On 5/23/2016 10:41 AM, Eric Auger wrote:
> On 05/16/2016 04:13 AM, Sinan Kaya 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.
>>
>> This patch checks the presence of _RST method and calls the _RST
>> method when reset is requested.
>>
>> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
>> ---
>> drivers/vfio/platform/vfio_platform_common.c | 44 ++++++++++++++++++++++++++++
>> 1 file changed, 44 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>> index d859d3b..095d5b7 100644
>> --- a/drivers/vfio/platform/vfio_platform_common.c
>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>> @@ -73,21 +73,59 @@ int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>> }
>> return 0;
>> }
>> +
>> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev)
>> +{
>> + 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))
>> + 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
>> int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>> struct device *dev)
>> {
>> return -EINVAL;
>> }
>> +
>> +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev)
>> +{
> nit: inline
>> + return -EINVAL;
>> +}
>> +
>> +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> nit: inline
sure
>
> Besides Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
>
thanks
> It is not explictly written in the ACPI spec that _RST is expected to
> stop DMA transfers and IRQs although this may be implicit in the notion
> of "function level reset ". May be worth adding this info in the commit msg?
>
yes, I'll add DMA and IRQ requirement to the commit message.
> Best Regards
>
> Eric
>> +{
>> + 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 +137,9 @@ 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 +218,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev)
>> dev_info(vdev->device, "reset\n");
>> vdev->of_reset(vdev);
>> return 0;
>> + } else if (vdev->acpihid) {
>> + dev_info(vdev->device, "reset\n");
>> + return vfio_platform_acpi_call_reset(vdev);
>> }
>>
>> dev_warn(vdev->device, "no reset function found!\n");
>>
>
--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
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