From: Sinan Kaya <okaya@codeaurora.org>
To: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org, timur@codeaurora.org,
cov@codeaurora.org, jcm@redhat.com, agross@codeaurora.org,
arnd@arndb.de, linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V7 2/3] dma: add Qualcomm Technologies HIDMA management driver
Date: Tue, 8 Dec 2015 09:36:02 -0500 [thread overview]
Message-ID: <5666EAD2.1060408@codeaurora.org> (raw)
In-Reply-To: <20151205075826.GI1854@localhost>
On 12/5/2015 2:58 AM, Vinod Koul wrote:
> On Tue, Dec 01, 2015 at 11:57:34PM -0500, Sinan Kaya wrote:
>> On 11/30/2015 10:17 PM, Vinod Koul wrote:
>>> On Mon, Nov 30, 2015 at 09:42:01AM -0500, Sinan Kaya wrote:
>>>
>>>>>> +static int hidma_mgmt_probe(struct platform_device *pdev)
>>>>>> +{
>>>>>> + struct hidma_mgmt_dev *mgmtdev;
>>>>>> + struct resource *res;
>>>>>> + void __iomem *virtaddr;
>>>>>> + int irq;
>>>>>> + int rc;
>>>>>> + u32 val;
>>>>>> +
>>>>>> + pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
>>>>>> + pm_runtime_use_autosuspend(&pdev->dev);
>>>>>> + pm_runtime_set_active(&pdev->dev);
>>>>>> + pm_runtime_enable(&pdev->dev);
>>>>>
>>>>> at this time pm core will treat device as fully enabled and pm methods can
>>>>> be invoked, but you are not ready yet right. Typically these are done at the
>>>>> end of the probe unless you have a reason...
>>>>
>>>> I need it here because the clocks are declared as ACPI power resources.
>>>> The kernel is turning off all power resources during initialization. In
>>>> order for this code to touch the hardware, I need to call enable so that
>>>> clocks are enabled once again.
>>>
>>> The question is are you ready in your driver routines to be invoked by pm
>>> core?
>>>
>>
>> I don't have any support for suspend and resume PM APIs. The only PM
>> interface I support is PM runtime. PM can turn on/off the clocks based
>> on the reference counts it maintains after get/set APIs. Since PM is
>> turning off the clocks during power up before my driver load, I do need
>> to grab this lock to re-enable it during HW initialization. Then, let PM
>> turn off the clocks again after the AUTOSUSPEND_TIMEOUT when I'm done.
>>
>> Is there any other interaction with the PM that I'm not aware of?
>
> No this is fine. The the runtime_resume will be onvoked and it will request
> resources are those set before you enable the device?
>
Yes, the only resource that this device needs for power management is
the ACPI power resources. The device does not support suspend/resume via
traditional _PS0 and _PS3 calls. ACPI power resources are initialized
during power up while ACPI is being enumerated.
The probing of the HIDMA driver happens much afterwards.
--
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
next prev parent reply other threads:[~2015-12-08 14:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-23 2:28 [PATCH V7 0/3] dma: add Qualcomm Technologies HIDMA driver Sinan Kaya
2015-11-23 2:28 ` [PATCH V7 1/3] dma: qcom_bam_dma: move to qcom directory Sinan Kaya
2015-11-25 21:42 ` Andy Gross
2015-11-28 15:06 ` Sinan Kaya
2015-11-23 2:28 ` [PATCH V7 2/3] dma: add Qualcomm Technologies HIDMA management driver Sinan Kaya
2015-11-23 18:06 ` Andy Shevchenko
2015-11-23 18:49 ` Sinan Kaya
2015-11-30 8:21 ` Vinod Koul
2015-11-30 14:42 ` Sinan Kaya
2015-12-01 3:17 ` Vinod Koul
2015-12-02 4:57 ` Sinan Kaya
2015-12-05 7:58 ` Vinod Koul
2015-12-08 14:36 ` Sinan Kaya [this message]
2015-11-23 2:28 ` [PATCH V7 3/3] dma: add Qualcomm Technologies HIDMA channel driver Sinan Kaya
2015-11-30 8:59 ` Vinod Koul
2015-11-30 20:06 ` Sinan Kaya
2015-12-01 11:34 ` Vinod Koul
2015-12-01 21:16 ` Sinan Kaya
2015-12-02 19:04 ` Sinan Kaya
2015-12-05 8:00 ` Vinod Koul
2015-12-08 14:33 ` Sinan Kaya
2015-12-10 20:10 ` Sinan Kaya
2015-12-11 9:35 ` Vinod Koul
2015-12-17 23:52 ` Sinan Kaya
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