forked from rrcarlosr/Jetpack
235 lines
8.5 KiB
C
235 lines
8.5 KiB
C
/*
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* Copyright 2008 Extreme Engineering Solutions, Inc.
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* Copyright 2008 Freescale Semiconductor, Inc.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <i2c.h>
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#include <fsl_ddr_sdram.h>
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#include <fsl_ddr_dimm_params.h>
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void get_spd(ddr2_spd_eeprom_t *spd, u8 i2c_address)
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{
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i2c_read(i2c_address, SPD_EEPROM_OFFSET, 2, (uchar *)spd,
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sizeof(ddr2_spd_eeprom_t));
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}
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/*
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* There are four board-specific SDRAM timing parameters which must be
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* calculated based on the particular PCB artwork. These are:
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* 1.) CPO (Read Capture Delay)
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* - TIMING_CFG_2 register
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* Source: Calculation based on board trace lengths and
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* chip-specific internal delays.
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* 2.) WR_DATA_DELAY (Write Command to Data Strobe Delay)
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* - TIMING_CFG_2 register
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* Source: Calculation based on board trace lengths.
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* Unless clock and DQ lanes are very different
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* lengths (>2"), this should be set to the nominal value
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* of 1/2 clock delay.
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* 3.) CLK_ADJUST (Clock and Addr/Cmd alignment control)
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* - DDR_SDRAM_CLK_CNTL register
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* Source: Signal Integrity Simulations
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* 4.) 2T Timing on Addr/Ctl
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* - TIMING_CFG_2 register
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* Source: Signal Integrity Simulations
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* Usually only needed with heavy load/very high speed (>DDR2-800)
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*
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* ====== XPedite5370 DDR2-600 read delay calculations ======
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*
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* See Freescale's App Note AN2583 as refrence. This document also
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* contains the chip-specific delays for 8548E, 8572, etc.
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*
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* For MPC8572E
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* Minimum chip delay (Ch 0): 1.372ns
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* Maximum chip delay (Ch 0): 2.914ns
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* Minimum chip delay (Ch 1): 1.220ns
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* Maximum chip delay (Ch 1): 2.595ns
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*
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* CLK adjust = 5 (from simulations) = 5/8* 3.33ns = 2080ps
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*
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* Minimum delay calc (Ch 0):
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* clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
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* 2.3" * 180 - 400ps + 1.9" * 180 + 2080ps + 1372ps
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* = 3808ps
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* = 3.808ns
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*
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* Maximum delay calc (Ch 0):
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* clock prop + dram skew + max dqs prop delay + clk_adjust + max chip dly
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* 2.3" * 180 + 400ps + 2.4" * 180 + 2080ps + 2914ps
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* = 6240ps
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* = 6.240ns
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*
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* Minimum delay calc (Ch 1):
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* clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
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* 1.46" * 180- 400ps + 0.7" * 180 + 2080ps + 1220ps
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* = 3288ps
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* = 3.288ns
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*
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* Maximum delay calc (Ch 1):
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* clock prop + dram skew + max dqs prop delay + clk_adjust + min chip dly
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* 1.46" * 180+ 400ps + 1.1" * 180 + 2080ps + 2595ps
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* = 5536ps
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* = 5.536ns
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*
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* Ch.0: 3.808ns to 6.240ns additional delay needed (pick 5ns as target)
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* This is 1.5 clock cycles, pick CPO = READ_LAT + 3/2 (0x8)
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* Ch.1: 3.288ns to 5.536ns additional delay needed (pick 4.4ns as target)
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* This is 1.32 clock cycles, pick CPO = READ_LAT + 5/4 (0x7)
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*
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*
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* ====== XPedite5370 DDR2-800 read delay calculations ======
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*
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* See Freescale's App Note AN2583 as refrence. This document also
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* contains the chip-specific delays for 8548E, 8572, etc.
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*
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* For MPC8572E
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* Minimum chip delay (Ch 0): 1.372ns
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* Maximum chip delay (Ch 0): 2.914ns
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* Minimum chip delay (Ch 1): 1.220ns
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* Maximum chip delay (Ch 1): 2.595ns
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*
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* CLK adjust = 5 (from simulations) = 5/8* 2.5ns = 1563ps
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*
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* Minimum delay calc (Ch 0):
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* clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
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* 2.3" * 180 - 350ps + 1.9" * 180 + 1563ps + 1372ps
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* = 3341ps
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* = 3.341ns
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*
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* Maximum delay calc (Ch 0):
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* clock prop + dram skew + max dqs prop delay + clk_adjust + max chip dly
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* 2.3" * 180 + 350ps + 2.4" * 180 + 1563ps + 2914ps
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* = 5673ps
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* = 5.673ns
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*
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* Minimum delay calc (Ch 1):
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* clock prop - dram skew + min dqs prop delay + clk_adjust + min chip dly
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* 1.46" * 180- 350ps + 0.7" * 180 + 1563ps + 1220ps
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* = 2822ps
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* = 2.822ns
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*
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* Maximum delay calc (Ch 1):
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* clock prop + dram skew + max dqs prop delay + clk_adjust + min chip dly
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* 1.46" * 180+ 350ps + 1.1" * 180 + 1563ps + 2595ps
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* = 4968ps
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* = 4.968ns
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*
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* Ch.0: 3.341ns to 5.673ns additional delay needed (pick 4.5ns as target)
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* This is 1.8 clock cycles, pick CPO = READ_LAT + 7/4 (0x9)
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* Ch.1: 2.822ns to 4.968ns additional delay needed (pick 3.9ns as target)
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* This is 1.56 clock cycles, pick CPO = READ_LAT + 3/2 (0x8)
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*
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* Write latency (WR_DATA_DELAY) is calculated by doing the following:
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*
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* The DDR SDRAM specification requires DQS be received no sooner than
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* 75% of an SDRAM clock period—and no later than 125% of a clock
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* period—from the capturing clock edge of the command/address at the
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* SDRAM.
