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.
>
>
>> }
>>
>> 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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