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SubjectRe: [PATCH v6 20/25] drivers: firmware: psci: Introduce psci_dt_topology_init()
On Wed, Mar 14, 2018 at 05:58:30PM +0100, Ulf Hansson wrote:
> In case the hierarchical layout is used in DT, we want to initialize the
> corresponding PM domain topology for the CPUs, by using the generic PM
> domain (aka genpd) infrastructure.
>
> At first glance, it may seem feasible to hook into the existing
> psci_dt_init() function, although because it's called quite early in the
> boot sequence, allocating the dynamic data structure for a genpd doesn't
> work.
>
> Therefore, let's export a new init function for PSCI,
> psci_dt_topology_init(), which the ARM machine code should call from a
> suitable initcall.
>
> Succeeding to initialize the PM domain topology, which means at least one
> instance of a genpd becomes created, allows us to continue to enable the
> PSCI OS initiated mode for the platform. If everything turns out fine,
> let's print a message in log to inform the user about the changed mode.
>
> In case of any failures, we stick to the default PSCI Platform Coordinated
> mode.

For kexec/kdump we'll need to explicitly set the suspend mode to
platform coordinated if for whatever reason we choose not to use OSI.

>
> Cc: Lina Iyer <ilina@codeaurora.org>
> Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
> drivers/firmware/psci.c | 31 +++++++++++++++++++++++++++++++
> include/linux/psci.h | 2 ++
> 2 files changed, 33 insertions(+)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index 463f78c..45d55fc 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -723,6 +723,37 @@ int __init psci_dt_init(void)
> return ret;
> }
>
> +int __init psci_dt_topology_init(void)
> +{
> + struct device_node *np;
> + int ret;
> +
> + if (!psci_has_osi_support())
> + return 0;
> +
> + np = of_find_matching_node_and_match(NULL, psci_of_match, NULL);
> + if (!np)
> + return -ENODEV;
> +
> + /* Initialize the CPU PM domains based on topology described in DT. */
> + ret = psci_dt_init_pm_domains(np);
> + if (ret <= 0)
> + goto out;
> +
> + /* Enable OSI mode. */
> + ret = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE,
> + PSCI_1_0_SUSPEND_MODE_OSI, 0, 0);

IIUC, this patch will need to be moved after the subsequent two patches
to ensure that this series bisects cleanly.

Thanks,
Mark.

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