Re: [RFC][PATCH] at91_ide driver

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Stanislaw Gruszka wrote:

>>>do special things before access Task File and Data Register (functions 
>>>set_8bit_mode() and set_16bit_mode()).

>>   That part really doesn't look well -- Atmel should have put more 
>>though into it and make the register stride 2 bytes, so that 16-bit 
>>access could alwys be used...

> Actually it is possible (I realize when seeing pata_at32) when address
> lines are connected in diffrent way, h/w trick is described in AVR32 ATA
> application note. Only register addresses are multiplied by 2 then.
> However Atmel reference documents for AT91 don't describe such
> connection. I suppose AT91 evaluation boards are designed without the trick.

    It's not much of a trick, just a usual way of connection a 16-bit 
device... I'd advise that you pass the register stride info via the platform 
data, alike to what pata_platform devices do.

>>>We did not tests on Atmel sam9263ek board, because we have no proper connector
>>>for 1,8'' HDD.

>>   Not sure I've understood that. You have 1,8'' drive and the board has 
>>stndard IDE connector?
> 
> Board has 44-pin male IDE connector (rather non standard one), we have no cable

    I think it's pretty standard laptop connector.

> or any device to connect. Kelvatek's board has Compact Flash connector, we use CF
> card for testing. We currently ordered proper cable and IDE->CF adapter, so
> I'll do tests on sam9263ek.

    Besides, not all CF connectors are DMA compatible (don't have pin 43/44 
wired for DMA).

MBR, Sergei