Hi Mario,
On 3/14/22 06:03, 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>
> ---
> 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 | 68 ++++++++++++++++++++++++++++++++++++++-
> include/linux/acpi.h | 11 ++++++-
> 2 files changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
> index abc06e7f89d8..69008c4a86ea 100644
> --- a/drivers/acpi/x86/s2idle.c
> +++ b/drivers/acpi/x86/s2idle.c
> @@ -86,6 +86,9 @@ struct lpi_device_constraint_amd {
> int min_dstate;
> };
>
> +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 +447,9 @@ 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 +480,34 @@ 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) {
> + if (handler->prepare_late_callback) {
> + 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)
> + if (handler->restore_early_callback)
> + 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 +550,44 @@ void acpi_s2idle_setup(void)
> s2idle_set_ops(&acpi_s2idle_ops_lps0);
> }
>
> +int acpi_register_lps0_callbacks(struct lps0_callback_handler *arg)
> +{
> + 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 = arg->prepare_late_callback;
> + handler->restore_early_callback = arg->restore_early_callback;
> + handler->context = arg->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);
Typically with calls like these we simply let the caller own the struct lps0_callback_handler
and only make the list_add() call here. Typically the struct lps0_callback_handler will
be embedded in the driver_data of the driver registering the handler and it will
call the unregister function before free-ing its driver_data.
> +
> +void acpi_unregister_lps0_callbacks(struct lps0_callback_handler *arg)
> +{
> + 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 == arg->prepare_late_callback &&
> + handler->restore_early_callback == arg->restore_early_callback &&
> + handler->context == arg->context) {
> + list_del(&handler->list_node);
> + kfree(handler);
> + break;
> + }
> + }
> + mutex_unlock(&lps0_callback_handler_mutex);
> +}
> +EXPORT_SYMBOL_GPL(acpi_unregister_lps0_callbacks);
And this then becomes just lock, list_del, unlock.
Regards,
Hans
> +
> #endif /* CONFIG_SUSPEND */
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 6274758648e3..df105f5e03e5 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -1023,7 +1023,16 @@ 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 lps0_callback_handler {
> + struct list_head list_node;
> + int (*prepare_late_callback)(void *context);
> + void (*restore_early_callback)(void *context);
> + void *context;
> +};
> +int acpi_register_lps0_callbacks(struct lps0_callback_handler *arg);
> +void acpi_unregister_lps0_callbacks(struct lps0_callback_handler *arg);
> +#endif /* CONFIG_X86 */
> #ifndef CONFIG_IA64
> void arch_reserve_mem_area(acpi_physical_address addr, size_t size);
> #else
