linux-kernel - Re: [PATCH v4 3/9] PCI: epf-mhi: Add support for handling D-state notify from EPC

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Message-ID: <0a6ca984-9797-88b1-ae12-c64916f6c61c@quicinc.com>
Date:   Tue, 1 Aug 2023 10:31:42 +0530
From:   Krishna Chaitanya Chundru <quic_krichai@...cinc.com>
To:     Manivannan Sadhasivam <mani@...nel.org>
CC:     <manivannan.sadhasivam@...aro.org>, <helgaas@...nel.org>,
        <linux-pci@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_vbadigan@...cinc.com>,
        <quic_nitegupt@...cinc.com>, <quic_skananth@...cinc.com>,
        <quic_ramkri@...cinc.com>, <krzysztof.kozlowski@...aro.org>,
        "Lorenzo Pieralisi" <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jeffrey Hugo <quic_jhugo@...cinc.com>,
        "open list:MHI BUS" <mhi@...ts.linux.dev>
Subject: Re: [PATCH v4 3/9] PCI: epf-mhi: Add support for handling D-state
 notify from EPC


On 7/31/2023 11:05 AM, Krishna Chaitanya Chundru wrote:
>
> On 7/28/2023 9:39 AM, Manivannan Sadhasivam wrote:
>> On Thu, Jul 13, 2023 at 12:40:12PM +0530, Krishna chaitanya chundru 
>> wrote:
>>> Add support for handling D-state notify for MHI EPF.
>>>
>>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
>>> ---
>>>   drivers/pci/endpoint/functions/pci-epf-mhi.c | 11 +++++++++++
>>>   include/linux/mhi_ep.h                       |  3 +++
>>>   2 files changed, 14 insertions(+)
>>>
>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c 
>>> b/drivers/pci/endpoint/functions/pci-epf-mhi.c
>>> index 9c1f5a1..ee91bfc 100644
>>> --- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
>>> +++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
>>> @@ -339,6 +339,16 @@ static int pci_epf_mhi_bme(struct pci_epf *epf)
>>>       return 0;
>>>   }
>>>   +static int pci_epf_mhi_dstate_notify(struct pci_epf *epf, 
>>> pci_power_t state)
>>> +{
>>> +    struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
>>> +    struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
>>> +
>>> +    mhi_cntrl->dstate = state;
>> Where is this variable being used? Also, don't we need any locking?
>>
>> - Mani
>
> we are using this variable in wakeup host op which is introduced on 
> patch [PATCH v4 8/9] PCI: epf-mhi: Add wakeup host op
>
> I will add lock in my next series.
>
> - KC

Mani, as this is being called from IRQ context do we need to add any 
lock here.

- KC

>
>>
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>   static int pci_epf_mhi_bind(struct pci_epf *epf)
>>>   {
>>>       struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
>>> @@ -394,6 +404,7 @@ static struct pci_epc_event_ops 
>>> pci_epf_mhi_event_ops = {
>>>       .link_up = pci_epf_mhi_link_up,
>>>       .link_down = pci_epf_mhi_link_down,
>>>       .bme = pci_epf_mhi_bme,
>>> +    .dstate_notify = pci_epf_mhi_dstate_notify,
>>>   };
>>>     static int pci_epf_mhi_probe(struct pci_epf *epf,
>>> diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h
>>> index f198a8a..c3a0685 100644
>>> --- a/include/linux/mhi_ep.h
>>> +++ b/include/linux/mhi_ep.h
>>> @@ -8,6 +8,7 @@
>>>     #include <linux/dma-direction.h>
>>>   #include <linux/mhi.h>
>>> +#include <linux/pci.h>
>>>     #define MHI_EP_DEFAULT_MTU 0x8000
>>>   @@ -139,6 +140,8 @@ struct mhi_ep_cntrl {
>>>         enum mhi_state mhi_state;
>>>   +    pci_power_t dstate;
>>> +
>>>       u32 max_chan;
>>>       u32 mru;
>>>       u32 event_rings;
>>> -- 
>>> 2.7.4
>>>
>