[U-Boot] U-BOOT DDR INITIALIZATION
Hi, We are using P4080DS demo board. It has two 2GB Ram. We want to optimize/reduce both bootloader time. For bootloader we use u-boot. While we are working on u-boot, DDR is the one that takes more time. When we have checked u-boot DDR initialization code timeout is stated 400 milliseconds for each GByte. So, after that point we have done some tests. First of all, we have removed one of DDR3 which is 2GB. We have booted demo board successfully, and check DDR initialization time. It was 200 milliseconds and that elapsed time is for clearing to D_INIT bit. After that, we have attached the removed DDR. We have booted demo board successfully and check DDR initialization time. It was 1000 milliseconds. The 800 milliseconds elapsed time is clearing D_INIT bit for both DDR. And the 200 milliseconds elapsed time is reallocating DDR. After that, we have removed the code that waits for D_INIT bit to be cleared and we have booted demo board successfully when all DDR attached (4GB). We were expecting to pass 200 milliseconds for relocation; however elapsed time was 400 milliseconds. So, 1. What are the reasons for that? 2. What are the reasons that when we update DDR RAM from 2 GByte to 4 GByte it takes much more time (From 200(2GB) + 0(relocation) = 200 millisecond to 400 (2GB ) + 400 (2GB) + 200(relocation) = 1000 millisecond)? 3. How can we reduce DDR initialization time? 4. When we comment out the code that waits D_INIT bir to be cleared, board boots successfully. So, do we really need to wait for D_INIT? Best Regards. -- View this message in context: http://u-boot.10912.n7.nabble.com/U-BOOT-DDR-INITIALIZATION-tp254576.html Sent from the U-Boot mailing list archive at Nabble.com. ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] DDR initialization
Dear Magnus Lilja, In message 59b21cf20908182251v6e023327h42fceb2ffb86c...@mail.gmail.com you wrote: It's often done in lowlevel_init.S, whether that's true for all platforms and all boards I do not know. lowlevel_init.S is only used on ARM boards. No other architecture does it like that. Usually we try to avoid using assembler code, especially for critical things like RAM initialization where you want to have the best possible debug support (and just adding a printf() here and there is often _very_ convenient). Just one of the many areas where the ARM port has been done wrong. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de There are two kinds of people, those who do the work and those who take the credit. Try to be in the first group; there is less competition there.- Indira Gandhi ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
[U-Boot] DDR initialization
Hi all, How do i go about the SDRAM/DDR initialization on my board. IS the function partitoned or is it just done in a single place. I would think that board specifc dram_init is just a generic function. There has to be a specific place where the SDRAM controller is told about the DRR/SDRAM. Is the porting documented somewhere or are there any good example to follow to stick to U-boot conventions. Please enlighten me. Thanks Regards, ALfred ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] DDR initialization
Hi 2009/8/19 alfred steele alfred.jaq...@gmail.com: Hi all, How do i go about the SDRAM/DDR initialization on my board. IS the function partitoned or is it just done in a single place. I would think that board specifc dram_init is just a generic function. There has to be a specific place where the SDRAM controller is told about the DRR/SDRAM. Is the porting documented somewhere or are there any good example to follow to stick to U-boot conventions. It's often done in lowlevel_init.S, whether that's true for all platforms and all boards I do not know. /Magnus ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
