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

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Date:   Mon, 26 Jun 2023 19:10:53 +0530
From:   Krishna Chaitanya Chundru <quic_krichai@...cinc.com>
To:     Manivannan Sadhasivam <mani@...nel.org>
CC:     <manivannan.sadhasivam@...aro.org>, <quic_vbadigan@...cinc.com>,
        <quic_ramkri@...cinc.com>, <linux-arm-msm@...r.kernel.org>,
        <konrad.dybcio@...aro.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "open list:PCI ENDPOINT SUBSYSTEM" <linux-pci@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC v1 1/3] PCI: endpoint: Add wakeup host API to EPC core


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@...cinc.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.

- 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
>>