    uint16_t dimm0_address,
+				    uint16_t dimm1_address)
+{
+	uint8_t bEqual = 0;
+	int dimm0_value = smbus_read_byte(dimm0_address, spd_byte_number);
+	int dimm1_value = smbus_read_byte(dimm1_address, spd_byte_number);
+
+	if ((dimm0_value >= 0) && (dimm1_value >= 0)
+	    && (dimm0_value == dimm1_value))
+		bEqual = 1;
+
+	return bEqual;
+}
+
+/**
+ * Scan for compatible DIMMs.
+ *
+ * The code in this module only supports dual-channel operation, so we test
+ * that compatible DIMMs are paired.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ * @return A bitmask indicating which of the possible sockets for each channel
+ *         was found to contain a compatible DIMM.
+ *         Bit 0 corresponds to the closest socket for channel 0
+ *         Bit 1 to the next socket for channel 0
+ *         ...
+ *         Bit MAX_DIMM_SOCKETS_PER_CHANNEL-1 to the last socket for channel 0
+ *         Bit MAX_DIMM_SOCKETS_PER_CHANNEL is the closest socket for channel 1
+ *         ...
+ *         Bit 2*MAX_DIMM_SOCKETS_PER_CHANNEL-1 is the last socket for channel 1
+ */
+static uint8_t spd_get_supported_dimms(const struct mem_controller *ctrl)
+{
+	int i;
+	uint8_t dimm_mask = 0;
+
+	// Have to increase size of dimm_mask if this assertion is violated
+	ASSERT(MAX_DIMM_SOCKETS_PER_CHANNEL <= 4);
+
+	// Find DIMMs we can support on channel 0.
+	// Then see if the corresponding channel 1 DIMM has the same parameters,
+	// since we only support dual-channel.
+
+	for (i = 0; i < MAX_DIMM_SOCKETS_PER_CHANNEL; i++) {
+
+		uint16_t channel0_dimm = ctrl->channel0[i];
+		uint16_t channel1_dimm = ctrl->channel1[i];
+		uint8_t bDualChannel = 1;
+		struct dimm_size page_size;
+		struct dimm_size sdram_width;
+		int spd_value;
+
+		if (channel0_dimm == 0)
+			continue;	// No such socket on this mainboard
+
+		if (smbus_read_byte(channel0_dimm, SPD_MEMORY_TYPE) !=
+		    SPD_MEMORY_TYPE_SDRAM_DDR)
+			continue;
+
+		if (smbus_read_byte(channel0_dimm, SPD_MODULE_VOLTAGE) !=
+		    SPD_VOLTAGE_SSTL2)
+			continue;	// Unsupported voltage
+
+		// E7501 does not support unregistered DIMMs
+		spd_value = smbus_read_byte(channel0_dimm, SPD_MODULE_ATTRIBUTES);
+		if (!(spd_value & MODULE_REGISTERED) || (spd_value < 0))
+			continue;
+
+		// Must support burst = 4 for dual-channel operation on E7501
+		// NOTE: for single-channel, burst = 8 is required
+		spd_value = smbus_read_byte(channel0_dimm,
+				  SPD_SUPPORTED_BURST_LENGTHS);
+		if (!(spd_value & SPD_BURST_LENGTH_4) || (spd_value < 0))
+			continue;
+
+		page_size = sdram_spd_get_page_size(channel0_dimm);
+		sdram_width = sdram_spd_get_width(channel0_dimm);
+
+		// Validate DIMM page size
+		// The E7501 only supports page sizes of 4, 8, 16, or 32 KB per channel
+		// NOTE: 4 KB =  32 Kb = 2^15
+		//              32 KB = 262 Kb = 2^18
+
+		if ((page_size.side1 < 15) || (page_size.side1 > 18))
+			continue;
+
+		// If DIMM is double-sided, verify side2 page size
+		if (page_size.side2 != 0) {
+			if ((page_size.side2 < 15)
+			    || (page_size.side2 > 18))
+				continue;
+		}
+		// Validate SDRAM width
+		// The E7501 only supports x4 and x8 devices
+
+		if ((sdram_width.side1 != 4) && (sdram_width.side1 != 8))
+			continue;
+
+		// If DIMM is double-sided, verify side2 width
+		if (sdram_width.side2 != 0) {
+			if ((sdram_width.side2 != 4)
+			    && (sdram_width.side2 != 8))
+				continue;
+		}
+
+		// Channel 0 DIMM looks compatible.
+		// Now see if it is paired with the proper DIMM on channel 1.
+
+		ASSERT(channel1_dimm != 0);	// No such socket on this mainboard??
+
+		// NOTE: unpopulated DIMMs cause read to fail
+		spd_value = smbus_read_byte(channel1_dimm, SPD_MODULE_ATTRIBUTES);
+		if (!(spd_value & MODULE_REGISTERED) || (spd_value < 0)) {
+
+			printk(BIOS_DEBUG, "Skipping un-matched DIMMs - only dual-channel operation supported\n");
+			continue;
+		}
+
+		spd_value = smbus_read_byte(channel1_dimm,
+				  SPD_SUPPORTED_BURST_LENGTHS);
+		if (!(spd_value & SPD_BURST_LENGTH_4) || (spd_value < 0))
+			continue;
+
+		int j;
+		for (j = 0; j < sizeof(dual_channel_parameters); ++j) {
+			if (!are_spd_values_equal
+			    (dual_channel_parameters[j], channel0_dimm,
+			     channel1_dimm)) {
+
+				bDualChannel = 0;
+				break;
+			}
+		}
+
+		if (bDualChannel) {
+			// This DIMM pair is usable
+			dimm_mask |= 1 << i;
+			dimm_mask |= 1 << (MAX_DIMM_SOCKETS_PER_CHANNEL + i);
+		} else
+			printk(BIOS_DEBUG, "Skipping un-matched DIMMs - only dual-channel operation supported\n");
+	}
+
+	return dimm_mask;
+}
+
+/*-----------------------------------------------------------------------------
+SDRAM configuration functions:
+-----------------------------------------------------------------------------*/
+
+/**
+ * Send the specified command to all DIMMs.
+ *
+ * @param command Specifies the command to be sent to the DIMMs.
+ * @param jedec_mode_bits For the MRS & EMRS commands, bits 0-12 contain the
+ *                        register value in JEDEC format.
+ */
+static void do_ram_command(uint8_t command, uint16_t jedec_mode_bits)
+{
+	uint8_t dimm_start_64M_multiple;
+	uintptr_t dimm_start_address;
+	uint32_t dram_controller_mode;
+	uint8_t i;
+
+	// Configure the RAM command
+	dram_controller_mode = pci_read_config32(MCHDEV, DRC);
+	dram_controller_mode &= 0xFFFFFF8F;
+	dram_controller_mode |= command;
+	pci_write_config32(MCHDEV, DRC, dram_controller_mode);
+
+	// RAM_COMMAND_NORMAL is an exception.
