From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mout.kundenserver.de ([212.227.126.187]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YBJk9-0007pi-70 for barebox@lists.infradead.org; Wed, 14 Jan 2015 08:56:02 +0000 Date: Wed, 14 Jan 2015 09:55:32 +0100 (CET) From: Rolf Evers-Fischer Message-ID: <805818852.49418.1421225733074.JavaMail.open-xchange@oxbaltgw09.schlund.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Rolf Evers-Fischer 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: Boot speed on 600MHz AM3354 To: barebox@lists.infradead.org, andy.pont@sdcsystems.com Dear Andy, we have another custom hardware platform that uses a 800MHz TI AM3359. Currently we store only barebox-MLO and the barebox itself in SPI NOR. The kernel is loaded over USB. When I checked the SPI bus during boot, I found that the ROM Code loads the first part of the barebox in chunks of 4 byte with a break of 1.7us between each 4-byte-packet, while the first part of the barebox (called "barebox_MLO") loads the second part "byte by byte" with a break of 500ns between the bytes. Adding the transfer time of 320ns per byte will result in a transfer rate of 1000/820 = 1,2MByte/s. This means that, if we would ever boot our 2,7MByte kernel from the SPI NOR, it would take at least 2.3 seconds to load it from the flash into the RAM. I don't have so much experience with U-Boot, but I'd expect similar figures there. Kind regards, Rolf _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox