On Wed, 13 Jul 2016 15:39:25 -0400
Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote:
> On 6/23/2016 2:59 PM, Alex Williamson 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.
>
> I'll reorder to be consistent.
>
> > 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.
>
> I like your idea. If you don't mind, I like capitals in macros.
Sure. Thanks,
Alex
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