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 <[email protected]> >> --- >> 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 <[email protected]> > 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
