I wrote the original linux loader for the alertme hub - fit the entire
NAND flash loader into about 1.2k of eeprom space, including CRC codes.
The development board for it was a ts7400.
When I was looking at the sdcard last year I figured that it would be
quite difficult to fit the boot loader into the 2k eeprom on the
ts7400. With about 5k I think its possible; but you'll need at least 3
stages of loader.
Incidentally, since you have done your own board, how have you connected
the sdcard to the ep9307 - are you gpio banging it?
The TS boards have a pretty simple 4 bit interface onto the sdcard that
is implemented in the CPLD.
If I remember correctly, they do something like a 3 stage loader on the
ts7400:
Stage 1: 2k loaded from eeprom into cirrus's ethernet buffer to start
the system and load the 1st page (which are supposed to be reliable)
from NAND and call it.
Stage 2: Load the first 16k from NAND using CRC and call it.
Stage 3: Load Linux from NAND or load Linux from partition 0 of the
sdcard (tsfastboot vs tssdboot).
Loading linux itself is quite easy - just copy the data into ram, setup
the registers correctly and jump to the start address.
Oh yeah - since you've done your own board, have you correctly managed
the ep93xx lockup-on-reset bug? About 1/3 of the chips have this
problem. TS works around it using their CPLD and watchdog.
-Brett
pkm_munot wrote:
> --- In Jason Stahls <> wrote:
>
>> pkm_munot wrote:
>>
>>> Hi Guys,
>>>
>>> As per the manual under boot section. This board as a initial bootloader in
>>> EEPROM which is loaded at power up and later talks to SDcard. Apter
>>> initializing of SDcard the boards boots from SDcard directly. I am trying
>>> to implement a similar boot sequence for my board based on EP9307 chip.
>>>
>>> Can anyone please provide some pointers to the source code for EEPROM
>>> bootloader and TS_SDBOOT.
>>>
>> I doubt TS will release the code for their bootloader but the best way
>> to get it would call them and ask for it. Now for SD boot, I believe
>> the SD interface is implemented in the FPGA so that would hose using
>> TS's boot loader anyways :(
>>
>> --
>> Jason Stahls
>>
>>
>
> Thanks Jason,
>
> I will trying calling them and see if I can get any pointers from them. As
> per the current design for TS7300 I guess the sdcard interface is implemented
> in FPGA. In my case I dont have a FPGA but I have a serial flash. I have
> downloaded spi_boot example from Cirrus logic website and its working
> successfully on my board.
>
> Now I am trying to write a second stage bootloader which will initialize the
> sdcard and load redboot from sdcard. This in turn will load rest of the bits
> from SDcard.
>
> Its this approach right?
> Cheers
> Tama
>
>
>
>
>
>
>
>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
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