From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from webbox1416.server-home.net ([77.236.96.61]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UPTvK-0003Xm-LZ for linux-mtd@lists.infradead.org; Tue, 09 Apr 2013 08:29:04 +0000 From: Alexander Stein To: Thomas.Betker@rohde-schwarz.com Subject: Re: serial Flash over SPI as rootdevice? Date: Tue, 09 Apr 2013 10:28:58 +0200 Message-ID: <4196867.FVmTr7jyS0@ws-stein> In-Reply-To: References: <5322202.sSFaOpDNta@ws-stein> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello Thomas, On Tuesday 09 April 2013 10:21:26, Thomas.Betker@rohde-schwarz.com wrote: > Hello Alexander: > > > is it currently possible to use a serial Flash connected over SPI to > > use as a rootdevice? > > If not, would it be possible and which drivers need to be written > > for that then? > > Yes, it is certainly possible; we are doing it ourselves. No extra drivers > are required for this beyond those you need anyway (SPI driver, SPI flash > driver). That sound great. Could you please point me to the driver needed for that? Do you have any performance comparisons to e.g. NOR flash? > The real problem, though, is that you cannot boot from standard SPI flash. > For this, you need memory which can be read directly by the CPU, such as > parallel NOR flash. Well, the idea is to use an AT91 which can boot directly from serial flash with it's own ROM code. This would load the bootloader (will be u-boot likely) which in turns needs to fetch the kernel from the serial flash too. Should be possible, no? Best regards, Alexander