+static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
+ struct ufshcd_lrb *lrbp, enum dev_cmd_type cmd_type, int tag)
+{
+ lrbp->cmd = NULL;
+ lrbp->sense_bufflen = 0;
+ lrbp->sense_buffer = NULL;
+ lrbp->task_tag = tag;
+ lrbp->lun = 0; /* device management cmd is not specific to any LUN */
+ lrbp->command_type = UTP_CMD_TYPE_DEV_MANAGE;
+ lrbp->intr_cmd = true; /* No interrupt aggregation */
+ hba->dev_cmd.type = cmd_type;
+
+ return ufshcd_compose_upiu(hba, lrbp);
+}
+
+static int
+ufshcd_clear_cmd(struct ufs_hba *hba, int tag)
+{
+ int err = 0;
+ unsigned long flags;
+ u32 mask = 1 << tag;
+
+ /* clear outstanding transaction before retry */
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ ufshcd_utrl_clear(hba, tag);
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+ /*
+ * wait for for h/w to clear corresponding bit in door-bell.
+ * max. wait is 1 sec.
+ */
+ err = ufshcd_wait_for_register(hba,
+ REG_UTP_TRANSFER_REQ_DOOR_BELL,
+ mask, ~mask, 1000, 1000);
+
+ return err;
+}
+
+/**
+ * ufshcd_dev_cmd_completion() - handles device management command responses
+ * @hba: per adapter instance
+ * @lrbp: pointer to local reference block
+ */
+static int
+ufshcd_dev_cmd_completion(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
+{
+ int resp;
+ int err = 0;
+
+ resp = ufshcd_get_req_rsp(lrbp->ucd_rsp_ptr);
+
+ switch (resp) {
+ case UPIU_TRANSACTION_NOP_IN:
+ if (hba->dev_cmd.type != DEV_CMD_TYPE_NOP) {
+ err = -EINVAL;
+ dev_err(hba->dev, "%s: unexpected response %x\n",
+ __func__, resp);
+ }
+ break;
+ case UPIU_TRANSACTION_REJECT_UPIU:
+ /* TODO: handle Reject UPIU Response */
+ err = -EPERM;
+ dev_err(hba->dev, "%s: Reject UPIU not fully implemented\n",
+ __func__);
+ break;
+ default:
+ err = -EINVAL;
+ dev_err(hba->dev, "%s: Invalid device management cmd response: %x\n",
+ __func__, resp);
+ break;
+ }
+
+ return err;
+}
+
+static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba,
+ struct ufshcd_lrb *lrbp, int max_timeout)
+{
+ int err = 0;
+ unsigned long time_left;
+ unsigned long flags;
+
+ time_left = wait_for_completion_timeout(hba->dev_cmd.complete,
+ msecs_to_jiffies(max_timeout));
+
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ hba->dev_cmd.complete = NULL;
+ if (likely(time_left)) {
+ err = ufshcd_get_tr_ocs(lrbp);
+ if (!err)
+ err = ufshcd_dev_cmd_completion(hba, lrbp);
+ }
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+ if (!time_left) {
+ err = -ETIMEDOUT;
+ if (!ufshcd_clear_cmd(hba, lrbp->task_tag))
+ /* sucessfully cleared the command, retry if needed */
+ err = -EAGAIN;
+ }
+
+ return err;
+}
+
+/**
+ * ufshcd_get_dev_cmd_tag - Get device management command tag
+ * @hba: per-adapter instance
+ * @tag: pointer to variable with available slot value
+ *
+ * Get a free slot and lock it until device management command
+ * completes.
+ *
+ * Returns false if free slot is unavailable for locking, else
+ * return true with tag value in @tag.
+ */
+static bool ufshcd_get_dev_cmd_tag(struct ufs_hba *hba, int *tag_out)
+{
+ int tag;
+ bool ret = false;
+ unsigned long tmp;
+
+ if (!tag_out)
+ goto out;
+
+ do {
+ tmp = ~hba->lrb_in_use;
+ tag = find_last_bit(&tmp, hba->nutrs);
+ if (tag >= hba->nutrs)
+ goto out;
+ } while (test_and_set_bit_lock(tag, &hba->lrb_in_use));
+
+ *tag_out = tag;
+ ret = true;
+out:
+ return ret;
+}
+
+static inline void ufshcd_put_dev_cmd_tag(struct ufs_hba *hba, int tag)
+{
+ clear_bit_unlock(tag, &hba->lrb_in_use);
+}
+
+/**
+ * ufshcd_exec_dev_cmd - API for sending device management requests
+ * @hba - UFS hba
+ * @cmd_type - specifies the type (NOP, Query...)
+ * @timeout - time in seconds
+ *
+ * NOTE: There is only one available tag for device management commands. Thus
+ * synchronisation is the responsibilty of the user.
+ */
+static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
+ enum dev_cmd_type cmd_type, int timeout)
+{
+ struct ufshcd_lrb *lrbp;
+ int err;
+ int tag;
+ struct completion wait;
+ unsigned long flags;
+
+ /*
+ * Get free slot, sleep if slots are unavailable.
+ * Even though we use wait_event() which sleeps indefinitely,
+ * the maximum wait time is bounded by SCSI request timeout.
+ */
+ wait_event(hba->dev_cmd.tag_wq, ufshcd_get_dev_cmd_tag(hba, &tag));
+
+ init_completion(&wait);
+ lrbp = &hba->lrb[tag];
+ WARN_ON(lrbp->cmd);
+ err = ufshcd_compose_dev_cmd(hba, lrbp, cmd_type, tag);
+ if (unlikely(err))
+ goto out_put_tag;
+
+ hba->dev_cmd.complete = &wait;
+
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ ufshcd_send_command(hba, tag);
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+ err = ufshcd_wait_for_dev_cmd(hba, lrbp, timeout);
+
+out_put_tag:
+ ufshcd_put_dev_cmd_tag(hba, tag);
+ wake_up(&hba->dev_cmd.tag_wq);
+ return err;
+}
+