Re: [PATCH V6 5/8] vfio: platform: call _RST method when using ACPI

[Auger Eric <eric.auger@redhat.com>]

Hi Sinan,
Le 29/05/2016 à 00:01, Sinan Kaya a écrit :
> 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 checks the presence of _RST method and calls the _RST
> method when reset is requested.
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> Reviewed-by: Eric Auger <eric.auger@linaro.org>
code has changed compared to previous version and the R-b. In the future, please add change logs.
Besides it looks ok to me.

Best Regards

Eric

> ---
>  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);
>  	}
>  
>  	dev_warn(vdev->device, "no reset function found!\n");
>