From d30daa33ec1d035acfdfc7662d7a5360592af44c Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Tue, 19 Jul 2016 09:01:46 -0400 Subject: vfio: platform: call _RST method when using ACPI The device tree code checks for the presence of a reset driver and calls the of_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. _RST method is expected to stop DMA transfers and IRQs. This patch introduces two functions as vfio_platform_acpi_has_reset and vfio_platform_acpi_call_reset. The has reset method is used to declare reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call reset function is used to execute the _RST ACPI method. Signed-off-by: Sinan Kaya Signed-off-by: Alex Williamson --- drivers/vfio/platform/vfio_platform_common.c | 50 +++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) (limited to 'drivers/vfio') diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index a9760c2e68ad..a15a69b52080 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -28,6 +28,8 @@ #define DRIVER_AUTHOR "Antonios Motakis " #define DRIVER_DESC "VFIO platform base module" +#define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL) + static LIST_HEAD(reset_list); static DEFINE_MUTEX(driver_lock); @@ -71,13 +73,53 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, return WARN_ON(!vdev->acpihid) ? -EINVAL : 0; } +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev, + const char **extra_dbg) +{ +#ifdef CONFIG_ACPI + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + struct device *dev = vdev->device; + acpi_handle handle = ACPI_HANDLE(dev); + acpi_status acpi_ret; + + acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer); + if (ACPI_FAILURE(acpi_ret)) { + if (extra_dbg) + *extra_dbg = acpi_format_exception(acpi_ret); + return -EINVAL; + } + + return 0; +#else + return -ENOENT; +#endif +} + +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev) +{ +#ifdef CONFIG_ACPI + struct device *dev = vdev->device; + acpi_handle handle = ACPI_HANDLE(dev); + + return acpi_has_method(handle, "_RST"); +#else + return false; +#endif +} + static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) { + if (VFIO_PLATFORM_IS_ACPI(vdev)) + return vfio_platform_acpi_has_reset(vdev); + return vdev->of_reset ? true : false; } static void vfio_platform_get_reset(struct vfio_platform_device *vdev) { + if (VFIO_PLATFORM_IS_ACPI(vdev)) + return; + vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, &vdev->reset_module); if (!vdev->of_reset) { @@ -89,6 +131,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev) static void vfio_platform_put_reset(struct vfio_platform_device *vdev) { + if (VFIO_PLATFORM_IS_ACPI(vdev)) + return; + if (vdev->of_reset) module_put(vdev->reset_module); } @@ -164,7 +209,10 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev) static int vfio_platform_call_reset(struct vfio_platform_device *vdev, const char **extra_dbg) { - if (vdev->of_reset) { + if (VFIO_PLATFORM_IS_ACPI(vdev)) { + dev_info(vdev->device, "reset\n"); + return vfio_platform_acpi_call_reset(vdev, extra_dbg); + } else if (vdev->of_reset) { dev_info(vdev->device, "reset\n"); return vdev->of_reset(vdev); } -- cgit v1.2.3