On Thu, Mar 17, 2022 at 3:15 PM Mario Limonciello
<mario.limonciello@xxxxxxx> wrote:
>
> Currenty the latest thing run during a suspend to idle attempt is
> the LPS0 `prepare_late` callback and the earliest thing is the
> `resume_early` callback.
>
> There is a desire for the `amd-pmc` driver to suspend later in the
> suspend process (ideally the very last thing), so create a callback
> that it or any other driver can hook into to do this.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
This looks good to me, so:
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
and I don't have any conflicting changes queued up for 5.17, so from
my POV it can go in via the x86 platform drivers tree along with the
other patches in the series.
> ---
> changes from v4->v5:
> * fix a check for handler->prepare
> Reported by Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> changes from v3->v4:
> * drop use of mutex, use lock_system_sleep instead
> * don't pass argument of context, driver will maintain this internally
> * don't allow failing prepare stage
> * don't allow unregistering if sleep_no_lps0 is set
> changes from v2->v3:
> * Check that callbacks exist before calling
> changes from v1->v2:
> * Change register/unregister arguments to be struct
>
> drivers/acpi/x86/s2idle.c | 40 +++++++++++++++++++++++++++++++++++++++
> include/linux/acpi.h | 10 +++++++++-
> 2 files changed, 49 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
> index abc06e7f89d8..031b20a547f9 100644
> --- a/drivers/acpi/x86/s2idle.c
> +++ b/drivers/acpi/x86/s2idle.c
> @@ -86,6 +86,8 @@ struct lpi_device_constraint_amd {
> int min_dstate;
> };
>
> +static LIST_HEAD(lps0_s2idle_devops_head);
> +
> static struct lpi_constraints *lpi_constraints_table;
> static int lpi_constraints_table_size;
> static int rev_id;
> @@ -444,6 +446,8 @@ static struct acpi_scan_handler lps0_handler = {
>
> int acpi_s2idle_prepare_late(void)
> {
> + struct acpi_s2idle_dev_ops *handler;
> +
> if (!lps0_device_handle || sleep_no_lps0)
> return 0;
>
> @@ -474,14 +478,26 @@ int acpi_s2idle_prepare_late(void)
> acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_ENTRY,
> lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
> }
> +
> + list_for_each_entry(handler, &lps0_s2idle_devops_head, list_node) {
> + if (handler->prepare)
> + handler->prepare();
> + }
> +
> return 0;
> }
>
> void acpi_s2idle_restore_early(void)
> {
> + struct acpi_s2idle_dev_ops *handler;
> +
> if (!lps0_device_handle || sleep_no_lps0)
> return;
>
> + list_for_each_entry(handler, &lps0_s2idle_devops_head, list_node)
> + if (handler->restore)
> + handler->restore();
> +
> /* Modern standby exit */
> if (lps0_dsm_func_mask_microsoft > 0)
> acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_EXIT,
> @@ -524,4 +540,28 @@ void acpi_s2idle_setup(void)
> s2idle_set_ops(&acpi_s2idle_ops_lps0);
> }
>
> +int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg)
> +{
> + if (!lps0_device_handle || sleep_no_lps0)
> + return -ENODEV;
> +
> + lock_system_sleep();
> + list_add(&arg->list_node, &lps0_s2idle_devops_head);
> + unlock_system_sleep();
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(acpi_register_lps0_dev);
> +
> +void acpi_unregister_lps0_dev(struct acpi_s2idle_dev_ops *arg)
> +{
> + if (!lps0_device_handle || sleep_no_lps0)
> + return;
> +
> + lock_system_sleep();
> + list_del(&arg->list_node);
> + unlock_system_sleep();
> +}
> +EXPORT_SYMBOL_GPL(acpi_unregister_lps0_dev);
> +
> #endif /* CONFIG_SUSPEND */
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 6274758648e3..47c16cdc8e0e 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -1023,7 +1023,15 @@ void acpi_os_set_prepare_extended_sleep(int (*func)(u8 sleep_state,
>
> acpi_status acpi_os_prepare_extended_sleep(u8 sleep_state,
> u32 val_a, u32 val_b);
> -
> +#ifdef CONFIG_X86
> +struct acpi_s2idle_dev_ops {
> + struct list_head list_node;
> + void (*prepare)(void);
> + void (*restore)(void);
> +};
> +int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg);
> +void acpi_unregister_lps0_dev(struct acpi_s2idle_dev_ops *arg);
> +#endif /* CONFIG_X86 */
> #ifndef CONFIG_IA64
> void arch_reserve_mem_area(acpi_physical_address addr, size_t size);
> #else
> --
> 2.34.1
>
