uboot eeprom read
[U-Boot-Users] how to use ‘eeprom read’ command
<code>> => help eeprom > eeprom read devaddr addr off cnt > eeprom write devaddr addr off cnt > - read/write `cnt' bytes from `devaddr` EEPROM at offset `off' > > -------------------------------------------------------------------------- > > I want to access boot eprom which is at 'devaddr' 0x54 and offset '0' to > '10'. > > But I am not clear what ro pass for the 'addr' argument. > > Regards, > Sachin Rane IIRC, "addr" is the memory (RAM) address that you read the eeprom data into or is the source tow rite the eeprom data out. To read your i2c device 0x54, you would do something like: eeprom read 54 0 0 10 and then would be able to see the 16 bytes of data with the md command: md 0 </code>
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Querying
At runtime, you can interrogate the SPI flash to make sure things are detected properly.
bfin> eeprom info
SPI Device: S25LF032 0x01 (Spansion) 0x02 0x16
Parameters: num sectors = 64, sector size = 65536, write size = 256
Flash Size: 32 mbit (4 mbyte)
Status: 0x00
Here we can see that there is a 32 megabit Spansion flash hooked up. Good times.
Reading
You use the eeprom read command to read a range of bytes from the serial flash into memory. From there, you can do anything you like with it. For example, if we want to read 0x1000 bytes at an offset of 0x300 bytes from the start of the serial flash into external memory at 0x2000000, we’d simply run:
bfin> eeprom read 0x2000000 0x300 0x1000
EEPROM @0x0 read: addr 02000000 off 0300 count 4096 … done
bfin> md.b 0x2000000
02000000: 0e e1 00 10 4e e1 b0 ff 90 61 10 3e 01 60 21 36 ….N….a.>.`!6
02000010: 29 36 31 36 39 36 01 3c 19 3c fc 31 00 e3 56 00 )61696.<.<.1..V.
02000020: 03 60 43 e1 00 20 98 09 03 18 00 e3 91 31 0e 60 .`C.. …….1.`
02000030: 00 e3 4c 00 02 e1 34 00 42 e1 fc 03 03 e1 00 00 ..L…4.B…….
Again, you do not need to worry about how the serial flash is split up into pages, so you could just as easily read multiple pages/sectors/blocks/whatever with one command.
You can ignore the @0x0 output in the output above. It does not apply to serial flashes.
Writing
You use the eeprom write command to write a range of bytes from memory into some offset into the serial flash. For example, if we want to write 0x100000 bytes from external memory at 0x20000000 into the serial flash at an offset of 0x0 bytes, we’d simply run:
bfin> eeprom write 0x20000000 0x0 0x100000
EEPROM @0x0 write: addr 20000000 off 0000 count 1048576 … …………………………..done
There is no need for you to issue a separate erase command as the U-Boot driver will take care of that. There is also no need for you to worry about writing out only a page of data at a time.
You can ignore the @0x0 output in the output above. It does not apply to serial flashes.”
u-boot移植随笔：EEPROM移植及测试 – 木草山人和水田居士的小窝 – 博客频道 – CSDN.NET
EEPROM @0x50 read: addr 33000000 off 0000 count 8 … done
LATE2440> md.b 33000000 8 读出的为0
33000000: 00 00 00 00 00 00 00 00 ……..
LATE2440> mm.b 33000000 修改内存中的数据
33000000: 00 ? 6c
33000001: 00 ? 61
33000002: 00 ? 74
33000003: 00 ? 65
33000004: 00 ? 20
33000005: 00 ? 6c
33000006: 00 ? 65
33000007: 00 ? 65
33000008: 00 ? q 退出
LATE2440> md.b 33000000 8 检查内存数据是否正确
33000000: 6c 61 74 65 20 6c 65 65 late lee
LATE2440> eeprom write 33000000 0 8 写到eeprom中
EEPROM @0x50 write: addr 33000000 off 0000 count 8 … done
LATE2440> eeprom read 33000030 0 8 读到另一个地址
EEPROM @0x50 read: addr 33000030 off 0000 count 8 … done
LATE2440> md.b 33000030 8 查看这个地址
33000030: 6c 61 74 65 20 6c 65 65 late lee
重启后再读到另一个地址
LATE2440> eeprom read 30008000 0 8
EEPROM @0x50 read: addr 30008000 off 0000 count 8 … done
LATE2440> md.b 30008000 8 查看
30008000: 6c 61 74 65 20 6c 65 65 late lee
LATE2440> mm.b 30008000 修改
30008000: 6c ? 4c
30008001: 61 ? (回车)
30008002: 74 ?
30008003: 65 ?
30008004: 20 ?
30008005: 6c ? 4c
30008006: 65 ?
30008007: 65 ?
30008008: 00 ? q 退出
LATE2440> eeprom write 30008000 0 8 写入eeprom
EEPROM @0x50 write: addr 30008000 off 0000 count 8 … done
LATE2440> eeprom read 30000000 0 8 读到另一个地址
EEPROM @0x50 read: addr 30000000 off 0000 count 8 … done
LATE2440> md.b 30000000 8 查看
30000000: 4c 61 74 65 20 4c 65 65 Late Lee
LATE2440>
注：进行eeprom操作出现的地址、数据等等，均为16进制。
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