Dear Stefano Babic, > On 01/04/2012 15:46, Marek Vasut wrote: > > Dear Stefano Babic, > > Hi Marek, > > >> If the range passed to flush_cache is not multiple > >> of ARCH_DMA_MINALIGN, a warning due to mislaignment > >> is printed. > >> Detected with fec_mxc, mx35 boards: > >> > >> CACHE: Misaligned operation at range [80800000, 8083c310] > >> > >> Signed-off-by: Stefano Babic <sba...@denx.de> > >> CC: Marek Vasut <ma...@denx.de> > >> CC: Joe Hershberger <joe.hershber...@gmail.com> > >> Cc: Wolfgang Denk <w...@denx.de> > >> --- > >> > >> common/cmd_net.c | 2 +- > >> 1 files changed, 1 insertions(+), 1 deletions(-) > >> > >> diff --git a/common/cmd_net.c b/common/cmd_net.c > >> index 65f32bc..a500919 100644 > >> --- a/common/cmd_net.c > >> +++ b/common/cmd_net.c > >> @@ -256,7 +256,7 @@ static int netboot_common(enum proto_t proto, > >> cmd_tbl_t *cmdtp, int argc, } > >> > >> /* flush cache */ > >> > >> - flush_cache(load_addr, size); > >> + flush_cache(load_addr, roundup(size, ARCH_DMA_MINALIGN)); > > > > This ain't gonna slide. You might overwrite something, even though this > > is just loading into memory, right? > > Really we do not reserve space before a network transfer and we pass > only the start address (load address) where the file is copied. It is > not known its size before the transfer. So maybe it is not important up > to further 31 bytes are flushed ;-) > > Anyway, for my understanding: we are calling a function to flush caches. > This means that if the size is something more as required there will be > a cache hit misseing, and the SOC will load data again - but without > corrupt data, right ?
Sure, but you can flush data into the RAM that should have never been flushed to the ram in the first place and that might confuse some controller -- or I might be overly paranoid. > > > I'm not quite sure how to handle this kind of > > unaligned access. > > Well, my first goal was to explain which is the cause of the > misalignment I found last friday testing Anatolij's patch, proofing that > it is not due to last FEC patches ;-) > > > But adding at least if (unaligned) debug(...); to aid people easily > > finding these trouble would be nice ;-) > > Not sure - where should be inserted or what do you exactly mean? size > is the length of the transfered bytes, and can assueme any value, so it > is often not aligned. Well just before the cache-line aligning. > Best regards, > Stefano Babic Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
