[U-Boot-Users] Unable to write to flash..

[rags <vijay.seshan@wipro.com>]

My responses are inlined with '==>'



Jerry Van Baren wrote:
> 
> rags wrote:
>> Hi,
>> We've been having a strange problem during our board bringup. I have
>> given a
>> brief description about our board, the problem we are facing and
>> investigation done so far. Would appreciate any comments/pointers for
>> further investigations..
>> I apologize in advance for the long post that follows..:-)
>> 
>> Regards
>> Vijay
>> 
>> Board description:
>> This is a MPC8360E based board with a S29GL01GP12T (16 bit) flash
>> (size=128MB) and 256 MB DDRRam + other peripherals. We have a BDI2000
>> JTAG
>> debugger connected to the board. Relevant sections of our BDI config file
>> are given below,
> 
> [snip - I'm going to assume the BDI config is OK, I don't have time or 
> expertise to check it]
> 
>> With this the processor halts at 0xFFF00100 on reset. We are able to read
>> the system configuration registers at the relocated IMMR address and able
>> to
>> access the DDR Ram (starting at 0x00000000) and Flash starting at
>> (0xF8000000). The flash contains some data that was pre-programmed (First
>> sector contains HRCW and a U-boot image is also burned at another
>> location).
> 
> Good.
> 
>> Problem description:
>> We are able to read the contents of the flash, but unable to erase or
>> program it (we have tried several combinations of sectors). We can
>> confirm
>> the read because of the pre-programmed content (HRCW + U-boot image). 
> 
> Read - good.  Not able to program - likely not using the right 
> addresses, data.  Possibly hardware problems, but lower probability.
> 
>> Is it possible to isolate this to a HW/SW(config file) issue??
> 
> Yes.  ;-)
> 
>> Investigation done so far:
>> We have done the following so far,
>> 
>> 1. We have probed the address and data lines along with other control
>> signals (Chip select etc..). Also we have made sure that the  write
>> protect
>> remains high for the flash. All the address lines are toggling and data
>> lines seem to be ok (since we are able to read stuff ok from the flash).
>> Also chip select is getting issued properly at the correct time. (All
>> these,
>> as per our hw guys).
> 
> I presume the WR* line is toggling properly too???
> 
> ==> Yes, as per our hardware folks the WR* line is toggling properly too..
> 
>> 2. We have tried mapping the flash at different addresses with the same
>> result
> 
> Not useful.
> 
>> 3. We used the same flash on a Freescale MDS reference board (with the
>> same
>> configuration for Flash) and are able to read and write successfully.
>> Also
>> the U-boot image burned in the flash comes up.
> 
> Good, you have something to compare your hardware to.
> 
>> 4. We tried using the protocol defined in the datasheet to read the
>> 'manufacturer id' using BDI MM/MD commands. But this seems to fail in
>> both
>> our board and the MDS board.
> 
> You need to figure this out.  If you figure this out, you will have the 
> answer to your problem (99.98% probability).
> 
> Figure out how it works on the MDS board first, since that is know 
> working, then do the same on your custom hardware.
> 
> Note the addresses (byte vs. word) in the 29GL10 data sheet (I'm looking 
> at <http://www.spansion.com/datasheets/s29gl-p_00_a5_e.pdf>)
>    Table 7.4 Autoselect Entry in System
> Important points:
> 1) You need to use the word addresses column in the table.
> 2) You need to use the correct BDI command modifier to generate word (16 
> bit) writes - this is VERY IMPORTANT.
> 
> The following is invalid syntax, but illustrates what I'm saying:
>    mw.w Basex555 00aa
>    mw.w Basex2AA 0055
>    mw.w Basex555 0090
> If that doesn't work, try a byte swap:
>    mw.w Basex555 aa00
>    mw.w Basex2AA 5500
>    mw.w Basex555 9000
> 
> Good luck,
> gvb
> 
> ==> We are currently trying to figure this out..Will post once I have a
> update..Meanwhile, pls let me know if there is anything else that could be
> checked..
> 
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