[Public]
> On Thu, 2022-03-10 at 09:17 -0600, Mario Limonciello 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>
> > ---
> > drivers/acpi/x86/s2idle.c | 76
> ++++++++++++++++++++++++++++++++++++++-
> > include/linux/acpi.h | 9 ++++-
> > 2 files changed, 83 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
> > index abc06e7f89d8..652dc2d75458 100644
> > --- a/drivers/acpi/x86/s2idle.c
> > +++ b/drivers/acpi/x86/s2idle.c
> > @@ -86,6 +86,16 @@ struct lpi_device_constraint_amd {
> > int min_dstate;
> > };
> >
> > +struct lps0_callback_handler {
> > + struct list_head list_node;
> > + int (*prepare_late_callback)(void *context);
> > + void (*restore_early_callback)(void *context);
> > + void *context;
> > +};
>
> Maybe put this in acpi.h
Wonderful suggestion, thanks!
I'll adopt this for v2 after some other feedback comes in on the approach.
>
> ...
>
>
> > +
> > +static LIST_HEAD(lps0_callback_handler_head);
> > +static DEFINE_MUTEX(lps0_callback_handler_mutex);
> > +
> > static struct lpi_constraints *lpi_constraints_table;
> > static int lpi_constraints_table_size;
> > static int rev_id;
> > @@ -444,6 +454,9 @@ static struct acpi_scan_handler lps0_handler = {
> >
> > int acpi_s2idle_prepare_late(void)
> > {
> > + struct lps0_callback_handler *handler;
> > + int rc = 0;
> > +
> > if (!lps0_device_handle || sleep_no_lps0)
> > return 0;
> >
> > @@ -474,14 +487,31 @@ int acpi_s2idle_prepare_late(void)
> > acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_ENTRY,
> > lps0_dsm_func_mask_microsoft,
> > lps0_dsm_guid_microsoft);
> > }
> > - return 0;
> > +
> > + mutex_lock(&lps0_callback_handler_mutex);
> > + list_for_each_entry(handler, &lps0_callback_handler_head,
> list_node) {
> > + rc = handler->prepare_late_callback(handler->context);
> > + if (rc)
> > + goto out;
> > + }
> > +out:
> > + mutex_unlock(&lps0_callback_handler_mutex);
> > +
> > + return rc;
> > }
> >
> > void acpi_s2idle_restore_early(void)
> > {
> > + struct lps0_callback_handler *handler;
> > +
> > if (!lps0_device_handle || sleep_no_lps0)
> > return;
> >
> > + mutex_lock(&lps0_callback_handler_mutex);
> > + list_for_each_entry(handler, &lps0_callback_handler_head,
> list_node)
> > + handler->restore_early_callback(handler->context);
> > + mutex_unlock(&lps0_callback_handler_mutex);
> > +
> > /* Modern standby exit */
> > if (lps0_dsm_func_mask_microsoft > 0)
> > acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_EXIT,
> > @@ -524,4 +554,48 @@ void acpi_s2idle_setup(void)
> > s2idle_set_ops(&acpi_s2idle_ops_lps0);
> > }
> >
> > +int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
> > + void (*restore_early)(void *context),
> > + void *context)
>
> ... and just have "struct lps0_callback_handler *handler" be the argument
> here.
>
> David
>
> > +{
> > + struct lps0_callback_handler *handler;
> > +
> > + if (!lps0_device_handle || sleep_no_lps0)
> > + return -ENODEV;
> > +
> > + handler = kmalloc(sizeof(*handler), GFP_KERNEL);
> > + if (!handler)
> > + return -ENOMEM;
> > + handler->prepare_late_callback = prepare_late;
> > + handler->restore_early_callback = restore_early;
> > + handler->context = context;
> > +
> > + mutex_lock(&lps0_callback_handler_mutex);
> > + list_add(&handler->list_node, &lps0_callback_handler_head);
> > + mutex_unlock(&lps0_callback_handler_mutex);
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(acpi_register_lps0_callbacks);
> > +
> > +void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context),
> > + void (*restore_early)(void *context),
> > + void *context)
> > +{
> > + struct lps0_callback_handler *handler;
> > +
> > + mutex_lock(&lps0_callback_handler_mutex);
> > + list_for_each_entry(handler, &lps0_callback_handler_head,
> list_node) {
> > + if (handler->prepare_late_callback == prepare_late &&
> > + handler->restore_early_callback == restore_early &&
> > + handler->context == context) {
> > + list_del(&handler->list_node);
> > + kfree(handler);
> > + break;
> > + }
> > + }
> > + mutex_unlock(&lps0_callback_handler_mutex);
> > +}
> > +EXPORT_SYMBOL_GPL(acpi_unregister_lps0_callbacks);
> > +
> > #endif /* CONFIG_SUSPEND */
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 6274758648e3..cae0fde309f2 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -1023,7 +1023,14 @@ 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
> > +int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
> > + void (*restore_early)(void *context),
> > + void *context);
> > +void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context),
> > + void (*restore_early)(void *context),
> > + void *context);
> > +#endif /* CONFIG_X86 */
> > #ifndef CONFIG_IA64
> > void arch_reserve_mem_area(acpi_physical_address addr, size_t size);
> > #else
