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Message-ID: <d82cc044-f3fb-f1a0-2ed2-e0d93c3a6667@quicinc.com>
Date: Mon, 31 Jul 2023 11:06:32 +0530
From: Krishna Chaitanya Chundru <quic_krichai@...cinc.com>
To: Manivannan Sadhasivam <mani@...nel.org>
CC: <manivannan.sadhasivam@...aro.org>, <helgaas@...nel.org>,
<linux-pci@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <quic_vbadigan@...cinc.com>,
<quic_nitegupt@...cinc.com>, <quic_skananth@...cinc.com>,
<quic_ramkri@...cinc.com>, <krzysztof.kozlowski@...aro.org>,
"Lorenzo Pieralisi" <lpieralisi@...nel.org>,
Krzysztof WilczyĆski <kw@...ux.com>,
Kishon Vijay Abraham I <kishon@...nel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Jonathan Corbet <corbet@....net>,
"open list:DOCUMENTATION" <linux-doc@...r.kernel.org>
Subject: Re: [PATCH v4 5/9] PCI: endpoint: Add wakeup host API to EPC core
On 7/28/2023 9:51 AM, Manivannan Sadhasivam wrote:
> On Thu, Jul 13, 2023 at 12:40:14PM +0530, Krishna chaitanya chundru wrote:
>> Endpoint cannot send any data/MSI when the D-state is in
>> D3cold or D3hot. Endpoint needs to wake up the host to
>> bring the D-state to D0.
>>
>> Endpoint can toggle wake signal when the D-state is in D3cold and vaux is
>> not supplied or can send inband PME.
>>
>> To support this add wakeup_host() callback to the EPC core.
>>
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
>> ---
>> Documentation/PCI/endpoint/pci-endpoint.rst | 6 ++++++
>> drivers/pci/endpoint/pci-epc-core.c | 31 +++++++++++++++++++++++++++++
>> include/linux/pci-epc.h | 11 ++++++++++
>> 3 files changed, 48 insertions(+)
>>
>> diff --git a/Documentation/PCI/endpoint/pci-endpoint.rst b/Documentation/PCI/endpoint/pci-endpoint.rst
>> index 3a54713..eb79b77 100644
>> --- a/Documentation/PCI/endpoint/pci-endpoint.rst
>> +++ b/Documentation/PCI/endpoint/pci-endpoint.rst
>> @@ -53,6 +53,7 @@ by the PCI controller driver.
>> * raise_irq: ops to raise a legacy, MSI or MSI-X interrupt
>> * start: ops to start the PCI link
>> * stop: ops to stop the PCI link
>> + * wakeup_host: ops to wakeup host
>>
>> The PCI controller driver can then create a new EPC device by invoking
>> devm_pci_epc_create()/pci_epc_create().
>> @@ -122,6 +123,11 @@ by the PCI endpoint function driver.
>> The PCI endpoint function driver should use pci_epc_mem_free_addr() to
>> free the memory space allocated using pci_epc_mem_alloc_addr().
>>
>> +* pci_epc_wakeup_host()
>> +
>> + The PCI endpoint function driver should use pci_epc_wakeup_host() to wakeup
>> + host.
>> +
>> Other EPC APIs
>> ~~~~~~~~~~~~~~
>>
>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>> index ea76baf..b419eff 100644
>> --- a/drivers/pci/endpoint/pci-epc-core.c
>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>> @@ -167,6 +167,37 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
>> EXPORT_SYMBOL_GPL(pci_epc_get_features);
>>
>> /**
>> + * pci_epc_wakeup_host() - Wakeup the host
>> + * @epc: the EPC device which has to wakeup the host
>> + * @func_no: the physical endpoint function number in the EPC device
>> + * @vfunc_no: the virtual endpoint function number in the physical function
>> + * @type: specify the type of wakeup: WAKEUP_FROM_D3COLD, WAKEUP_FROM_D3HOT
>> + *
>> + * Invoke to wakeup host
>> + */
>> +bool pci_epc_wakeup_host(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> + enum pci_epc_wakeup_host_type type)
>> +{
>> + int ret;
>> +
>> + if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
>> + return false;
>> +
>> + if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
>> + return false;
>> +
>> + if (!epc->ops->wakeup_host)
>> + return true;
>> +
>> + mutex_lock(&epc->lock);
>> + ret = epc->ops->wakeup_host(epc, func_no, vfunc_no, type);
>> + 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 26a1108..d262179 100644
>> --- a/include/linux/pci-epc.h
>> +++ b/include/linux/pci-epc.h
>> @@ -26,6 +26,12 @@ enum pci_epc_irq_type {
>> PCI_EPC_IRQ_MSIX,
>> };
>>
>> +enum pci_epc_wakeup_host_type {
>> + PCI_WAKEUP_UNKNOWN,
>> + PCI_WAKEUP_SEND_PME,
>> + PCI_WAKEUP_TOGGLE_WAKE,
> I think I asked you to get rid of these enums and use a bool. I don't see any
> new wakeup mechanism going to be added to the spec. So using enums for just 2
> options looks overkill to me.
>
> If you defer, please discuss it here.
>
> - Mani
I will remove the enum move in to bool in next series.
- KC
>> +};
>> +
>> static inline const char *
>> pci_epc_interface_string(enum pci_epc_interface_type type)
>> {
>> @@ -59,6 +65,7 @@ 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 +95,8 @@ 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);
>> + bool (*wakeup_host)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> + enum pci_epc_wakeup_host_type type);
>> struct module *owner;
>> };
>>
>> @@ -234,6 +243,8 @@ 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);
>> +bool pci_epc_wakeup_host(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> + enum pci_epc_wakeup_host_type type);
>> 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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