On Sat, Nov 16, 2024 at 09:40:42AM -0500, Frank Li wrote:
> Doorbell feature is implemented by mapping the EP's MSI interrupt
> controller message address to a dedicated BAR in the EPC core. It is the
> responsibility of the EPF driver to pass the actual message data to be
> written by the host to the doorbell BAR region through its own logic.
>
> Tested-by: Niklas Cassel <cassel@xxxxxxxxxx>
> Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> ---
> change from v5 to v8
> -none
>
> Change from v4 to v5
> - Remove request_irq() in pci_epc_alloc_doorbell() and leave to EP function
> driver, so ep function driver can register differece call back function for
> difference doorbell events and set irq affinity to differece CPU core.
> - Improve error message when MSI allocate failure.
>
> Change from v3 to v4
> - msi change to use msi_get_virq() avoid use msi_for_each_desc().
> - add new struct for pci_epf_doorbell_msg to msi msg,virq and irq name.
> - move mutex lock to epc function
> - initialize variable at declear place.
> - passdown epf to epc*() function to simplify code.
> ---
> drivers/pci/endpoint/Makefile | 2 +-
> drivers/pci/endpoint/pci-ep-msi.c | 99 +++++++++++++++++++++++++++++++++++++++
> include/linux/pci-ep-msi.h | 15 ++++++
> include/linux/pci-epf.h | 16 +++++++
> 4 files changed, 131 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/endpoint/Makefile b/drivers/pci/endpoint/Makefile
> index 95b2fe47e3b06..a1ccce440c2c5 100644
> --- a/drivers/pci/endpoint/Makefile
> +++ b/drivers/pci/endpoint/Makefile
> @@ -5,4 +5,4 @@
>
> obj-$(CONFIG_PCI_ENDPOINT_CONFIGFS) += pci-ep-cfs.o
> obj-$(CONFIG_PCI_ENDPOINT) += pci-epc-core.o pci-epf-core.o\
> - pci-epc-mem.o functions/
> + pci-epc-mem.o pci-ep-msi.o functions/
> diff --git a/drivers/pci/endpoint/pci-ep-msi.c b/drivers/pci/endpoint/pci-ep-msi.c
> new file mode 100644
> index 0000000000000..7868a529dce37
> --- /dev/null
> +++ b/drivers/pci/endpoint/pci-ep-msi.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCI Endpoint *Controller* (EPC) MSI library
> + *
> + * Copyright (C) 2024 NXP
> + * Author: Frank Li <Frank.Li@xxxxxxx>
> + */
> +
> +#include <linux/cleanup.h>
> +#include <linux/device.h>
> +#include <linux/slab.h>
Please sort alphabetically.
> +#include <linux/module.h>
> +#include <linux/msi.h>
> +#include <linux/pci-epc.h>
> +#include <linux/pci-epf.h>
> +#include <linux/pci-ep-cfs.h>
> +#include <linux/pci-ep-msi.h>
> +
> +static bool pci_epc_match_parent(struct device *dev, void *param)
> +{
> + return dev->parent == param;
> +}
> +
> +static void pci_epc_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
> +{
> + struct pci_epc *epc __free(pci_epc_put) = NULL;
> + struct pci_epf *epf;
> +
> + epc = pci_epc_get_fn(pci_epc_match_parent, desc->dev);
You were passing 'epc->dev.parent' to platform_device_msi_init_and_alloc_irqs().
So 'desc->dev' should be the EPC parent, right? If so, you can do:
epc = pci_epc_get(dev_name(msi_desc_to_dev(desc)));
since we are reusing the parent dev name for EPC.
> + if (!epc)
> + return;
> +
> + /* Only support one EPF for doorbell */
> + epf = list_first_entry_or_null(&epc->pci_epf, struct pci_epf, list);
Why don't you impose this restriction in pci_epf_alloc_doorbell() itself?
> +
> + if (epf && epf->db_msg && desc->msi_index < epf->num_db)
> + memcpy(&epf->db_msg[desc->msi_index].msg, msg, sizeof(*msg));
> +}
> +
> +static void pci_epc_free_doorbell(struct pci_epc *epc, struct pci_epf *epf)
> +{
> + guard(mutex)(&epc->lock);
> +
> + platform_device_msi_free_irqs_all(epc->dev.parent);
> +}
> +
> +static int pci_epc_alloc_doorbell(struct pci_epc *epc, struct pci_epf *epf)
> +{
> + struct device *dev = epc->dev.parent;
> + u16 num_db = epf->num_db;
> + int i = 0;
> + int ret;
> +
> + guard(mutex)(&epc->lock);
> +
> + ret = platform_device_msi_init_and_alloc_irqs(dev, num_db, pci_epc_write_msi_msg);
> + if (ret) {
> + dev_err(dev, "Failed to allocate MSI, may miss 'msi-parent' at your DTS\n");
No need to mention 'msi-parent'. Just 'Failed to allocate MSI' is enough.
> + return -ENOMEM;
-ENODEV?
- Mani
--
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