Messages in this thread | | | From | Patrice CHOTARD <> | Subject | Re: [PATCH 1/1] ARM: STi: Restore secondary CPU's bringup | Date | Wed, 19 Dec 2018 12:14:38 +0000 |
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On 12/19/18 12:28 PM, Russell King - ARM Linux wrote: > On Wed, Dec 19, 2018 at 10:31:35AM +0000, Patrice CHOTARD wrote: >> Hi Russell >> >> On 12/18/18 6:27 PM, Russell King - ARM Linux wrote: >>> On Tue, Dec 18, 2018 at 05:05:18PM +0000, Patrice CHOTARD wrote: >>>> Hi Russell >>>> >>>> On 12/18/18 4:52 PM, Russell King - ARM Linux wrote: >>>>> On Tue, Dec 18, 2018 at 03:48:13PM +0100, patrice.chotard@st.com wrote: >>>>>> From: Patrice Chotard <patrice.chotard@st.com> >>>>>> >>>>>> Due to pen_release and boot_lock removal, secondary CPU's bringup >>>>>> was broken. Restore CPU's bringup by reworking properly >>>>>> .smp_prepare_cpus and .smp_boot_secondary STi callbacks. >>>>> >>>>> Sorry, maybe I don't understand your commit message, but you seem to be >>>>> saying that removal of the pen_release and boot_lock broke STi's secondary >>>>> CPU bring up? Please clarify, and explain how that happened. >>>> >>>> Correct, CPU1 failed to come online. >>>> >>>> It seems that writing secondary_startup address at cpu-release-addr in >>>> .smp_prepare_cpus callback was too early. >>>> >>>> Doing it in .smp_boot_secondary callback, insures that secondary_data >>>> struct is populated in __cpu_up() (stack, pgdir and swapper_pg_dir fields). >>> >>> Ah, you're saying that it causes the CPU to jump to secondary_startup >>> while the boot CPU is in smp_prepare_cpus()? What triggers the CPU >> >> Yes >> >>> to jump to the address written to cpu_strt_ptr? What you're saying >>> seems to suggest that it's the write to that address, rather than the >>> IPI that's sent in sti_boot_secondary(). >> >> At platform startup, an U-Bootrom firmware initialize secondary CPU and >> make it spinning waiting for a jump address to be written at cpu_strt_ptr. >> >> I didn't pay attention to the IPI, you are right IPI is useless, i will >> remove it. > > Okay, in that case may I suggest an alternative to taking my patch > which will break this, and then fixing it in a subsequent patch - > please merge the two patches together so it becomes one "clean up" > patch which doesn't cause any breakage. > > Thanks. >
Ok, agree with your proposal. I will squash our 2 patches.
Thanks
Patrice | |