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*
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* Based on the above tracelengths, the following are calculated:
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* Ch. 0 8572 to DRAM propagation (DQ lanes) : 1.9" * 180 = 0.342ns
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* Ch. 0 8572 to DRAM propagation (CLKs) : 2.3" * 180 = 0.414ns
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* Ch. 1 8572 to DRAM propagation (DQ lanes) : 0.7" * 180 = 0.126ns
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* Ch. 1 8572 to DRAM propagation (CLKs ) : 1.47" * 180 = 0.264ns
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*
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* Difference in arrival time CLK vs. DQS:
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* Ch. 0 0.072ns
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* Ch. 1 0.138ns
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*
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* Both of these values are much less than 25% of the clock
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* period at DDR2-600 or DDR2-800, so no additional delay is needed over
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* the 1/2 cycle which normally aligns the first DQS transition
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* exactly WL (CAS latency minus one cycle) after the CAS strobe.
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* See Figure 9-53 in MPC8572E manual: "1/2 delay" in Freescale's
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* terminology corresponds to exactly one clock period delay after
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* the CAS strobe. (due to the fact that the "delay" is referenced
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* from the *falling* edge of the CLK, just after the rising edge
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* which the CAS strobe is latched on.
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*/
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typedef struct board_memctl_options {
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uint16_t datarate_mhz_low;
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uint16_t datarate_mhz_high;
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uint8_t clk_adjust;
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uint8_t cpo_override;
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uint8_t write_data_delay;
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} board_memctl_options_t;
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static struct board_memctl_options bopts_ctrl[][2] = {
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{
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/* Controller 0 */
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{
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/* DDR2 600/667 */
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.datarate_mhz_low = 500,
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.datarate_mhz_high = 750,
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.clk_adjust = 5,
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.cpo_override = 8,
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.write_data_delay = 2,
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},
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{
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/* DDR2 800 */
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.datarate_mhz_low = 750,
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.datarate_mhz_high = 850,
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.clk_adjust = 5,
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.cpo_override = 9,
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.write_data_delay = 2,
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},
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},
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{
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/* Controller 1 */
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{
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/* DDR2 600/667 */
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.datarate_mhz_low = 500,
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.datarate_mhz_high = 750,
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.clk_adjust = 5,
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.cpo_override = 7,
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.write_data_delay = 2,
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},
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{
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/* DDR2 800 */
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.datarate_mhz_low = 750,
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.datarate_mhz_high = 850,
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.clk_adjust = 5,
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.cpo_override = 8,
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.write_data_delay = 2,
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},
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},
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};
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void fsl_ddr_board_options(memctl_options_t *popts,
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dimm_params_t *pdimm,
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unsigned int ctrl_num)
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{
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struct board_memctl_options *bopts = bopts_ctrl[ctrl_num];
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sys_info_t sysinfo;
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int i;
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unsigned int datarate;
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get_sys_info(&sysinfo);
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datarate = sysinfo.freq_ddrbus / 1000 / 1000;
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for (i = 0; i < ARRAY_SIZE(bopts_ctrl[ctrl_num]); i++) {
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if ((bopts[i].datarate_mhz_low <= datarate) &&
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(bopts[i].datarate_mhz_high >= datarate)) {
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debug("controller %d:\n", ctrl_num);
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debug(" clk_adjust = %d\n", bopts[i].clk_adjust);
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debug(" cpo = %d\n", bopts[i].cpo_override);
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debug(" write_data_delay = %d\n",
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bopts[i].write_data_delay);
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popts->clk_adjust = bopts[i].clk_adjust;
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popts->cpo_override = bopts[i].cpo_override;
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popts->write_data_delay = bopts[i].write_data_delay;
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}
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}
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/*
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* Factors to consider for half-strength driver enable:
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* - number of DIMMs installed
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*/
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popts->half_strength_driver_enable = 0;
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}
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