Re: [U-Boot] DRAM clock frequency issue
Hi Chris. Thanks for your response. There was a typo earlier, the correct U-boot version is 1.1.4. The current RAM consists of two physical chips of 64 MB each, it is the Winbond W9751G6JB (DDR2). 1T/2T is not supported as I understand. I'll examine the board layout to see how it is affecting the DDR. On Sun, Jun 3, 2018 at 9:46 PM, Chris Packham wrote: > > > On Fri, 1 Jun 2018, 10:42 PM Greg Maitz, wrote: >> >> Hi - I have a target Atheros 9344 board on which I have loaded U-boot >> version 1.23.2. On the reference board, the DRAM clock frequency has >> been set to 400 MHz and it works well. > > > Sounds like you've got a vendor bootloader. 1.23.2 isn't a version number > used by u-boot. You might get more informed support from wherever you > obtained this. > >> But when the same clock >> frequency is used on my target board , mtest (memory test) fails. >> However, when I reduced the clock frequency to 300 MHz, the mtest >> passes and it appears to be stable. >> The reference and target boards are alike in almost every respect. > > > Double check this assertion. Even if things appear similar on a schematic > the board layout is significant when it comes to ddr. > >> The >> DRAM specifications are the same but the manufacturer is different. >> >> I tried setting the DRAM timing parameters on my target DRAM to be >> aligned with the numbers in the data sheet. When I load the Linux >> kernel after this, there are a variety of kernel panics seen if I >> leave it on overnight. They are OOPS messages such as "Unable to >> handle kernel paging request at virtual address", I think they may be >> related to the DRAM clock frequency setting. > > > A plug here for memtester http://pyropus.ca/software/memtester/ it's been > quite handy for excercising ram. Unfortunately it won't fix the problem, but > it will let you know when you have. > >> I'd like to eventually use 400 MHz clock for the DRAM clock frequency >> on my target board. If anyone has faced a similar scenario earlier, >> kindly share your tips to debug the problem. > > > I've used enabled 2T timing (assuming your ddr controller supports it) for > similar issues in the past. If it works it's usually an indication of some > hardware issue but it may get you through to the next board spin. ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Re: [U-Boot] DRAM clock frequency issue
On Fri, 1 Jun 2018, 10:42 PM Greg Maitz, wrote: > Hi - I have a target Atheros 9344 board on which I have loaded U-boot > version 1.23.2. On the reference board, the DRAM clock frequency has > been set to 400 MHz and it works well. Sounds like you've got a vendor bootloader. 1.23.2 isn't a version number used by u-boot. You might get more informed support from wherever you obtained this. But when the same clock > frequency is used on my target board , mtest (memory test) fails. > However, when I reduced the clock frequency to 300 MHz, the mtest > passes and it appears to be stable. > The reference and target boards are alike in almost every respect. Double check this assertion. Even if things appear similar on a schematic the board layout is significant when it comes to ddr. The > DRAM specifications are the same but the manufacturer is different. > > I tried setting the DRAM timing parameters on my target DRAM to be > aligned with the numbers in the data sheet. When I load the Linux > kernel after this, there are a variety of kernel panics seen if I > leave it on overnight. They are OOPS messages such as "Unable to > handle kernel paging request at virtual address", I think they may be > related to the DRAM clock frequency setting. > A plug here for memtester http://pyropus.ca/software/memtester/ it's been quite handy for excercising ram. Unfortunately it won't fix the problem, but it will let you know when you have. I'd like to eventually use 400 MHz clock for the DRAM clock frequency > on my target board. If anyone has faced a similar scenario earlier, > kindly share your tips to debug the problem. I've used enabled 2T timing (assuming your ddr controller supports it) for similar issues in the past. If it works it's usually an indication of some hardware issue but it may get you through to the next board spin. ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
[U-Boot] DRAM clock frequency issue
Hi - I have a target Atheros 9344 board on which I have loaded U-boot version 1.23.2. On the reference board, the DRAM clock frequency has been set to 400 MHz and it works well. But when the same clock frequency is used on my target board , mtest (memory test) fails. However, when I reduced the clock frequency to 300 MHz, the mtest passes and it appears to be stable. The reference and target boards are alike in almost every respect. The DRAM specifications are the same but the manufacturer is different. I tried setting the DRAM timing parameters on my target DRAM to be aligned with the numbers in the data sheet. When I load the Linux kernel after this, there are a variety of kernel panics seen if I leave it on overnight. They are OOPS messages such as "Unable to handle kernel paging request at virtual address", I think they may be related to the DRAM clock frequency setting. I'd like to eventually use 400 MHz clock for the DRAM clock frequency on my target board. If anyone has faced a similar scenario earlier, kindly share your tips to debug the problem. ___ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
