On Thu, Dec 23, 2021 at 11:16:17AM +0300, Heikki Krogerus wrote: > 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. > > Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> Building ia64:tinyconfig ... failed ia64-linux-ld: drivers/acpi/scan.o: in function `__acpi_device_add': scan.c:(.text+0x27e2): undefined reference to `crc32_le' ACPI now depends on CRC32. #regzbot introduced: 882c982dada4d5 Guenter > --- > drivers/acpi/scan.c | 16 ++++++++++++++++ > include/acpi/acpi_bus.h | 1 + > 2 files changed, 17 insertions(+) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 7ff55a197a583..113414c46b713 100644 > --- 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" > > @@ -667,6 +668,19 @@ 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 *)) > { > @@ -725,6 +739,8 @@ 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 8e87ead2af341..f8c945418df23 100644 > --- a/include/acpi/acpi_bus.h > +++ b/include/acpi/acpi_bus.h > @@ -360,6 +360,7 @@ 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;