+	// It affects only the memory controller and does not need to be "sent" to the DIMMs.
+	if (command == RAM_COMMAND_NORMAL) {
+		EXTRA_DELAY;
+		return;
+	}
+
+	// NOTE: for mode select commands, some of the location address bits are part of the command
+	// Map JEDEC mode bits to E7505
+	if (command == RAM_COMMAND_MRS) {
+		// Host address lines [25:18] map to DIMM address lines [7:0]
+		// Host address lines [17:16] map to DIMM address lines [9:8]
+		// Host address lines [15:4] map to DIMM address lines [11:0]
+		dimm_start_address = (jedec_mode_bits & 0x00ff) << 18;
+		dimm_start_address |= (jedec_mode_bits & 0x0300) << 8;
+		dimm_start_address |= (jedec_mode_bits & 0x0fff) << 4;
+	} else if (command == RAM_COMMAND_EMRS) {
+		// Host address lines [15:4] map to DIMM address lines [11:0]
+		dimm_start_address = (jedec_mode_bits << 4);
+	} else {
+		ASSERT(jedec_mode_bits == 0);
+		dimm_start_address = 0;
+	}
+
+	// Send the command to all DIMMs by accessing a memory location within each
+
+	dimm_start_64M_multiple = 0;
+
+	/* FIXME: Only address the number of rows present in the system?
+	 * Seems like rows 4-7 overlap with 0-3.
+	 */
+	for (i = 0; i < (MAX_NUM_CHANNELS * MAX_DIMM_SOCKETS_PER_CHANNEL); ++i) {
+
+		uint8_t dimm_end_64M_multiple = pci_read_config8(MCHDEV, DRB_ROW_0 + i);
+
+		if (dimm_end_64M_multiple > dimm_start_64M_multiple) {
+			dimm_start_address &= 0x3ffffff;
+			dimm_start_address |= dimm_start_64M_multiple << 26;
+			read32((void *)dimm_start_address);
+			// Set the start of the next DIMM
+			dimm_start_64M_multiple = dimm_end_64M_multiple;
+		}
+	}
+	EXTRA_DELAY;
+}
+
+/**
+ * Set the mode register of all DIMMs.
+ *
+ * The proper CAS# latency setting is added to the mode bits specified
+ * by the caller.
+ *
+ * @param jedec_mode_bits For the MRS & EMRS commands, bits 0-12 contain the
+ *                        register value in JEDEC format.
+ */
+static void set_ram_mode(uint16_t jedec_mode_bits)
+{
+	ASSERT(!(jedec_mode_bits & SDRAM_CAS_MASK));
+
+	uint32_t dram_cas_latency =
+	    pci_read_config32(MCHDEV, DRT) & DRT_CAS_MASK;
+
+	switch (dram_cas_latency) {
+	case DRT_CAS_2_5:
+		jedec_mode_bits |= SDRAM_CAS_2_5;
+		break;
+
+	case DRT_CAS_2_0:
+		jedec_mode_bits |= SDRAM_CAS_2_0;
+		break;
+
+	default:
+		BUG();
+		break;
+	}
+
+	do_ram_command(RAM_COMMAND_MRS, jedec_mode_bits);
+}
+
+/*-----------------------------------------------------------------------------
+DIMM-independent configuration functions:
+-----------------------------------------------------------------------------*/
+
+/**
+ * Configure the E7501's DRAM Row Boundary (DRB) registers for the memory
+ * present in the specified DIMM.
+ *
+ * @param dimm_log2_num_bits Specifies log2(number of bits) for each side of
+ *                           the DIMM.
+ * @param total_dram_64M_multiple Total DRAM in the system (as a multiple of
+ *                                64 MB) for DIMMs < dimm_index.
+ * @param dimm_index Which DIMM pair is being processed
+ *                   (0..MAX_DIMM_SOCKETS_PER_CHANNEL).
+ * @return New multiple of 64 MB total DRAM in the system.
+ */
+static uint8_t configure_dimm_row_boundaries(struct dimm_size dimm_log2_num_bits, uint8_t total_dram_64M_multiple, unsigned int dimm_index)
+{
+	int i;
+
+	ASSERT(dimm_index < MAX_DIMM_SOCKETS_PER_CHANNEL);
+
+	// DIMM sides must be at least 32 MB
+	ASSERT(dimm_log2_num_bits.side1 >= 28);
+	ASSERT((dimm_log2_num_bits.side2 == 0)
+	       || (dimm_log2_num_bits.side2 >= 28));
+
+	// In dual-channel mode, we are called only once for each pair of DIMMs.
+	// Each time we process twice the capacity of a single DIMM.
+
+	// Convert single DIMM capacity to paired DIMM capacity
+	// (multiply by two ==> add 1 to log2)
+	dimm_log2_num_bits.side1++;
+	if (dimm_log2_num_bits.side2 > 0)
+		dimm_log2_num_bits.side2++;
+
+	// Add the capacity of side 1 this DIMM pair (as a multiple of 64 MB)
+	// to the total capacity of the system
+	// NOTE: 64 MB == 512 Mb, and log2(512 Mb) == 29
+
+	total_dram_64M_multiple += (1 << (dimm_log2_num_bits.side1 - 29));
+
+	// Configure the boundary address for the row on side 1
+	pci_write_config8(MCHDEV, DRB_ROW_0 + (dimm_index << 1),
+			  total_dram_64M_multiple);
+
+	// If the DIMMs are double-sided, add the capacity of side 2 this DIMM pair
+	// (as a multiple of 64 MB) to the total capacity of the system
+	if (dimm_log2_num_bits.side2 >= 29)
+		total_dram_64M_multiple +=
+		    (1 << (dimm_log2_num_bits.side2 - 29));
+
+	// Configure the boundary address for the row (if any) on side 2
+	pci_write_config8(MCHDEV, DRB_ROW_1 + (dimm_index << 1),
+			  total_dram_64M_multiple);
+
+	// Update boundaries for rows subsequent to these.
+	// These settings will be overridden by a subsequent call if a populated physical slot exists
+
+	for (i = dimm_index + 1; i < MAX_DIMM_SOCKETS_PER_CHANNEL; i++) {
+		pci_write_config8(MCHDEV, DRB_ROW_0 + (i << 1),
+				  total_dram_64M_multiple);
+		pci_write_config8(MCHDEV, DRB_ROW_1 + (i << 1),
+				  total_dram_64M_multiple);
+	}
+
+	return total_dram_64M_multiple;
+}
+
+/**
+ * Set the E7501's DRAM row boundary addresses & its Top Of Low Memory (TOLM).
