2 * Copyright 2008 Extreme Engineering Solutions, Inc.
3 * Copyright 2008 Freescale Semiconductor, Inc.
5 * SPDX-License-Identifier: GPL-2.0+
11 #include <asm/fsl_ddr_sdram.h>
12 #include <asm/fsl_ddr_dimm_params.h>
14 void get_spd(ddr2_spd_eeprom_t *spd, u8 i2c_address)
16 i2c_read(i2c_address, SPD_EEPROM_OFFSET, 2, (uchar *)spd,
17 sizeof(ddr2_spd_eeprom_t));
21 * There are four board-specific SDRAM timing parameters which must be
22 * calculated based on the particular PCB artwork. These are:
23 * 1.) CPO (Read Capture Delay)
24 * - TIMING_CFG_2 register
25 * Source: Calculation based on board trace lengths and
26 * chip-specific internal delays.
27 * 2.) WR_DATA_DELAY (Write Command to Data Strobe Delay)
28 * - TIMING_CFG_2 register
29 * Source: Calculation based on board trace lengths.
30 * Unless clock and DQ lanes are very different
31 * lengths (>2"), this should be set to the nominal value
33 * 3.) CLK_ADJUST (Clock and Addr/Cmd alignment control)
34 * - DDR_SDRAM_CLK_CNTL register
35 * Source: Signal Integrity Simulations
36 * 4.) 2T Timing on Addr/Ctl
37 * - TIMING_CFG_2 register
38 * Source: Signal Integrity Simulations
39 * Usually only needed with heavy load/very high speed (>DDR2-800)
41 * ====== XPedite5370 DDR2-600 read delay calculations ======
43 * See Freescale's App Note AN2583 as refrence. This document also
44 * contains the chip-specific delays for 8548E, 8572, etc.
47 * Minimum chip delay (Ch 0): 1.372ns
48 * Maximum chip delay (Ch 0): 2.914ns
49 * Minimum chip delay (Ch 1): 1.220ns
50 * Maximum chip delay (Ch 1): 2.595ns
52 * CLK adjust = 5 (from simulations) = 5/8* 3.33ns = 2080ps
54 * Minimum delay calc (Ch 0):
55 * clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
56 * 2.3" * 180 - 400ps + 1.9" * 180 + 2080ps + 1372ps
60 * Maximum delay calc (Ch 0):
61 * clock prop + dram skew + max dqs prop delay + clk_adjust + max chip dly
62 * 2.3" * 180 + 400ps + 2.4" * 180 + 2080ps + 2914ps
66 * Minimum delay calc (Ch 1):
67 * clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
68 * 1.46" * 180- 400ps + 0.7" * 180 + 2080ps + 1220ps
72 * Maximum delay calc (Ch 1):
73 * clock prop + dram skew + max dqs prop delay + clk_adjust + min chip dly
74 * 1.46" * 180+ 400ps + 1.1" * 180 + 2080ps + 2595ps
78 * Ch.0: 3.808ns to 6.240ns additional delay needed (pick 5ns as target)
79 * This is 1.5 clock cycles, pick CPO = READ_LAT + 3/2 (0x8)
80 * Ch.1: 3.288ns to 5.536ns additional delay needed (pick 4.4ns as target)
81 * This is 1.32 clock cycles, pick CPO = READ_LAT + 5/4 (0x7)
84 * ====== XPedite5370 DDR2-800 read delay calculations ======
86 * See Freescale's App Note AN2583 as refrence. This document also
87 * contains the chip-specific delays for 8548E, 8572, etc.
