The current code only supports the device tree based platforms. The code checks for the presence of a reset driver and calls the reset function pointer by looking up the reset driver as a module. ACPI defines _RST method to perform device level reset. After the _RST method is executed, the OS can resume using the device. The patchset is moving the device tree specific pieces out of the code to common functions so that ACPI support is added without impacting the rest of the code. During probe, the ACPI HID of the object will be saved and will be used to determine if this is an ACPI capable platform or not. If acpihid is NULL then, device tree functions are called. In addition to plumbing ACPI support, reset functionality is now a requirement by default. The code was allowing platform devices to be used without a supporting VFIO reset driver. The hardware can be left in some inconsistent state after a guest machine abort. The reset driver will put the hardware back to safe state and disable interrupts before returning the control back to the host machine. Adding a new reset_required kernel module option to AMBA and platform VFIO drivers with a default value of true. New requirements are: 1. A reset function needs to be implemented by the corresponding driver via DT/ACPI. 2. The reset function needs to be discovered via DT/ACPI. The probe of the driver will fail if any of the above conditions are not satisfied. Changes from V7: 1. Move the reset function test before IOMMU group set up so that we can clean up properly when reset function is not found. 2. Correct the _RST function call. _RST method does not return any value. We were calling acpi_evaluate_integer. The correct API needs to be acpi_evaluate_object. Sinan Kaya (9): vfio: platform: rename reset function vfio: platform: move reset call to a common function vfio: platform: determine reset capability vfio: platform: add support for ACPI probe vfio: platform: add extra debug info argument to call reset vfio: platform: call _RST method when using ACPI vfio, platform: make reset driver a requirement by default vfio: platform: check reset call return code during open vfio: platform: check reset call return code during release drivers/vfio/platform/vfio_amba.c | 5 + drivers/vfio/platform/vfio_platform.c | 5 + drivers/vfio/platform/vfio_platform_common.c | 197 +++++++++++++++++++++----- drivers/vfio/platform/vfio_platform_private.h | 8 +- 4 files changed, 177 insertions(+), 38 deletions(-) -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
