[RFC PATCH 09/13] fwctl/cxl: Add support for get driver information

[Dave Jiang <dave.jiang@intel.com>]

Add definition for fwctl_ops->info() to return driver information. The
function will return the commands supported by the fwctl char device as
a bitmap of enable commands.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/fwctl/cxl/cxl.c  | 20 ++++++++++++++++++--
 include/uapi/fwctl/cxl.h | 25 +++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 include/uapi/fwctl/cxl.h

diff --git a/drivers/fwctl/cxl/cxl.c b/drivers/fwctl/cxl/cxl.c
index 518ba2afada8..22f62034c021 100644
--- a/drivers/fwctl/cxl/cxl.c
+++ b/drivers/fwctl/cxl/cxl.c
@@ -6,6 +6,7 @@
 #include <linux/auxiliary_bus.h>
 #include <linux/cxl/mailbox.h>
 #include <linux/auxiliary_bus.h>
+#include <uapi/fwctl/cxl.h>
 
 struct cxlctl_uctx {
 	struct fwctl_uctx uctx;
@@ -22,6 +23,12 @@ DEFINE_FREE(cxlctl, struct cxlctl_dev *, if (_T) fwctl_put(&_T->fwctl))
 
 static int cxlctl_open_uctx(struct fwctl_uctx *uctx)
 {
+	struct cxlctl_uctx *cxlctl_uctx =
+		container_of(uctx, struct cxlctl_uctx, uctx);
+
+	cxlctl_uctx->uctx_caps = BIT(FWCTL_CXL_QUERY_COMMANDS) |
+				 BIT(FWCTL_CXL_SEND_COMMAND);
+
 	return 0;
 }
 
@@ -31,8 +38,17 @@ static void cxlctl_close_uctx(struct fwctl_uctx *uctx)
 
 static void *cxlctl_info(struct fwctl_uctx *uctx, size_t *length)
 {
-	/* Place holder */
-	return ERR_PTR(-EOPNOTSUPP);
+	struct cxlctl_uctx *cxlctl_uctx =
+		container_of(uctx, struct cxlctl_uctx, uctx);
+	struct fwctl_info_cxl *info;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	info->uctx_caps = cxlctl_uctx->uctx_caps;
+
+	return info;
 }
 
 static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
diff --git a/include/uapi/fwctl/cxl.h b/include/uapi/fwctl/cxl.h
new file mode 100644
index 000000000000..d3a735f1fe4e
--- /dev/null
+++ b/include/uapi/fwctl/cxl.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright (c) 2024, Intel Corporation
+ *
+ * These are definitions for the mailbox command interface of CXL subsystem.
+ */
+#ifndef _UAPI_FWCTL_CXL_H_
+#define _UAPI_FWCTL_CXL_H_
+
+enum fwctl_cxl_commands {
+	FWCTL_CXL_QUERY_COMMANDS = 0,
+	FWCTL_CXL_SEND_COMMAND,
+};
+
+/**
+ * struct fwctl_info_cxl - ioctl(FWCTL_INFO) out_device_data
+ * @uctx_caps: The command capabilities driver accepts.
+ *
+ * Return basic information about the FW interface available.
+ */
+struct fwctl_info_cxl {
+	__u32 uctx_caps;
+};
+
+#endif
-- 
2.45.2