Commit 3b9d0a78 authored by James Morse's avatar James Morse Committed by Catalin Marinas
Browse files

ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug 



struct acpi_scan_handler has a detach callback that is used to remove
a driver when a bus is changed. When interacting with an eject-request,
the detach callback is called before _EJ0.

This means the ACPI processor driver can't use _STA to determine if a
CPU has been made not-present, or some of the other _STA bits have been
changed. acpi_processor_remove() needs to know the value of _STA after
_EJ0 has been called.

Add a post_eject callback to struct acpi_scan_handler. This is called
after acpi_scan_hot_remove() has successfully called _EJ0. Because
acpi_scan_check_and_detach() also clears the handler pointer,
it needs to be told if the caller will go on to call
acpi_bus_post_eject(), so that acpi_device_clear_enumerated()
and clearing the handler pointer can be deferred.
An extra flag is added to flags field introduced in the previous
patch to achieve this.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Tested-by: default avatarMiguel Luis <miguel.luis@oracle.com>
Tested-by: default avatarVishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: default avatarJianyong Wu <jianyong.wu@arm.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240529133446.28446-11-Jonathan.Cameron@huawei.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 1859a671

drivers/acpi/acpi_processor.c

+2 −2
Original line number Diff line number Diff line
@@ -475,7 +475,7 @@ static int acpi_processor_add(struct acpi_device *device, 


#ifdef CONFIG_ACPI_HOTPLUG_CPU

/* Removal */

static void acpi_processor_remove(struct acpi_device *device)

static void acpi_processor_post_eject(struct acpi_device *device)

{

	struct acpi_processor *pr;
@@ -643,7 +643,7 @@ static struct acpi_scan_handler processor_handler = { 
	.ids = processor_device_ids,

	.attach = acpi_processor_add,

#ifdef CONFIG_ACPI_HOTPLUG_CPU

	.detach = acpi_processor_remove,

	.post_eject = acpi_processor_post_eject,

#endif

	.hotplug = {

		.enabled = true,

drivers/acpi/scan.c

+27 −3
Original line number Diff line number Diff line
@@ -244,6 +244,7 @@ static int acpi_scan_try_to_offline(struct acpi_device *device) 
}



#define ACPI_SCAN_CHECK_FLAG_STATUS	BIT(0)

#define ACPI_SCAN_CHECK_FLAG_EJECT	BIT(1)



static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)

{
@@ -272,8 +273,6 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p) 
	if (handler) {

		if (handler->detach)

			handler->detach(adev);



		adev->handler = NULL;

	} else {

		device_release_driver(&adev->dev);

	}
@@ -283,6 +282,28 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p) 
	 */

	acpi_device_set_power(adev, ACPI_STATE_D3_COLD);

	adev->flags.initialized = false;



	/* For eject this is deferred to acpi_bus_post_eject() */

	if (!(flags & ACPI_SCAN_CHECK_FLAG_EJECT)) {

		adev->handler = NULL;

		acpi_device_clear_enumerated(adev);

	}

	return 0;

}



static int acpi_bus_post_eject(struct acpi_device *adev, void *not_used)

{

	struct acpi_scan_handler *handler = adev->handler;



	acpi_dev_for_each_child_reverse(adev, acpi_bus_post_eject, NULL);



	if (handler) {

		if (handler->post_eject)

			handler->post_eject(adev);



		adev->handler = NULL;

	}



	acpi_device_clear_enumerated(adev);



	return 0;
@@ -300,6 +321,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device) 
	acpi_handle handle = device->handle;

	unsigned long long sta;

	acpi_status status;

	uintptr_t flags = ACPI_SCAN_CHECK_FLAG_EJECT;



	if (device->handler && device->handler->hotplug.demand_offline) {

		if (!acpi_scan_is_offline(device, true))
@@ -312,7 +334,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device) 


	acpi_handle_debug(handle, "Ejecting\n");



	acpi_bus_trim(device);

	acpi_scan_check_and_detach(device, (void *)flags);



	acpi_evaluate_lck(handle, 0);

	/*
@@ -335,6 +357,8 @@ static int acpi_scan_hot_remove(struct acpi_device *device) 
	} else if (sta & ACPI_STA_DEVICE_ENABLED) {

		acpi_handle_warn(handle,

			"Eject incomplete - status 0x%llx\n", sta);

	} else {

		acpi_bus_post_eject(device, NULL);

	}



	return 0;

include/acpi/acpi_bus.h

+1 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ struct acpi_scan_handler { 
	bool (*match)(const char *idstr, const struct acpi_device_id **matchid);

	int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);

	void (*detach)(struct acpi_device *dev);

	void (*post_eject)(struct acpi_device *dev);

	void (*bind)(struct device *phys_dev);

	void (*unbind)(struct device *phys_dev);

	struct acpi_hotplug_profile hotplug;