Re: [PATCH v5 1/4] PCI: endpoint: Add D-state change notifier support

[Krishna Chaitanya Chundru]

On 8/3/2023 11:18 PM, Bjorn Helgaas wrote:
> On Wed, Aug 02, 2023 at 09:21:18AM +0530, Krishna chaitanya chundru wrote:
> > Add support to notify the EPF device about the D-state change event
> > from the EPC device.
> >
> > Signed-off-by: Krishna chaitanya chundru <quic_krichai@xxxxxxxxxxx>
> > ---
> >   Documentation/PCI/endpoint/pci-endpoint.rst |  4 ++++
> >   drivers/pci/endpoint/pci-epc-core.c         | 27 +++++++++++++++++++++++++++
> >   include/linux/pci-epc.h                     |  1 +
> >   include/linux/pci-epf.h                     |  1 +
> >   4 files changed, 33 insertions(+)
> >
> > diff --git a/Documentation/PCI/endpoint/pci-endpoint.rst b/Documentation/PCI/endpoint/pci-endpoint.rst
> > index 4f5622a..66f3191 100644
> > --- a/Documentation/PCI/endpoint/pci-endpoint.rst
> > +++ b/Documentation/PCI/endpoint/pci-endpoint.rst
> > @@ -78,6 +78,10 @@ by the PCI controller driver.
> >      Cleanup the pci_epc_mem structure allocated during pci_epc_mem_init().
> >   
> >   
> > +* pci_epc_dstate_notity()
> s/notity/notify/ (several instances)

sorry for late reply, till now I was using a different branch which has 
some out of tree patches for testing and rebasing the patch on 
linux-next to send them because of that few things are getting missed.

Now I took time to completely move to the linux next so that testing and 
sending patches will be on same code base.

> > +
> > +   Notify all the function drivers that the EPC device has changed its D-state.
> > +
> >   EPC APIs for the PCI Endpoint Function Driver
> >   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   
> > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> > index 6c54fa5..4cf9c82 100644
> > --- a/drivers/pci/endpoint/pci-epc-core.c
> > +++ b/drivers/pci/endpoint/pci-epc-core.c
> > @@ -785,6 +785,33 @@ void pci_epc_bme_notify(struct pci_epc *epc)
> >   EXPORT_SYMBOL_GPL(pci_epc_bme_notify);
> >   
> >   /**
> > + * pci_epc_dstate_notity() - Notify the EPF driver that EPC device D-state
> > + *			has changed
> > + * @epc: the EPC device which has change in D-state
> > + * @state: the changed D-state
> > + *
> > + * Invoke to Notify the EPF device that the EPC device has D-state has
> > + * changed.
> s/device has D-state/device D-state/
>
> > + */
> > +void pci_epc_dstate_notity(struct pci_epc *epc, pci_power_t state)
> > +{
> > +	struct pci_epf *epf;
> > +
> > +	if (!epc || IS_ERR(epc))
> > +		return;
> Is this needed?  Looks like a programming error if we return here.  I
> don't like silently ignoring errors like this.  I generally prefer
> taking the NULL pointer dereference oops so we know the caller is
> broken and can fix it.
sure I will remove this check in the next patch series.
> > +	mutex_lock(&epc->list_lock);
> > +	list_for_each_entry(epf, &epc->pci_epf, list) {
> > +		mutex_lock(&epf->lock);
> > +		if (epf->event_ops && epf->event_ops->dstate_notify)
> > +			epf->event_ops->dstate_notify(epf, state);
> > +		mutex_unlock(&epf->lock);
> > +	}
> > +	mutex_unlock(&epc->list_lock);
> > +}
> > +EXPORT_SYMBOL_GPL(pci_epc_dstate_notity);
> > +
> > +/**
> >    * 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 5cb6940..26a1108 100644
> > --- a/include/linux/pci-epc.h
> > +++ b/include/linux/pci-epc.h
> > @@ -251,4 +251,5 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> >   				     phys_addr_t *phys_addr, size_t size);
> >   void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> >   			   void __iomem *virt_addr, size_t size);
> > +void pci_epc_dstate_change(struct pci_epc *epc, pci_power_t state);
> >   #endif /* __LINUX_PCI_EPC_H */
> > diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
> > index 3f44b6a..529075b 100644
> > --- a/include/linux/pci-epf.h
> > +++ b/include/linux/pci-epf.h
> > @@ -79,6 +79,7 @@ struct pci_epc_event_ops {
> >   	int (*link_up)(struct pci_epf *epf);
> >   	int (*link_down)(struct pci_epf *epf);
> >   	int (*bme)(struct pci_epf *epf);
> > +	int (*dstate_notify)(struct pci_epf *epf, pci_power_t state);
> >   };
> >   
> >   /**
> > --
> > 2.7.4