Re: [PATCH v3 1/2] mtd: nand: pxa3xx: Fix PIO FIFO draining

[Ezequiel Garcia <ezequiel.garcia@free-electrons.com>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

On 02/16/2015 01:41 PM, Maxime Ripard wrote:
> On Mon, Feb 16, 2015 at 05:27:53PM +0100, Thomas Petazzoni wrote:
>> Dear Maxime Ripard,
>>
>> On Mon, 16 Feb 2015 13:51:11 +0100, Maxime Ripard wrote:
>>
>>> +		while (index < (len * 4)) {
>>> +			u32 timeout;
>>> +
>>> +			__raw_readsl(info->mmio_base + NDDB, data + index, 8);
>>
>> Are you guaranteed that 'len' is a multiple of 32 bytes?
> 
> I don't know if you're guaranteed of anything, but the controller
> supports only 512, 2k, 4k and 8k pages, which are all mutiples of 32
> bytes.
> 

'len' here comes from:

do_bytes = min(info->data_size, info->chunk_size);

and

DIV_ROUND_UP(do_bytes, 4)

Where chunk_size is the size we want to read/write in each command step
(keep in mind that with extended commands we issue multiple commands, and
read/write data in chunks for each page).

And data_size is initialized at mtd->writesize (i.e. the size of a page).

Given all the flash pages I'm aware of are multiples of 32-bytes, and
given a chunk is either a quarter or half a page... I'd say it's
guaranteed to be 32-byte multiple, but perhaps it's a good idea to enforce it.
- -- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
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=nkDF
-----END PGP SIGNATURE-----