acpi: Store CRC-32 hash of the _PLD in struct acpi_device

Storing CRC-32 hash of the Physical Location of Device
object (_PLD) with devices that have it. The hash is stored
to a new struct acpi_device member "pld_crc".

The hash makes it easier to find devices that share a
location, as there is no need to evaluate the entire object
every time. Knowledge about devices that share a location
can be used in device drivers that need to know the
connections to other components inside a system. USB3 ports
will for example always share their location with a USB2
port.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20211223081620.45479-3-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 2c80765670bc7fc35508ad91347f8343f5f1f1d6..e86e216894c4cdfe246b67434f8a8c5cf1208a7b 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -19,6 +19,7 @@
 #include <linux/dma-map-ops.h>
 #include <linux/platform_data/x86/apple.h>
 #include <linux/pgtable.h>
+#include <linux/crc32.h>
 
 #include "internal.h"
 
@@ -654,6 +655,19 @@ static int acpi_tie_acpi_dev(struct acpi_device *adev)
        return 0;
 }
 
+static void acpi_store_pld_crc(struct acpi_device *adev)
+{
+       struct acpi_pld_info *pld;
+       acpi_status status;
+
+       status = acpi_get_physical_device_location(adev->handle, &pld);
+       if (ACPI_FAILURE(status))
+               return;
+
+       adev->pld_crc = crc32(~0, pld, sizeof(*pld));
+       ACPI_FREE(pld);
+}
+
 static int __acpi_device_add(struct acpi_device *device,
                             void (*release)(struct device *))
 {
@@ -712,6 +726,8 @@ static int __acpi_device_add(struct acpi_device *device,
        if (device->wakeup.flags.valid)
                list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
 
+       acpi_store_pld_crc(device);
+
        mutex_unlock(&acpi_device_lock);
 
        if (device->parent)

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 480f9207a4c6bcfdb065983281c2bc5e2b6071e0..3a1280649ddfe0a590fe87e8d161685214da9bd3 100644 (file)
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -358,6 +358,7 @@ struct acpi_gpio_mapping;
 
 /* Device */
 struct acpi_device {
+       u32 pld_crc;
        int device_type;
        acpi_handle handle;             /* no handle for fixed hardware */
        struct fwnode_handle fwnode;