+ *
+ * If necessary, set up a remap window so we don't waste DRAM that ordinarily
+ * would lie behind addresses reserved for memory-mapped I/O.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ * @param dimm_mask Bitmask of populated DIMMs, see spd_get_supported_dimms().
+ */
+static void configure_e7501_ram_addresses(const struct mem_controller
+					  *ctrl, uint8_t dimm_mask)
+{
+	int i;
+	uint8_t total_dram_64M_multiple = 0;
+	uint64_t tolm, tom;
+	uint16_t reg;
+
+	/* FIXME: Is there standard presence detect bit somewhere. */
+	const int agp_slot_disabled = 1;
+
+	/* Start with disabled remap range. */
+	uint16_t remapbase_r = 0x3ff;
+	uint16_t remaplimit_r = 0;
+
+	// Configure the E7501's DRAM row boundaries
+	// Start by zeroing out the temporary initial configuration
+	pci_write_config32(MCHDEV, DRB_ROW_0, 0);
+	pci_write_config32(MCHDEV, DRB_ROW_4, 0);
+
+	for (i = 0; i < MAX_DIMM_SOCKETS_PER_CHANNEL; i++) {
+
+		uint16_t dimm_socket_address = ctrl->channel0[i];
+		struct dimm_size sz;
+
+		if (!(dimm_mask & (1 << i)))
+			continue;	// This DIMM not present
+
+		sz = spd_get_dimm_size(dimm_socket_address);
+
+		RAM_DEBUG_MESSAGE("dimm size =");
+		RAM_DEBUG_HEX32((u32)sz.side1);
+		RAM_DEBUG_MESSAGE(" ");
+		RAM_DEBUG_HEX32((u32)sz.side2);
+		RAM_DEBUG_MESSAGE("\n");
+
+		if (sz.side1 == 0)
+			die("Bad SPD value\n");
+
+		total_dram_64M_multiple =
+		    configure_dimm_row_boundaries(sz, total_dram_64M_multiple, i);
+	}
+
+	tom = total_dram_64M_multiple * 64ULL * MiB;
+
+	/* Reserve MMIO space. */
+	tolm = 4ULL * GiB - 512 * MiB;
+	if (agp_slot_disabled) {
+		/* Reduce apertures to 2 x 4 MiB. */
+		pci_write_config8(MCHDEV, APSIZE, 0x3F);
+		pci_write_config16(AGPDEV, APSIZE1, 0x3F);
+	} else {
+		/* Add MMIO reserve for 2 x 256 MiB apertures. */
+		tolm -= 512 * MiB;
+	}
+	tolm = MIN(tolm, tom);
+
+	/* The PCI memory hole overlaps memory setup the remap window. */
+	if (tolm < tom) {
+		uint64_t remapbase = MAX(tom, 4ULL * GiB);
+		uint64_t remaplimit = remapbase + (4ULL * GiB - tolm);
+
+		remapbase_r = remapbase / (64 * MiB);
+		remaplimit_r = remaplimit / (64 * MiB);
+
+		/* Limit register is inclusive. */
+		remaplimit_r -= 1;
+	}
+
+	/* Write the RAM configuration registers,
+	   preserving the reserved bits. */
+	reg = pci_read_config16(MCHDEV, TOLM) & 0x7ff;
+	reg |= (tolm / (128 * MiB)) << 11;
+	pci_write_config16(MCHDEV, TOLM, reg);
+
+	reg = pci_read_config16(MCHDEV, REMAPBASE) & 0xfc00;
+	reg |= remapbase_r;
+	pci_write_config16(MCHDEV, REMAPBASE, reg);
+
+	reg = pci_read_config16(MCHDEV, REMAPLIMIT) & 0xfc00;
+	reg |= remaplimit_r;
+	pci_write_config16(MCHDEV, REMAPLIMIT, reg);
+}
+
+/**
+ * Program the DRAM Timing register (DRT) of the E7501 (except for CAS#
+ * latency, which is assumed to have been programmed already), based on the
+ * parameters of the various installed DIMMs.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ * @param dimm_mask Bitmask of populated DIMMs, see spd_get_supported_dimms().
+ */
+static void configure_e7501_dram_timing(const struct mem_controller *ctrl,
+					uint8_t dimm_mask)
+{
+	int i;
+	uint32_t dram_timing;
+	int value;
+	uint8_t slowest_row_precharge = 0;
+	uint8_t slowest_ras_cas_delay = 0;
+	uint8_t slowest_active_to_precharge_delay = 0;
+	uint32_t current_cas_latency =
+	    pci_read_config32(MCHDEV, DRT) & DRT_CAS_MASK;
+
+	// CAS# latency must be programmed beforehand
+	ASSERT((current_cas_latency == DRT_CAS_2_0)
+	       || (current_cas_latency == DRT_CAS_2_5));
+
+	// Each timing parameter is determined by the slowest DIMM
+
+	for (i = 0; i < MAX_DIMM_SOCKETS; i++) {
+		uint16_t dimm_socket_address;
+
+		if (!(dimm_mask & (1 << i)))
+			continue;	// This DIMM not present
+
+		if (i < MAX_DIMM_SOCKETS_PER_CHANNEL)
+			dimm_socket_address = ctrl->channel0[i];
+		else
+			dimm_socket_address =
+			    ctrl->channel1[i - MAX_DIMM_SOCKETS_PER_CHANNEL];
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_MIN_ROW_PRECHARGE_TIME);
+		if (value < 0)
+			goto hw_err;
+		if (value > slowest_row_precharge)
+			slowest_row_precharge = value;
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_MIN_RAS_TO_CAS_DELAY);
+		if (value < 0)
+			goto hw_err;
+		if (value > slowest_ras_cas_delay)
+			slowest_ras_cas_delay = value;
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_MIN_ACTIVE_TO_PRECHARGE_DELAY);
+		if (value < 0)
+			goto hw_err;
+		if (value > slowest_active_to_precharge_delay)
+			slowest_active_to_precharge_delay = value;
+	}
+
+	// NOTE for timing parameters:
+	//              At 133 MHz, 1 clock == 7.52 ns
+
+	/* Read the initial state */
+	dram_timing = pci_read_config32(MCHDEV, DRT);
+
+	/* Trp */
+
+	// E7501 supports only 2 or 3 clocks for tRP
