RE: Unlocking flash problem with the epxa10db device

RE: Unlocking flash problem with the epxa10db device

[Christopher Hoover]

I wrote cfi_intelext_varsize_frob().  It is behaving as intended.

You have to unlock/lock/erase/etc. an *entire* block/sector at a time.  

There's no way to unlock 4 bytes and leave the other (erasesize - 4)
bytes locked.  So the function returns EINVAL if the size isn't an even
"multiple" of the block size(s).  ("Multiple" here is not meant strictly
in the mathematical sense; consider variably-sized blocks.)

You'll find the other functions behave identically, e.g. erase.

-ch


-----Original Message-----
From: linux-arm-kernel-admin@lists.arm.linux.org.uk
[mailto:linux-arm-kernel-admin@lists.arm.linux.org.uk] On Behalf Of
Louie Boczek
Sent: Thursday, September 19, 2002 8:11 PM
To: ARM Linux kernel Mailinglist
Subject: Unlocking flash problem with the epxa10db device


I just started working with the Altera Excalibur board and ran into the 
following problem.

I was not able to write to the flash and found the problem lied in the 
unlocking code.  
In the epxa10db-flash.c:epxa10db_mtd_init() routine it calls:

       mymtd->unlock(mymtd, mymtd->eraseregions[i].offset + j * 
mymtd->eraseregions[i].erasesize, 4);

which eventually calls "cfi_cmdsetc_001.c:cfi_intelext_varsize_frob()" 
in this routine there is a check to make sure that the region being 
unlocked is the whole region with  the check:
        if ((ofs + len) & (regions[i].erasesize -1))
            return -EINVAL;

this fails since the call was only to unlock 4 bytes not erasesize.  So 
I fixed the problem by changing the call to mymtd->unlock()  to pass the

erasesize instead of 4.

But the question is, should "cfi_intelext_varsize_frob()" check to see 
if the whole region is specifed or should it unlock the region that the 
specified location is located.  I think the later.

I am using the linux-2.4.18-rmk7 but I also checked linux-2.4.19 and the

problem is also there.


I am new to this, I hope I gave enough and thorough informartion.

thanks
louie


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Re: Unlocking flash problem with the epxa10db device

[Louie Boczek]

Sounds good to me.  I could have gone either way.    So I actually fixed 
it the way you want.

On a side note, is there any reason that the entire flash is unlocked on 
boot instead of just the filesystem.  I am referencing the unlock code 
in epxa10db-flash.c.

thanks
louie


Christopher Hoover wrote:

>I wrote cfi_intelext_varsize_frob().  It is behaving as intended.
>
>You have to unlock/lock/erase/etc. an *entire* block/sector at a time.  
>
>There's no way to unlock 4 bytes and leave the other (erasesize - 4)
>bytes locked.  So the function returns EINVAL if the size isn't an even
>"multiple" of the block size(s).  ("Multiple" here is not meant strictly
>in the mathematical sense; consider variably-sized blocks.)
>
>You'll find the other functions behave identically, e.g. erase.
>
>-ch
>
>
>-----Original Message-----
>From: linux-arm-kernel-admin@lists.arm.linux.org.uk
>[mailto:linux-arm-kernel-admin@lists.arm.linux.org.uk] On Behalf Of
>Louie Boczek
>Sent: Thursday, September 19, 2002 8:11 PM
>To: ARM Linux kernel Mailinglist
>Subject: Unlocking flash problem with the epxa10db device
>
>
>I just started working with the Altera Excalibur board and ran into the 
>following problem.
>
>I was not able to write to the flash and found the problem lied in the 
>unlocking code.  
>In the epxa10db-flash.c:epxa10db_mtd_init() routine it calls:
>
>       mymtd->unlock(mymtd, mymtd->eraseregions[i].offset + j * 
>mymtd->eraseregions[i].erasesize, 4);
>
>which eventually calls "cfi_cmdsetc_001.c:cfi_intelext_varsize_frob()" 
>in this routine there is a check to make sure that the region being 
>unlocked is the whole region with  the check:
>        if ((ofs + len) & (regions[i].erasesize -1))
>            return -EINVAL;
>
>this fails since the call was only to unlock 4 bytes not erasesize.  So 
>I fixed the problem by changing the call to mymtd->unlock()  to pass the
>
>erasesize instead of 4.
>
>But the question is, should "cfi_intelext_varsize_frob()" check to see 
>if the whole region is specifed or should it unlock the region that the 
>specified location is located.  I think the later.
>
>I am using the linux-2.4.18-rmk7 but I also checked linux-2.4.19 and the
>
>problem is also there.
>
>
>I am new to this, I hope I gave enough and thorough informartion.
>
>thanks
>louie
>
>
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>
>  
>

Re: Unlocking flash problem with the epxa10db device

[Clive Davies]

> On a side note, is there any reason that the entire flash is unlocked on
> boot instead of just the filesystem.  I am referencing the unlock code
> in epxa10db-flash.c.
>
Not really, I didn't feel that the flash locking added much so I just 
unlocked the whole flash at boot time and forgot about it.

Clive