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

Add support for handling D-state notify for MHI EPF.

Signed-off-by: Krishna chaitanya chundru <[email protected]>
---
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;
+
+ 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



2023-07-28 04:19:12

by Manivannan Sadhasivam

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

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 <[email protected]>
> ---
> 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

> +
> + 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
>

--
மணிவண்ணன் சதாசிவம்

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


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 <[email protected]>
>> ---
>> 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

>
>> +
>> + 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
>>

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

2023-08-01 18:26:29

by Manivannan Sadhasivam

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

On Tue, Aug 01, 2023 at 10:31:42AM +0530, Krishna Chaitanya Chundru wrote:
>
> 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 <[email protected]>
> > > > ---
> > > >   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.
>

Notifiers are invoked in process context. And here, the context doesn't matter
as either way you need locking to prevent concurrent access to dstate variable.

But I think it is safe to ignore lock for now provided that wakeup_host callback
is only called while MHI is in M3 state. Even if dstate changes while processing
wakeup_host, it won't affect the behavior.

- Mani

> - 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
> > > >
> >

--
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