[PATCH v4 11/15] cxl: Add support to handle user feature commands for get feature

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

Add helper function to parse the user data from fwctl RPC ioctl and
send the parsed input parameters to cxl_get_feature() call.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/cxl/core/features.c | 45 +++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 2682067dd2d7..b359353fd4d2 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -468,6 +468,50 @@ static void *cxlctl_get_supported_features(struct cxl_features_state *cxlfs,
 	return no_free_ptr(rpc_out);
 }
 
+static void *cxlctl_get_feature(struct cxl_features_state *cxlfs,
+				const struct fwctl_rpc_cxl *rpc_in,
+				size_t *out_len)
+{
+	struct cxl_mailbox *cxl_mbox = &cxlfs->cxlds->cxl_mbox;
+	struct cxl_mbox_get_feat_in feat_in;
+	u16 offset, count, return_code;
+	size_t out_size = *out_len;
+
+	if (rpc_in->op_size != sizeof(feat_in))
+		return ERR_PTR(-EINVAL);
+
+	if (copy_from_user(&feat_in, u64_to_user_ptr(rpc_in->in_payload),
+			   rpc_in->op_size))
+		return ERR_PTR(-EFAULT);
+
+	offset = le16_to_cpu(feat_in.offset);
+	count = le16_to_cpu(feat_in.count);
+
+	if (!count)
+		return ERR_PTR(-EINVAL);
+
+	struct fwctl_rpc_cxl_out *rpc_out __free(kvfree) =
+		kvzalloc(out_size, GFP_KERNEL);
+	if (!rpc_out)
+		return ERR_PTR(-ENOMEM);
+
+	out_size = cxl_get_feature(cxl_mbox, &feat_in.uuid,
+				   feat_in.selection, rpc_out->payload,
+				   count, offset, &return_code);
+	*out_len = sizeof(struct fwctl_rpc_cxl_out);
+	if (!out_size) {
+		rpc_out->size = 0;
+		rpc_out->retval = return_code;
+		return no_free_ptr(rpc_out);
+	}
+
+	rpc_out->size = out_size;
+	rpc_out->retval = CXL_MBOX_CMD_RC_SUCCESS;
+	*out_len += out_size;
+
+	return no_free_ptr(rpc_out);
+}
+
 static bool cxlctl_validate_set_features(struct cxl_features_state *cxlfs,
 					 const struct fwctl_rpc_cxl *rpc_in,
 					 enum fwctl_rpc_scope scope)
@@ -565,6 +609,7 @@ static void *cxlctl_handle_commands(struct cxl_features_state *cxlfs,
 	case CXL_MBOX_OP_GET_SUPPORTED_FEATURES:
 		return cxlctl_get_supported_features(cxlfs, rpc_in, out_len);
 	case CXL_MBOX_OP_GET_FEATURE:
+		return cxlctl_get_feature(cxlfs, rpc_in, out_len);
 	case CXL_MBOX_OP_SET_FEATURE:
 	default:
 		return ERR_PTR(-EOPNOTSUPP);
-- 
2.48.1