[PATCH v1 11/19] 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 a mask of the feature mailbox commands supported
by the fwctl char device.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v1:
- Add missed setting of *length for ->info().
- Use BIT() instead of enum directly.
---
 drivers/cxl/features.c   | 30 ++++++++++++++++++++++++++++--
 include/cxl/features.h   |  7 -------
 include/cxl/mailbox.h    |  1 +
 include/uapi/fwctl/cxl.h | 31 +++++++++++++++++++++++++++++++
 4 files changed, 60 insertions(+), 9 deletions(-)
 create mode 100644 include/uapi/fwctl/cxl.h

diff --git a/drivers/cxl/features.c b/drivers/cxl/features.c
index 5a2b771586d3..cc72e73ae8d6 100644
--- a/drivers/cxl/features.c
+++ b/drivers/cxl/features.c
@@ -9,6 +9,8 @@
 #include "cxl.h"
 #include "cxlmem.h"
 
+#define to_cxl_features_state(fwctl) container_of(fwctl, struct cxl_features_state, fwctl)
+
 static int cxlctl_open_uctx(struct fwctl_uctx *uctx)
 {
 	return 0;
@@ -18,10 +20,34 @@ static void cxlctl_close_uctx(struct fwctl_uctx *uctx)
 {
 }
 
+static void set_command_mask(struct cxl_features_state *cfs, u32 *mask)
+{
+	struct cxl_mailbox *cxl_mbox = cfs->features->cxl_mbox;
+
+	*mask = 0;
+	if (test_bit(CXL_FEATURE_ID_GET_SUPPORTED_FEATURES,
+		     cxl_mbox->feature_cmds))
+		*mask |= BIT(CXL_FEATURE_ID_GET_SUPPORTED_FEATURES);
+	if (test_bit(CXL_FEATURE_ID_GET_FEATURE, cxl_mbox->feature_cmds))
+		*mask |= BIT(CXL_FEATURE_ID_GET_FEATURE);
+	if (test_bit(CXL_FEATURE_ID_SET_FEATURE, cxl_mbox->feature_cmds))
+		*mask |= BIT(CXL_FEATURE_ID_SET_FEATURE);
+}
+
 static void *cxlctl_info(struct fwctl_uctx *uctx, size_t *length)
 {
-	/* Place holder */
-	return ERR_PTR(-EOPNOTSUPP);
+	struct fwctl_device *fwctl = uctx->fwctl;
+	struct cxl_features_state *cfs = to_cxl_features_state(fwctl);
+	struct fwctl_info_cxl *info;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	set_command_mask(cfs, &info->cmd_mask);
+	*length = sizeof(*info);
+
+	return info;
 }
 
 static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
diff --git a/include/cxl/features.h b/include/cxl/features.h
index 69697c069e63..e38ee777328d 100644
--- a/include/cxl/features.h
+++ b/include/cxl/features.h
@@ -40,13 +40,6 @@
 
 struct cxl_mailbox;
 
-enum feature_cmds {
-	CXL_FEATURE_ID_GET_SUPPORTED_FEATURES = 0,
-	CXL_FEATURE_ID_GET_FEATURE,
-	CXL_FEATURE_ID_SET_FEATURE,
-	CXL_FEATURE_ID_MAX,
-};
-
 struct cxl_features {
 	int id;
 	struct device dev;
diff --git a/include/cxl/mailbox.h b/include/cxl/mailbox.h
index 263fc346aeb1..1157b19175a5 100644
--- a/include/cxl/mailbox.h
+++ b/include/cxl/mailbox.h
@@ -4,6 +4,7 @@
 #define __CXL_MBOX_H__
 #include <linux/rcuwait.h>
 #include <cxl/features.h>
+#include <uapi/fwctl/cxl.h>
 #include <uapi/linux/cxl_mem.h>
 
 /**
diff --git a/include/uapi/fwctl/cxl.h b/include/uapi/fwctl/cxl.h
new file mode 100644
index 000000000000..79b822dbfafd
--- /dev/null
+++ b/include/uapi/fwctl/cxl.h
@@ -0,0 +1,31 @@
+/* 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_
+
+#include <linux/types.h>
+
+enum feature_cmds {
+	CXL_FEATURE_ID_GET_SUPPORTED_FEATURES = 0,
+	CXL_FEATURE_ID_GET_FEATURE,
+	CXL_FEATURE_ID_SET_FEATURE,
+	CXL_FEATURE_ID_MAX,
+};
+
+/**
+ * struct fwctl_info_cxl - ioctl(FWCTL_INFO) out_device_data
+ * @cmd_mask: Mask indicate which commands are supported based on 'enum feature_cmds'
+ *
+ * Return basic information about the FW interface available.
+ *
+ * nr_commands is number of hardware commands the driver supports. Use
+ * FWCTL_CMD_HW_INFO ioctl to request additional information.
+ */
+struct fwctl_info_cxl {
+	__u32 cmd_mask;
+};
+#endif
-- 
2.47.1