From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fuCuZ-0003AQ-Lo for barebox@lists.infradead.org; Mon, 27 Aug 2018 08:30:14 +0000 Date: Mon, 27 Aug 2018 10:29:59 +0200 From: Sascha Hauer Message-ID: <20180827082959.dbpkqm7kvofembrh@pengutronix.de> References: <20180824151739.8883-1-m.grzeschik@pengutronix.de> <20180824170407.geeahhgkqntovpi5@pengutronix.de> <20180824195556.jihqkka6bj5tbqpq@pengutronix.de> <20180827074741.rnmenb6mvjzv2qto@pengutronix.de> <20180827075224.zmouhtgevz4masrd@pengutronix.de> <20180827081322.bgtjhamviu5p7byd@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180827081322.bgtjhamviu5p7byd@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] imx{5,6}: reset otg port after usb-serial boot To: Michael Grzeschik Cc: Barebox List On Mon, Aug 27, 2018 at 10:13:22AM +0200, Michael Grzeschik wrote: > On Mon, Aug 27, 2018 at 09:52:24AM +0200, Sascha Hauer wrote: > > On Mon, Aug 27, 2018 at 09:47:41AM +0200, Michael Grzeschik wrote: > > > On Fri, Aug 24, 2018 at 05:18:02PM -0300, Fabio Estevam wrote: > > > > Hi Michael, > > > > > > > > On Fri, Aug 24, 2018 at 4:55 PM, Michael Grzeschik wrote: > > > > > > > > > I get that it is not safe to toggle bits if the clock is not > > > > > there. We could check for the bootsource. Is it possible to > > > > > ensure that we are started by imx-usb-loader? > > > > > > > > It is possible to determine if we have started via USB download mode. > > > > > > > > Check the is_boot_from_usb() implementation in U-Boot for a reference. > > > > > > Right, So it seems to be safe to reach for the phys registers on mx6. > > > > > > On mx5 and similar we have a nop phy and the only way to > > > communicate with it is through usbmisc, which is also in the > > > register space that leads to a hang if one clock is missing. > > > > > > I will search for another solutions on those SoCs. > > > > It's not necessary to ask for the bootsource. You just have to enable > > the clocks necessary to access the USB registers. Or the other way > > round: When the clocks are not enabled already, you could assume we have > > not booted from USB. > > Right, I think enabling the clocks is a little bit more safe > as we otherwise would need to ensure that nobody slips in > a DCD that already ungates all clocks. What could happen is that somebody *dis*abled the USB clocks in DCD. In that case though the USB on the host will already be confused and we already have lost - no need to do anything in that case. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox