On Thu, 23 Jun 2016 12:59:48 -0600
Alex Williamson <alex.williamson@xxxxxxxxxx> wrote:
> On Mon, 13 Jun 2016 00:26:38 -0400
> Sinan Kaya <okaya@xxxxxxxxxxxxxx> 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. _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 <okaya@xxxxxxxxxxxxxx>
> > Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
> > ---
> > drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++
> > 1 file changed, 51 insertions(+)
> >
> > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> > index e7ce2c2..0ea8c26 100644
> > --- a/drivers/vfio/platform/vfio_platform_common.c
> > +++ b/drivers/vfio/platform/vfio_platform_common.c
> > @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> > }
> > return 0;
> > }
> > +
> > +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> > + const char **extra_dbg)
> > +{
> > + 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)) {
> > + if (extra_dbg)
> > + *extra_dbg = acpi_format_exception(acpi_ret);
> > + return -EINVAL;
> > + }
> > +
> > + 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
> > static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> > struct device *dev)
> > {
> > return -ENOENT;
> > }
> > +
> > +static inline
> > +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> > + const char **extra_dbg)
> > +{
> > + return -ENOENT;
> > +}
> > +
> > +static inline
> > +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 +144,9 @@ 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 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
> > if (vdev->of_reset) {
> > dev_info(vdev->device, "reset\n");
> > return vdev->of_reset(vdev);
> > + } else if (vdev->acpihid) {
> > + dev_info(vdev->device, "reset\n");
> > + return vfio_platform_acpi_call_reset(vdev, extra_dbg);
>
>
> nit, all the cases until this one prioritize ACPI over DT, here we have
> the opposite. Granted we should never have of_reset set when acpihid
> is set. A macro like
>
> #define vfio_platform_is_acpi(vdev) (vdev->acpihid != NULL)
>
> might be useful.
Oops, I accidentally picked the v7 version to reply to, but the nit
exists in v8 as well. Thanks,
Alex
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