On 12/12/16 10:02, Michal Simek wrote: > On 12.12.2016 08:13, Nathan Rossi wrote: >> On 12 December 2016 at 03:11, Igor Grinberg <grinb...@compulab.co.il> wrote: >>> dropping the list for this one as the question seems to me irrelevant to >>> your patch set. >>> >>> On 12/11/16 18:47, Nathan Rossi wrote: >>>> On 12 December 2016 at 01:08, Igor Grinberg <grinb...@compulab.co.il> >>>> wrote: >>>>> Hi Nathan, >>>>> >>>>> On 12/11/16 15:58, Nathan Rossi wrote: >>>>>> This series adds two functions for handling the memory bank decoding and >>>>>> initialization of global data for use by boards in their dram_init and >>>>>> dram_init_banksize functions. >>>>> >>>>> I might have missed some discussions on this meter, >>>>> can you please provide the use cases for this? >>>>> IMO, the bootloader's job is to initialize the DRAM, detect its size, and >>>>> pass >>>>> the detected DRAM configuration on to an OS. >>>> >>>> Hi Igor, >>>> >>>> I do not think there have been any discussions on this (at least none >>>> that I am aware of). >>>> >>>> Some boards (like Zynq and ZynqMP ones) are using >>>> CONFIG_SYS_SDRAM_SIZE to define the amount of memory that is available >>>> (since detection is not possible). >>> >>> May I ask why is detection not possible on these boards (may be SoCs)? >> >> That is correct, Zynq and ZynqMP are ARM SoCs. Which in the majority >> of cases are used in boards which have fixed memory device setups >> (without any SPD or equivalent). > > For example zcu102 zynqmp development board is using modules with SPD on > it but if you look at generic SPD support then you will find out that > FSL(drivers/ddr/fsl) is one of the major platform which is using it for > ddr size detection. > Anyway as Nathan wrote above the majority of boards with zynq/zynqmp > devices need to be configured at build time or at run time by DTB. > > There is also topic.nl boards which contain ddr configuration the same > for different ddr sizes and Mike sent this patch to get it work > http://lists.denx.de/pipermail/u-boot/2016-November/273385.html
That's exactly my point. I think Mike's patch does a way better job detecting at run time than any compiled in or a DT based pseudo detection... > > Anyway in general there are some ways how to configure DDR size > - build time setup (CONFIG_SYS_SDRAM*) > - run time setup > - ddr detection > - via SPD (like FSL) > - via algorithm (like topic.nl) > - configuration > - read DTB > > Nathan's path is trying to address last run time DTB configuration > method to be shared across platforms because similar stuff Uniphier is > using too. And it doesn't make sense to copy that functions everywhere > that's why this should go core parts. Yep. That's exactly what I thought. I see Nathan's patch set as an improvement of the current situation anyway. Also I think Mike's patch does a much better job on this. -- Regards, Igor. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot