soc: ti: add firmware file name as part of the driver

Currently firmware file name is included in the DTS. This is not scalable
as user has to change the DTS if they need upgrade to a new firmware.
Instead, add the firmware file name in the driver itself. As long as there
is no API change, new firmware upgrade is easy and require no driver
change. User is expected to copy the firmware image to the file system
and add a sym link to the new firmware for doing an upgrade. Driver add
a array of firmware file names to search for the available firmware blobs.
This scheme also prepare the driver for future changes to API if ever
happens. In such case it is assumed that driver needs to change to
accommodate the new firmware and new firmware file name will get added to
the array.

Also update the DT document to remove the firmware attribute and add
description about firmware in the driver documentation.

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

Documentation/arm/keystone/knav-qmss.txt

···
 knav qmss driver provides a set of APIs to drivers to open/close qmss queues,
 allocate descriptor pools, map the descriptors, push/pop to queues etc. For
 details of the available APIs, please refers to include/linux/soc/ti/knav_qmss.h
+
+DT documentation is available at
+Documentation/devicetree/bindings/soc/ti/keystone-navigator-qmss.txt
+
+Accumulator QMSS queues using PDSP firmware
+============================================
+The QMSS PDSP firmware support accumulator channel that can monitor a single
+queue or multiple contiguous queues. drivers/soc/ti/knav_qmss_acc.c is the
+driver that interface with the accumulator PDSP. This configures
+accumulator channels defined in DTS (example in DT documentation) to monitor
+1 or 32 queues per channel. More description on the firmware is available in
+CPPI/QMSS Low Level Driver document (docs/CPPI_QMSS_LLD_SDS.pdf) at
+	git://git.ti.com/keystone-rtos/qmss-lld.git
+
+k2_qmss_pdsp_acc48_k2_le_1_0_0_9.bin firmware supports upto 48 accumulator
+channels. This firmware is available under ti-keystone folder of
+firmware.git at
+   git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
+
+To use copy the firmware image to lib/firmware folder of the initramfs or
+ubifs file system and provide a sym link to k2_qmss_pdsp_acc48_k2_le_1_0_0_9.bin
+in the file system and boot up the kernel. User would see
+
+ "firmware file ks2_qmss_pdsp_acc48.bin downloaded for PDSP"
+
+in the boot up log if loading of firmware to PDSP is successful.

Documentation/devicetree/bindings/soc/ti/keystone-navigator-qmss.txt

···
 		#size-cells = <1>;
 		ranges;
 		pdsp0@0x2a10000 {
-			firmware = "keystone/qmss_pdsp_acc48_k2_le_1_0_0_8.fw";
 			reg = <0x2a10000 0x1000>,
 			      <0x2a0f000 0x100>,
 			      <0x2a0c000 0x3c8>,

drivers/soc/ti/knav_qmss.h

···
 	};
 	void __iomem					*intd;
 	u32 __iomem					*iram;
-	const char					*firmware;
 	u32						id;
 	struct list_head				list;
 };

drivers/soc/ti/knav_qmss_queue.c

···
 	     idx < (kdev)->num_queues_in_use;			\
 	     idx++, inst = knav_queue_idx_to_inst(kdev, idx))
 
+/* All firmware file names end up here. List the firmware file names below.
+ * Newest followed by older ones. Search is done from start of the array
+ * until a firmware file is found.
+ */
+const char *knav_acc_firmwares[] = {"ks2_qmss_pdsp_acc48.bin"};
+
 /**
  * knav_queue_notify: qmss queue notfier call
  *
···
 	struct device *dev = kdev->dev;
 	struct knav_pdsp_info *pdsp;
 	struct device_node *child;
-	int ret;
 
 	for_each_child_of_node(pdsps, child) {
 		pdsp = devm_kzalloc(dev, sizeof(*pdsp), GFP_KERNEL);
···
 			return -ENOMEM;
 		}
 		pdsp->name = knav_queue_find_name(child);
-		ret = of_property_read_string(child, "firmware",
-					      &pdsp->firmware);
-		if (ret < 0 || !pdsp->firmware) {
-			dev_err(dev, "unknown firmware for pdsp %s\n",
-				pdsp->name);
-			devm_kfree(dev, pdsp);
-			continue;
-		}
-		dev_dbg(dev, "pdsp name %s fw name :%s\n", pdsp->name,
-			pdsp->firmware);
-
 		pdsp->iram =
 			knav_queue_map_reg(kdev, child,
 					   KNAV_QUEUE_PDSP_IRAM_REG_INDEX);
···
 		}
 		of_property_read_u32(child, "id", &pdsp->id);
 		list_add_tail(&pdsp->list, &kdev->pdsps);
-		dev_dbg(dev, "added pdsp %s: command %p, iram %p, regs %p, intd %p, firmware %s\n",
+		dev_dbg(dev, "added pdsp %s: command %p, iram %p, regs %p, intd %p\n",
 			pdsp->name, pdsp->command, pdsp->iram, pdsp->regs,
-			pdsp->intd, pdsp->firmware);
+			pdsp->intd);
 	}
 	return 0;
 }
···
 {
 	int i, ret, fwlen;
 	const struct firmware *fw;
+	bool found = false;
 	u32 *fwdata;
 
-	ret = request_firmware(&fw, pdsp->firmware, kdev->dev);
-	if (ret) {
-		dev_err(kdev->dev, "failed to get firmware %s for pdsp %s\n",
-			pdsp->firmware, pdsp->name);
-		return ret;
+	for (i = 0; i < ARRAY_SIZE(knav_acc_firmwares); i++) {
+		if (knav_acc_firmwares[i]) {
+			ret = request_firmware(&fw,
+					       knav_acc_firmwares[i],
+					       kdev->dev);
+			if (!ret) {
+				found = true;
+				break;
+			}
+		}
 	}
+
+	if (!found) {
+		dev_err(kdev->dev, "failed to get firmware for pdsp\n");
+		return -ENODEV;
+	}
+
+	dev_info(kdev->dev, "firmware file %s downloaded for PDSP\n",
+		 knav_acc_firmwares[i]);
+
 	writel_relaxed(pdsp->id + 1, pdsp->command + 0x18);
 	/* download the firmware */
 	fwdata = (u32 *)fw->data;