On Mon, Jun 09, 2025 at 12:34:14PM GMT, 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@kernel.org Signed-off-by: Frank Li Frank.Li@nxp.com
Change from v15 to v16
- fix rebase conflict
Change from v14 to v15
- check CONFIG_GENERIC_MSI
Fix below build error | Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202502082204.6PRR3cfG-lkp@intel.com/
All errors (new ones prefixed by >>):
drivers/pci/endpoint/pci-ep-msi.c: In function 'pci_epf_alloc_doorbell':
drivers/pci/endpoint/pci-ep-msi.c:53:15: error: implicit declaration of function 'platform_device_msi_init_and_alloc_irqs' [-Werror=implicit-function-declaration]
53 | ret = platform_device_msi_init_and_alloc_irqs(&epf->dev, num_db, pci_epf_write_msi_msg);| Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202502082242.pOq1hB1d-lkp@intel.com/
All errors (new ones prefixed by >>):
drivers/pci/endpoint/pci-ep-msi.c: In function 'pci_epf_alloc_doorbell':
drivers/pci/endpoint/pci-ep-msi.c:49:14: error: implicit declaration of function 'irq_domain_is_msi_immutable'; did you mean 'irq_domain_is_msi_device'? [-Werror=implicit-function-declaration]
49 | if (!irq_domain_is_msi_immutable(dom)) {Change from v13 to v14
- basic roll back to v9
- use device:id as msi-map input, its will handle it
- use existed platform_device_msi_init_and_alloc_irqs()
- pass down epf->dev point, because epf->dev of-node will be the same as
epc's parent.
Change from v12 to v13
- Use DOMAIN_BUS_DEVICE_PCI_EP_MSI
Change from v10 to v12
- none
Change from v9 to v10
- Create msi domain for each function device.
- Remove only function support limiation. My hardware only support one
function, so not test more than one case.
use "msi-map" descript msi information
msi-map = <func_no << 8 | vfunc_no, &its, start_stream_id, size>;
Chagne from v8 to v9
- sort header file
- use pci_epc_get(dev_name(msi_desc_to_dev(desc)));
- check epf number at pci_epf_alloc_doorbell
- Add comments for miss msi-parent case
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 | 1 + drivers/pci/endpoint/pci-ep-msi.c | 82 +++++++++++++++++++++++++++++++++++++++ include/linux/pci-ep-msi.h | 28 +++++++++++++ include/linux/pci-epf.h | 16 ++++++++ 4 files changed, 127 insertions(+)
diff --git a/drivers/pci/endpoint/Makefile b/drivers/pci/endpoint/Makefile index 95b2fe47e3b06..c502ea7ef367c 100644 --- a/drivers/pci/endpoint/Makefile +++ b/drivers/pci/endpoint/Makefile @@ -6,3 +6,4 @@ 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/ +obj-$(CONFIG_GENERIC_MSI_IRQ) += pci-ep-msi.o
I don't think we should build this driver for generic CONFIG_GENERIC_MSI_IRQ Kconfig. You should create a new EP specific Kconfig and make it depend on CONFIG_GENERIC_MSI_IRQ.
diff --git a/drivers/pci/endpoint/pci-ep-msi.c b/drivers/pci/endpoint/pci-ep-msi.c new file mode 100644 index 0000000000000..549b55b864d0e --- /dev/null +++ b/drivers/pci/endpoint/pci-ep-msi.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- PCI Endpoint *Controller* (EPC) MSI library
- Copyright (C) 2025 NXP
- Author: Frank Li Frank.Li@nxp.com
- */
+#include <linux/device.h> +#include <linux/irqdomain.h> +#include <linux/module.h> +#include <linux/msi.h> +#include <linux/of_irq.h> +#include <linux/pci-epc.h> +#include <linux/pci-epf.h> +#include <linux/pci-ep-cfs.h> +#include <linux/pci-ep-msi.h> +#include <linux/slab.h>
+static void pci_epf_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg) +{
- struct pci_epf *epf = to_pci_epf(desc->dev);
- if (epf && epf->db_msg && desc->msi_index < epf->num_db)
memcpy(&epf->db_msg[desc->msi_index].msg, msg, sizeof(*msg));+}
+int pci_epf_alloc_doorbell(struct pci_epf *epf, u16 num_db) +{
- struct pci_epc *epc = epf->epc;
- struct device *dev = &epf->dev;
- struct irq_domain *dom;
- void *msg;
- u32 rid;
- int ret;
- int i;
- rid = PCI_EPF_DEVID(epf->func_no, epf->vfunc_no);
- dom = of_msi_map_get_device_domain(epc->dev.parent, rid, DOMAIN_BUS_PLATFORM_MSI);
- if (!dom) {
dev_err(dev, "Can't find msi domain\n");
s/msi/MSI
Perhaps, "Can't find MSI domain for parent device" to be more explicit that we are searching for MSI domain in parent device?
