From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marco Cavallini Date: Tue, 06 Jun 2006 10:38:40 +0200 Subject: [U-Boot-Users] AT91 u-boot lowlevel init Dataflash In-Reply-To: <4485386D.5060908@schweigstill.de> References: <44845F26.90504@koansoftware.com> <4485386D.5060908@schweigstill.de> Message-ID: <44853F10.3060600@koansoftware.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Andreas Schweigstill ha scritto: > Dear Marco! > > Marco Cavallini schrieb: >> Hi, >> I am trying to use u-boot-1.1.4 with AT91RM9200 based board. >> Using Parallel flash all works perfectly, but if I try using u-boot >> stored in Dataflash i face to some problems and comparing two cases I >> see that CPU clock are different. >> Seems that is required a RomBoot provided by Atmel which launch u-boot. >> Is it really necessary ? >> Maybe I've miss an option that avoid RomBoot usage ? > > You can omit the RomBoot step if you are able to build an U-Boot which > fits into ~12KB of the internal SRAM. > > RomBoot has to be adopted to your target hardware, especially for CPU > clock and memory initialisation. The Atmel provided RomBoot can only be > compiled with ARM ADS but there is also a GCC version available: > > http://www.teest.com/at91/romboot.tar.gz > Andreas thank you for answering. I can't and I don't want to store anything into internal SRAM. I simply want to use Dataflash AT45xxx instead of Parallel AT49xxx I digged and found that RomBoot leaves the CPU speed at its initial safe state (slow). Clocks: CPU 59 MHz, master 59 MHz, main 18.432 MHz ^^^^^^^^^^ Then I added board_late_init into at91rm9200dk.c and there I've set PLLAR, PLLBR, MCKR like into lowlevel_init.S Now my board boots with the desired clock speed. Clocks: CPU 179 MHz, master 59 MHz, main 18.432 MHz ^^^^^^^^^^ BTW I wonder if could be useful (and appreciated) if I should merge RomBoot settings into u-boot allowing u-boot to be the one and only loader for Dataflash too. Ciao -- Marco Cavallini Koan s.a.s. - Bergamo - ITALIA Embedded and Real-Time Software Engineering www.KoanSoftware.com | www.KaeilOS.com