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From: Pierre Ossman <drzeus-list@drzeus.cx>
To: Ian Stirling <ian.stirling@mauve.plus.com>
Cc: madhu chikkature <crmadhu210@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: SDIO card support in Linux
Date: Fri, 01 Sep 2006 17:53:59 +0200	[thread overview]
Message-ID: <44F85797.9070208@drzeus.cx> (raw)
In-Reply-To: <44F85646.4030100@mauve.plus.com>

Ian Stirling wrote:
>>
>> SD mandates a star topology (just a single card per bus), so we'll just
>> force a single card into the list. SD memory cards can actually work on
>> a shared bus, SDIO can not. It's not a big problem in practice though.
>
> Is this true in SD-1 bit mode, or SPI?

Yes, no. :)

> I see nothing on a quick read-through of the abbreviated SDIO spec
> precluding  this.
> Of course, it'd mean wire-or'd interrupt lines.
>

The problem is that there is no "king-of-the-hill" mechanism in the SDIO
init sequence (like there is in SD mem). The protocol assumes that the
desired card always receives the command.

Rgds
Pierre


  reply	other threads:[~2006-09-01 15:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-31 15:04 SDIO card support in Linux madhu chikkature
2006-08-31 19:53 ` Pierre Ossman
2006-09-01 15:48   ` Ian Stirling
2006-09-01 15:53     ` Pierre Ossman [this message]
2006-09-05 23:51   ` madhu chikkature
2006-09-06  5:20     ` Pierre Ossman
2006-09-06 23:22       ` madhu chikkature
2006-09-07 14:54         ` Pierre Ossman
2006-09-14 12:01     ` Bhavani

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