+	if (slowest_row_precharge > ((22 << 2) | (2 << 0)))
+		die("unsupported DIMM tRP");	// > 22.5 ns: 4 or more clocks
+	else if (slowest_row_precharge > (15 << 2))
+		dram_timing &= ~(1 << 0);	// > 15.0 ns: 3 clocks
+	else
+		dram_timing |= (1 << 0);	// <= 15.0 ns: 2 clocks
+
+	/*  Trcd */
+
+	// E7501 supports only 2 or 3 clocks for tRCD
+	// Use the same value for both read & write
+	dram_timing &= ~((1 << 3) | (3 << 1));
+	if (slowest_ras_cas_delay > ((22 << 2) | (2 << 0)))
+		die("unsupported DIMM tRCD");	// > 22.5 ns: 4 or more clocks
+	else if (slowest_ras_cas_delay > (15 << 2))
+		dram_timing |= (2 << 1);	// > 15.0 ns: 3 clocks
+	else
+		dram_timing |= ((1 << 3) | (3 << 1));	// <= 15.0 ns: 2 clocks
+
+	/* Tras */
+
+	// E7501 supports only 5, 6, or 7 clocks for tRAS
+	// 5 clocks ~= 37.6 ns, 6 clocks ~= 45.1 ns, 7 clocks ~= 52.6 ns
+	dram_timing &= ~(3 << 9);
+
+	if (slowest_active_to_precharge_delay > 52)
+		die("unsupported DIMM tRAS");	// > 52 ns:      8 or more clocks
+	else if (slowest_active_to_precharge_delay > 45)
+		dram_timing |= (0 << 9);	// 46-52 ns: 7 clocks
+	else if (slowest_active_to_precharge_delay > 37)
+		dram_timing |= (1 << 9);	// 38-45 ns: 6 clocks
+	else
+		dram_timing |= (2 << 9);	// < 38 ns:      5 clocks
+
+	/* Trd */
+
+	/* Set to a 7 clock read delay. This is for 133MHz
+	 *  with a CAS latency of 2.5  if 2.0 a 6 clock
+	 *  delay is good  */
+
+	dram_timing &= ~(7 << 24);	// 7 clocks
+	if (current_cas_latency == DRT_CAS_2_0)
+		dram_timing |= (1 << 24);	// 6 clocks
+
+	/*
+	 * Back to Back Read-Write Turn Around
+	 */
+	/* Set to a 5 clock back to back read to write turn around.
+	 *  4 is a good delay if the CAS latency is 2.0 */
+
+	dram_timing &= ~(1 << 28);	// 5 clocks
+	if (current_cas_latency == DRT_CAS_2_0)
+		dram_timing |= (1 << 28);	// 4 clocks
+
+	pci_write_config32(MCHDEV, DRT, dram_timing);
+
+	return;
+
+hw_err:
+	die(SPD_ERROR);
+}
+
+/**
+ * Determine the shortest CAS# latency that the E7501 and all DIMMs have in
+ * common, and program the E7501 to use it.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ * @param dimm_mask Bitmask of populated DIMMs, spd_get_supported_dimms().
+ */
+static void configure_e7501_cas_latency(const struct mem_controller *ctrl,
+					uint8_t dimm_mask)
+{
+	int i;
+	int value;
+	uint32_t dram_timing;
+	uint16_t dram_read_timing;
+	uint32_t dword;
+
+	// CAS# latency bitmasks in SPD_ACCEPTABLE_CAS_LATENCIES format
+	// NOTE: E7501 supports only 2.0 and 2.5
+	uint32_t system_compatible_cas_latencies =
+	    SPD_CAS_LATENCY_2_0 | SPD_CAS_LATENCY_2_5;
+	uint32_t current_cas_latency;
+	uint32_t dimm_compatible_cas_latencies;
+
+	for (i = 0; i < MAX_DIMM_SOCKETS; i++) {
+
+		uint16_t dimm_socket_address;
+
+		if (!(dimm_mask & (1 << i)))
+			continue;	// This DIMM not usable
+
+		if (i < MAX_DIMM_SOCKETS_PER_CHANNEL)
+			dimm_socket_address = ctrl->channel0[i];
+		else
+			dimm_socket_address =
+			    ctrl->channel1[i - MAX_DIMM_SOCKETS_PER_CHANNEL];
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_ACCEPTABLE_CAS_LATENCIES);
+		if (value < 0)
+			goto hw_err;
+
+		dimm_compatible_cas_latencies = value & 0x7f;	// Start with all supported by DIMM
+		current_cas_latency = 1 << log2(dimm_compatible_cas_latencies);	// Max supported by DIMM
+
+		// Can we support the highest CAS# latency?
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_MIN_CYCLE_TIME_AT_CAS_MAX);
+		if (value < 0)
+			goto hw_err;
+
+		// NOTE: At 133 MHz, 1 clock == 7.52 ns
+		if (value > 0x75) {
+			// Our bus is too fast for this CAS# latency
+			// Remove it from the bitmask of those supported by the DIMM that are compatible
+			dimm_compatible_cas_latencies &= ~current_cas_latency;
+		}
+		// Can we support the next-highest CAS# latency (max - 0.5)?
+
+		current_cas_latency >>= 1;
+		if (current_cas_latency != 0) {
+			value = smbus_read_byte(dimm_socket_address,
+					  SPD_SDRAM_CYCLE_TIME_2ND);
+			if (value < 0)
+				goto hw_err;
+			if (value > 0x75)
+				dimm_compatible_cas_latencies &=
+				    ~current_cas_latency;
+		}
+		// Can we support the next-highest CAS# latency (max - 1.0)?
+		current_cas_latency >>= 1;
+		if (current_cas_latency != 0) {
+			value = smbus_read_byte(dimm_socket_address,
+					  SPD_SDRAM_CYCLE_TIME_3RD);
+			if (value < 0)
+				goto hw_err;
+			if (value > 0x75)
+				dimm_compatible_cas_latencies &=
+				    ~current_cas_latency;
+		}
+		// Restrict the system to CAS# latencies compatible with this DIMM
+		system_compatible_cas_latencies &=
+		    dimm_compatible_cas_latencies;
+
+		/* go to the next DIMM */
+	}
+
+	/* After all of the arduous calculation setup with the fastest
+	 * cas latency I can use.
