diff mbox series

[v4,1/3] ACPI / x86: Add support for LPS0 callback handler

Message ID 20220316212924.5619-1-mario.limonciello@amd.com (mailing list archive)
State Superseded, archived
Headers show
Series [v4,1/3] ACPI / x86: Add support for LPS0 callback handler | expand

Commit Message

Mario Limonciello March 16, 2022, 9:29 p.m. UTC
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@amd.com>
---
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(-)

Comments

Dan Carpenter March 17, 2022, 8:48 a.m. UTC | #1
Hi Mario,

url:    https://github.com/0day-ci/linux/commits/Mario-Limonciello/ACPI-x86-Add-support-for-LPS0-callback-handler/20220317-053103 
base:    a32cd981a6da2373c093d471ee4405a915e217d5
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220317/202203171657.uF7h6TEG-lkp@intel.com/config )
compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/acpi/x86/s2idle.c:478 acpi_s2idle_prepare_late() error: we previously assumed 'handler' could be null (see line 479)

vim +/handler +478 drivers/acpi/x86/s2idle.c

fa209644a7124b Mario Limonciello  2021-09-01  474  		acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_ENTRY,
fa209644a7124b Mario Limonciello  2021-09-01  475  				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
fef98671194be0 Rafael J. Wysocki  2020-12-17  476  	}
4be2feac72a3ad Mario Limonciello  2022-03-16  477  
4be2feac72a3ad Mario Limonciello  2022-03-16 @478  	list_for_each_entry(handler, &lps0_s2idle_devops_head, list_node) {
4be2feac72a3ad Mario Limonciello  2022-03-16 @479  		if (handler)
4be2feac72a3ad Mario Limonciello  2022-03-16  480  			handler->prepare();

The list iterator can never be NULL so there is no need to check.

4be2feac72a3ad Mario Limonciello  2022-03-16  481  	}
4be2feac72a3ad Mario Limonciello  2022-03-16  482  
fef98671194be0 Rafael J. Wysocki  2020-12-17  483  	return 0;
fef98671194be0 Rafael J. Wysocki  2020-12-17  484  }

---
0-DAY CI Kernel Test Service
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index abc06e7f89d8..8cd9a1016368 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)
+			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