On 12 December 2016 at 03:08, Igor Grinberg <grinb...@compulab.co.il> wrote: > 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). However with the introduction of >> dtbs for some boards they are also capable of loading the size of >> memory from the embedded/appended dtb (instead of hardcoded). This >> allows for more of the board config to be loaded from the device tree >> instead of from include/configs/*.h. This however is up to the >> individual board to implement in its dram_init* functions. > > Thanks for the explanation! > I assume that the key point is "detection is not possible" and therefore > we must rely on a user or a production process to place (append) the correct > dtb. > Makes sense to me now and looks like an improvement to the current situation. > >> >> The first patch of the series is only adding some decoding helper >> functions to make this generic between the Zynq and ZynqMP boards as >> well as to allow for any other boards that may want to use the same >> mechanism to get the memory size from the fdt. There is no requirement >> for boards to use these functions. > > Can you please next time place a similar explanation in at least the cover > letter. This way, the intent might be understood the first time ;-)
Sorry about that, I will make sure future series have more complete descriptions in the cover letter. I have however updated the description for this in the v2 for completeness. > I would also like to see some parts of the above explanation in the functions > documentation (e.g. this allows to improve the DRAM configuration mechanics > on boards that cannot detect its DRAM size/config). Will add in v2. Regards, Nathan > > Thanks! > >> >> Regards, >> Nathan >> >>> >>>> >>>> The series also changes the zynq and zynqmp board implementations to use >>>> these functions to resolve a issue with static variable use. >>>> >>>> Nathan Rossi (3): >>>> fdt: add memory bank decoding functions for board setup >>>> ARM: zynq: Replace board specific with generic memory bank decoding >>>> ARM64: zynqmp: Replace board specific with generic memory bank >>>> decoding >>>> >>>> board/xilinx/zynq/board.c | 112 >>>> ++----------------------------------------- >>>> board/xilinx/zynqmp/zynqmp.c | 112 >>>> ++----------------------------------------- >>>> include/fdtdec.h | 25 ++++++++++ >>>> lib/fdtdec.c | 54 +++++++++++++++++++++ >>>> 4 files changed, 85 insertions(+), 218 deletions(-) >>>> >>> >>> -- >>> Regards, >>> Igor. >> > > -- > Regards, > Igor. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
