A peer-visible DMA descriptor window needs a little more context than
just address and size. In particular, a generic consumer needs to know
which DMAEngine channel it belongs to and in which direction that
channel operates.

Extend struct pci_epc_aux_resource with dma_chan metadata for
PCI_EPC_AUX_DMA_CHAN_DESC resources so controllers can expose that
information in a uniform way.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
 include/linux/pci-epc.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index d6b0a0833e9f..7dd2e4d5d952 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -78,6 +78,11 @@ enum pci_epc_aux_resource_type {
 	PCI_EPC_AUX_DOORBELL_MMIO,
 };
 
+enum pci_epc_aux_dma_dir {
+	PCI_EPC_AUX_DMA_DIR_READ = 0,
+	PCI_EPC_AUX_DMA_DIR_WRITE = 1,
+};
+
 /**
  * struct pci_epc_aux_resource - a physical auxiliary resource that may be
  *                               exposed for peer use
@@ -103,6 +108,13 @@ struct pci_epc_aux_resource {
 			int irq; /* IRQ number for the doorbell handler */
 			u32 data; /* write value to ring the doorbell */
 		} db_mmio;
+
+		/* PCI_EPC_AUX_DMA_CHAN_DESC */
+		struct {
+			int chan_id;
+			u8 dir;
+			u8 reserved[3];
+		} dma_chan;
 	} u;
 };
 
-- 
2.51.0