Hi Siva, On 14 June 2018 at 00:53, Siva Durga Prasad Paladugu <siva...@xilinx.com> wrote: > Hi Simon, > >> -----Original Message----- >> From: s...@google.com [mailto:s...@google.com] On Behalf Of Simon Glass >> Sent: Saturday, June 09, 2018 3:29 AM >> To: Michal Simek <michal.si...@xilinx.com> >> Cc: Siva Durga Prasad Paladugu <siva...@xilinx.com>; U-Boot Mailing List >> <u-boot@lists.denx.de>; Tom Rini <tr...@konsulko.com> >> Subject: Re: [PATCH 1/4] lib: fdtdec: Fill initial ram top with DDR start >> value >> from dt >> >> Hi, >> >> >> On 7 June 2018 at 06:18, Michal Simek <michal.si...@xilinx.com> wrote: >> > Hi, >> > >> > On 5.6.2018 09:20, Siva Durga Prasad Paladugu wrote: >> >> Fill initial ram top with DDR base addr value from DT as not filling >> >> it here always assumes it as zero while calculating relocation offset >> >> and hence lead to failures in somecases. This will assumed as zero if >> >> CONFIG_SYS_SDRAM_BASE is not defined. >> >> >> >> Signed-off-by: Siva Durga Prasad Paladugu >> >> <siva.durga.palad...@xilinx.com> >> >> Signed-off-by: Michal Simek <michal.si...@xilinx.com> >> >> --- >> >> lib/fdtdec.c | 1 + >> >> 1 file changed, 1 insertion(+) >> >> >> >> diff --git a/lib/fdtdec.c b/lib/fdtdec.c index f4e8dbf..34ef9b8 >> >> 100644 >> >> --- a/lib/fdtdec.c >> >> +++ b/lib/fdtdec.c >> >> @@ -1172,6 +1172,7 @@ int fdtdec_setup_memory_size(void) >> >> } >> >> >> >> gd->ram_size = (phys_size_t)(res.end - res.start + 1); >> >> + gd->ram_top = (unsigned long)res.start; >> >> debug("%s: Initial DRAM size %llx\n", __func__, >> >> (unsigned long long)gd->ram_size); >> >> >> >> >> > >> > I am curious about ram_top meaning. It is used more as ram_base. >> > >> > I expect we can workaround it by board_get_usable_ram_top() where we >> > decode it exactly the same as patched fdtdec_setup_memory_size() but I >> > don't think it is better solution than this one. >> > >> > Simon/Tom: any comment? >> >> I wonder why it is not set to res.end in this patch? >> >> Comments from global_data.h: >> >> unsigned long ram_top; /* Top address of RAM used by U-Boot */ >> phys_size_t ram_size; /* RAM size */ > > Yes, it holds the ram high address but, initially it should contain start > address then in routine setup_dest_addr() (file common_board_f.c), it will be > updated by getting the > total mem size as below. > gd->ram_top += get_effective_memsize(); > > Lets consider if start address is non zero then it results in wrong ram_top > without this patch. So, this patch fixes it by initializing it to ram start > address and later in setup_dest_addr(), it will be updated to actual ram high > address. > Otherway of fixing it is, we should add new variable to gd_t to hold > ram_start and then while calculating ram_top in setup_dest_addr(), we should > use it as gd->ram_top = gd->ram_start + get_effective_memsize() as > gd->bd->bi_dram[0].start didn’t get filled by this time during init.
Thanks for the explanation. I think adding that new variable would be better and less confusing. But then fdtdec_setup_memory_size() needs to be renamed. Also I think it is confusing to set gd->ram_size to CONFIG_SYS_SDRAM_BASE and then increase it, so you should be able to change that to ram_start also. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
