From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mundt Date: Mon, 21 Jan 2008 07:05:53 +0000 Subject: Re: [PATCH] sh: add resource of USB for SH7720 Message-Id: <20080121070552.GA19803@linux-sh.org> List-Id: References: <47860ABA.7000407@renesas.com> In-Reply-To: <47860ABA.7000407@renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org 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&m0027668329758&w=2 http://marc.info/?l=linux-usb-devel&m0055283608988&w=2