+	 */
+
+	dram_timing = pci_read_config32(MCHDEV, DRT);
+	dram_timing &= ~(DRT_CAS_MASK);
+
+	dram_read_timing =
+	    pci_read_config16(MCHDEV, DRDCTL);
+	dram_read_timing &= 0xF000;
+
+	if (system_compatible_cas_latencies & SPD_CAS_LATENCY_2_0) {
+		dram_timing |= DRT_CAS_2_0;
+		dram_read_timing |= 0x0222;
+	} else if (system_compatible_cas_latencies & SPD_CAS_LATENCY_2_5) {
+
+		uint32_t dram_row_attributes =
+		    pci_read_config32(MCHDEV, DRA);
+
+		dram_timing |= DRT_CAS_2_5;
+
+		// At CAS# 2.5, DRAM Read Timing (if that's what it its) appears to need a slightly
+		// different value if all DIMM slots are populated
+
+		if ((dram_row_attributes & 0xff)
+		    && (dram_row_attributes & 0xff00)
+		    && (dram_row_attributes & 0xff0000)
+		    && (dram_row_attributes & 0xff000000)) {
+
+			// All slots populated
+			dram_read_timing |= 0x0882;
+		} else {
+			// Some unpopulated slots
+			dram_read_timing |= 0x0662;
+		}
+	} else
+		die("No CAS# latencies compatible with all DIMMs!!\n");
+
+	pci_write_config32(MCHDEV, DRT, dram_timing);
+
+	/* set master DLL reset */
+	dword = pci_read_config32(MCHDEV, 0x88);
+	dword |= (1 << 26);
+	pci_write_config32(MCHDEV, 0x88, dword);
+	/* patch try register 88 is undocumented tnz */
+	dword &= 0x0ca17fff;
+	dword |= 0xd14a5000;
+	pci_write_config32(MCHDEV, 0x88, dword);
+
+	pci_write_config16(MCHDEV, DRDCTL,
+			   dram_read_timing);
+
+	/* clear master DLL reset */
+	dword = pci_read_config32(MCHDEV, 0x88);
+	dword &= ~(1 << 26);
+	pci_write_config32(MCHDEV, 0x88, dword);
+
+	return;
+
+hw_err:
+	die(SPD_ERROR);
+}
+
+/**
+ * Configure the refresh interval so that we refresh no more often than
+ * required by the "most needy" DIMM. Also disable ECC if any of the DIMMs
+ * don't support it.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ * @param dimm_mask Bitmask of populated DIMMs, spd_get_supported_dimms().
+ */
+static void configure_e7501_dram_controller_mode(const struct mem_controller *ctrl,
+						 uint8_t dimm_mask)
+{
+	int i;
+
+	// Initial settings
+	uint32_t controller_mode = pci_read_config32(MCHDEV, DRC);
+	uint32_t system_refresh_mode = (controller_mode >> 8) & 7;
+
+	// Code below assumes that most aggressive settings are in
+	// force when we are called, either via E7501 reset defaults
+	// or by sdram_set_registers():
+	//      - ECC enabled
+	//      - No refresh
+
+	ASSERT((controller_mode & (3 << 20)) == (2 << 20));	// ECC
+	ASSERT(!(controller_mode & (7 << 8)));	// Refresh
+
+	/* Walk through _all_ dimms and find the least-common denominator for:
+	 *  - ECC support
+	 *  - refresh rates
+	 */
+
+	for (i = 0; i < MAX_DIMM_SOCKETS; i++) {
+
+		uint32_t dimm_refresh_mode;
+		int value;
+		uint16_t dimm_socket_address;
+
+		if (!(dimm_mask & (1 << i))) {
+			continue;	// This DIMM not usable
+		}
+
+		if (i < MAX_DIMM_SOCKETS_PER_CHANNEL)
+			dimm_socket_address = ctrl->channel0[i];
+		else
+			dimm_socket_address =
+			    ctrl->channel1[i -
+					   MAX_DIMM_SOCKETS_PER_CHANNEL];
+
+		// Disable ECC mode if any one of the DIMMs does not support ECC
+		// SJM: Should we just die here? E7501 datasheet says non-ECC DIMMs aren't supported.
+
+		value = smbus_read_byte(dimm_socket_address,
+				  SPD_DIMM_CONFIG_TYPE);
+		die_on_spd_error(value);
+		if (value != ERROR_SCHEME_ECC) {
+			controller_mode &= ~(3 << 20);
+		}
+
+		value = smbus_read_byte(dimm_socket_address, SPD_REFRESH);
+		die_on_spd_error(value);
+		value &= 0x7f;	// Mask off self-refresh bit
+		if (value > MAX_SPD_REFRESH_RATE) {
+			printk(BIOS_ERR, "unsupported refresh rate\n");
+			continue;
+		}
+		// Get the appropriate E7501 refresh mode for this DIMM
+		dimm_refresh_mode = refresh_rate_map[value];
+		if (dimm_refresh_mode > 7) {
+			printk(BIOS_ERR, "unsupported refresh rate\n");
+			continue;
+		}
+		// If this DIMM requires more frequent refresh than others,
+		// update the system setting
+		if (refresh_frequency[dimm_refresh_mode] >
+		    refresh_frequency[system_refresh_mode])
+			system_refresh_mode = dimm_refresh_mode;
+
+		/* go to the next DIMM */
+	}
+
+	controller_mode |= (system_refresh_mode << 8);
+
+	// Configure the E7501
+	pci_write_config32(MCHDEV, DRC, controller_mode);
+}
+
+/**
+ * Configure the E7501's DRAM Row Attributes (DRA) registers based on DIMM
+ * parameters read via SPD. This tells the controller the width of the SDRAM
+ * chips on each DIMM side (x4 or x8) and the page size of each DIMM side
+ * (4, 8, 16, or 32 KB).
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ * @param dimm_mask Bitmask of populated DIMMs, spd_get_supported_dimms().
+ */
+static void configure_e7501_row_attributes(const struct mem_controller
+					   *ctrl, uint8_t dimm_mask)
+{
+	int i;
+	uint32_t row_attributes = 0;
+
+	for (i = 0; i < MAX_DIMM_SOCKETS_PER_CHANNEL; i++) {
+
+		uint16_t dimm_socket_address = ctrl->channel0[i];
+		struct dimm_size page_size;
+		struct dimm_size sdram_width;
+
+		if (!(dimm_mask & (1 << i)))
+			continue;	// This DIMM not usable
+
+		// Get the relevant parameters via SPD
+		page_size = sdram_spd_get_page_size(dimm_socket_address);
+		sdram_width = sdram_spd_get_width(dimm_socket_address);
+
+		// Update the DRAM Row Attributes.
+		// Page size is encoded as log2(page size in bits) - log2(8 Kb)
+		// NOTE: 8 Kb = 2^13
+		row_attributes |= (page_size.side1 - 13) << (i << 3);	// Side 1 of each DIMM is an EVEN row
+
+		if (sdram_width.side2 > 0)
+			row_attributes |= (page_size.side2 - 13) << ((i << 3) + 4);	// Side 2 is ODD
+
+		// Set x4 flags if appropriate
+		if (sdram_width.side1 == 4) {
+			row_attributes |= 0x08 << (i << 3);
+		}
+
+		if (sdram_width.side2 == 4) {
+			row_attributes |= 0x08 << ((i << 3) + 4);
+		}
+
+		/* go to the next DIMM */
+	}
+
+	/* Write the new row attributes register */
+	pci_write_config32(MCHDEV, DRA, row_attributes);
+}
+
+/*
+ * Enable clock signals for populated DIMM sockets and disable them for
+ * unpopulated sockets (to reduce EMI).