90 * Minimum chip delay (Ch 0): 1.372ns
91 * Maximum chip delay (Ch 0): 2.914ns
92 * Minimum chip delay (Ch 1): 1.220ns
93 * Maximum chip delay (Ch 1): 2.595ns
95 * CLK adjust = 5 (from simulations) = 5/8* 2.5ns = 1563ps
97 * Minimum delay calc (Ch 0):
98 * clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
99 * 2.3" * 180 - 350ps + 1.9" * 180 + 1563ps + 1372ps
103 * Maximum delay calc (Ch 0):
104 * clock prop + dram skew + max dqs prop delay + clk_adjust + max chip dly
105 * 2.3" * 180 + 350ps + 2.4" * 180 + 1563ps + 2914ps
109 * Minimum delay calc (Ch 1):
110 * clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
111 * 1.46" * 180- 350ps + 0.7" * 180 + 1563ps + 1220ps
115 * Maximum delay calc (Ch 1):
116 * clock prop + dram skew + max dqs prop delay + clk_adjust + min chip dly
117 * 1.46" * 180+ 350ps + 1.1" * 180 + 1563ps + 2595ps
121 * Ch.0: 3.341ns to 5.673ns additional delay needed (pick 4.5ns as target)
122 * This is 1.8 clock cycles, pick CPO = READ_LAT + 7/4 (0x9)
123 * Ch.1: 2.822ns to 4.968ns additional delay needed (pick 3.9ns as target)
124 * This is 1.56 clock cycles, pick CPO = READ_LAT + 3/2 (0x8)
126 * Write latency (WR_DATA_DELAY) is calculated by doing the following:
128 * The DDR SDRAM specification requires DQS be received no sooner than
129 * 75% of an SDRAM clock period—and no later than 125% of a clock
130 * period—from the capturing clock edge of the command/address at the
133 * Based on the above tracelengths, the following are calculated:
134 * Ch. 0 8572 to DRAM propagation (DQ lanes) : 1.9" * 180 = 0.342ns
135 * Ch. 0 8572 to DRAM propagation (CLKs) : 2.3" * 180 = 0.414ns
136 * Ch. 1 8572 to DRAM propagation (DQ lanes) : 0.7" * 180 = 0.126ns
137 * Ch. 1 8572 to DRAM propagation (CLKs ) : 1.47" * 180 = 0.264ns
139 * Difference in arrival time CLK vs. DQS:
143 * Both of these values are much less than 25% of the clock
144 * period at DDR2-600 or DDR2-800, so no additional delay is needed over
145 * the 1/2 cycle which normally aligns the first DQS transition
146 * exactly WL (CAS latency minus one cycle) after the CAS strobe.
147 * See Figure 9-53 in MPC8572E manual: "1/2 delay" in Freescale's
148 * terminology corresponds to exactly one clock period delay after
149 * the CAS strobe. (due to the fact that the "delay" is referenced
150 * from the *falling* edge of the CLK, just after the rising edge
151 * which the CAS strobe is latched on.
154 typedef struct board_memctl_options {
155 uint16_t datarate_mhz_low;
156 uint16_t datarate_mhz_high;
158 uint8_t cpo_override;
159 uint8_t write_data_delay;
160 } board_memctl_options_t;
162 static struct board_memctl_options bopts_ctrl[][2] = {
167 .datarate_mhz_low = 500,
168 .datarate_mhz_high = 750,
171 .write_data_delay = 2,
175 .datarate_mhz_low = 750,
176 .datarate_mhz_high = 850,
179 .write_data_delay = 2,
186 .datarate_mhz_low = 500,
187 .datarate_mhz_high = 750,
190 .write_data_delay = 2,
194 .datarate_mhz_low = 750,
195 .datarate_mhz_high = 850,
198 .write_data_delay = 2,
203 void fsl_ddr_board_options(memctl_options_t *popts,
204 dimm_params_t *pdimm,
205 unsigned int ctrl_num)
207 struct board_memctl_options *bopts = bopts_ctrl[ctrl_num];
210 unsigned int datarate;
212 get_sys_info(&sysinfo);
213 datarate = sysinfo.freq_ddrbus / 1000 / 1000;
215 for (i = 0; i < ARRAY_SIZE(bopts_ctrl[ctrl_num]); i++) {
216 if ((bopts[i].datarate_mhz_low <= datarate) &&
217 (bopts[i].datarate_mhz_high >= datarate)) {
218 debug("controller %d:\n", ctrl_num);
219 debug(" clk_adjust = %d\n", bopts[i].clk_adjust);
220 debug(" cpo = %d\n", bopts[i].cpo_override);
221 debug(" write_data_delay = %d\n",
222 bopts[i].write_data_delay);
223 popts->clk_adjust = bopts[i].clk_adjust;
224 popts->cpo_override = bopts[i].cpo_override;
225 popts->write_data_delay = bopts[i].write_data_delay;
230 * Factors to consider for half-strength driver enable:
231 * - number of DIMMs installed
233 popts->half_strength_driver_enable = 0;