This patch set enables custom ACPI board configuration by adding mechanisms in the Linux kernel for loading user defined SSDTs. In order to support ACPI open-ended hardware configurations we need a way to augment the ACPI configuration provided by the firmware image. A common example is connecting sensors on I2C / SPI buses on development boards. Although this can be accomplished by creating a kernel platform driver or recompiling the firmware image with updated ACPI tables, neither is practical: the former proliferates board specific kernel code while the latter requires access to firmware tools which are often not publicly available. Because ACPI supports external references in AML code a more practical way to augment firmware ACPI configuration is by dynamically loading user defined SSDT tables that contain the board specific information. Currently it is possible to load SSDT overlays using the upgrade initrd mechanism introduced in 4.7. This patch series adds support for two more methods: * From an EFI variable This is the preferred method, when EFI is supported on the platform, because it allows a persistent, OS independent way of storing and updating the user defined SSDTs. There is also work underway to implement EFI support for loading user defined SSDTs and using this method will make it easier to convert to the EFI loading mechanism when that will arrive. * From userspace via configfs This is useful when we want to defer the operation to userspace for platform detection, loading the SSDTs from a custom partition, etc. Changes from v3: * fix a bisectability issue reported by kbuild * rework the enumeration fix to support PRP0001 enumeration; also, introduce acpi_device_set/clear_enumerated() for clarity * clear the enumerated status for acpi_device when the I2C/SPI clients are removed (for example as a result of an adapter removal) to allow the devices to be re-enumerated later Changes from v2: * fix a few issues caught by the kbuild test robot * add more configfs table attributes * removed the initrd based loading functionality from this patch set as this can already be accomplished in 4.7 using the ACPI table upgrade mechanism * rebased to 4.7-rc3 Changes from v1: * rebased on top of the ACPI install from initrd table functionality; there is significant overlap between the 1st patch in this series and these patch [1] from Lv - I kept it in this series until the discussions around the taint and config option are resolved * make sure EFI_RUNTIME_SERVICES are available before trying to use EFI variables to load tables * rework the ACPI reconfiguration notifications to work on device granularity (device added or removed) instead of table granularity (table loaded or unloaded) * add support for table unloading / device removal * note that the last patch is just a hack to be able to test the table unload / device remove functionality, if someone wants to try out this patch set [1] https://patchwork.kernel.org/patch/8795931/ Octavian Purdila (8): Documentation: acpi: add SSDT overlays documentation acpi: fix enumeration (visited) flags for bus rescans acpi: add support for ACPI reconfiguration notifiers i2c: add support for ACPI reconfigure notifications spi: add support for ACPI reconfigure notifications efi: load SSTDs from EFI variables acpi: add support for configfs acpi: add support for loading SSDTs via configfs Documentation/ABI/testing/configfs-acpi | 36 +++++ Documentation/acpi/ssdt-overlays.txt | 172 ++++++++++++++++++++ Documentation/kernel-parameters.txt | 7 + MAINTAINERS | 1 + drivers/acpi/Kconfig | 9 ++ drivers/acpi/Makefile | 1 + drivers/acpi/bus.c | 9 ++ drivers/acpi/configfs.c | 267 ++++++++++++++++++++++++++++++++ drivers/acpi/internal.h | 3 + drivers/acpi/scan.c | 81 +++++++++- drivers/acpi/sysfs.c | 6 +- drivers/firmware/efi/efi.c | 106 +++++++++++++ drivers/i2c/i2c-core.c | 172 +++++++++++++++----- drivers/spi/spi.c | 96 +++++++++++- include/linux/acpi.h | 36 +++++ 15 files changed, 946 insertions(+), 56 deletions(-) create mode 100644 Documentation/ABI/testing/configfs-acpi create mode 100644 Documentation/acpi/ssdt-overlays.txt create mode 100644 drivers/acpi/configfs.c -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
