From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ilya Averyanov Date: Mon, 23 Apr 2012 17:40:32 +0400 Subject: [U-Boot] [PATCH v3] Add support for MINI2440 (s3c2440). Documentation about the product can be found on: http://www.friendlyarm.net/products/mini2440 In-Reply-To: <201204211519.30964.marex@denx.de> References: <20120416174633.GA7463@debian> <201204211519.30964.marex@denx.de> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Dear Marek Vasut, Would you please explain, why do you want to initialize the sdram has been in C code. If for provide this feature should be written assembly code. And it would sometimes even harder than the initialization code sdram? 2012/4/21 Marek Vasut > Dear Ilya Averyanov, > > > 2012/4/21 Vasily Khoruzhick > > > > > 2012/4/21 Ilya Averyanov : > > > > No have problem. > > > > Available only if you boot from NOR flash. > > > > If you boot from the NAND 4kb of SRAM (steppingstone) not available. > > > > > > For NAND boot it's mapped at 0x0 > > > For NOR boot it's mapped at 0x40000000 > > > > > > NAND controller uses it for booting purpose, but anyway for SPL we > > > should fit code into > > > 4k (hardware limitation), so I think using assembly here for SDRAM init > > > is OK. > > > > > > And how will you use the internal SRAM when you boot from NAND, if the > > > SoC > > > > writes in the SDRAM read data from NAND, and your data will be > overwritten. > > Why? You'll load SPL into SRAM, then in SPL you'll copy the rest of uboot > from > NAND to - then already inited - SDRAM and execute it. We even have > ready-to-use > NAND SPL. > > > > > > Regards > > > Vasily > > Best regards, > Marek Vasut >