[PATCH v4 fwctl 1/3] fwctl: Add driver_data field to fwctl_rpc

[Pavan Chebbi <pavan.chebbi@broadcom.com>]

Add a driver_data field to struct fwctl_rpc in the UAPI and thread the
value through the fw_rpc() ops callback as a new __u64 parameter.  The
field is opaque and driver-defined.

Drivers that do not define a driver_data format may return -EOPNOTSUPP.
Update the existing drivers' fw_rpc implementations to enforce this.

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
---
 drivers/cxl/core/features.c | 6 +++++-
 drivers/fwctl/bnxt/main.c   | 6 +++++-
 drivers/fwctl/main.c        | 3 ++-
 drivers/fwctl/mlx5/main.c   | 6 +++++-
 drivers/fwctl/pds/main.c    | 6 +++++-
 include/linux/fwctl.h       | 8 ++++++--
 include/uapi/fwctl/fwctl.h  | 3 +++
 7 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 3435db9ea6b1..a0d7f26c5b6d 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -643,7 +643,8 @@ static void *cxlctl_handle_commands(struct cxl_features_state *cxlfs,
 }
 
 static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
-			   void *in, size_t in_len, size_t *out_len)
+			   void *in, size_t in_len, size_t *out_len,
+			   __u64 driver_data)
 {
 	struct fwctl_device *fwctl_dev = uctx->fwctl;
 	struct cxl_memdev *cxlmd = fwctl_to_memdev(fwctl_dev);
@@ -651,6 +652,9 @@ static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
 	const struct fwctl_rpc_cxl *rpc_in = in;
 	u16 opcode = rpc_in->opcode;
 
+	if (driver_data)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	if (!cxlctl_validate_hw_command(cxlfs, rpc_in, scope, opcode))
 		return ERR_PTR(-EINVAL);
 
diff --git a/drivers/fwctl/bnxt/main.c b/drivers/fwctl/bnxt/main.c
index 951c8ac2e0a1..5eb3651a1784 100644
--- a/drivers/fwctl/bnxt/main.c
+++ b/drivers/fwctl/bnxt/main.c
@@ -172,7 +172,8 @@ static unsigned int bnxtctl_get_timeout(struct input *req)
 
 static void *bnxtctl_fw_rpc(struct fwctl_uctx *uctx,
 			    enum fwctl_rpc_scope scope,
-			    void *in, size_t in_len, size_t *out_len)
+			    void *in, size_t in_len, size_t *out_len,
+			    __u64 driver_data)
 {
 	struct bnxtctl_dev *bnxtctl =
 		container_of(uctx->fwctl, struct bnxtctl_dev, fwctl);
@@ -180,6 +181,9 @@ static void *bnxtctl_fw_rpc(struct fwctl_uctx *uctx,
 	struct bnxt_fw_msg rpc_in = {0};
 	int rc;
 
+	if (driver_data)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	if (in_len < sizeof(struct input) || in_len > HWRM_MAX_REQ_LEN)
 		return ERR_PTR(-EINVAL);
 
diff --git a/drivers/fwctl/main.c b/drivers/fwctl/main.c
index 098c3824ad75..32c4c66dd7d5 100644
--- a/drivers/fwctl/main.c
+++ b/drivers/fwctl/main.c
@@ -122,7 +122,8 @@ static int fwctl_cmd_rpc(struct fwctl_ucmd *ucmd)
 
 	out_len = cmd->out_len;
 	void *outbuf __free(kvfree) = fwctl->ops->fw_rpc(
-		ucmd->uctx, cmd->scope, inbuf, cmd->in_len, &out_len);
+		ucmd->uctx, cmd->scope, inbuf, cmd->in_len, &out_len,
+		cmd->driver_data);
 	if (IS_ERR(outbuf))
 		return PTR_ERR(outbuf);
 	if (outbuf == inbuf) {
diff --git a/drivers/fwctl/mlx5/main.c b/drivers/fwctl/mlx5/main.c
index e86ab703c767..2a5105769126 100644
--- a/drivers/fwctl/mlx5/main.c
+++ b/drivers/fwctl/mlx5/main.c
@@ -304,7 +304,8 @@ static bool mlx5ctl_validate_rpc(const void *in, enum fwctl_rpc_scope scope)
 }
 
