[U-Boot] Boot from USB support for Kirkwood SOC

[xiangfu <xiangfu.z@gmail.com>]

Hi Prafulla Wadashar

Prafulla Wadaskar wrote:
>>>
>>> I am going to start "boot from USB Support" development for 
>> kirkwood.
>> what this "boot from USB Support" means?
> Dear Xiangfu Liu
> To my development "Boot from USB Support" means, fetching kernel and rfs binaries from the file system/partition on storage connected on USB interface.

sounds good.

> There will be native u-boot on NAND or SPI flash that will bring up the system
> In the auto boot sequence through h/w triggers on the board like pushbutton/reset key we can initiate bootcmd for "boot_from_USB"
> For this I need to support h/w driver for Kirkwood and u-boot USB framework.
> 
> This is one of good standalone method to recover system using USB interface (similar to pxeboot)
> in case of small embedded systems it would be very useful.
yes, agree.

> 
> FYI: Kirkwood h/w supports Boot from SF/NANDF/SATA/PEX/UART but not USB :-) as you referenced for JZ4740
> 
> Regards..
> Prafulla . .
> 
>> I know "boot from nand",
>> and I know that the Ingenic CPU, support "boot from USB". is 
>> the same meaning?
>>
>> here is part of JZ4740 cpu data sheet [1]
>> --
>> 3.7.3   BOOT
>> Jz4740 support 3 different boot sources depending on 
>> BOOT_SEL0 and BOOT_SEL1 pin values.
>> Table 3-29 lists them.
>>                              Table 3-29 Boot from 3 boot sources
>>
>> BOOT_SEL1 BOOT_SEL0                Boot Source
>>     0         0     Boot from NOR flash at CS4
>>     0         1     Boot from USB device
>>     1         0     Boot from 512 page NAND flash at CS1
>>     1         1     Boot from 2k page NAND flash at CS1
>> --
>>
>> [1] ftp://ftp.ingenic.cn/2soc/Jz4740_ds.pdf
>>


-- 
Best Regards
Xiangfu Liu

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