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SubjectRe: [PATCH 3/5] powernv:idle: Define idle init function for power8
On Wed,  5 Jul 2017 22:08:14 +0530
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com> wrote:

> From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
>
> In this patch we define a new function named pnv_power8_idle_init().
>
> We move the following code from pnv_init_idle_states() into this newly
> defined function.
> a) That patches out pnv_fastsleep_workaround_at_entry/exit when
> no states with OPAL_PM_SLEEP_ENABLED_ER1 are present.
> b) Creating a sysfs control to choose how the workaround has to be
> applied when a OPAL_PM_SLEEP_ENABLED_ER1 state is present.
> c) Set ppc_md.power_save to power7_idle when OPAL_PM_NAP_ENABLED is
> present.
>
> With this, all the power8 specific initializations are in one place.
>
> Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> ---
> arch/powerpc/platforms/powernv/idle.c | 59 ++++++++++++++++++++++++-----------
> 1 file changed, 40 insertions(+), 19 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index a5990d9..c400ff9 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -564,6 +564,44 @@ static void __init pnv_power9_idle_init(void)
> pnv_first_deep_stop_state);
> }
>
> +
> +static void __init pnv_power8_idle_init(void)
> +{
> + int i;
> + bool has_nap = false;
> + bool has_sleep_er1 = false;
> + int dt_idle_states = pnv_idle.nr_states;
> +
> + for (i = 0; i < dt_idle_states; i++) {
> + struct pnv_idle_state *state = &pnv_idle.states[i];
> +
> + if (state->flags & OPAL_PM_NAP_ENABLED)
> + has_nap = true;
> + if (state->flags & OPAL_PM_SLEEP_ENABLED_ER1)
> + has_sleep_er1 = true;
> + }
> +
> + if (!has_sleep_er1) {
> + patch_instruction(
> + (unsigned int *)pnv_fastsleep_workaround_at_entry,
> + PPC_INST_NOP);
> + patch_instruction(
> + (unsigned int *)pnv_fastsleep_workaround_at_exit,
> + PPC_INST_NOP);
> + } else {
> + /*
> + * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that
> + * workaround is needed to use fastsleep. Provide sysfs
> + * control to choose how this workaround has to be applied.
> + */
> + device_create_file(cpu_subsys.dev_root,
> + &dev_attr_fastsleep_workaround_applyonce);
> + }
> +
> + if (has_nap)
> + ppc_md.power_save = power7_idle;
> +}
> +
> /*
> * Returns 0 if prop1_len == prop2_len. Else returns -1
> */
> @@ -837,6 +875,8 @@ static int __init pnv_probe_idle_states(void)
>
> if (cpu_has_feature(CPU_FTR_ARCH_300))
> pnv_power9_idle_init();
> + else
> + pnv_power8_idle_init();
>
> for (i = 0; i < dt_idle_states; i++) {
> if (!pnv_idle.states[i].valid)
> @@ -858,22 +898,6 @@ static int __init pnv_init_idle_states(void)
> if (pnv_probe_idle_states())
> goto out;
>
> - if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
> - patch_instruction(
> - (unsigned int *)pnv_fastsleep_workaround_at_entry,
> - PPC_INST_NOP);
> - patch_instruction(
> - (unsigned int *)pnv_fastsleep_workaround_at_exit,
> - PPC_INST_NOP);

So previously this would run on POWER9 and patch out those branches.
But POWER9 never runs that code, so no problem. Good cleanup.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

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