+ *
+ * @param dimm_mask Bitmask of populated DIMMs, see spd_get_supported_dimms().
+ */
+static void enable_e7501_clocks(uint8_t dimm_mask)
+{
+	int i;
+	uint8_t clock_disable = pci_read_config8(MCHDEV, CKDIS);
+
+	pci_write_config8(MCHDEV, 0x8e, 0xb0);
+
+	for (i = 0; i < MAX_DIMM_SOCKETS_PER_CHANNEL; i++) {
+
+		uint8_t socket_mask = 1 << i;
+
+		if (dimm_mask & socket_mask)
+			clock_disable &= ~socket_mask;	// DIMM present, enable clock
+		else
+			clock_disable |= socket_mask;	// DIMM absent, disable clock
+	}
+
+	pci_write_config8(MCHDEV, CKDIS, clock_disable);
+}
+
+/* DIMM-dependent configuration functions */
+
+/**
+ * DDR Receive FIFO RE-Sync (?)
+ */
+static void RAM_RESET_DDR_PTR(void)
+{
+	uint8_t byte;
+	byte = pci_read_config8(MCHDEV, 0x88);
+	byte |= (1 << 4);
+	pci_write_config8(MCHDEV, 0x88, byte);
+
+	byte = pci_read_config8(MCHDEV, 0x88);
+	byte &= ~(1 << 4);
+	pci_write_config8(MCHDEV, 0x88, byte);
+}
+
+/**
+ * Copy 64 bytes from one location to another.
+ *
+ * @param src_addr TODO
+ * @param dst_addr TODO
+ */
+static void write_8dwords(const uint32_t *src_addr, u8 *dst_addr)
+{
+	int i;
+	for (i = 0; i < 8; i++) {
+		write32(dst_addr, *src_addr);
+		src_addr++;
+		dst_addr += sizeof(uint32_t);
+	}
+}
+
+/**
+ * Set the E7501's (undocumented) RCOMP registers.
+ *
+ * Per the 855PM datasheet and IXP2800 HW Initialization Reference Manual,
+ * RCOMP registers appear to affect drive strength, pullup/pulldown offset,
+ * and slew rate of various signal groups.
+ *
+ * Comments below are conjecture based on apparent similarity between the
+ * E7501 and these two chips.
+ */
+static void rcomp_copy_registers(void)
+{
+	uint32_t dword;
+	uint8_t strength_control;
+
+	RAM_DEBUG_MESSAGE("Setting RCOMP registers.\n");
+
+	/* Begin to write the RCOMP registers */
+	write8(RCOMP_MMIO + 0x2c, 0x0);
+
+	// Set CMD and DQ/DQS strength to 2x (?)
+	strength_control = read8(RCOMP_MMIO + DQCMDSTR) & 0x88;
+	strength_control |= 0x40;
+	write8(RCOMP_MMIO + DQCMDSTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0x80);
+	write16(RCOMP_MMIO + 0x42, 0);
+
+	// Set CMD and DQ/DQS strength to 2x (?)
+	strength_control = read8(RCOMP_MMIO + DQCMDSTR) & 0xF8;
+	strength_control |= 0x04;
+	write8(RCOMP_MMIO + DQCMDSTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0x60);
+	write16(RCOMP_MMIO + 0x40, 0);
+
+	// Set RCVEnOut# strength to 2x (?)
+	strength_control = read8(RCOMP_MMIO + RCVENSTR) & 0xF8;
+	strength_control |= 0x04;
+	write8(RCOMP_MMIO + RCVENSTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0x1c0);
+	write16(RCOMP_MMIO + 0x50, 0);
+
+	// Set CS# strength for x4 SDRAM to 2x (?)
+	strength_control = read8(RCOMP_MMIO + CSBSTR) & 0x88;
+	strength_control |= 0x04;
+	write8(RCOMP_MMIO + CSBSTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0x140);
+	write16(RCOMP_MMIO + 0x48, 0);
+
+	// Set CS# strength for x4 SDRAM to 2x (?)
+	strength_control = read8(RCOMP_MMIO + CSBSTR) & 0x8F;
+	strength_control |= 0x40;
+	write8(RCOMP_MMIO + CSBSTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0x160);
+	write16(RCOMP_MMIO + 0x4a, 0);
+
+	// Set CKE strength for x4 SDRAM to 2x (?)
+	strength_control = read8(RCOMP_MMIO + CKESTR) & 0x88;
+	strength_control |= 0x04;
+	write8(RCOMP_MMIO + CKESTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0xa0);
+	write16(RCOMP_MMIO + 0x44, 0);
+
+	// Set CKE strength for x4 SDRAM to 2x (?)
+	strength_control = read8(RCOMP_MMIO + CKESTR) & 0x8F;
+	strength_control |= 0x40;
+	write8(RCOMP_MMIO + CKESTR, strength_control);
+	write_8dwords(slew_2x, RCOMP_MMIO + 0xc0);
+	write16(RCOMP_MMIO + 0x46, 0);
+
+	// Set CK strength for x4 SDRAM to 1x (?)
+	strength_control = read8(RCOMP_MMIO + CKSTR) & 0x88;
+	strength_control |= 0x01;
+	write8(RCOMP_MMIO + CKSTR, strength_control);
+	write_8dwords(pull_updown_offset_table, RCOMP_MMIO + 0x180);
+	write16(RCOMP_MMIO + 0x4c, 0);
+
+	// Set CK strength for x4 SDRAM to 1x (?)
