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SubjectRe: [PATCH 1/5] PCI: endpoint: Add linkdown notifier support
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On 6/16/2021 5:29 PM, Manivannan Sadhasivam wrote:
> External email: Use caution opening links or attachments
>
>
> Add support to notify the EPF device about the linkdown event from the
> EPC device.
>
> Usage:
> ======
>
> EPC
> ---
>
> ```
> static irqreturn_t pcie_ep_irq(int irq, void *data)
> {
> ...
> case PCIE_EP_INT_LINK_DOWN:
> pci_epc_linkdown(epc);
> break;
Can you provide use case/scenario when epc will get LINK_DOWN interrupt?

> ...
> }
> ```
>
> EPF
> ---
>
> ```
> static int pci_epf_notifier(struct notifier_block *nb, unsigned long val,
> void *data)
> {
> ...
> case LINK_DOWN:
> /* Handle link down event */
> break;
> ...
> }
> ```
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
> drivers/pci/endpoint/pci-epc-core.c | 17 +++++++++++++++++
> include/linux/pci-epc.h | 1 +
> include/linux/pci-epf.h | 1 +
> 3 files changed, 19 insertions(+)
>
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index adec9bee72cf..f29d78c18438 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -641,6 +641,23 @@ void pci_epc_linkup(struct pci_epc *epc)
> }
> EXPORT_SYMBOL_GPL(pci_epc_linkup);
>
> +/**
> + * pci_epc_linkdown() - Notify the EPF device that EPC device has dropped the
> + * connection with the Root Complex.
> + * @epc: the EPC device which has dropped the link with the host
> + *
> + * Invoke to Notify the EPF device that the EPC device has dropped the
> + * connection with the Root Complex.
> + */
> +void pci_epc_linkdown(struct pci_epc *epc)
> +{
> + if (!epc || IS_ERR(epc))
> + return;
> +
> + atomic_notifier_call_chain(&epc->notifier, LINK_DOWN, NULL);
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_linkdown);
> +
> /**
> * pci_epc_init_notify() - Notify the EPF device that EPC device's core
> * initialization is completed.
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index b82c9b100e97..23590efc13e7 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -202,6 +202,7 @@ void pci_epc_destroy(struct pci_epc *epc);
> 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_linkdown(struct pci_epc *epc);
> void pci_epc_init_notify(struct pci_epc *epc);
> void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
> enum pci_epc_interface_type type);
> diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
> index 6833e2160ef1..e9ad634b1575 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,
> + LINK_DOWN,
> };
>
> enum pci_barno {
> --
> 2.25.1
>

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