Hi Leo, On Mon, Sep 14, 2020 at 2:10 PM Leo Liang <ycli...@andestech.com> wrote: > > Hi, Bin > On Mon, Sep 14, 2020 at 10:07:57AM +0800, Bin Meng wrote: > > Hi Leo, > > > > On Mon, Sep 14, 2020 at 9:58 AM Leo Liang <ycli...@andestech.com> wrote: > > > > > > On Fri, Sep 11, 2020 at 04:04:13PM +0800, Bin Meng wrote: > > > > On Tue, Sep 8, 2020 at 2:17 AM Sean Anderson <sean...@gmail.com> wrote: > > > > > > > > > > Some IPIs may already be pending when U-Boot is started. This could > > > > > be a > > > > > problem if a secondary hart tries to handle an IPI before the boot > > > > > hart has > > > > > initialized the IPI device. > > > > > > > > > > This commit uses NULL as a sentinel for secondary harts so they know > > > > > when > > > > > the IPI is initialized, and it is safe to use the IPI API. The smp > > > > > addr > > > > > parameter is initialized to NULL by board_init_f_init_reserve. Before > > > > > this, > > > > > secondary harts wait in wait_for_gd_init. > > > > > > > > > > This imposes a minor restriction because harts may no longer jump to > > > > > NULL. > > > > > However, given that the RISC-V debug device is likely to be located at > > > > > 0x400, it is unlikely for any RISC-V implementation to have usable ram > > > > > located at 0x0. > > > > > > > > > > Signed-off-by: Sean Anderson <sean...@gmail.com> > > > > > --- > > > > > > > > > > arch/riscv/lib/smp.c | 26 ++++++++++++++++++++++---- > > > > > 1 file changed, 22 insertions(+), 4 deletions(-) > > > > > > > > > > > > > Reviewed-by: Bin Meng <bin.m...@windriver.com> > > > > > > Hi Bin, > > > > > > There is a series of follow-up discussion on this patch that you might > > > miss reading. > > > > > > This current patch will cause AE350 to fail booting, > > > > > > so maybe we should wait until Sean's next patch comes up to consider a > > > reviewed-by tag. > > > > > > > Do we know why AE350 fails to boot with this patch? > > > > When booting with bootm command, > boot hart will use smp_call_function(addr, arg0, arg1) to tell other harts to > jump to "addr", > and other hart will use handle_ipi() to get the "addr". > > The address of bbl+kernel payload when booting with AE350 is at 0x0, > so the "addr" would be 0x0 that other harts have to jump to. >
Thanks for the info! It's weird that AE350 has set the kernel boot entry at address 0. > With this patch > > + if (!ipi->addr) { > + pr_err("smp_function cannot be set to 0x0\n"); > + return -EINVAL; > + } > > + if (!smp_function) > + return; > > these two code snippets would cause u-boot to hang and thus fail the booting > process. > > > If some big changes are reworked in newer patches, I believe author > > should remove the tag and re-request the review. > > > > Oh I see! Thanks for the explanation. Regards, Bin