+	strength_control = read8(RCOMP_MMIO + CKSTR) & 0x8F;
+	strength_control |= 0x10;
+	write8(RCOMP_MMIO + CKSTR, strength_control);
+	write_8dwords(pull_updown_offset_table, RCOMP_MMIO + 0x1a0);
+	write16(RCOMP_MMIO + 0x4e, 0);
+
+	dword = read32(RCOMP_MMIO + 0x400);
+	dword &= 0x7f7fffff;
+	write32(RCOMP_MMIO + 0x400, dword);
+
+	dword = read32(RCOMP_MMIO + 0x408);
+	dword &= 0x7f7fffff;
+	write32(RCOMP_MMIO + 0x408, dword);
+}
+
+static void ram_set_rcomp_regs(void)
+{
+	/* Set the RCOMP MMIO base address */
+	mchtest_control(RCOMP_BAR_ENABLE);
+	pci_write_config32(MCHDEV, SMRBASE, (uintptr_t)RCOMP_MMIO);
+
+	/* Block RCOMP updates while we configure the registers */
+	rcomp_smr_control(RCOMP_HOLD);
+	rcomp_copy_registers();
+	d060_control(D060_CMD_0);
+	mchtest_control(MCHTST_CMD_0);
+
+	uint8_t revision = pci_read_config8(MCHDEV, 0x08);
+	if (revision >= 3) {
+		rcomp_smr_control(RCOMP_SMR_00);
+		rcomp_smr_control(RCOMP_SMR_01);
+	}
+	rcomp_smr_control(RCOMP_RELEASE);
+
+	/* Wait 40 usec */
+	SLOW_DOWN_IO;
+
+	/* Clear the RCOMP MMIO base address */
+	pci_write_config32(MCHDEV, SMRBASE, 0);
+	mchtest_control(RCOMP_BAR_DISABLE);
+}
+
+/*-----------------------------------------------------------------------------
+Public interface:
+-----------------------------------------------------------------------------*/
+
+/**
+ * Go through the JEDEC initialization sequence for all DIMMs, then enable
+ * refresh and initialize ECC and memory to zero. Upon exit, SDRAM is up
+ * and running.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ */
+static void sdram_enable(const struct mem_controller *ctrl)
+{
+	uint8_t dimm_mask = pci_read_config16(MCHDEV, SKPD);
+	uint32_t dram_controller_mode;
+
+	if (dimm_mask == 0)
+		return;
+
+	/* 1 & 2 Power up and start clocks */
+	RAM_DEBUG_MESSAGE("Ram Enable 1\n");
+	RAM_DEBUG_MESSAGE("Ram Enable 2\n");
+
+	/* A 200us delay is needed */
+	DO_DELAY; EXTRA_DELAY;
+
+	/* 3. Apply NOP */
+	RAM_DEBUG_MESSAGE("Ram Enable 3\n");
+	do_ram_command(RAM_COMMAND_NOP, 0);
+
+	/* 4 Precharge all */
+	RAM_DEBUG_MESSAGE("Ram Enable 4\n");
+	do_ram_command(RAM_COMMAND_PRECHARGE, 0);
+	/* wait until the all banks idle state... */
+
+	/* 5. Issue EMRS to enable DLL */
+	RAM_DEBUG_MESSAGE("Ram Enable 5\n");
+	do_ram_command(RAM_COMMAND_EMRS,
+		       SDRAM_EXTMODE_DLL_ENABLE |
+		       SDRAM_EXTMODE_DRIVE_NORMAL);
+
+	/* 6. Reset DLL */
+	RAM_DEBUG_MESSAGE("Ram Enable 6\n");
+	set_ram_mode(E7501_SDRAM_MODE | SDRAM_MODE_DLL_RESET);
+	EXTRA_DELAY;
+	/* Ensure a 200us delay between the DLL reset in step 6 and the final
+	 * mode register set in step 9.
+	 * Infineon needs this before any other command is sent to the ram.
+	 */
+	DO_DELAY; EXTRA_DELAY;
+
+	/* 7 Precharge all */
+	RAM_DEBUG_MESSAGE("Ram Enable 7\n");
+	do_ram_command(RAM_COMMAND_PRECHARGE, 0);
+
+	/* 8 Now we need 2 AUTO REFRESH / CBR cycles to be performed */
+	/* And for good luck 6 more CBRs */
+	RAM_DEBUG_MESSAGE("Ram Enable 8\n");
+	int i;
+	for (i = 0; i < 8; i++)
+		do_ram_command(RAM_COMMAND_CBR, 0);
+
+	/* 9 mode register set */
+	RAM_DEBUG_MESSAGE("Ram Enable 9\n");
+	set_ram_mode(E7501_SDRAM_MODE | SDRAM_MODE_NORMAL);
+
+	/* 10 DDR Receive FIFO RE-Sync */
+	RAM_DEBUG_MESSAGE("Ram Enable 10\n");
+	RAM_RESET_DDR_PTR();
+	EXTRA_DELAY;
+
+	/* 11 normal operation */
+	RAM_DEBUG_MESSAGE("Ram Enable 11\n");
+	do_ram_command(RAM_COMMAND_NORMAL, 0);
+
+	// Reconfigure the row boundaries and Top of Low Memory
+	// to match the true size of the DIMMs
+	configure_e7501_ram_addresses(ctrl, dimm_mask);
+
+	/* Finally enable refresh */
+	dram_controller_mode = pci_read_config32(MCHDEV, DRC);
+	dram_controller_mode |= (1 << 29);
+	pci_write_config32(MCHDEV, DRC, dram_controller_mode);
+	EXTRA_DELAY;
+}
+
+/**
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ */
+static void sdram_post_ecc(const struct mem_controller *ctrl)
+{
+	/* Fast CS# Enable. */
+	uint32_t dram_controller_mode = pci_read_config32(MCHDEV, DRC);
+	dram_controller_mode = pci_read_config32(MCHDEV, DRC);
+	dram_controller_mode |= (1 << 17);
+	pci_write_config32(MCHDEV, DRC, dram_controller_mode);
+}
+
+/**
+ * Configure SDRAM controller parameters that depend on characteristics of the
+ * DIMMs installed in the system. These characteristics are read from the
+ * DIMMs via the standard Serial Presence Detect (SPD) interface.
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ */
+static void sdram_set_spd_registers(const struct mem_controller *ctrl)
+{
+	uint8_t dimm_mask;
+
+	RAM_DEBUG_MESSAGE("Reading SPD data...\n");
+
+	dimm_mask = spd_get_supported_dimms(ctrl);
+
+	if (dimm_mask == 0) {
+		printk(BIOS_DEBUG, "No usable memory for this controller\n");
+	} else {
+		enable_e7501_clocks(dimm_mask);
+
+		RAM_DEBUG_MESSAGE("setting based on SPD data...\n");
+
+		configure_e7501_row_attributes(ctrl, dimm_mask);
+		configure_e7501_dram_controller_mode(ctrl, dimm_mask);
+		configure_e7501_cas_latency(ctrl, dimm_mask);
+		RAM_RESET_DDR_PTR();
+
+		configure_e7501_dram_timing(ctrl, dimm_mask);
+		DO_DELAY;
+		RAM_DEBUG_MESSAGE("done\n");
+	}
+
+	/* NOTE: configure_e7501_ram_addresses() is NOT called here.
+	 * We want to keep the default 64 MB/row mapping until sdram_enable() is called,
+	 * even though the default mapping is almost certainly incorrect.
