Re: [PATCH RFC v1 1/3] PCI: endpoint: Add wakeup host API to EPC core

[Manivannan Sadhasivam <mani@kernel.org>]

On Mon, Jun 26, 2023 at 07:10:53PM +0530, Krishna Chaitanya Chundru wrote:
> 
> On 6/23/2023 11:13 AM, Manivannan Sadhasivam wrote:
> > On Wed, Jun 14, 2023 at 08:30:47PM +0530, Krishna chaitanya chundru wrote:
> > > Endpoint cannot send any data/MSI when the device state is in
> > > D3cold or D3hot. Endpoint needs to bring the device back to D0
> > > to send any kind of data.
> > > 
> > > For this endpoint can send inband PME the device is in D3hot or
> > > toggle wake when the device is D3 cold.
> > > 
> > Are you referring to "host" as the "device"? If so, then it is a wrong
> > terminology.
> I will correct this in next series.
> > 
> > > To support this adding wake up host to epc core.
> > > 
> > Commit message should be imperative.
> > 
> > > Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> > > ---
> > >   drivers/pci/endpoint/pci-epc-core.c | 29 +++++++++++++++++++++++++++++
> > >   include/linux/pci-epc.h             |  3 +++
> > >   2 files changed, 32 insertions(+)
> > > 
> > > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> > > index 46c9a5c..d203947 100644
> > > --- a/drivers/pci/endpoint/pci-epc-core.c
> > > +++ b/drivers/pci/endpoint/pci-epc-core.c
> > > @@ -167,6 +167,35 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
> > >   EXPORT_SYMBOL_GPL(pci_epc_get_features);
> > >   /**
> > > + * pci_epc_wakeup_host() - interrupt the host system
> > s/interrupt the host system/Wakeup the host
> > 
> > > + * @epc: the EPC device which has to interrupt the host
> > s/interrupt/wake
> > 
> > > + * @func_no: the physical endpoint function number in the EPC device
> > > + * @vfunc_no: the virtual endpoint function number in the physical function
> > > + *
> > > + * Invoke to wakeup host
> > > + */
> > > +int pci_epc_wakeup_host(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
> > > +{
> > > +	int ret;
> > > +
> > > +	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> > > +		return -EINVAL;
> > > +
> > > +	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> > > +		return -EINVAL;
> > > +
> > Use proper errno for both of the above.
> > 
> > - Mani
> 
> raise_irq functions also using errno can you please suggest correct value.
> 

Let's keep it as it is, we can change all later.

- Mani

> - KC
> 
> > > +	if (!epc->ops->wakeup_host)
> > > +		return 0;
> > > +
> > > +	mutex_lock(&epc->lock);
> > > +	ret = epc->ops->wakeup_host(epc, func_no, vfunc_no);
> > > +	mutex_unlock(&epc->lock);
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL_GPL(pci_epc_wakeup_host);
> > > +
> > > +/**
> > >    * pci_epc_stop() - stop the PCI link
> > >    * @epc: the link of the EPC device that has to be stopped
> > >    *
> > > diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> > > index 301bb0e..a8496be 100644
> > > --- a/include/linux/pci-epc.h
> > > +++ b/include/linux/pci-epc.h
> > > @@ -59,6 +59,7 @@ pci_epc_interface_string(enum pci_epc_interface_type type)
> > >    * @start: ops to start the PCI link
> > >    * @stop: ops to stop the PCI link
> > >    * @get_features: ops to get the features supported by the EPC
> > > + * @wakeup_host: ops to wakeup the host
> > >    * @owner: the module owner containing the ops
> > >    */
> > >   struct pci_epc_ops {
> > > @@ -88,6 +89,7 @@ struct pci_epc_ops {
> > >   	void	(*stop)(struct pci_epc *epc);
> > >   	const struct pci_epc_features* (*get_features)(struct pci_epc *epc,
> > >   						       u8 func_no, u8 vfunc_no);
> > > +	int	(*wakeup_host)(struct pci_epc *epc, u8 func_no, u8 vfunc_no);
> > >   	struct module *owner;
> > >   };
> > > @@ -232,6 +234,7 @@ int pci_epc_start(struct pci_epc *epc);
> > >   void pci_epc_stop(struct pci_epc *epc);
> > >   const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
> > >   						    u8 func_no, u8 vfunc_no);
> > > +int pci_epc_wakeup_host(struct pci_epc *epc, u8 func_no, u8 vfunc_no);
> > >   enum pci_barno
> > >   pci_epc_get_first_free_bar(const struct pci_epc_features *epc_features);
> > >   enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features
> > > -- 
> > > 2.7.4
> > > 

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