PCI: endpoint: Add pci_epc_ops to map MSI IRQ

Add pci_epc_ops to map physical address to MSI address and return MSI data.
The physical address is an address in the outbound region. This is required
to implement doorbell functionality of NTB (non-transparent bridge) wherein
EPC on either side of the interface (primary and secondary) can directly
write to the physical address (in outbound region) of the other interface
to ring doorbell using MSI.

Link: https://lore.kernel.org/r/20210201195809.7342-9-kishon@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 3693eca5b030..cc8f9eb2b177 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -231,6 +231,47 @@ int pci_epc_raise_irq(struct pci_epc *epc, u8 func_no,
 EXPORT_SYMBOL_GPL(pci_epc_raise_irq);
 
 /**
+ * pci_epc_map_msi_irq() - Map physical address to MSI address and return
+ *                         MSI data
+ * @epc: the EPC device which has the MSI capability
+ * @func_no: the physical endpoint function number in the EPC device
+ * @phys_addr: the physical address of the outbound region
+ * @interrupt_num: the MSI interrupt number
+ * @entry_size: Size of Outbound address region for each interrupt
+ * @msi_data: the data that should be written in order to raise MSI interrupt
+ *            with interrupt number as 'interrupt num'
+ * @msi_addr_offset: Offset of MSI address from the aligned outbound address
+ *                   to which the MSI address is mapped
+ *
+ * Invoke to map physical address to MSI address and return MSI data. The
+ * physical address should be an address in the outbound region. This is
+ * required to implement doorbell functionality of NTB wherein EPC on either
+ * side of the interface (primary and secondary) can directly write to the
+ * physical address (in outbound region) of the other interface to ring
+ * doorbell.
+ */
+int pci_epc_map_msi_irq(struct pci_epc *epc, u8 func_no, phys_addr_t phys_addr,
+			u8 interrupt_num, u32 entry_size, u32 *msi_data,
+			u32 *msi_addr_offset)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(epc))
+		return -EINVAL;
+
+	if (!epc->ops->map_msi_irq)
+		return -EINVAL;
+
+	mutex_lock(&epc->lock);
+	ret = epc->ops->map_msi_irq(epc, func_no, phys_addr, interrupt_num,
+				    entry_size, msi_data, msi_addr_offset);
+	mutex_unlock(&epc->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pci_epc_map_msi_irq);
+
+/**
  * pci_epc_get_msi() - get the number of MSI interrupt numbers allocated
  * @epc: the EPC device to which MSI interrupts was requested
  * @func_no: the endpoint function number in the EPC device