| Message ID | 1502190295-53391-2-git-send-email-phil@raspberrypi.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/08/2017 04:04 AM, Phil Elwell wrote: > Secondary cores should enter a low-power idle state when waiting to > be started. The "wfe" instruction causes a core to wait until an event > or interrupt arrives before continuing to the next instruction, and > the "sev" instruction sends a wakeup event to the other cores. > > Add an "sev" (and a memory barrier) to bcm2836_boot_secondary, the > function that wakes the waiting cores during booting. This is required > if the secondary cores are sitting in "wfe", and harmless if not. Eric, should I just pick this up for the upcoming ARM SoC pull requests that I am preparing, or do you have more changes aside from the two tags I already merged? Thanks! > > Signed-off-by: Phil Elwell <phil@raspberrypi.org> > --- > arch/arm/mach-bcm/platsmp.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/arm/mach-bcm/platsmp.c b/arch/arm/mach-bcm/platsmp.c > index 3fa1a99..7811160 100644 > --- a/arch/arm/mach-bcm/platsmp.c > +++ b/arch/arm/mach-bcm/platsmp.c > @@ -312,6 +312,9 @@ static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle) > writel(virt_to_phys(secondary_startup), > intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu); > > + dsb(sy); > + sev(); > + > iounmap(intc_base); > > return 0; >
Hi Florian, > Florian Fainelli <f.fainelli@gmail.com> hat am 14. August 2017 um 18:25 geschrieben: > > > > > On 08/08/2017 04:04 AM, Phil Elwell wrote: > > Secondary cores should enter a low-power idle state when waiting to > > be started. The "wfe" instruction causes a core to wait until an event > > or interrupt arrives before continuing to the next instruction, and > > the "sev" instruction sends a wakeup event to the other cores. > > > > Add an "sev" (and a memory barrier) to bcm2836_boot_secondary, the > > function that wakes the waiting cores during booting. This is required > > if the secondary cores are sitting in "wfe", and harmless if not. > > Eric, should I just pick this up for the upcoming ARM SoC pull requests > that I am preparing, or do you have more changes aside from the two tags > I already merged? this patch depends on series "ARM: bcm2836: Move SMP startup code to arch/arm". I didn't had the time to test Phil's patch in all relevant cases. But i could at least prepare a branch with my changes with the acks. Stefan > > Thanks! > > > > > Signed-off-by: Phil Elwell <phil@raspberrypi.org> > > --- > > arch/arm/mach-bcm/platsmp.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/arm/mach-bcm/platsmp.c b/arch/arm/mach-bcm/platsmp.c > > index 3fa1a99..7811160 100644 > > --- a/arch/arm/mach-bcm/platsmp.c > > +++ b/arch/arm/mach-bcm/platsmp.c > > @@ -312,6 +312,9 @@ static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle) > > writel(virt_to_phys(secondary_startup), > > intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu); > > > > + dsb(sy); > > + sev(); > > + > > iounmap(intc_base); > > > > return 0; > > > > -- > Florian
Hi Eric, > Stefan Wahren <stefan.wahren@i2se.com> hat am 14. August 2017 um 19:11 geschrieben: > > > Hi Florian, > > > Florian Fainelli <f.fainelli@gmail.com> hat am 14. August 2017 um 18:25 geschrieben: > > > > > > > > > > On 08/08/2017 04:04 AM, Phil Elwell wrote: > > > Secondary cores should enter a low-power idle state when waiting to > > > be started. The "wfe" instruction causes a core to wait until an event > > > or interrupt arrives before continuing to the next instruction, and > > > the "sev" instruction sends a wakeup event to the other cores. > > > > > > Add an "sev" (and a memory barrier) to bcm2836_boot_secondary, the > > > function that wakes the waiting cores during booting. This is required > > > if the secondary cores are sitting in "wfe", and harmless if not. > > > > Eric, should I just pick this up for the upcoming ARM SoC pull requests > > that I am preparing, or do you have more changes aside from the two tags > > I already merged? > > this patch depends on series "ARM: bcm2836: Move SMP startup code to arch/arm". > > I didn't had the time to test Phil's patch in all relevant cases. But i could at least prepare a branch with my changes with the acks. i prepared the branches bcm2835-dt-next-v2 and bcm2835-soc-next. Stefan
Stefan Wahren <stefan.wahren@i2se.com> writes: > Hi Eric, > >> Stefan Wahren <stefan.wahren@i2se.com> hat am 14. August 2017 um 19:11 geschrieben: >> >> >> Hi Florian, >> >> > Florian Fainelli <f.fainelli@gmail.com> hat am 14. August 2017 um 18:25 geschrieben: >> > >> > >> > >> > >> > On 08/08/2017 04:04 AM, Phil Elwell wrote: >> > > Secondary cores should enter a low-power idle state when waiting to >> > > be started. The "wfe" instruction causes a core to wait until an event >> > > or interrupt arrives before continuing to the next instruction, and >> > > the "sev" instruction sends a wakeup event to the other cores. >> > > >> > > Add an "sev" (and a memory barrier) to bcm2836_boot_secondary, the >> > > function that wakes the waiting cores during booting. This is required >> > > if the secondary cores are sitting in "wfe", and harmless if not. >> > >> > Eric, should I just pick this up for the upcoming ARM SoC pull requests >> > that I am preparing, or do you have more changes aside from the two tags >> > I already merged? >> >> this patch depends on series "ARM: bcm2836: Move SMP startup code to arch/arm". >> >> I didn't had the time to test Phil's patch in all relevant cases. But i could at least prepare a branch with my changes with the acks. > > i prepared the branches bcm2835-dt-next-v2 and bcm2835-soc-next. bcm2835-soc-next on its own breaks boot for me on the Pi2, so I had to merge in the DT branch first. I've rebased to do that, pulled in this patch (and the clk one), and sent PRs for -dt and -soc.
diff --git a/arch/arm/mach-bcm/platsmp.c b/arch/arm/mach-bcm/platsmp.c index 3fa1a99..7811160 100644 --- a/arch/arm/mach-bcm/platsmp.c +++ b/arch/arm/mach-bcm/platsmp.c @@ -312,6 +312,9 @@ static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle) writel(virt_to_phys(secondary_startup), intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu); + dsb(sy); + sev(); + iounmap(intc_base); return 0;
Secondary cores should enter a low-power idle state when waiting to be started. The "wfe" instruction causes a core to wait until an event or interrupt arrives before continuing to the next instruction, and the "sev" instruction sends a wakeup event to the other cores. Add an "sev" (and a memory barrier) to bcm2836_boot_secondary, the function that wakes the waiting cores during booting. This is required if the secondary cores are sitting in "wfe", and harmless if not. Signed-off-by: Phil Elwell <phil@raspberrypi.org> --- arch/arm/mach-bcm/platsmp.c | 3 +++ 1 file changed, 3 insertions(+)