On Tue, 2019-02-12 at 01:48 +0000, Anup Patel wrote: > > -----Original Message----- > > From: Lukas Auer [mailto:lukas.a...@aisec.fraunhofer.de] > > Sent: Tuesday, February 12, 2019 3:44 AM > > To: u-boot@lists.denx.de > > Cc: Atish Patra <atish.pa...@wdc.com>; Anup Patel > > <anup.pa...@wdc.com>; Bin Meng <bmeng...@gmail.com>; Andreas > > Schwab <sch...@suse.de>; Palmer Dabbelt <pal...@sifive.com>; > > Alexander Graf <ag...@suse.de>; Lukas Auer > > <lukas.a...@aisec.fraunhofer.de>; Anup Patel <a...@brainfault.org>; > > Rick > > Chen <r...@andestech.com>; Baruch Siach <bar...@tkos.co.il>; Stefan > > Roese <s...@denx.de> > > Subject: [PATCH 5/7] riscv: add support for multi-hart systems > > > > On RISC-V, all harts boot independently. To be able to run on a > > multi-hart > > system, U-Boot must be extended with the functionality to manage > > all harts > > in the system. A new config option, CONFIG_MAIN_HART, is used to > > select > > the hart U-Boot runs on. All other harts are halted. > > U-Boot can delegate functions to them using smp_call_function(). > > > > Every hart has a valid pointer to the global data structure and a > > 8KiB stack by > > default. The stack size is set with CONFIG_STACK_SIZE_SHIFT. > > > > Signed-off-by: Lukas Auer <lukas.a...@aisec.fraunhofer.de> > > --- > > > > arch/riscv/Kconfig | 12 +++++ > > arch/riscv/cpu/start.S | 102 > > ++++++++++++++++++++++++++++++++++- > > arch/riscv/include/asm/csr.h | 1 + > > 3 files changed, 114 insertions(+), 1 deletion(-) > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index > > 3a51339c4d..af8d0f8d67 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -140,4 +140,16 @@ config SBI_IPI > > default y if RISCV_SMODE > > depends on SMP > > > > +config MAIN_HART > > + int "Main hart in system" > > + default 0 > > + help > > + Some SoCs include harts of various sizes, some of which might > > not > > + be suitable for running U-Boot. CONFIG_MAIN_HART is used to > > select > > + the hart U-Boot runs on. > > This config option can be avoided altogether if we have > lottery based system to select "Main HART" in start.S. > > With the MAIN_HART config option in-place, every system > will have to pick a "Main HART". What if the "Main HART" > itself does not come online due to HW failure. >
Good point, I did not consider this. I will add a lottery-based system in the next version. Thanks, Lukas _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
