Santosh Shilimkar <[email protected]> writes:
> The SGI(Software Generated Interrupts) are not wakeup capable from
> low power states. This is known limitation on OMAP4 and needs to be
> worked around by using software forced clockdomain wake-up. CPU0 forces
> the CPU1 clockdomain to software force wakeup. After the wakeup, CPU1
> restores its clockdomain hardware supervised mode.
>
> More details can be found in OMAP4430 TRM - Version J
> Section :
> 4.3.4.2 Power States of CPU0 and CPU1
>
> Signed-off-by: Santosh Shilimkar <[email protected]>
> Reviewed-by: Kevin Hilman <[email protected]>
> ---
> arch/arm/mach-omap2/omap-hotplug.c | 9 +++++++++
> arch/arm/mach-omap2/omap-smp.c | 27 ++++++++++++++++++++++++++-
> 2 files changed, 35 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap-hotplug.c
> b/arch/arm/mach-omap2/omap-hotplug.c
> index 9f8f097..cf4ab15 100644
> --- a/arch/arm/mach-omap2/omap-hotplug.c
> +++ b/arch/arm/mach-omap2/omap-hotplug.c
> @@ -23,6 +23,7 @@
> #include <mach/omap-wakeupgen.h>
>
> #include "powerdomain.h"
> +#include "clockdomain.h"
>
> int platform_cpu_kill(unsigned int cpu)
> {
> @@ -36,6 +37,11 @@ int platform_cpu_kill(unsigned int cpu)
> void platform_cpu_die(unsigned int cpu)
> {
> unsigned int this_cpu;
> + static struct clockdomain *cpu1_clkdm;
> +
> + /* To avoid cpu1 clockdomain lookup every time */
minor: comment doesn't really match code and could just be removed
> + if (!cpu1_clkdm)
> + cpu1_clkdm = clkdm_lookup("mpu1_clkdm");
>
> flush_cache_all();
> dsb();
> @@ -59,6 +65,9 @@ void platform_cpu_die(unsigned int cpu)
> * OK, proper wakeup, we're done
> */
> omap_wakeupgen_irqmask_all(this_cpu, 0);
> +
> + /* Restore clockdomain to hardware supervised */
> + clkdm_allow_idle(cpu1_clkdm);
> break;
> }
> pr_debug("CPU%u: spurious wakeup call\n", cpu);
> diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
> index b105a29..31c9b79 100644
> --- a/arch/arm/mach-omap2/omap-smp.c
> +++ b/arch/arm/mach-omap2/omap-smp.c
> @@ -25,6 +25,8 @@
> #include <mach/hardware.h>
> #include <mach/omap4-common.h>
>
> +#include "clockdomain.h"
> +
> /* SCU base address */
> void __iomem *scu_base;
>
> @@ -48,6 +50,8 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
>
> int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
> {
> + static struct clockdomain *cpu1_clkdm;
> + static bool booted;
> /*
> * Set synchronisation state between this boot processor
> * and the secondary one
> @@ -63,7 +67,28 @@ int __cpuinit boot_secondary(unsigned int cpu, struct
> task_struct *idle)
> omap_modify_auxcoreboot0(0x200, 0xfffffdff);
> flush_cache_all();
> smp_wmb();
> - smp_cross_call(cpumask_of(cpu), 1);
> +
> + /* To avoid cpu1 clockdomain lookup every time */
ditto
> + if (!cpu1_clkdm)
> + cpu1_clkdm = clkdm_lookup("mpu1_clkdm");
> +
> + /*
> + * The SGI(Software Generated Interrupts) are not wakeup capable
> + * from low power states. This is known limitation on OMAP4 and
> + * needs to be worked around by using software forced clockdomain
> + * wake-up. To wakeup CPU1, CPU0 forces the CPU1 clockdomain to
> + * software force wakeup. After the wakeup, CPU1 restores its
> + * clockdomain hardware supervised mode.
> + * More details can be found in OMAP4430 TRM - Version J
> + * Section :
> + * 4.3.4.2 Power States of CPU0 and CPU1
> + */
> + if (booted) {
> + clkdm_wakeup(cpu1_clkdm);
> + } else {
> + dsb_sev();
> + booted = true;
> + }
>
> /*
> * Now the secondary core is starting up let it run its
--
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