Commit d0562674 authored by Suthikulpanit, Suravee's avatar Suthikulpanit, Suravee Committed by Rafael J. Wysocki
Browse files

ACPI / scan: Parse _CCA and setup device coherency 



This patch implements support for ACPI _CCA object, which is introduced in
ACPIv5.1, can be used for specifying device DMA coherency attribute.

The parsing logic traverses device namespace to parse coherency
information, and stores it in acpi_device_flags. Then uses it to call
arch_setup_dma_ops() when creating each device enumerated in DSDT
during ACPI scan.

This patch also introduces acpi_dma_is_coherent(), which provides
an interface for device drivers to check the coherency information
similarly to the of_dma_is_coherent().

Signed-off-by: default avatarMark Salter <msalter@redhat.com>
Signed-off-by: default avatarSuravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent faacd5ad

drivers/acpi/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -54,6 +54,9 @@ config ACPI_GENERIC_GSI 
config ACPI_SYSTEM_POWER_STATES_SUPPORT

	bool



config ACPI_CCA_REQUIRED

	bool



config ACPI_SLEEP

	bool

	depends on SUSPEND || HIBERNATION

drivers/acpi/acpi_platform.c

+1 −1
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev) 
	pdevinfo.res = resources;

	pdevinfo.num_res = count;

	pdevinfo.fwnode = acpi_fwnode_handle(adev);

	pdevinfo.dma_mask = DMA_BIT_MASK(32);

	pdevinfo.dma_mask = acpi_check_dma(adev, NULL) ? DMA_BIT_MASK(32) : 0;

	pdev = platform_device_register_full(&pdevinfo);

	if (IS_ERR(pdev))

		dev_err(&adev->dev, "platform device creation failed: %ld\n",

drivers/acpi/glue.c

+5 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/slab.h>

#include <linux/rwsem.h>

#include <linux/acpi.h>

#include <linux/dma-mapping.h>



#include "internal.h"
@@ -167,6 +168,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev) 
	struct list_head *physnode_list;

	unsigned int node_id;

	int retval = -EINVAL;

	bool coherent;



	if (has_acpi_companion(dev)) {

		if (acpi_dev) {
@@ -223,6 +225,9 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev) 
	if (!has_acpi_companion(dev))

		ACPI_COMPANION_SET(dev, acpi_dev);



	if (acpi_check_dma(acpi_dev, &coherent))

		arch_setup_dma_ops(dev, 0, 0, NULL, coherent);



	acpi_physnode_link_name(physical_node_name, node_id);

	retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,

				   physical_node_name);

drivers/acpi/scan.c

+35 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/kthread.h>

#include <linux/dmi.h>

#include <linux/nls.h>

#include <linux/dma-mapping.h>



#include <asm/pgtable.h>
@@ -2111,6 +2112,39 @@ void acpi_free_pnp_ids(struct acpi_device_pnp *pnp) 
	kfree(pnp->unique_id);

}



static void acpi_init_coherency(struct acpi_device *adev)

{

	unsigned long long cca = 0;

	acpi_status status;

	struct acpi_device *parent = adev->parent;



	if (parent && parent->flags.cca_seen) {

		/*

		 * From ACPI spec, OSPM will ignore _CCA if an ancestor

		 * already saw one.

		 */

		adev->flags.cca_seen = 1;

		cca = parent->flags.coherent_dma;

	} else {

		status = acpi_evaluate_integer(adev->handle, "_CCA",

					       NULL, &cca);

		if (ACPI_SUCCESS(status))

			adev->flags.cca_seen = 1;

		else if (!IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED))

			/*

			 * If architecture does not specify that _CCA is

			 * required for DMA-able devices (e.g. x86),

			 * we default to _CCA=1.

			 */

			cca = 1;

		else

			acpi_handle_debug(adev->handle,

					  "ACPI device is missing _CCA.\n");

	}



	adev->flags.coherent_dma = cca;

}



void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,

			     int type, unsigned long long sta)

{
@@ -2129,6 +2163,7 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle, 
	device->flags.visited = false;

	device_initialize(&device->dev);

	dev_set_uevent_suppress(&device->dev, true);

	acpi_init_coherency(device);

}



void acpi_device_add_finalize(struct acpi_device *device)

include/acpi/acpi_bus.h

+36 −1
Original line number Diff line number Diff line
@@ -209,7 +209,9 @@ struct acpi_device_flags { 
	u32 hotplug_notify:1;

	u32 is_dock_station:1;

	u32 of_compatible_ok:1;

	u32 reserved:22;

	u32 coherent_dma:1;

	u32 cca_seen:1;

	u32 reserved:20;

};



/* File System */
@@ -381,6 +383,39 @@ struct acpi_device { 
	void (*remove)(struct acpi_device *);

};



static inline bool acpi_check_dma(struct acpi_device *adev, bool *coherent)

{

	bool ret = false;



	if (!adev)

		return ret;



	/**

	 * Currently, we only support _CCA=1 (i.e. coherent_dma=1)

	 * This should be equivalent to specifyig dma-coherent for

	 * a device in OF.

	 *

	 * For the case when _CCA=0 (i.e. coherent_dma=0 && cca_seen=1),

	 * There are two cases:

	 * case 1. Do not support and disable DMA.

	 * case 2. Support but rely on arch-specific cache maintenance for

	 *         non-coherence DMA operations.

	 * Currently, we implement case 1 above.

	 *

	 * For the case when _CCA is missing (i.e. cca_seen=0) and

	 * platform specifies ACPI_CCA_REQUIRED, we do not support DMA,

	 * and fallback to arch-specific default handling.

	 *

	 * See acpi_init_coherency() for more info.

	 */

	if (adev->flags.coherent_dma) {

		ret = true;

		if (coherent)

			*coherent = adev->flags.coherent_dma;

	}

	return ret;

}



static inline bool is_acpi_node(struct fwnode_handle *fwnode)

{

	return fwnode && fwnode->type == FWNODE_ACPI;

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