return -EINVAL;
-ENODATA
- }
- dev_set_msi_domain(dev, dom);
- msg = kcalloc(num_db, sizeof(struct pci_epf_doorbell_msg), GFP_KERNEL);
- if (!msg)
return -ENOMEM;- epf->num_db = num_db;
- epf->db_msg = msg;
- ret = platform_device_msi_init_and_alloc_irqs(&epf->dev, num_db, pci_epf_write_msi_msg);
- if (ret) {
/** The pcie_ep DT node has to specify 'msi-parent' for EP* doorbell support to work. Right now only GIC ITS is* supported. If you have GIC ITS and reached this print,* perhaps you are missing 'msi-map' in DT.*/
msi-map is a generic property, no need to tie it with GIC ITS. Also, this API could fail for different reasons. So please get rid of this comment.
dev_err(dev, "Failed to allocate MSI\n");kfree(msg);return -ENOMEM;
Why are you overriding the errno and not using 'ret'?
- }
- for (i = 0; i < num_db; i++)
epf->db_msg[i].virq = msi_get_virq(dev, i);- return ret;
+} +EXPORT_SYMBOL_GPL(pci_epf_alloc_doorbell);
+void pci_epf_free_doorbell(struct pci_epf *epf) +{
- platform_device_msi_free_irqs_all(&epf->dev);
- kfree(epf->db_msg);
- epf->db_msg = NULL;
- epf->num_db = 0;
+} +EXPORT_SYMBOL_GPL(pci_epf_free_doorbell); diff --git a/include/linux/pci-ep-msi.h b/include/linux/pci-ep-msi.h new file mode 100644 index 0000000000000..6dfbe9353f0d8 --- /dev/null +++ b/include/linux/pci-ep-msi.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*
- PCI Endpoint *Function* side MSI header file
- Copyright (C) 2024 NXP
- Author: Frank Li Frank.Li@nxp.com
- */
+#ifndef __PCI_EP_MSI__ +#define __PCI_EP_MSI__
+struct pci_epf;
+#ifdef CONFIG_GENERIC_MSI_IRQ +int pci_epf_alloc_doorbell(struct pci_epf *epf, u16 nums); +void pci_epf_free_doorbell(struct pci_epf *epf); +#else +static inline int pci_epf_alloc_doorbell(struct pci_epf *epf, u16 nums) +{
- return -EINVAL;
-ENODATA
+}
+static inline void pci_epf_free_doorbell(struct pci_epf *epf) +{ +} +#endif /* CONFIG_GENERIC_MSI_IRQ */
+#endif /* __PCI_EP_MSI__ */ diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h index c0864935c6864..9634bf2c1ac06 100644 --- a/include/linux/pci-epf.h +++ b/include/linux/pci-epf.h @@ -12,6 +12,7 @@ #include <linux/configfs.h> #include <linux/device.h> #include <linux/mod_devicetable.h> +#include <linux/msi.h> #include <linux/pci.h> struct pci_epf; @@ -128,6 +129,17 @@ struct pci_epf_bar { int flags; }; +/**
- struct pci_epf_doorbell_msg - represents doorbell message
- @msi_msg: MSI message
- @virq: irq number of this doorbell MSI message
- @name: irq name for doorbell interrupt
'name' is not present in the struct.
- Mani