From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailrelay009.isp.belgacom.be (mailrelay009.isp.belgacom.be [195.238.6.176]) by ozlabs.org (Postfix) with ESMTP id 147EEDDE42 for ; Sat, 1 Dec 2007 02:28:40 +1100 (EST) From: Laurent Pinchart To: avorontsov@ru.mvista.com Subject: Re: CPM2 USB host driver Date: Fri, 30 Nov 2007 16:28:27 +0100 References: <200711301145.52926.laurentp@cse-semaphore.com> <200711301330.25100.laurentp@cse-semaphore.com> <20071130124801.GA13141@localhost.localdomain> In-Reply-To: <20071130124801.GA13141@localhost.localdomain> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1253608.uRCErA5FLE"; protocol="application/pgp-signature"; micalg=pgp-sha1 Message-Id: <200711301628.33526.laurentp@cse-semaphore.com> Cc: mike@compulab.co.il, linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --nextPart1253608.uRCErA5FLE Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Friday 30 November 2007 13:48, Anton Vorontsov wrote: > On Fri, Nov 30, 2007 at 01:30:18PM +0100, Laurent Pinchart wrote: > > On Friday 30 November 2007 12:16, Vitaly Bordug wrote: > > > On Fri, 30 Nov 2007 11:45:49 +0100 > > > > > > Laurent Pinchart wrote: > > > > Hi everybody, > > > > > > > > Linux USB host support for the CPM, CPM2 and CPM2 pro is far from > > > > complete. Many people showed interest on this list (and on > > > > linuxppc-embedded) in the past, but nobody managed to complete a > > > > driver and get it merged. > > > > > > that is mainly because of its semi-software nature. However, any > > > approach would be helpful I beleive. > > > > The CPM/CPM2 USB host controller does indeed put some pressure on the > > CPU. The PowerQuick III family is much better in that respect as its USB > > host controller is EHCI compliant. > > I didn't yet compare with CPM/CPM2, but I wonder if PQIIPro (MPC8360E) > USB controller is similar to cpms?.. If I'm not mistaken it is very similar to the CPM2 USB host controller, wit= h=20 the added ability to generate SOF packets automatically. The CPM has a packet-level USB host controller. CPM2 introduced a=20 transaction-level mode (it still supports packet-level mode). CPM2 pro fixe= s=20 the SOF packets generation issue that wakes the CPU once per millisecond wi= th=20 CPM and CPM2. Some members of the PQ2 and PQ2 pro families don't have a CPM but include a= =20 USB EHCI controller. I suppose those processors are less versatile (as the= =20 communication controllers are hardware-based instead of software-based) but= =20 offer more communication performance. If I'm not mistaken, the only processor to support USB in the PQ3 family is= =20 the MPC8555E. Its USB host controller is similar to the CPM2 as it supports= =20 both packet-level and transaction-level modes, but doesn't generate SOF=20 packets automatically. I assume the PQ3 integrates a CPM2 and not a CPM2 pr= o. To summarize the issue (and I'd appreciate if someone could confirm this), = a=20 packet-level FHCI driver would work with CPM, CPM2 and CPM2 pro based=20 processors. A transaction-level FHCI driver would work with the CPM2 and CP= M2=20 pro based processors. For CPM2 pro based processors, SOF packet generation= =20 can be handled by the CPM. > I tried to forward-port FHCI from Freescale 2.6.11 kernels. Twice. > But these efforts always stumbled over more important tasks. Do you think I start from the FHCI driver provided by Freescale for 2.6.11,= =20 from the cpm2usb driver or from scratch ? Both the cpm2usb and FHCI drivers seem to use the packet-level interface. I= s=20 there any reason not to use the transaction-level interface ? Best regards, =2D-=20 Laurent Pinchart CSE Semaphore Belgium Chauss=C3=A9e de Bruxelles, 732A B-1410 Waterloo Belgium T +32 (2) 387 42 59 =46 +32 (2) 387 42 75 --nextPart1253608.uRCErA5FLE Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) iD8DBQBHUCwh8y9gWxC9vpcRAnM3AJ9AXs6magCh+qapZSTTxnKRUAXEMQCgucz0 nzxYZfccclrHMIAITd5lSzE= =Nja6 -----END PGP SIGNATURE----- --nextPart1253608.uRCErA5FLE--