From: Pawel Laszczak <pawell@cadence.com>
To: Felipe Balbi <felipe.balbi@linux.intel.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"hdegoede@redhat.com" <hdegoede@redhat.com>,
"heikki.krogerus@linux.intel.com"
<heikki.krogerus@linux.intel.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"rogerq@ti.com" <rogerq@ti.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jbergsagel@ti.com" <jbergsagel@ti.com>,
"nsekhar@ti.com" <nsekhar@ti.com>, "nm@ti.com" <nm@ti.com>,
Suresh Punnoose <sureshp@cadence.com>,
"peter.chen@nxp.com" <peter.chen@nxp.com>,
Jayshri Dajiram Pawar <jpawar@cadence.com>,
Rahul Kumar <kurahul@cadence.com>
Subject: RE: [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
Date: Tue, 9 Jul 2019 07:29:10 +0000 [thread overview]
Message-ID: <BYAPR07MB4709648F659AB5A11B0EB621DDF10@BYAPR07MB4709.namprd07.prod.outlook.com> (raw)
In-Reply-To: <87muhn65a7.fsf@linux.intel.com>
>
>
>Hi,
>
>Pawel Laszczak <pawell@cadence.com> writes:
>>>>>> IRQF_ONESHOT can be used only in threaded handled.
>>>>>> "
>>>>>> * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
>>>>>> * Used by threaded interrupts which need to keep the
>>>>>> * irq line disabled until the threaded handler has been run.
>>>>>> "
>>>>>
>>>>>so?
>>>>
>>>> I don't understand why If I don't have threaded handler why I need IRQF_ONESHOT.
>>>> Why interrupt cannot be reenabled after hardirq handler finished ?
>>>> I do not use threaded handler so this flag seem unnecessary.
>>>
>>>Unless this has changed over the years, it was a requirement from IRQ susbystem.
>>>
>>> /*
>>> * Drivers are often written to work w/o knowledge about the
>>> * underlying irq chip implementation, so a request for a
>>> * threaded irq without a primary hard irq context handler
>>> * requires the ONESHOT flag to be set. Some irq chips like
>>> * MSI based interrupts are per se one shot safe. Check the
>>> * chip flags, so we can avoid the unmask dance at the end of
>>> * the threaded handler for those.
>>> */
>>> if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
>>> new->flags &= ~IRQF_ONESHOT;
>>
>> From description I understand that it should be set when driver uses only
>> threaded handler without hard irq handler.
>> eg.
>>
>> ret = devm_request_threaded_irq(dev, data->usb_id_irq,
>> NULL, int3496_thread_isr,
>> IRQF_SHARED | IRQF_ONESHOT |
>> IRQF_TRIGGER_RISING |
>> IRQF_TRIGGER_FALLING,
>> dev_name(dev), data);
>>
>> It make sense, we don't have hard irq handler so we can't clear source of interrupt.
>> If we clear it immediately in interrupt controller then the same interrupt could
>> be raised again, because it was not cleared e.g in controller register.
>
>You are correct. Big mistake on my side. Apologies.
All right, you're welcome. I learn a lot of during such discussions :).
>--
>balbi
next prev parent reply other threads:[~2019-07-09 7:30 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-05 10:57 [PATCH v9 0/6] Introduced new Cadence USBSS DRD Driver Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 1/6] dt-bindings: add binding for USBSS-DRD controller Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 2/6] usb:gadget Separated decoding functions from dwc3 driver Pawel Laszczak
2019-07-05 11:27 ` Greg KH
2019-07-05 11:39 ` Pawel Laszczak
2019-07-05 11:49 ` Greg KH
2019-07-05 12:03 ` Pawel Laszczak
2019-07-05 11:39 ` Felipe Balbi
2019-07-05 11:44 ` Pawel Laszczak
2019-08-07 10:17 ` Roger Quadros
2019-08-07 10:22 ` Felipe Balbi
2019-08-08 3:07 ` Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 3/6] usb:gadget Patch simplify usb_decode_set_clear_feature function Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 4/6] usb:gadget Simplify usb_decode_get_set_descriptor function Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver Pawel Laszczak
2019-07-05 11:55 ` Felipe Balbi
2019-07-07 17:56 ` Pawel Laszczak
2019-07-08 6:29 ` Felipe Balbi
2019-07-08 10:59 ` Pawel Laszczak
2019-07-08 11:15 ` Felipe Balbi
2019-07-08 11:45 ` Pawel Laszczak
2019-07-08 11:59 ` Felipe Balbi
2019-07-08 12:39 ` Pawel Laszczak
2019-07-09 4:23 ` Pawel Laszczak
2019-07-09 6:36 ` Felipe Balbi
2019-07-09 7:07 ` Pawel Laszczak
2019-07-09 7:22 ` Felipe Balbi
2019-07-09 7:29 ` Pawel Laszczak [this message]
2019-07-10 8:25 ` Pawel Laszczak
2019-07-08 7:11 ` Felipe Balbi
2019-07-15 11:00 ` Pawel Laszczak
2019-08-07 10:34 ` Felipe Balbi
2019-08-10 20:39 ` Pawel Laszczak
2019-08-12 1:55 ` Peter Chen
2019-08-12 4:43 ` Pawel Laszczak
2019-08-12 5:24 ` Felipe Balbi
2019-08-12 7:13 ` Pawel Laszczak
2019-08-12 8:19 ` Felipe Balbi
2019-08-12 9:13 ` Pawel Laszczak
2019-08-12 9:45 ` Felipe Balbi
2019-08-12 10:26 ` Pawel Laszczak
2019-08-12 10:34 ` Felipe Balbi
2019-08-12 14:20 ` Alan Stern
2019-07-05 10:57 ` [PATCH v9 6/6] usb:cdns3 Fix for stuck packets in on-chip OUT buffer Pawel Laszczak
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