[PATCH v8 2/8] PCI: endpoint: Add support to add virtual function in endpoint core

Kishon Vijay Abraham I
2021-08-11T06:47:42Z

Add support to add virtual function in endpoint core. The virtual
function can only be associated with a physical function instead of a
endpoint controller. Provide APIs to associate a virtual function with
a physical function here.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
drivers/pci/endpoint/pci-epc-core.c | 2 +-
drivers/pci/endpoint/pci-epf-core.c | 96 ++++++++++++++++++++++++++++-
include/linux/pci-epf.h | 16 ++++-
3 files changed, 111 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index adec9bee72cf..01c58ca84dcc 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -548,7 +548,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
u32 func_no;
int ret = 0;

- if (IS_ERR_OR_NULL(epc))
+ if (IS_ERR_OR_NULL(epc) || epf->is_vf)
return -EINVAL;

if (type == PRIMARY_INTERFACE && epf->epc)
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index e9289d10f822..ae7107a3196e 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -62,13 +62,20 @@ EXPORT_SYMBOL_GPL(pci_epf_type_add_cfs);
*/
void pci_epf_unbind(struct pci_epf *epf)
{
+ struct pci_epf *epf_vf;
+
if (!epf->driver) {
dev_WARN(&epf->dev, "epf device not bound to driver\n");
return;
}

mutex_lock(&epf->lock);
- epf->driver->ops->unbind(epf);
+ list_for_each_entry(epf_vf, &epf->pci_vepf, list) {
+ if (epf_vf->is_bound)
+ epf_vf->driver->ops->unbind(epf_vf);
+ }
+ if (epf->is_bound)
+ epf->driver->ops->unbind(epf);
mutex_unlock(&epf->lock);
module_put(epf->driver->owner);
}
@@ -83,6 +90,7 @@ EXPORT_SYMBOL_GPL(pci_epf_unbind);
*/
int pci_epf_bind(struct pci_epf *epf)
{
+ struct pci_epf *epf_vf;
int ret;

if (!epf->driver) {
@@ -94,13 +102,95 @@ int pci_epf_bind(struct pci_epf *epf)
return -EAGAIN;

mutex_lock(&epf->lock);
+ list_for_each_entry(epf_vf, &epf->pci_vepf, list) {
+ epf_vf->func_no = epf->func_no;
+ epf_vf->epc = epf->epc;
+ epf_vf->sec_epc = epf->sec_epc;
+ ret = epf_vf->driver->ops->bind(epf_vf);
+ if (ret)
+ goto ret;
+ epf_vf->is_bound = true;
+ }
+
ret = epf->driver->ops->bind(epf);
+ if (ret)
+ goto ret;
+ epf->is_bound = true;
+
+ mutex_unlock(&epf->lock);
+ return 0;
+
+ret:
mutex_unlock(&epf->lock);
+ pci_epf_unbind(epf);

return ret;
}
EXPORT_SYMBOL_GPL(pci_epf_bind);