 static void *mlx5ctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
-			    void *rpc_in, size_t in_len, size_t *out_len)
+			    void *rpc_in, size_t in_len, size_t *out_len,
+			    __u64 driver_data)
 {
 	struct mlx5ctl_dev *mcdev =
 		container_of(uctx->fwctl, struct mlx5ctl_dev, fwctl);
@@ -313,6 +314,9 @@ static void *mlx5ctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
 	void *rpc_out;
 	int ret;
 
+	if (driver_data)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	if (in_len < MLX5_ST_SZ_BYTES(mbox_in_hdr) ||
 	    *out_len < MLX5_ST_SZ_BYTES(mbox_out_hdr))
 		return ERR_PTR(-EMSGSIZE);
diff --git a/drivers/fwctl/pds/main.c b/drivers/fwctl/pds/main.c
index 08872ee8422f..bb61e60843cf 100644
--- a/drivers/fwctl/pds/main.c
+++ b/drivers/fwctl/pds/main.c
@@ -348,7 +348,8 @@ static int pdsfc_validate_rpc(struct pdsfc_dev *pdsfc,
 }
 
 static void *pdsfc_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
-			  void *in, size_t in_len, size_t *out_len)
+			  void *in, size_t in_len, size_t *out_len,
+			  __u64 driver_data)
 {
 	struct pdsfc_dev *pdsfc = container_of(uctx->fwctl, struct pdsfc_dev, fwctl);
 	struct device *dev = &uctx->fwctl->dev;
@@ -362,6 +363,9 @@ static void *pdsfc_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
 	void *out = NULL;
 	int err;
 
+	if (driver_data)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	err = pdsfc_validate_rpc(pdsfc, rpc, scope);
 	if (err)
 		return ERR_PTR(err);
diff --git a/include/linux/fwctl.h b/include/linux/fwctl.h
index 5d61fc8a6871..afb7f72d0cb1 100644
--- a/include/linux/fwctl.h
+++ b/include/linux/fwctl.h
@@ -51,10 +51,14 @@ struct fwctl_ops {
 	 * @fw_rpc: Implement FWCTL_RPC. Deliver rpc_in/in_len to the FW and
 	 * return the response and set out_len. rpc_in can be returned as the
 	 * response pointer. Otherwise the returned pointer is freed with
-	 * kvfree().
+	 * kvfree(). driver_data is the opaque value from fwctl_rpc, passed
+	 * verbatim from userspace. The driver is responsible for interpreting
+	 * and validating it. Drivers that do not define a driver_data format
+	 * must return -EOPNOTSUPP if driver_data is non-zero.
 	 */
 	void *(*fw_rpc)(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
-			void *rpc_in, size_t in_len, size_t *out_len);
+			void *rpc_in, size_t in_len, size_t *out_len,
+			__u64 driver_data);
 };
 
 /**
diff --git a/include/uapi/fwctl/fwctl.h b/include/uapi/fwctl/fwctl.h
index 2d6d4049c205..2e07425402a3 100644
--- a/include/uapi/fwctl/fwctl.h
+++ b/include/uapi/fwctl/fwctl.h
@@ -120,6 +120,8 @@ enum fwctl_rpc_scope {
  * @out_len: Length of the out memory
  * @in: Request message in device specific format
  * @out: Response message in device specific format
+ * @driver_data: Opaque userspace pointer passed verbatim to the driver.
+ *   Must be 0 for drivers that do not define a driver_data format.
  *
  * Deliver a Remote Procedure Call to the device FW and return the response. The
  * call's parameters and return are marshaled into linear buffers of memory. Any
@@ -136,6 +138,7 @@ struct fwctl_rpc {
 	__u32 out_len;
 	__aligned_u64 in;
 	__aligned_u64 out;
+	__aligned_u64 driver_data;
 };
 #define FWCTL_RPC _IO(FWCTL_TYPE, FWCTL_CMD_RPC)
 
-- 
2.52.0