diff mbox series

PCI: endpoint: Add custom notifier support

Message ID 20210615133704.88169-1-manivannan.sadhasivam@linaro.org
State New
Headers show
Series PCI: endpoint: Add custom notifier support | expand

Commit Message

Manivannan Sadhasivam June 15, 2021, 1:37 p.m. UTC 
Add support for passing the custom notifications between the endpoint
controller and the function driver. This helps in passing the
notifications that are more specific to the controller and corresponding
function driver. The opaque `data` arugument in pci_epc_custom_notify()
function can be used to carry the event specific data that helps in
differentiating the events.

For instance, the Qcom EPC device generates specific events such as
MHI_A7, BME, DSTATE_CHANGE, PM_TURNOFF etc... These events needs to be
passed to the function driver for proper handling. Hence, this custom
notifier can be used to pass these events.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

---
 drivers/pci/endpoint/pci-epc-core.c | 19 +++++++++++++++++++
 include/linux/pci-epc.h             |  1 +
 include/linux/pci-epf.h             |  1 +
 3 files changed, 21 insertions(+)

-- 
2.25.1

Comments

Kishon Vijay Abraham I June 15, 2021, 3:01 p.m. UTC | #1 
Hi Manivannan,

On 15/06/21 7:07 pm, Manivannan Sadhasivam wrote:
> Add support for passing the custom notifications between the endpoint

> controller and the function driver. This helps in passing the

> notifications that are more specific to the controller and corresponding

> function driver. The opaque `data` arugument in pci_epc_custom_notify()

> function can be used to carry the event specific data that helps in

> differentiating the events.

> 

> For instance, the Qcom EPC device generates specific events such as

> MHI_A7, BME, DSTATE_CHANGE, PM_TURNOFF etc... These events needs to be

> passed to the function driver for proper handling. Hence, this custom

> notifier can be used to pass these events.


Bus master enable and PME events sounds generic events and not QCOM
specific. Also this patch should be sent along with how it's going to be
used in function driver.

In general my preference would be to add only well defined notifiers
given that the endpoint function drivers are generic.

Thanks
Kishon

> 

> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

> ---

>  drivers/pci/endpoint/pci-epc-core.c | 19 +++++++++++++++++++

>  include/linux/pci-epc.h             |  1 +

>  include/linux/pci-epf.h             |  1 +

>  3 files changed, 21 insertions(+)

> 

> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c

> index adec9bee72cf..86b6934c6297 100644

> --- a/drivers/pci/endpoint/pci-epc-core.c

> +++ b/drivers/pci/endpoint/pci-epc-core.c

> @@ -658,6 +658,25 @@ void pci_epc_init_notify(struct pci_epc *epc)

>  }

>  EXPORT_SYMBOL_GPL(pci_epc_init_notify);

>  

> +/**

> + * pci_epc_custom_notify() - Notify the EPF device about the custom events

> + *			     in the EPC device

> + * @epc: EPC device that generates the custom notification

> + * @data: Data for the custom notifier

> + *

> + * Invoke to notify the EPF device about the custom events in the EPC device.

> + * This notifier can be used to pass the EPC specific custom events that are

> + * shared with the EPF device.

> + */

> +void pci_epc_custom_notify(struct pci_epc *epc, void *data)

> +{

> +	if (!epc || IS_ERR(epc))

> +		return;

> +

> +	atomic_notifier_call_chain(&epc->notifier, CUSTOM, data);

> +}

> +EXPORT_SYMBOL_GPL(pci_epc_custom_notify);

> +

>  /**

>   * pci_epc_destroy() - destroy the EPC device

>   * @epc: the EPC device that has to be destroyed

> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h

> index b82c9b100e97..13140fdbcdf6 100644

> --- a/include/linux/pci-epc.h

> +++ b/include/linux/pci-epc.h

> @@ -203,6 +203,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,

>  		    enum pci_epc_interface_type type);

>  void pci_epc_linkup(struct pci_epc *epc);

>  void pci_epc_init_notify(struct pci_epc *epc);

> +void pci_epc_custom_notify(struct pci_epc *epc, void *data);

>  void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,

>  			enum pci_epc_interface_type type);

>  int pci_epc_write_header(struct pci_epc *epc, u8 func_no,

> diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h

> index 6833e2160ef1..8d740c5cf0e3 100644

> --- a/include/linux/pci-epf.h

> +++ b/include/linux/pci-epf.h

> @@ -20,6 +20,7 @@ enum pci_epc_interface_type;

>  enum pci_notify_event {

>  	CORE_INIT,

>  	LINK_UP,

> +	CUSTOM,

>  };

>  

>  enum pci_barno {

>
Manivannan Sadhasivam June 15, 2021, 3:11 p.m. UTC | #2 
Hi Kishon,

On Tue, Jun 15, 2021 at 08:31:48PM +0530, Kishon Vijay Abraham I wrote:
> Hi Manivannan,

> 

> On 15/06/21 7:07 pm, Manivannan Sadhasivam wrote:

> > Add support for passing the custom notifications between the endpoint

> > controller and the function driver. This helps in passing the

> > notifications that are more specific to the controller and corresponding

> > function driver. The opaque `data` arugument in pci_epc_custom_notify()

> > function can be used to carry the event specific data that helps in

> > differentiating the events.

> > 

> > For instance, the Qcom EPC device generates specific events such as

> > MHI_A7, BME, DSTATE_CHANGE, PM_TURNOFF etc... These events needs to be

> > passed to the function driver for proper handling. Hence, this custom

> > notifier can be used to pass these events.

