From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by casper.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Rxdg3-0008W7-O5 for barebox@lists.infradead.org; Wed, 15 Feb 2012 12:09:45 +0000 Date: Wed, 15 Feb 2012 13:09:11 +0100 From: Sascha Hauer Message-ID: <20120215120911.GB3852@pengutronix.de> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: iMX27 clock settings To: Igor Trevisan Cc: barebox@lists.infradead.org On Tue, Feb 14, 2012 at 04:10:08PM +0100, Igor Trevisan wrote: > Hi, > > I'm working on a custom board based on iMX27L. Initially I worked with Redboot > as Linux bootloader but now, I'm happily working with Barebox (2012.01.0) > having replaced Redboot with it. > > Everithing is fine (thanks to the guys in the list for helping me!) but... > I noticed that my Linux apps run more slowly within my system if it's > started by Barebox > then if it's started by Redbbot. > I think it's a matter of internal clocks settings. > > I see that Redboot, for example, set: > CSR=0x33F38107 > while Barebox does: > writel(0x33F30307 | CSCR_MPLL_RESTART | CSCR_SPLL_RESTART, CSCR) > That brings to CSR=0x33F30307 at the end of the PLLs restart procedure. > > Reading the Manual I can see that the differences between the two settings > mean having an arm_clk that is 2/3 and an AHB_clk that's the half. > > Is there a particular reason for having these "slower configuration"? One thing that might be interesting in such cases is the output of the dump_clocks command. 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