+/**
+ * pci_epf_add_vepf() - associate virtual EP function to physical EP function
+ * @epf_pf: the physical EP function to which the virtual EP function should be
+ * associated
+ * @epf_vf: the virtual EP function to be added
+ *
+ * A physical endpoint function can be associated with multiple virtual
+ * endpoint functions. Invoke pci_epf_add_epf() to add a virtual PCI endpoint
+ * function to a physical PCI endpoint function.
+ */
+int pci_epf_add_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf)
+{
+ u32 vfunc_no;
+
+ if (IS_ERR_OR_NULL(epf_pf) || IS_ERR_OR_NULL(epf_vf))
+ return -EINVAL;
+
+ if (epf_pf->epc || epf_vf->epc || epf_vf->epf_pf)
+ return -EBUSY;
+
+ if (epf_pf->sec_epc || epf_vf->sec_epc)
+ return -EBUSY;
+
+ mutex_lock(&epf_pf->lock);
+ vfunc_no = find_first_zero_bit(&epf_pf->vfunction_num_map,
+ BITS_PER_LONG);
+ if (vfunc_no >= BITS_PER_LONG)
+ return -EINVAL;
+
+ set_bit(vfunc_no, &epf_pf->vfunction_num_map);
+ epf_vf->vfunc_no = vfunc_no;
+
+ epf_vf->epf_pf = epf_pf;
+ epf_vf->is_vf = true;
+
+ list_add_tail(&epf_vf->list, &epf_pf->pci_vepf);
+ mutex_unlock(&epf_pf->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pci_epf_add_vepf);
+
+/**
+ * pci_epf_remove_vepf() - remove virtual EP function from physical EP function
+ * @epf_pf: the physical EP function from which the virtual EP function should
+ * be removed
+ * @epf_vf: the virtual EP function to be removed
+ *
+ * Invoke to remove a virtual endpoint function from the physcial endpoint
+ * function.
+ */
+void pci_epf_remove_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf)
+{
+ if (IS_ERR_OR_NULL(epf_pf) || IS_ERR_OR_NULL(epf_vf))
+ return;
+
+ mutex_lock(&epf_pf->lock);
+ clear_bit(epf_vf->vfunc_no, &epf_pf->vfunction_num_map);
+ list_del(&epf_vf->list);
+ mutex_unlock(&epf_pf->lock);
+}
+EXPORT_SYMBOL_GPL(pci_epf_remove_vepf);
+
/**
* pci_epf_free_space() - free the allocated PCI EPF register space
* @epf: the EPF device from whom to free the memory
@@ -317,6 +407,10 @@ struct pci_epf *pci_epf_create(const char *name)
return ERR_PTR(-ENOMEM);
}

+ /* VFs are numbered starting with 1. So set BIT(0) by default */
+ epf->vfunction_num_map = 1;
+ INIT_LIST_HEAD(&epf->pci_vepf);
+
dev = &epf->dev;
device_initialize(dev);
dev->bus = &pci_epf_bus_type;
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index 2debc27ba95e..043b4c9c7188 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -121,8 +121,10 @@ struct pci_epf_bar {
* @bar: represents the BAR of EPF device
* @msi_interrupts: number of MSI interrupts required by this function
* @msix_interrupts: number of MSI-X interrupts required by this function
- * @func_no: unique function number within this endpoint device
+ * @func_no: unique (physical) function number within this endpoint device
+ * @vfunc_no: unique virtual function number within a physical function
* @epc: the EPC device to which this EPF device is bound
+ * @epf_pf: the physical EPF device to which this virtual EPF device is bound
* @driver: the EPF driver to which this EPF device is bound
* @list: to add pci_epf as a list of PCI endpoint functions to pci_epc
* @nb: notifier block to notify EPF of any EPC events (like linkup)
@@ -133,6 +135,10 @@ struct pci_epf_bar {
* @sec_epc_bar: represents the BAR of EPF device associated with secondary EPC
* @sec_epc_func_no: unique (physical) function number within the secondary EPC
* @group: configfs group associated with the EPF device
+ * @is_bound: indicates if bind notification to function driver has been invoked
+ * @is_vf: true - virtual function, false - physical function
+ * @vfunction_num_map: bitmap to manage virtual function number
+ * @pci_vepf: list of virtual endpoint functions associated with this function
*/
struct pci_epf {
struct device dev;
@@ -142,8 +148,10 @@ struct pci_epf {
u8 msi_interrupts;
u16 msix_interrupts;
u8 func_no;
+ u8 vfunc_no;

struct pci_epc *epc;
+ struct pci_epf *epf_pf;
struct pci_epf_driver *driver;
struct list_head list;
struct notifier_block nb;
@@ -156,6 +164,10 @@ struct pci_epf {
struct pci_epf_bar sec_epc_bar[6];
u8 sec_epc_func_no;
struct config_group *group;
+ unsigned int is_bound;
+ unsigned int is_vf;
+ unsigned long vfunction_num_map;
+ struct list_head pci_vepf;
};

/**
@@ -199,4 +211,6 @@ int pci_epf_bind(struct pci_epf *epf);
void pci_epf_unbind(struct pci_epf *epf);
struct config_group *pci_epf_type_add_cfs(struct pci_epf *epf,
struct config_group *group);
+int pci_epf_add_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf);
+void pci_epf_remove_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf);
#endif /* __LINUX_PCI_EPF_H */
--
2.17.1