Hi, Marek sorry for possible format issue.
ср, 27 февр. 2019 г., 23:02 Marek Vasut <[email protected]>: > On 2/26/19 8:37 PM, Oleksandr wrote: > > > > Hi, Marek > > Hi, > > >>>>>>>> +} > >>>>>>>> + > >>>>>>>> +/* > >>>>>>>> + * Reset vector for secondary CPUs. > >>>>>>>> + * This will be mapped at address 0 by SBAR register. > >>>>>>>> + * We need _long_ jump to the physical address. > >>>>>>>> + */ > >>>>>>>> +asm(" .arm\n" > >>>>>>>> + " .align 12\n" > >>>>>>>> + " .globl shmobile_boot_vector\n" > >>>>>>>> + "shmobile_boot_vector:\n" > >>>>>>>> + " ldr r1, 1f\n" > >>>>>>>> + " bx r1\n" > >>>>>>>> + " .type shmobile_boot_vector, %function\n" > >>>>>>>> + " .size shmobile_boot_vector, .-shmobile_boot_vector\n" > >>>>>>>> + " .align 2\n" > >>>>>>>> + " .globl shmobile_boot_fn\n" > >>>>>>>> + "shmobile_boot_fn:\n" > >>>>>>>> + "1: .space 4\n" > >>>>>>>> + " .globl shmobile_boot_size\n" > >>>>>>>> + "shmobile_boot_size:\n" > >>>>>>>> + " .long .-shmobile_boot_vector\n"); > >>>>>>> Why can't this be implemented in C ? > >>>>>> This "reset vector" code was ported from Linux: > >>>>>> > >>>>>> > https://elixir.bootlin.com/linux/v5.0-rc5/source/arch/arm/mach-shmobile/headsmp.S#L21 > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> Really don't know whether it can be implemented in C. > >>>>>> > >>>>>> I was thinking of moving this code to a separate ASM file in order > >>>>>> not > >>>>>> to mix C and ASM. What do you think about it? > >>>>> U-Boot already has a reset vector code, can't that be reused ? > >>>> I don't think. Being honest, I couldn't find an obvious way how to > >>>> reuse > >>>> (I assume you meant arch/arm/cpu/armv7/start.S). > >>> Maybe it needs some additional work first ? > >>> It seems Altera socfpga somehow uses the U-Boot reset vectors for PSCI, > >>> so it should at least be possible. > >> > >> Could you, please, point me in code? Unfortunately, I wasn't able to > >> find. > >> > >> > >>> > >>>> The newly turned on secondary CPU entry should be common > >>>> "psci_cpu_entry", which does proper things. > >>>> > >>>> And this reset vector is just "a small piece of code" to be located in > >>>> on-chip RAM (with limited size) and used for the jump stub... > >>> We already have the SPL reset vectors in SRAM, maybe that can be > >>> recycled somehow ? > >> > >> > >> The only idea I have, how it may be recycled (not sure whether it will > >> work...) > >> > >> > >> diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S > >> index 0cb6dd39cc..69acf4677b 100644 > >> --- a/arch/arm/cpu/armv7/start.S > >> +++ b/arch/arm/cpu/armv7/start.S > >> @@ -36,6 +36,12 @@ > >> #endif > >> > >> reset: > >> + > >> +#if defined(CONFIG_ARMV7_PSCI) && !defined(CONFIG_SPL_BUILD) > >> + b psci_cpu_entry_jump > >> + /* return only if this is not "a newly turned on CPU" using > >> PSCI) */ > >> +#endif > >> + > >> /* Allow the board to save important registers */ > >> b save_boot_params > >> save_boot_params_ret: > >> @@ -128,6 +134,21 @@ ENDPROC(switch_to_hypervisor) > >> .weak switch_to_hypervisor > >> #endif > >> > >> +/* > >> + * Each platform which implements psci_cpu_entry_jump function should > >> perform > >> + * in the following way: > >> + * > >> + * If the executing this call CPU is exactly that CPU we are > >> expecting to be > >> + * powered on, then jump to psci_cpu_entry and never return. > >> + * Otherwise return to the caller. > >> + */ > >> +#if defined(CONFIG_ARMV7_PSCI) && !defined(CONFIG_SPL_BUILD) > >> +ENTRY(psci_cpu_entry_jump) > >> + movs pc, lr > >> +ENDPROC(psci_cpu_entry_jump) > >> +.weak psci_cpu_entry_jump > >> +#endif > >> + > >> > /************************************************************************* > >> > >> * > >> * cpu_init_cp15 > >> > >> > >> What do you think? > >> > >> > >> It would be much appreciated, if you could provide some hints. > > > > > > Don't want to be annoying, but it would be really nice to get my > > questions answered... > > I am sorry, I am too busy right now. I will answer that once I can > properly study the problem and give you a useful answer. > No problem, I will wait. Thank you. > -- > Best regards, > Marek Vasut > _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
