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Message-ID: <5254892B.3050507@bakulin.de>
Date: Wed, 09 Oct 2013 00:37:31 +0200
From: Ilya Bakulin <ilya@bakulin.de>
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To: Warner Losh <imp@bsdimp.com>
Subject: Re: SDIO for FreeBSD
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Cc: Adrian Chadd <adrian.chadd@gmail.com>, Alexander Motin <mav@freebsd.org>,
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On 07.10.13 01:19, Warner Losh wrote:
> I've often thought that having an SDIO protocol for CAM would be where we'd wind up because once you start adding in GPIO pin interrupt signalling, message "interrupt" signaling, message completion, etc, it looks a lot like many of the mechanisms we have in CAM...  I'm not at all sure that USB is the right model to use, frankly...  But it does have some superficial similarities...
> 
> Warner

The idea seems to be interesting -- at least we can reuse the CAM queues
and interrupt handling algorithms...
One thing that I'd like to ask after initial reading about CAM in FreeBSD:
is it possible for SIM devices to initiate data transfer?
the CAM subsystem is primarily used for storage devices,
where the host issues a SCSI command, schedules it to the SIM,
and then SIM receives an interrupt from the h/w and updates the existing
CCB,
signaling command completion.

In SDIO case we can have the interrupts from the card
that are not associated with any previous command.
Is it possible to handle such situation using CAM framework?
-- 
Regards,
Ilya Bakulin