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Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

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  Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI Sinan Kaya <okaya@codeaurora.org> - 2016-07-13 21:50 +0200
    Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI Alex Williamson <alex.williamson@redhat.com> - 2016-07-13 22:20 +0200

#1442792 — Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI

On 6/23/2016 2:59 PM, Alex Williamson wrote:
> On Mon, 13 Jun 2016 00:26:38 -0400
> Sinan Kaya <okaya@codeaurora.org> 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@codeaurora.org>
>> Reviewed-by: Eric Auger <eric.auger@linaro.org>
>> ---
>>  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. 

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


-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

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#1442808

On Wed, 13 Jul 2016 15:39:25 -0400
Sinan Kaya <okaya@codeaurora.org> wrote:

> On 6/23/2016 2:59 PM, Alex Williamson wrote:
> > On Mon, 13 Jun 2016 00:26:38 -0400
> > Sinan Kaya <okaya@codeaurora.org> 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@codeaurora.org>
> >> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> >> ---
> >>  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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