Hi Sinan,
On 05/16/2016 04:13 AM, Sinan Kaya wrote:
> 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.
>
> This patch checks the presence of _RST method and calls the _RST
> method when reset is requested.
>
> Signed-off-by: Sinan Kaya <[email protected]>
> ---
> drivers/vfio/platform/vfio_platform_common.c | 44
> ++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/vfio/platform/vfio_platform_common.c
> b/drivers/vfio/platform/vfio_platform_common.c
> index d859d3b..095d5b7 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -73,21 +73,59 @@ int vfio_platform_acpi_probe(struct vfio_platform_device
> *vdev,
> }
> return 0;
> }
> +
> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev)
> +{
> + struct device *dev = vdev->device;
> + acpi_handle handle = ACPI_HANDLE(dev);
> + acpi_status acpi_ret;
> + unsigned long long val;
> +
> + acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
> + if (ACPI_FAILURE(acpi_ret))
> + return -EINVAL;
Can't you return something more explicit here? The error code will be
visible to the userspace. Difficult for him to understand the cause of
the failure in that case.
Eric
> +
> + return 0;
> +}
> +
> +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> +{
> + struct device *dev = vdev->device;
> + acpi_handle handle = ACPI_HANDLE(dev);
> +
> + return acpi_has_method(handle, "_RST");
> +}
> #else
> int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> struct device *dev)
> {
> return -EINVAL;
> }
> +
> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev)
> +{
> + return -EINVAL;
> +}
> +
> +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> +{
> + return false;
> +}
> #endif
>
> static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
> {
> + if (vdev->acpihid)
> + 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 (vdev->acpihid)
> + return;
> +
> vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
> &vdev->reset_module);
> if (!vdev->of_reset) {
> @@ -99,6 +137,9 @@ static void vfio_platform_get_reset(struct
> vfio_platform_device *vdev)
>
> static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
> {
> + if (vdev->acpihid)
> + return;
> +
> if (vdev->of_reset)
> module_put(vdev->reset_module);
> }
> @@ -177,6 +218,9 @@ static int vfio_platform_call_reset(struct
> vfio_platform_device *vdev)
> dev_info(vdev->device, "reset\n");
> vdev->of_reset(vdev);
> return 0;
> + } else if (vdev->acpihid) {
> + dev_info(vdev->device, "reset\n");
> + return vfio_platform_acpi_call_reset(vdev);
> }
>
> dev_warn(vdev->device, "no reset function found!\n");
>
