github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 17:47:41 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

PCI: endpoint: Add auxiliary resource query API

Browse Source 
Endpoint controller drivers may integrate auxiliary blocks (e.g. DMA
engines) whose register windows and descriptor memories metadata need to
be exposed to a remote peer. Endpoint function drivers need a generic
way to discover such resources without hard-coding controller-specific
helpers.

Add pci_epc_get_aux_resources_count() / pci_epc_get_aux_resources() and
the corresponding pci_epc_ops callbacks. The count helper returns the
number of available resources, while the get helper fills a
caller-provided array of resources described by type, physical address
and size, plus type-specific metadata.

Suggested-by: Manivannan Sadhasivam <mani@kernel.org>
Suggested-by: Frank Li <Frank.li@nxp.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20260414141514.1341429-2-den@valinux.co.jp
This commit is contained in:
Koichiro Den 2026-04-14 23:15:08 +09:00 committed by Manivannan Sadhasivam
parent 254f49634e
commit cc07b903a6
2 changed files with 134 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
drivers/pci/endpoint/pci-epc-core.c
View File

@ -156,6 +156,86 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
}
EXPORT_SYMBOL_GPL(pci_epc_get_features);
/**
* pci_epc_get_aux_resources_count() - get the number of EPC-provided auxiliary resources
* @epc: EPC device
* @func_no: function number
* @vfunc_no: virtual function number
*
* Some EPC backends integrate auxiliary blocks (e.g. DMA engines) whose control
* registers and/or descriptor memories can be exposed to the host by mapping
* them into BAR space. This helper queries how many such resources the backend
* provides.
*
* Return: the number of available resources on success, -EOPNOTSUPP if the
* backend does not support auxiliary resource queries, or another -errno on
* failure.
*/
int pci_epc_get_aux_resources_count(struct pci_epc *epc, u8 func_no,
u8 vfunc_no)
{
int count;
if (!epc || !epc->ops)
return -EINVAL;
if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
return -EINVAL;
if (!epc->ops->get_aux_resources_count)
return -EOPNOTSUPP;
mutex_lock(&epc->lock);
count = epc->ops->get_aux_resources_count(epc, func_no,
vfunc_no);
mutex_unlock(&epc->lock);
return count;
}
EXPORT_SYMBOL_GPL(pci_epc_get_aux_resources_count);
/**
* pci_epc_get_aux_resources() - query EPC-provided auxiliary resources
* @epc: EPC device
* @func_no: function number
* @vfunc_no: virtual function number
* @resources: output array
* @num_resources: size of @resources array in entries
*
* Some EPC backends integrate auxiliary blocks (e.g. DMA engines) whose control
* registers and/or descriptor memories can be exposed to the host by mapping
* them into BAR space. This helper queries the backend for such resources.
*
* Return: 0 on success, -EOPNOTSUPP if the backend does not support auxiliary
* resource queries, or another -errno on failure.
*/
int pci_epc_get_aux_resources(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
struct pci_epc_aux_resource *resources,
int num_resources)
{
int ret;
if (!resources || num_resources <= 0)
return -EINVAL;
if (!epc || !epc->ops)
return -EINVAL;
if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
return -EINVAL;
if (!epc->ops->get_aux_resources)
return -EOPNOTSUPP;
mutex_lock(&epc->lock);
ret = epc->ops->get_aux_resources(epc, func_no, vfunc_no, resources,
num_resources);
mutex_unlock(&epc->lock);
return ret;
}
EXPORT_SYMBOL_GPL(pci_epc_get_aux_resources);
/**
* pci_epc_stop() - stop the PCI link
* @epc: the link of the EPC device that has to be stopped

54
include/linux/pci-epc.h
View File

@ -61,6 +61,47 @@ struct pci_epc_map {
void __iomem *virt_addr;
};
/**
* enum pci_epc_aux_resource_type - auxiliary resource type identifiers
* @PCI_EPC_AUX_DOORBELL_MMIO: Doorbell MMIO, that might be outside the DMA
* controller register window
*
* EPC backends may expose auxiliary blocks (e.g. DMA engines) by mapping their
* register windows and descriptor memories into BAR space. This enum
* identifies the type of each exposable resource.
*/
enum pci_epc_aux_resource_type {
PCI_EPC_AUX_DOORBELL_MMIO,
};
/**
* struct pci_epc_aux_resource - a physical auxiliary resource that may be
* exposed for peer use
* @type: resource type, see enum pci_epc_aux_resource_type
* @phys_addr: physical base address of the resource
* @size: size of the resource in bytes
* @bar: BAR number where this resource is already exposed to the RC
* (NO_BAR if not)
* @bar_offset: offset within @bar where the resource starts (valid iff
* @bar != NO_BAR)
* @u: type-specific metadata
*/
struct pci_epc_aux_resource {
enum pci_epc_aux_resource_type type;
phys_addr_t phys_addr;
resource_size_t size;
enum pci_barno bar;
resource_size_t bar_offset;
union {
/* PCI_EPC_AUX_DOORBELL_MMIO */
struct {
int irq; /* IRQ number for the doorbell handler */
u32 data; /* write value to ring the doorbell */
} db_mmio;
} u;
};
/**
* struct pci_epc_ops - set of function pointers for performing EPC operations
* @write_header: ops to populate configuration space header
@ -84,6 +125,9 @@ struct pci_epc_map {
* @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
* @get_aux_resources_count: ops to get the number of controller-owned
* auxiliary resources
* @get_aux_resources: ops to retrieve controller-owned auxiliary resources
* @owner: the module owner containing the ops
*/
struct pci_epc_ops {
@ -115,6 +159,11 @@ 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);
int (*get_aux_resources_count)(struct pci_epc *epc, u8 func_no,
u8 vfunc_no);
int (*get_aux_resources)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
struct pci_epc_aux_resource *resources,
int num_resources);
struct module *owner;
};
@ -343,6 +392,11 @@ 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);
int pci_epc_get_aux_resources_count(struct pci_epc *epc, u8 func_no,
u8 vfunc_no);
int pci_epc_get_aux_resources(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
struct pci_epc_aux_resource *resources,
int num_resources);
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