On Fri, Feb 19, 2021 at 09:46:49PM +0000, Aleksandar Gerasimovski wrote: > This is a draft patch to describe the problem and to initiate > a discussion for solution. > > PRAM usage is not taken into account when reserving lmb for ARM > architecture, this means that predefined PRAM region is reserved > by the u-boot and cannot be used by the u-boot users. > > In our case this bug leads to non functional ramfs boot, as the PRAM and > ram rootfs address ranges are getting reserved by the u-boot. > > It is obvious that here PRAM region is ignored, but my question is is this > clear to everyone and expected? > > Taking board_f.c as reference, when calculating relocation address PRAM > area is taken into account so I would expect that to be case here. > Here the intention is to reserve unused space at the end of the effective > RAM but PRAM is not part of that. > > Possible solution would be to introduce something like > get_effective_memsize here e.g powerpc/lib/bootm.c but then also > NR_DRAM_BANKS has to be considered? > > Signed-off-by: Aleksandar Gerasimovski > <[email protected]> > --- > arch/arm/lib/bootm.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c > index 11af9e2..4b06d25 100644 > --- a/arch/arm/lib/bootm.c > +++ b/arch/arm/lib/bootm.c > @@ -54,7 +54,7 @@ static ulong get_sp(void) > > void arch_lmb_reserve(struct lmb *lmb) > { > - ulong sp, bank_end; > + ulong sp, bank_end, pram = 0; > int bank; > > /* > @@ -69,6 +69,11 @@ void arch_lmb_reserve(struct lmb *lmb) > sp = get_sp(); > debug("## Current stack ends at 0x%08lx ", sp); > > +#ifdef CONFIG_PRAM > + pram = env_get_ulong("pram", 10, CONFIG_PRAM); > + pram = pram << 10; /* size is in kB */ > +#endif > + > /* adjust sp by 4K to be safe */ > sp -= 4096; > for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) { > @@ -76,8 +81,9 @@ void arch_lmb_reserve(struct lmb *lmb) > sp < gd->bd->bi_dram[bank].start) > continue; > /* Watch out for RAM at end of address space! */ > + /* @todo: pram obviously wrong if NR_DRAM_BANKS > 1 */ > bank_end = gd->bd->bi_dram[bank].start + > - gd->bd->bi_dram[bank].size - 1; > + gd->bd->bi_dram[bank].size - pram - 1; > if (sp > bank_end) > continue; > if (bank_end > gd->ram_top)
Adding a few folks who have touched lmb code relatively recently for their thoughts. Thanks! -- Tom
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