From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lpp01m020-f177.google.com ([209.85.217.177]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1RxK1X-00026M-0l for barebox@lists.infradead.org; Tue, 14 Feb 2012 15:10:31 +0000 Received: by lbon10 with SMTP id n10so3942852lbo.36 for ; Tue, 14 Feb 2012 07:10:28 -0800 (PST) MIME-Version: 1.0 From: Igor Trevisan Date: Tue, 14 Feb 2012 16:10:08 +0100 Message-ID: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: iMX27 clock settings To: barebox@lists.infradead.org Hi, I'm working on a custom board based on iMX27L. Initially I worked with Redb= oot 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=3D0x33F38107 while Barebox does: writel(0x33F30307 | CSCR_MPLL_RESTART | CSCR_SPLL_RESTART, CSCR) That brings to CSR=3D0x33F30307 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"? I tried to change the lowlevel_init.S to force 0x33F38107 into CSCR at startup but, after that change, my board starts, has time to write somenthing on the serial console: "barebox 2012.01.0-svn11070-dirty1 (Feb 14 2012 - 11:10:39) Board: Freescale i=FF" and then restarts... continuously. Can anybody help me to understand this and to make (if possible) my system faster? Thanks in advance, Igor -- = "Don't find fault, find a remedy." (Henry Ford) _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox