1a4596601f
Signed-off-by: Wolfgang Denk <wd@denx.de> [trini: Fixup common/cmd_io.c] Signed-off-by: Tom Rini <trini@ti.com>
132 lines
4.5 KiB
Plaintext
132 lines
4.5 KiB
Plaintext
This directory contains board specific code for a generic MPC860T based
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embedded computer, called 'GEN860T'. The design is generic in the sense that
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common, readily available components are used and that the architecture of the
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system is relatively straightforward:
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One eight bit wide boot (FLASH) memory
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32 bit main memory using SDRAM
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DOC 2000+
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Ethernet PHY
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Some I2C peripheral devices: Atmel AT24C256 EEPROM, Maxim DS1337 RTC.
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Some other miscellaneous peripherals
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NOTE: There are references to a XIlinx FPGA and Mil-Std 1553 databus in this
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port. I guess the computer is not as generic as I first said 8) However,
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these extras can be safely ignored.
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Given the GEN860T files, it should be pretty easy to reverse engineer the
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hardware configuration, if that's useful to you. Hopefully, this code will
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be useful to someone as a basis for a port to a new system or as a head start
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on a custom design. If you end up using any of this, I would appreciate
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hearing from you, especially if you discover bugs or find ways to improve the
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quality of this U-Boot port.
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Here are the salient features of the system:
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Clock : 33.3 Mhz oscillator
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Processor core frequency : 66.6 Mhz if in 1:2:1 mode; can also run 1:1
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Bus frequency : 33.3 Mhz
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Main memory:
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Type : SDRAM
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Width : 32 bits
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Size : 64 mibibytes
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Chip : Two Micron MT48LC16M16A2TG-7E
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CS : MPC860T CS1*/UPMA
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UPMA CONNECTIONS:
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SDRAM A10 : GPLA0*
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SDRAM CAS* : GPLA2*
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SDRAM WE* : GPLA3*
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SDRAM RAS* : GPLA4*
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Boot memory:
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Type : FLASH
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Width : 8 bits
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Size : 16 mibibytes
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Chip : One Intel 28F128J3A (StrataFlash)
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CS : MPC860T CS0*/GPCM (this is the "boot" chip select)
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EEPROM memory:
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Type : Serial I2C EEPROM
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Width : 8 bits
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Size : 32 kibibytes
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Chip : One Atmel AT25C256
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CS : 0x50 (external I2C address pins on device are tied to GND)
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Filesystem memory:
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Type : NAND FLASH (Toshiba)
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Width : 8 bits (i.e. interface to DOC is 8 bits)
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Size : 32 mibibytes
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Chip : One DiskOnCHip Millenium Plus (DOC 2000+)
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CS : MPC860T CS2*/GPCM
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Network support:
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MAC : MPC86OT FEC (Fast Ethernet Controller)
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PHY : Intel LXT971A
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MII Addr: 0x0 (hardwired on the board)
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MII IRQ :
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Console:
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RS-232 on SMC1 (Maxim MAX3232 LVCMOS-RS232 level shifter)
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Real Time Clock:
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Type : Low power, I2C interface
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Chip : Maxim DS1337
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CS : Address 0x68 on I2C bus
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The MPC860T's internal RTC has a defect in Mask rev D that increases
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the current drain on the KAPWR line to 10 mA. Since this is an
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unreasonable amount of current draw for a RTC, and Motorola does not
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plan to fix this in future mask revisions, a serial (I2C) RTC that
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works has been included instead. NOTE that the DS1337 can be
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configured to output a 32768 Hz clock while the main power is on.
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This clock output has been routed to the MPC860T's EXTAL pin to allow
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the internal RTC to be used. NOTE also that due to yet another
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defect in the rev D mask, the RTC does not operate reliably when the
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internal RTC divisor is set to use a 32768 Hz reference. So just use
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the I2C RTC.
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Miscellaneous:
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Xilinx Virtex FPGA on CS3*/GPCM.
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Virtex FPGA slave SelectMap interface on cs4*/UPMB.
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Mil-Std 1553 databus interface on CS5*/GPCM.
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Audio sounder (beeper) with digital volume control connected to SPKROUT.
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SC variant:
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A reduced-feature version of the GEN860T port is also supported: GEN860T_SC.
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The 'SC' variant only provides support for the Virtex FPGA, SDRAM main
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memory, EEPROM and flash memory. The system clock frequency is reduced
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to 24 MHz.
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Issues:
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The DOC 2000+ returns 0x40 as its device ID when probed using the method
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desxribed in the DOC datasheet. Unfortunately, the U-Boot DOC driver
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does not recognize this device. As of this writing, it seems that MTD
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does not support the DOC 2000+ either.
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Status:
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Everything appears to work except DOC support. As of this writing,
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David Woodhouse has stated on the MTD mailing list that he has no
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knowledge of the DOC Millineum Plus and therfore there is no support
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in MTD for this device. I wish I had known this sooner :(
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The GEN860T board specific files and configuration is based on the work
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of others who have contributed to U-Boot. The copyright and license notices
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of these authors have been retained wherever their code has been reused.
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All new code to support the GEN860T board is:
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(C) Copyright 2001-2003
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Keith Outwater (keith_outwater@mvis.com)
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and the following license applies:
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SPDX-License-Identifier: GPL-2.0+
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Thanks to Wolfgang Denk for a great software package and to everyone
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who contributed to its development.
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Keith Outwater
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Sr. Staff Engineer
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Microvision, Inc.
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<keith_outwater@mvis.com>
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<outwater@eskimo.com>
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