Hi, You could try to cc whoever wrote the code. You can use git blame to find out.
But it sounds like you are on the right track. I may be able to help, will email tomorrow if so. Regards, Simon On Sep 16, 2013 8:26 PM, "MJ embd" <mj.e...@gmail.com> wrote: > Reminder, Please can anyone respond > > On 9/16/13, MJ embd <mj.e...@gmail.com> wrote: > > Hi, > > > > I was trying to understand the booting (till linux) on samsung exynos > > 5250. As this is my first on ARM Cortex. I have a few questions, so > > following is a step by step understanding and [Q] mentions the > > question I am asking > > > > [1] At POR (Power on Reset) the Internal Boot rom code executes, and > > checks the boot location and if it finds sd card, it copies 14k from > > the sd card (which is u-boot-spl.bin) into iRAM. > > [2] the internal boot rom branches pc to the entry point of spl at > > __start (0x2023400) > > [3] First instruction at __start is b reset. > > [4] this takes the route reset | cpu_init_crit | low_level_init | > first_cpu > > > > [Q 1] At this point what is the state of secondary core, is it held in > reset > > ? > > As per document, "" > > "the secondary CPUs (CPU1, CPU2, and CPU3) execute a WFI instruction, > > which is actually a loop that checks the value of SYS_FLAGS register." > > > > I couldnt find the SYS_FLAGS register in Cortex A15 manual, can some one > > point. > > > > [Q 2] The secondary core until the point the boot core calls > > smp_kick_secondary is just waiting in WFI. > > [5] the smp_kick_secondary does the following > > (a) at the address SYSFLAGS_ADDR (0x2020000) which is not in spl but > > above it, it write the b reset instruction and > > (b) Issues a SGI to the secondary core > > > > [Q 3] Does this mean that secondary core is listening at address > > 0x2020000, I couldnt find that in any document? > > > > [6] Supposedly it does and it starts executing the reset function, > > secondary core would end up in enter_smp_pen. > > [Q 4] I dont understand what is trying to achieve here, Can some one > > explain. > > > > > > I am planning to pen down the complete boot sequence, all help > appreciated. > > > > Thanks in advance. > > mj > > > > > -- > -mj > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot >
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