net/mlx5: cmdif, Return value improvements

Make sure that the two basic command interface functions cmd_exec and
cmd_invoke will return well defined return values:

return < 0 : Command execution couldn't be submitted by driver
return > 0 : Command execution couldn't be performed by firmware
return = 0 : Command was executed by FW, Caller must check FW
outbox status.

These statuses are valid for the blocking call of cmd_exec() e.g. when
callback == NULL, in a downstream patch, will refactor the code to
provide the same return value semantics to the callback.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
index 17fe0580965331623055940f46c4578e585abad7..3c6a533ee0c959dd8a0211b1e63e88917cd18519 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
@@ -190,10 +190,10 @@ static int verify_block_sig(struct mlx5_cmd_prot_block *block)
        int xor_len = sizeof(*block) - sizeof(block->data) - 1;
 
        if (xor8_buf(block, rsvd0_off, xor_len) != 0xff)
-               return -EINVAL;
+               return -EHWPOISON;
 
        if (xor8_buf(block, 0, sizeof(*block)) != 0xff)
-               return -EINVAL;
+               return -EHWPOISON;
 
        return 0;
 }
@@ -259,12 +259,12 @@ static int verify_signature(struct mlx5_cmd_work_ent *ent)
 
        sig = xor8_buf(ent->lay, 0, sizeof(*ent->lay));
        if (sig != 0xff)
-               return -EINVAL;
+               return -EHWPOISON;
 
        for (i = 0; i < n && next; i++) {
                err = verify_block_sig(next->buf);
                if (err)
-                       return err;
+                       return -EHWPOISON;
 
                next = next->next;
        }
@@ -479,7 +479,7 @@ static int mlx5_internal_err_ret_value(struct mlx5_core_dev *dev, u16 op,
        case MLX5_CMD_OP_ALLOC_SF:
                *status = MLX5_DRIVER_STATUS_ABORTED;
                *synd = MLX5_DRIVER_SYND;
-               return -EIO;
+               return -ENOLINK;
        default:
                mlx5_core_err(dev, "Unknown FW command (%d)\n", op);
                return -EINVAL;
@@ -1101,16 +1101,27 @@ out_err:
 /*  Notes:
  *    1. Callback functions may not sleep
  *    2. page queue commands do not support asynchrous completion
+ *
+ * return value in case (!callback):
+ *     ret < 0 : Command execution couldn't be submitted by driver
+ *     ret > 0 : Command execution couldn't be performed by firmware
+ *     ret == 0: Command was executed by FW, Caller must check FW outbox status.
+ *
+ * return value in case (callback):
+ *     ret < 0 : Command execution couldn't be submitted by driver
+ *     ret == 0: Command will be submitted to FW for execution
+ *               and the callback will be called for further status updates
  */
 static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in,
                           struct mlx5_cmd_msg *out, void *uout, int uout_size,
                           mlx5_cmd_cbk_t callback,
-                          void *context, int page_queue, u8 *status,
+                          void *context, int page_queue,
                           u8 token, bool force_polling)
 {
        struct mlx5_cmd *cmd = &dev->cmd;
        struct mlx5_cmd_work_ent *ent;
        struct mlx5_cmd_stats *stats;
+       u8 status = 0;
        int err = 0;
        s64 ds;
        u16 op;
@@ -1141,12 +1152,12 @@ static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in,
                cmd_work_handler(&ent->work);
        } else if (!queue_work(cmd->wq, &ent->work)) {
                mlx5_core_warn(dev, "failed to queue work\n");
-               err = -ENOMEM;
+               err = -EALREADY;
                goto out_free;
        }
 
        if (callback)
-               goto out; /* mlx5_cmd_comp_handler() will put(ent) */
+               return 0; /* mlx5_cmd_comp_handler() will put(ent) */
 
        err = wait_func(dev, ent);
        if (err == -ETIMEDOUT || err == -ECANCELED)
@@ -1164,12 +1175,11 @@ static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in,
        mlx5_core_dbg_mask(dev, 1 << MLX5_CMD_TIME,
                           "fw exec time for %s is %lld nsec\n",
                           mlx5_command_str(op), ds);
-       *status = ent->status;
 
 out_free:
+       status = ent->status;
        cmd_ent_put(ent);
-out:
-       return err;
+       return err ? : status;
 }
 
 static ssize_t dbg_write(struct file *filp, const char __user *buf,
@@ -1719,7 +1729,7 @@ void mlx5_cmd_flush(struct mlx5_core_dev *dev)
                up(&cmd->sem);
 }
 
-static int status_to_err(u8 status)
+static int deliv_status_to_err(u8 status)
 {
        switch (status) {
        case MLX5_CMD_DELIVERY_STAT_OK:
@@ -1787,22 +1797,25 @@ static int is_manage_pages(void *in)
        return MLX5_GET(mbox_in, in, opcode) == MLX5_CMD_OP_MANAGE_PAGES;
 }
 
+/*  Notes:
+ *    1. Callback functions may not sleep
+ *    2. Page queue commands do not support asynchrous completion
+ */
 static int cmd_exec(struct mlx5_core_dev *dev, void *in, int in_size, void *out,
                    int out_size, mlx5_cmd_cbk_t callback, void *context,
                    bool force_polling)
 {
-       struct mlx5_cmd_msg *inb;
-       struct mlx5_cmd_msg *outb;
+       u16 opcode = MLX5_GET(mbox_in, in, opcode);
+       struct mlx5_cmd_msg *inb, *outb;
        int pages_queue;
        gfp_t gfp;
-       int err;
-       u8 status = 0;
-       u32 drv_synd;
-       u16 opcode;
        u8 token;
+       int err;
 
-       opcode = MLX5_GET(mbox_in, in, opcode);
        if (mlx5_cmd_is_down(dev) || !opcode_allowed(&dev->cmd, opcode)) {
+               u32 drv_synd;
+               u8 status;
+
                err = mlx5_internal_err_ret_value(dev, opcode, &drv_synd, &status);
                MLX5_SET(mbox_out, out, status, status);
                MLX5_SET(mbox_out, out, syndrome, drv_synd);
@@ -1833,26 +1846,22 @@ static int cmd_exec(struct mlx5_core_dev *dev, void *in, int in_size, void *out,
        }
 
        err = mlx5_cmd_invoke(dev, inb, outb, out, out_size, callback, context,
-                             pages_queue, &status, token, force_polling);
-       if (err)
-               goto out_out;
+                             pages_queue, token, force_polling);
+       if (callback)
+               return err;
 
-       mlx5_core_dbg(dev, "err %d, status %d\n", err, status);
-       if (status) {
-               err = status_to_err(status);
-               goto out_out;
-       }
+       if (err > 0) /* Failed in FW, command didn't execute */
+               err = deliv_status_to_err(err);
 
-       if (!callback)
-               err = mlx5_copy_from_msg(out, outb, out_size);
+       if (err)
+               goto out_out;
 
+       /* command completed by FW */
+       err = mlx5_copy_from_msg(out, outb, out_size);
 out_out:
-       if (!callback)
-               mlx5_free_cmd_msg(dev, outb);
-
+       mlx5_free_cmd_msg(dev, outb);
 out_in:
-       if (!callback)
-               free_msg(dev, inb);
+       free_msg(dev, inb);
        return err;
 }