From: Paul Mundt <lethal@linux-sh.org>
To: linux-sh@vger.kernel.org
Subject: Re: [PATCH] sh: add resource of USB for SH7720
Date: Mon, 21 Jan 2008 07:05:53 +0000 [thread overview]
Message-ID: <20080121070552.GA19803@linux-sh.org> (raw)
In-Reply-To: <47860ABA.7000407@renesas.com>
On Mon, Jan 21, 2008 at 08:00:33AM +0100, Manuel Lauss wrote:
> On Sun, Jan 20, 2008 at 01:15:16AM -0800, Kristoffer Ericson wrote:
> > Greetings,
> >
> > Without looking to heavily in the hd64465 datasheet, you think this
> > would work for hd64465+SH7729 platform? It contains an OHCI based usb
> > host.
>
> Not without some additional changes to the OHCI stack.
> The HD64465 OHCI (and the SH7760 OHCI too) can only do transfers
> from/to its internal SRAM; the Linux OHCI stack simply assumes
> that the HC can read all Transfer Descriptors (TD) and data
> from main memory.
> Also, SRAM is rather small (8kB IIRC) so you can forget about
> USB mass storage outright (and bluetooth dongles too), only
> keyboards and mice work right.
> Finally, the SRAM has different addresses, depending on who's
> accessing it (HC or CPU), making it necessary to go over the
> TDs and adjust the data pointers to 'HC-view' before transfer
> and 'CPU-view' after they're done.
>
> In short: the hardware sucks... ;-)
>
http://marc.info/?l=linux-usb-devel&m\x120027668329758&w=2
http://marc.info/?l=linux-usb-devel&m\x120055283608988&w=2
next prev parent reply other threads:[~2008-01-21 7:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-10 12:08 [PATCH] sh: add resource of USB for SH7720 Yoshihiro Shimoda
2008-01-11 1:35 ` Paul Mundt
2008-01-20 0:16 ` Kristoffer Ericson
2008-01-21 7:00 ` Manuel Lauss
2008-01-21 7:05 ` Paul Mundt [this message]
2008-01-21 7:09 ` Manuel Lauss
2008-01-21 12:10 ` Yutaro Ebihara
2008-01-21 14:40 ` Kristoffer Ericson
2008-01-22 0:46 ` Paul Mundt
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