On Mon, 30 Dec 2019 at 17:35, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>
> On Mon, Dec 30, 2019 at 03:43:57PM +0100, Ulf Hansson wrote:
> > The per CPU variable psci_power_state, contains an array of fixed values,
> > which reflects the corresponding arm,psci-suspend-param parsed from DT, for
> > each of the available CPU idle states.
> >
> > This isn't sufficient when using the hierarchical CPU topology in DT, in
> > combination with having PSCI OS initiated (OSI) mode enabled. More
> > precisely, in OSI mode, Linux is responsible of telling the PSCI FW what
> > idle state the cluster (a group of CPUs) should enter, while in PSCI
> > Platform Coordinated (PC) mode, each CPU independently votes for an idle
> > state of the cluster.
> >
> > For this reason, introduce a per CPU variable called domain_state and
> > implement two helper functions to read/write its value. Then let the
> > domain_state take precedence over the regular selected state, when entering
> > and idle state.
> >
> > To avoid executing the above OSI specific code in the ->enter() callback,
> > while operating in the default PSCI Platform Coordinated mode, let's also
> > add a new enter-function and use it for OSI.
> >
> > Co-developed-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
> > Signed-off-by: Lina Iyer <lina.iyer@xxxxxxxxxx>
> > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> > ---
> >
> > Changes in v5:
> > - None.
> >
> > ---
> > drivers/cpuidle/cpuidle-psci.c | 56 ++++++++++++++++++++++++++++++----
> > 1 file changed, 50 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> > index 6a87848be3c3..9600fe674a89 100644
> > --- a/drivers/cpuidle/cpuidle-psci.c
> > +++ b/drivers/cpuidle/cpuidle-psci.c
> > @@ -29,14 +29,47 @@ struct psci_cpuidle_data {
> > };
> >
> > static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data);
> > +static DEFINE_PER_CPU(u32, domain_state);
> > +
> > +static inline void psci_set_domain_state(u32 state)
> > +{
> > + __this_cpu_write(domain_state, state);
> > +}
> > +
> > +static inline u32 psci_get_domain_state(void)
> > +{
> > + return __this_cpu_read(domain_state);
> > +}
> > +
> > +static inline int psci_enter_state(int idx, u32 state)
> > +{
> > + return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, idx, state);
> > +}
> > +
> > +static int psci_enter_domain_idle_state(struct cpuidle_device *dev,
> > + struct cpuidle_driver *drv, int idx)
> > +{
> > + struct psci_cpuidle_data *data = this_cpu_ptr(&psci_cpuidle_data);
> > + u32 *states = data->psci_states;
> > + u32 state = psci_get_domain_state();
> > + int ret;
> > +
> > + if (!state)
> > + state = states[idx];
> > +
> > + ret = psci_enter_state(idx, state);
> > +
> > + /* Clear the domain state to start fresh when back from idle. */
> > + psci_set_domain_state(0);
> > + return ret;
> > +}
> >
> > static int psci_enter_idle_state(struct cpuidle_device *dev,
> > struct cpuidle_driver *drv, int idx)
> > {
> > u32 *state = __this_cpu_read(psci_cpuidle_data.psci_states);
> >
> > - return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
> > - idx, state[idx]);
> > + return psci_enter_state(idx, state[idx]);
> > }
> >
> > static struct cpuidle_driver psci_idle_driver __initdata = {
> > @@ -79,7 +112,8 @@ static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
> > return 0;
> > }
> >
> > -static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node,
> > +static int __init psci_dt_cpu_init_idle(struct cpuidle_driver *drv,
> > + struct device_node *cpu_node,
> > unsigned int state_count, int cpu)
> > {
> > int i, ret = 0;
> > @@ -118,6 +152,15 @@ static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node,
> > ret = PTR_ERR(data->dev);
> > goto free_mem;
> > }
> > +
> > + /*
> > + * Using the deepest state for the CPU to trigger a potential
> > + * selection of a shared state for the domain, assumes the
> > + * domain states are all deeper states.
> > + */
> > + if (data->dev)
>
> Do we still need this check ? I thought we won't attach genpd if OSI is
> not enabled. If possible, please drop the check.
This check is still needed. psci_dt_attach_cpu() now returns NULL when
OSI has not been enabled (see patch 14), as we agreed on during the
discussions around the previous version.
>
> Other than that, looks good to me.
>
> Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Thanks!
Kind regards
Uffe
