[PATCH] accel/ivpu: Don't enter d0i3 during FLR

[Jeffrey Hugo]

On 10/17/2023 2:43 AM, Stanislaw Gruszka wrote:
> On Fri, Oct 06, 2023 at 09:25:29AM -0600, Jeffrey Hugo wrote:
>> On 10/3/2023 12:42 AM, Stanislaw Gruszka wrote:
>>> From: Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com>
>>>
>>> Fix a bug on some platforms where FLR causes complete system
>>> hang when CPU is low power states (C8 or above).
>>
>> Why does FLR cause a complete system hang?
> 
> This HW bug is still under debug and it is not yet root caused.

Ouch.  Good luck with that.

> 
>> Why does avoiding d0i3 fix the
>> issue?  Feels like there could be a lot more detail here.
> 
> We only know that we should avoid entering D0i3.
> 
> I will change the log this way:
> 
> Avoid HW bug on some platforms where we enter D0i3 state
> and CPU is in low power states (C8 or above).
> 
> Regards
> Stanislaw
> 
>>> Fixes: 852be13f3bd3 ("accel/ivpu: Add PM support")
>>> Cc: stable at vger.kernel.org
>>> Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com>
>>> Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka at linux.intel.com>
>>> Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka at linux.intel.com>
>>> ---
>>>    drivers/accel/ivpu/ivpu_drv.c     | 11 ++++++++---
>>>    drivers/accel/ivpu/ivpu_drv.h     |  1 +
>>>    drivers/accel/ivpu/ivpu_hw.h      |  8 ++++++++
>>>    drivers/accel/ivpu/ivpu_hw_37xx.c |  1 +
>>>    drivers/accel/ivpu/ivpu_hw_40xx.c |  1 +
>>>    drivers/accel/ivpu/ivpu_pm.c      |  3 ++-
>>>    6 files changed, 21 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/accel/ivpu/ivpu_drv.c b/drivers/accel/ivpu/ivpu_drv.c
>>> index 3f4efa07ce7c..1eb232e903e8 100644
>>> --- a/drivers/accel/ivpu/ivpu_drv.c
>>> +++ b/drivers/accel/ivpu/ivpu_drv.c
>>> @@ -367,14 +367,19 @@ int ivpu_boot(struct ivpu_device *vdev)
>>>    	return 0;
>>>    }
>>> -int ivpu_shutdown(struct ivpu_device *vdev)
>>> +void ivpu_prepare_for_reset(struct ivpu_device *vdev)
>>>    {
>>> -	int ret;
>>> -
>>>    	ivpu_hw_irq_disable(vdev);
>>>    	disable_irq(vdev->irq);
>>>    	ivpu_ipc_disable(vdev);
>>>    	ivpu_mmu_disable(vdev);
>>> +}
>>> +
>>> +int ivpu_shutdown(struct ivpu_device *vdev)
>>> +{
>>> +	int ret;
>>> +
>>> +	ivpu_prepare_for_reset(vdev);
>>>    	ret = ivpu_hw_power_down(vdev);
>>>    	if (ret)
>>> diff --git a/drivers/accel/ivpu/ivpu_drv.h b/drivers/accel/ivpu/ivpu_drv.h
>>> index 98380c1db9fa..a3b45032e6cf 100644
>>> --- a/drivers/accel/ivpu/ivpu_drv.h
>>> +++ b/drivers/accel/ivpu/ivpu_drv.h
>>> @@ -158,6 +158,7 @@ void ivpu_file_priv_put(struct ivpu_file_priv **link);
>>>    int ivpu_boot(struct ivpu_device *vdev);
>>>    int ivpu_shutdown(struct ivpu_device *vdev);
>>> +void ivpu_prepare_for_reset(struct ivpu_device *vdev);
>>>    static inline u8 ivpu_revision(struct ivpu_device *vdev)
>>>    {
