PCI/DOE: Add DOE mailbox support functions

Introduced in a PCIe r6.0, sec 6.30, DOE provides a config space based
mailbox with standard protocol discovery.  Each mailbox is accessed
through a DOE Extended Capability.

Each DOE mailbox must support the DOE discovery protocol in addition to
any number of additional protocols.

Define core PCIe functionality to manage a single PCIe DOE mailbox at a
defined config space offset.  Functionality includes iterating,
creating, query of supported protocol, and task submission.  Destruction
of the mailboxes is device managed.

Cc: "Li, Ming" <ming4.li@intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Acked-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20220719205249.566684-4-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/include/linux/pci-doe.h b/include/linux/pci-doe.h
new file mode 100644
index 000000000000..ed9b4df792b8
--- /dev/null
+++ b/include/linux/pci-doe.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Data Object Exchange
+ *	PCIe r6.0, sec 6.30 DOE
+ *
+ * Copyright (C) 2021 Huawei
+ *     Jonathan Cameron <Jonathan.Cameron@huawei.com>
+ *
+ * Copyright (C) 2022 Intel Corporation
+ *	Ira Weiny <ira.weiny@intel.com>
+ */
+
+#ifndef LINUX_PCI_DOE_H
+#define LINUX_PCI_DOE_H
+
+struct pci_doe_protocol {
+	u16 vid;
+	u8 type;
+};
+
+struct pci_doe_mb;
+
+/**
+ * struct pci_doe_task - represents a single query/response
+ *
+ * @prot: DOE Protocol
+ * @request_pl: The request payload
+ * @request_pl_sz: Size of the request payload (bytes)
+ * @response_pl: The response payload
+ * @response_pl_sz: Size of the response payload (bytes)
+ * @rv: Return value.  Length of received response or error (bytes)
+ * @complete: Called when task is complete
+ * @private: Private data for the consumer
+ * @work: Used internally by the mailbox
+ * @doe_mb: Used internally by the mailbox
+ *
+ * The payload sizes and rv are specified in bytes with the following
+ * restrictions concerning the protocol.
+ *
+ *	1) The request_pl_sz must be a multiple of double words (4 bytes)
+ *	2) The response_pl_sz must be >= a single double word (4 bytes)
+ *	3) rv is returned as bytes but it will be a multiple of double words
+ *
+ * NOTE there is no need for the caller to initialize work or doe_mb.
+ */
+struct pci_doe_task {
+	struct pci_doe_protocol prot;
+	u32 *request_pl;
+	size_t request_pl_sz;
+	u32 *response_pl;
+	size_t response_pl_sz;
+	int rv;
+	void (*complete)(struct pci_doe_task *task);
+	void *private;
+
+	/* No need for the user to initialize these fields */
+	struct work_struct work;
+	struct pci_doe_mb *doe_mb;
+};
+
+/**
+ * pci_doe_for_each_off - Iterate each DOE capability
+ * @pdev: struct pci_dev to iterate
+ * @off: u16 of config space offset of each mailbox capability found
+ */
+#define pci_doe_for_each_off(pdev, off) \
+	for (off = pci_find_next_ext_capability(pdev, off, \
+					PCI_EXT_CAP_ID_DOE); \
+		off > 0; \
+		off = pci_find_next_ext_capability(pdev, off, \
+					PCI_EXT_CAP_ID_DOE))
+
+struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset);
+bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type);
+int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task);
+
+#endif