From 1c3b002c6bf684b445a7107609979bca5f21bc03 Mon Sep 17 00:00:00 2001 From: Frank Li Date: Thu, 10 Jul 2025 15:13:49 -0400 Subject: PCI: endpoint: Add RC-to-EP doorbell support using platform MSI controller Implement the doorbell feature by mapping the EP's MSI interrupt controller message address to a dedicated BAR. The EPF driver should pass the actual message data to be written to the message address by the host through implementation-specific logic. Signed-off-by: Frank Li [mani: minor code cleanups and reworded commit message] Signed-off-by: Manivannan Sadhasivam [bhelgaas: fix kernel-doc] Signed-off-by: Bjorn Helgaas Tested-by: Niklas Cassel Link: https://patch.msgid.link/20250710-ep-msi-v21-3-57683fc7fb25@nxp.com --- include/linux/pci-ep-msi.h | 28 ++++++++++++++++++++++++++++ include/linux/pci-epf.h | 15 +++++++++++++++ 2 files changed, 43 insertions(+) create mode 100644 include/linux/pci-ep-msi.h (limited to 'include/linux') diff --git a/include/linux/pci-ep-msi.h b/include/linux/pci-ep-msi.h new file mode 100644 index 000000000000..7c5db90f9620 --- /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 + */ + +#ifndef __PCI_EP_MSI__ +#define __PCI_EP_MSI__ + +struct pci_epf; + +#ifdef CONFIG_PCI_ENDPOINT_MSI_DOORBELL +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 -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 749cee0bcf2c..52e07602f08e 100644 --- a/include/linux/pci-epf.h +++ b/include/linux/pci-epf.h @@ -12,6 +12,7 @@ #include #include #include +#include #include struct pci_epf; @@ -128,6 +129,16 @@ struct pci_epf_bar { int flags; }; +/** + * struct pci_epf_doorbell_msg - represents doorbell message + * @msg: MSI message + * @virq: IRQ number of this doorbell MSI message + */ +struct pci_epf_doorbell_msg { + struct msi_msg msg; + int virq; +}; + /** * struct pci_epf - represents the PCI EPF device * @dev: the PCI EPF device @@ -155,6 +166,8 @@ struct pci_epf_bar { * @vfunction_num_map: bitmap to manage virtual function number * @pci_vepf: list of virtual endpoint functions associated with this function * @event_ops: callbacks for capturing the EPC events + * @db_msg: data for MSI from RC side + * @num_db: number of doorbells */ struct pci_epf { struct device dev; @@ -185,6 +198,8 @@ struct pci_epf { unsigned long vfunction_num_map; struct list_head pci_vepf; const struct pci_epc_event_ops *event_ops; + struct pci_epf_doorbell_msg *db_msg; + u16 num_db; }; /** -- cgit v1.2.3 From 4ff4252a2355f585c5cad8dc959ff1097300aa47 Mon Sep 17 00:00:00 2001 From: Frank Li Date: Thu, 10 Jul 2025 15:13:51 -0400 Subject: PCI: endpoint: Add pci_epf_align_inbound_addr() helper for inbound address alignment Add pci_epf_align_inbound_addr() to align the inbound addresses according to PCI BAR alignment requirements. The aligned base address and offset are returned via 'base' and 'off' parameters. Signed-off-by: Frank Li [mani: reworded kernel-doc and commit message] Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Tested-by: Niklas Cassel Link: https://patch.msgid.link/20250710-ep-msi-v21-5-57683fc7fb25@nxp.com --- drivers/pci/endpoint/pci-epf-core.c | 38 +++++++++++++++++++++++++++++++++++++ include/linux/pci-epf.h | 3 +++ 2 files changed, 41 insertions(+) (limited to 'include/linux') diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c index 577a9e490115..09b90e1631d5 100644 --- a/drivers/pci/endpoint/pci-epf-core.c +++ b/drivers/pci/endpoint/pci-epf-core.c @@ -477,6 +477,44 @@ struct pci_epf *pci_epf_create(const char *name) } EXPORT_SYMBOL_GPL(pci_epf_create); +/** + * pci_epf_align_inbound_addr() - Align the given address based on the BAR + * alignment requirement + * @epf: the EPF device + * @addr: inbound address to be aligned + * @bar: the BAR number corresponding to the given addr + * @base: base address matching the @bar alignment requirement + * @off: offset to be added to the @base address + * + * Helper function to align input @addr based on BAR's alignment requirement. + * The aligned base address and offset are returned via @base and @off. + * + * NOTE: The pci_epf_alloc_space() function already accounts for alignment. + * This API is primarily intended for use with other memory regions not + * allocated by pci_epf_alloc_space(), such as peripheral register spaces or + * the message address of a platform MSI controller. + * + * Return: 0 on success, errno otherwise. + */ +int pci_epf_align_inbound_addr(struct pci_epf *epf, enum pci_barno bar, + u64 addr, dma_addr_t *base, size_t *off) +{ + /* + * Most EP controllers require the BAR start address to be aligned to + * the BAR size, because they mask off the lower bits. + * + * Alignment to BAR size also works for controllers that support + * unaligned addresses. + */ + u64 align = epf->bar[bar].size; + + *base = round_down(addr, align); + *off = addr & (align - 1); + + return 0; +} +EXPORT_SYMBOL_GPL(pci_epf_align_inbound_addr); + static void pci_epf_dev_release(struct device *dev) { struct pci_epf *epf = to_pci_epf(dev); diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h index 52e07602f08e..2e85504ba2ba 100644 --- a/include/linux/pci-epf.h +++ b/include/linux/pci-epf.h @@ -241,6 +241,9 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, enum pci_epc_interface_type type); void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar, enum pci_epc_interface_type type); + +int pci_epf_align_inbound_addr(struct pci_epf *epf, enum pci_barno bar, + u64 addr, dma_addr_t *base, size_t *off); int pci_epf_bind(struct pci_epf *epf); void pci_epf_unbind(struct pci_epf *epf); int pci_epf_add_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf); -- cgit v1.2.3