> 

> Bus master enable and PME events sounds generic events and not QCOM

> specific.


Yes, that's correct! I thought about adding the notifiers for them but not sure
about the convetion in EP stack. So went with an opaque notifier but I don't
have any issue in adding them.

> Also this patch should be sent along with how it's going to be

> used in function driver.

> 


The function driver which is going to use this notifier is under development but
I can share a snippet if that helps.

> In general my preference would be to add only well defined notifiers

> given that the endpoint function drivers are generic.

> 


Not all functions are generic ones. For example, on Qcom modems there is a MHI
function driver which transports the IP packets to the host and talks to the
MHI host stack[1].

So for sure we need to have a custom notifier for vendor specific events.

Thanks,
Mani

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/bus/mhi

> Thanks

> Kishon

> 

> > 

> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

> > ---

> >  drivers/pci/endpoint/pci-epc-core.c | 19 +++++++++++++++++++

> >  include/linux/pci-epc.h             |  1 +

> >  include/linux/pci-epf.h             |  1 +

> >  3 files changed, 21 insertions(+)

> > 

> > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c

> > index adec9bee72cf..86b6934c6297 100644

> > --- a/drivers/pci/endpoint/pci-epc-core.c

> > +++ b/drivers/pci/endpoint/pci-epc-core.c

> > @@ -658,6 +658,25 @@ void pci_epc_init_notify(struct pci_epc *epc)

> >  }

> >  EXPORT_SYMBOL_GPL(pci_epc_init_notify);

> >  

> > +/**

> > + * pci_epc_custom_notify() - Notify the EPF device about the custom events

> > + *			     in the EPC device

> > + * @epc: EPC device that generates the custom notification

> > + * @data: Data for the custom notifier

> > + *

> > + * Invoke to notify the EPF device about the custom events in the EPC device.

> > + * This notifier can be used to pass the EPC specific custom events that are

> > + * shared with the EPF device.

> > + */

> > +void pci_epc_custom_notify(struct pci_epc *epc, void *data)

> > +{

> > +	if (!epc || IS_ERR(epc))

> > +		return;

> > +

> > +	atomic_notifier_call_chain(&epc->notifier, CUSTOM, data);

> > +}

> > +EXPORT_SYMBOL_GPL(pci_epc_custom_notify);

> > +

> >  /**

> >   * pci_epc_destroy() - destroy the EPC device

> >   * @epc: the EPC device that has to be destroyed

> > diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h

> > index b82c9b100e97..13140fdbcdf6 100644

> > --- a/include/linux/pci-epc.h

> > +++ b/include/linux/pci-epc.h

> > @@ -203,6 +203,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,

> >  		    enum pci_epc_interface_type type);

> >  void pci_epc_linkup(struct pci_epc *epc);

> >  void pci_epc_init_notify(struct pci_epc *epc);

> > +void pci_epc_custom_notify(struct pci_epc *epc, void *data);

> >  void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,

> >  			enum pci_epc_interface_type type);

> >  int pci_epc_write_header(struct pci_epc *epc, u8 func_no,

> > diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h

> > index 6833e2160ef1..8d740c5cf0e3 100644

> > --- a/include/linux/pci-epf.h

> > +++ b/include/linux/pci-epf.h

> > @@ -20,6 +20,7 @@ enum pci_epc_interface_type;

> >  enum pci_notify_event {

> >  	CORE_INIT,

> >  	LINK_UP,

> > +	CUSTOM,

> >  };

> >  

> >  enum pci_barno {

> >
diff mbox series

Patch

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index adec9bee72cf..86b6934c6297 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -658,6 +658,25 @@  void pci_epc_init_notify(struct pci_epc *epc)
 }
 EXPORT_SYMBOL_GPL(pci_epc_init_notify);
 
+/**
+ * pci_epc_custom_notify() - Notify the EPF device about the custom events
+ *			     in the EPC device
+ * @epc: EPC device that generates the custom notification
+ * @data: Data for the custom notifier
+ *
+ * Invoke to notify the EPF device about the custom events in the EPC device.
+ * This notifier can be used to pass the EPC specific custom events that are
+ * shared with the EPF device.
+ */
+void pci_epc_custom_notify(struct pci_epc *epc, void *data)
+{
+	if (!epc || IS_ERR(epc))
+		return;
+
+	atomic_notifier_call_chain(&epc->notifier, CUSTOM, data);
+}
+EXPORT_SYMBOL_GPL(pci_epc_custom_notify);
+
 /**
  * pci_epc_destroy() - destroy the EPC device
  * @epc: the EPC device that has to be destroyed
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index b82c9b100e97..13140fdbcdf6 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -203,6 +203,7 @@  int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
 		    enum pci_epc_interface_type type);
 void pci_epc_linkup(struct pci_epc *epc);
 void pci_epc_init_notify(struct pci_epc *epc);
+void pci_epc_custom_notify(struct pci_epc *epc, void *data);
 void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
 			enum pci_epc_interface_type type);
 int pci_epc_write_header(struct pci_epc *epc, u8 func_no,
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index 6833e2160ef1..8d740c5cf0e3 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -20,6 +20,7 @@  enum pci_epc_interface_type;
 enum pci_notify_event {
 	CORE_INIT,
 	LINK_UP,
+	CUSTOM,
 };
 
 enum pci_barno {