soc: ti: qmss: make acc queue support optional in the driver

acc channels are available only if accumulator PDSP is loaded and
running in the SoC. As this requires firmware and user may not have
firmware in the file system, make the accumulator queue support
available in qmss driver optional. To use accumulator queus user needs
to add firmware to the file system and boot up kernel.

Signed-off-by: Murali Karicheri <[e-mail]>
Signed-off-by: Santosh Shilimkar <[e-mail]>

Documentation/arm/keystone/knav-qmss.txt

···
  "firmware file ks2_qmss_pdsp_acc48.bin downloaded for PDSP"
 
 in the boot up log if loading of firmware to PDSP is successful.
+
+Use of accumulated queues requires the firmware image to be present in the
+file system. The driver doesn't acc queues to the supported queue range if
+PDSP is not running in the SoC. The API call fails if there is a queue open
+request to an acc queue and PDSP is not running. So make sure to copy firmware
+to file system before using these queue types.

drivers/soc/ti/knav_qmss.h

···
 	u32 __iomem					*iram;
 	u32						id;
 	struct list_head				list;
+	bool						loaded;
+	bool						started;
 };
 
 struct knav_qmgr_info {

drivers/soc/ti/knav_qmss_acc.c

···
  * Return 0 on success or error
  */
 int knav_init_acc_range(struct knav_device *kdev,
-				struct device_node *node,
-				struct knav_range_info *range)
+			struct device_node *node,
+			struct knav_range_info *range)
 {
 	struct knav_acc_channel *acc;
 	struct knav_pdsp_info *pdsp;
···
 		dev_err(kdev->dev, "pdsp id %d not found for range %s\n",
 			info->pdsp_id, range->name);
 		return -EINVAL;
+	}
+
+	if (!pdsp->started) {
+		dev_err(kdev->dev, "pdsp id %d not started for range %s\n",
+			info->pdsp_id, range->name);
+		return -ENODEV;
 	}
 
 	info->pdsp = pdsp;

drivers/soc/ti/knav_qmss_queue.c

···
 		dev_err(kdev->dev, "timed out on pdsp %s stop\n", pdsp->name);
 		return ret;
 	}
+	pdsp->loaded = false;
+	pdsp->started = false;
 	return 0;
 }
 
···
 	int ret;
 
 	knav_queue_stop_pdsps(kdev);
-	/* now load them all */
+	/* now load them all. We return success even if pdsp
+	 * is not loaded as acc channels are optional on having
+	 * firmware availability in the system. We set the loaded
+	 * and stated flag and when initialize the acc range, check
+	 * it and init the range only if pdsp is started.
+	 */
 	for_each_pdsp(kdev, pdsp) {
 		ret = knav_queue_load_pdsp(kdev, pdsp);
-		if (ret < 0)
-			return ret;
+		if (!ret)
+			pdsp->loaded = true;
 	}
 
 	for_each_pdsp(kdev, pdsp) {
-		ret = knav_queue_start_pdsp(kdev, pdsp);
-		WARN_ON(ret);
+		if (pdsp->loaded) {
+			ret = knav_queue_start_pdsp(kdev, pdsp);
+			if (!ret)
+				pdsp->started = true;
+		}
 	}
 	return 0;
 }