+	 * The default mapping makes it easy to initialize all of the DIMMs
+	 * even if the total system memory is > 4 GB.
+	 *
+	 * Save the dimm_mask for when sdram_enable is called, so it can call
+	 * configure_e7501_ram_addresses() without having to regenerate the bitmask
+	 * of usable DIMMs.
+	 */
+	pci_write_config16(MCHDEV, SKPD, dimm_mask);
+}
+
+/**
+ * Do basic RAM setup that does NOT depend on serial presence detect
+ * information (i.e. independent of DIMM specifics).
+ *
+ * @param ctrl PCI addresses of memory controller functions, and SMBus
+ *             addresses of DIMM slots on the mainboard.
+ */
+static void sdram_set_registers(const struct mem_controller *ctrl)
+{
+	uint32_t dword;
+	uint16_t word;
+	uint8_t byte;
+
+	ram_set_rcomp_regs();
+
+	/* Enable 0:0.1, 0:2.1 */
+	word = pci_read_config16(MCHDEV, DVNP);
+	word &= ~0x05;
+	pci_write_config16(MCHDEV, DVNP, word);
+
+	/* Disable high-memory remap (power-on defaults, really) */
+	pci_write_config16(MCHDEV, REMAPBASE, 0x03ff);
+	pci_write_config16(MCHDEV, REMAPLIMIT, 0x0);
+
+	/* Disable legacy MMIO (0xC0000-0xEFFFF is DRAM) */
+	int i;
+	pci_write_config8(MCHDEV, PAM_0, 0x30);
+	for (i = 1; i <= 6; i++)
+		pci_write_config8(MCHDEV, PAM_0 + i, 0x33);
+
+	/* Conservatively say each row has 64MB of ram, we will fix this up later
+	 * Initial TOLM 8 rows 64MB each  (1<<3 * 1<<26) >> 16 = 1<<13
+	 *
+	 * FIXME: Hard-coded limit to first four rows to prevent overlap!
+	 */
+	pci_write_config32(MCHDEV, DRB_ROW_0, 0x04030201);
+	pci_write_config32(MCHDEV, DRB_ROW_4, 0x04040404);
+	//pci_write_config32(MCHDEV, DRB_ROW_4, 0x08070605);
+	pci_write_config16(MCHDEV, TOLM, (1<<13));
+
+	/* DIMM clocks off */
+	pci_write_config8(MCHDEV, CKDIS, 0xff);
+
+	/* reset row attributes */
+	pci_write_config32(MCHDEV, DRA, 0x0);
+
+	// The only things we need to set here are DRAM idle timer, Back-to-Back Read Turnaround, and
+	// Back-to-Back Write-Read Turnaround. All others are configured based on SPD.
+	dword = pci_read_config32(MCHDEV, DRT);
+	dword &= 0xC7F8FFFF;
+	dword |= (0x28<<24)|(0x03<<16);
+	pci_write_config32(MCHDEV, DRT, dword);
+
+	dword = pci_read_config32(MCHDEV, DRC);
+	dword &= 0xffcef8f7;
+	dword |= 0x00210008;
+	pci_write_config32(MCHDEV, DRC, dword);
+
+	/* Undocumented */
+	pci_write_config8(MCHDEV, 0x88, 0x80);
+
+	/* Undocumented. Set much later in vendor BIOS. */
+	byte = pci_read_config8(MCHDEV, 0xd9);
+	byte &= ~0x60;
+	pci_write_config8(MCHDEV, 0xd9, byte);
+
+	uint8_t revision = pci_read_config8(MCHDEV, 0x08);
+	if (revision >= 3)
+		d060_control(D060_CMD_1);
+}
+
+static int e7505_mch_is_ready(void)
+{
+	uint32_t dword = pci_read_config32(MCHDEV, DRC);
+	return !!(dword & DRC_DONE);
+}
+
+void sdram_initialize(void)
+{
+	static const struct mem_controller memctrl[] = {
+		{
+			.d0 = PCI_DEV(0, 0, 0),
+			.d0f1 = PCI_DEV(0, 0, 1),
+			.channel0 = { 0x50, 0x52, 0, 0 },
+			.channel1 = { 0x51, 0x53, 0, 0 },
+		},
+	};
+
+	/* If this is a warm boot, some initialisation can be skipped */
+	if (!e7505_mch_is_ready()) {
+
+		/* The real MCH initialisation. */
+		timestamp_add_now(TS_INITRAM_START);
+
+		sdram_set_registers(memctrl);
+		sdram_set_spd_registers(memctrl);
+		sdram_enable(memctrl);
+
+		/* Hook for post ECC scrub settings and debug. */
+		sdram_post_ecc(memctrl);
+
+		timestamp_add_now(TS_INITRAM_END);
+	}
+
+	printk(BIOS_DEBUG, "SDRAM is up.\n");
+}
diff --git a/src/northbridge/intel/e7505/raminit.h b/src/northbridge/intel/e7505/raminit.h
new file mode 100644
index 0000000000..1e0128ce72
--- /dev/null
+++ b/src/northbridge/intel/e7505/raminit.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef RAMINIT_H
+#define RAMINIT_H
+
+#include <stdint.h>
+
+#define MAX_DIMM_SOCKETS_PER_CHANNEL 4
+#define MAX_NUM_CHANNELS 2
+#define MAX_DIMM_SOCKETS (MAX_NUM_CHANNELS * MAX_DIMM_SOCKETS_PER_CHANNEL)
+
+struct mem_controller {
+	pci_devfn_t d0, d0f1; // PCI bus/device/fcns of E7501 memory controller
+
+	// SMBus addresses of DIMM slots for each channel,
+	// in order from closest to MCH to furthest away
+	// 0 == not present
+	uint16_t channel0[MAX_DIMM_SOCKETS_PER_CHANNEL];
+	uint16_t channel1[MAX_DIMM_SOCKETS_PER_CHANNEL];
+};
+
+void sdram_initialize(void);
+
+#endif /* RAMINIT_H */
diff --git a/src/northbridge/intel/e7505/romstage.c b/src/northbridge/intel/e7505/romstage.c
new file mode 100644
index 0000000000..df10f9dbcf
--- /dev/null
+++ b/src/northbridge/intel/e7505/romstage.c
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <cbmem.h>
+#include <arch/romstage.h>
+
+#include <southbridge/intel/i82801dx/i82801dx.h>
+#include <northbridge/intel/e7505/raminit.h>
+
+void mainboard_romstage_entry(void)
+{
+	/* Perform some early chipset initialization required
+	 * before RAM initialization can work
+	 */
+	i82801dx_early_init();
+
+	sdram_initialize();
+
+	cbmem_recovery(0);
+}