>>> diff --git a/drivers/accel/ivpu/ivpu_hw.h b/drivers/accel/ivpu/ivpu_hw.h
>>> index ab341237bcf9..1079e06255ba 100644
>>> --- a/drivers/accel/ivpu/ivpu_hw.h
>>> +++ b/drivers/accel/ivpu/ivpu_hw.h
>>> @@ -13,6 +13,7 @@ struct ivpu_hw_ops {
>>>    	int (*power_up)(struct ivpu_device *vdev);
>>>    	int (*boot_fw)(struct ivpu_device *vdev);
>>>    	int (*power_down)(struct ivpu_device *vdev);
>>> +	int (*reset)(struct ivpu_device *vdev);
>>>    	bool (*is_idle)(struct ivpu_device *vdev);
>>>    	void (*wdt_disable)(struct ivpu_device *vdev);
>>>    	void (*diagnose_failure)(struct ivpu_device *vdev);
>>> @@ -91,6 +92,13 @@ static inline int ivpu_hw_power_down(struct ivpu_device *vdev)
>>>    	return vdev->hw->ops->power_down(vdev);
>>>    };
>>> +static inline int ivpu_hw_reset(struct ivpu_device *vdev)
>>> +{
>>> +	ivpu_dbg(vdev, PM, "HW reset\n");
>>> +
>>> +	return vdev->hw->ops->reset(vdev);
>>> +};
>>> +
>>>    static inline void ivpu_hw_wdt_disable(struct ivpu_device *vdev)
>>>    {
>>>    	vdev->hw->ops->wdt_disable(vdev);
>>> diff --git a/drivers/accel/ivpu/ivpu_hw_37xx.c b/drivers/accel/ivpu/ivpu_hw_37xx.c
>>> index edd4d860f135..1e842739e937 100644
>>> --- a/drivers/accel/ivpu/ivpu_hw_37xx.c
>>> +++ b/drivers/accel/ivpu/ivpu_hw_37xx.c
>>> @@ -1036,6 +1036,7 @@ const struct ivpu_hw_ops ivpu_hw_37xx_ops = {
>>>    	.power_up = ivpu_hw_37xx_power_up,
>>>    	.is_idle = ivpu_hw_37xx_is_idle,
>>>    	.power_down = ivpu_hw_37xx_power_down,
>>> +	.reset = ivpu_hw_37xx_reset,
>>>    	.boot_fw = ivpu_hw_37xx_boot_fw,
>>>    	.wdt_disable = ivpu_hw_37xx_wdt_disable,
>>>    	.diagnose_failure = ivpu_hw_37xx_diagnose_failure,
>>> diff --git a/drivers/accel/ivpu/ivpu_hw_40xx.c b/drivers/accel/ivpu/ivpu_hw_40xx.c
>>> index a48cd36f9931..d7b8ec0410af 100644
>>> --- a/drivers/accel/ivpu/ivpu_hw_40xx.c
>>> +++ b/drivers/accel/ivpu/ivpu_hw_40xx.c
>>> @@ -1186,6 +1186,7 @@ const struct ivpu_hw_ops ivpu_hw_40xx_ops = {
>>>    	.power_up = ivpu_hw_40xx_power_up,
>>>    	.is_idle = ivpu_hw_40xx_is_idle,
>>>    	.power_down = ivpu_hw_40xx_power_down,
>>> +	.reset = ivpu_hw_40xx_reset,
>>>    	.boot_fw = ivpu_hw_40xx_boot_fw,
>>>    	.wdt_disable = ivpu_hw_40xx_wdt_disable,
>>>    	.diagnose_failure = ivpu_hw_40xx_diagnose_failure,
>>> diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
>>> index 28a0d1111e12..da46f95b008a 100644
>>> --- a/drivers/accel/ivpu/ivpu_pm.c
>>> +++ b/drivers/accel/ivpu/ivpu_pm.c
>>> @@ -261,7 +261,8 @@ void ivpu_pm_reset_prepare_cb(struct pci_dev *pdev)
>>>    	ivpu_dbg(vdev, PM, "Pre-reset..\n");
>>>    	atomic_inc(&vdev->pm->reset_counter);
>>>    	atomic_set(&vdev->pm->in_reset, 1);
>>> -	ivpu_shutdown(vdev);
>>> +	ivpu_prepare_for_reset(vdev);
>>> +	ivpu_hw_reset(vdev);
>>>    	ivpu_pm_prepare_cold_boot(vdev);
>>>    	ivpu_jobs_abort_all(vdev);
>>>    	ivpu_dbg(vdev, PM, "Pre-reset done.\n");
>>