ASoC: SOF: harden the FW boot sequence

For ACPI platforms, FW booting fails on the first try after
unloading and reloasing the SOF module. But trying to
reset the DSP and then boot the FW again helps fix the problem.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Author: ranj063

sound/soc/sof/loader.c

@@ -14,6 +14,8 @@
 #include <sound/sof.h>
 #include "ops.h"
 
+#define FW_BOOT_RETRIES 5
+
 static int get_ext_windows(struct snd_sof_dev *sdev,
 			   struct sof_ipc_ext_data_hdr *ext_hdr)
 {
@@ -507,6 +509,7 @@ int snd_sof_run_firmware(struct snd_sof_dev *sdev)
 {
 	int ret;
 	int init_core_mask;
+	int i;
 
 	init_waitqueue_head(&sdev->boot_wait);
 	sdev->boot_complete = false;
@@ -532,25 +535,51 @@ int snd_sof_run_firmware(struct snd_sof_dev *sdev)
 
 	dev_dbg(sdev->dev, "booting DSP firmware\n");
 
-	/* boot the firmware on the DSP */
-	ret = snd_sof_dsp_run(sdev);
-	if (ret < 0) {
-		dev_err(sdev->dev, "error: failed to reset DSP\n");
-		return ret;
-	}
+	for (i = 0; i < FW_BOOT_RETRIES; i++) {
+		/* prepare the DSP for FW loading for subsequent tries */
+		if (i > 0) {
+			ret = snd_sof_dsp_reset(sdev);
+			if (ret < 0) {
+				dev_err(sdev->dev, "error: failed to reset DSP\n");
+				return ret;
+			}
+		}
+
+		/* boot the firmware on the DSP */
+		ret = snd_sof_dsp_run(sdev);
+		if (ret < 0) {
+			if (i == FW_BOOT_RETRIES) {
+				dev_err(sdev->dev, "error: failed to reset DSP\n");
+				return ret;
+			}
+
+			/* try again */
+			continue;
+		}
+
+		init_core_mask = ret;
+
+		/* now wait for the DSP to boot */
+		ret = wait_event_timeout(sdev->boot_wait, sdev->boot_complete,
+					 msecs_to_jiffies(sdev->boot_timeout));
+		if (ret == 0) {
+			if (i == FW_BOOT_RETRIES) {
+				dev_err(sdev->dev,
+					"error: firmware boot failure after %d iterations\n",
+					i);
+				snd_sof_dsp_dbg_dump(sdev, SOF_DBG_REGS |
+						     SOF_DBG_MBOX |
+						     SOF_DBG_TEXT |
+						     SOF_DBG_PCI);
+
+				/* FW_READY msg ignored from now on */
+				sdev->boot_complete = true;
+				return -EIO;
+			}
+		}
 
-	init_core_mask = ret;
-
-	/* now wait for the DSP to boot */
-	ret = wait_event_timeout(sdev->boot_wait, sdev->boot_complete,
-				 msecs_to_jiffies(sdev->boot_timeout));
-	if (ret == 0) {
-		dev_err(sdev->dev, "error: firmware boot failure\n");
-		snd_sof_dsp_dbg_dump(sdev, SOF_DBG_REGS | SOF_DBG_MBOX |
-			SOF_DBG_TEXT | SOF_DBG_PCI);
-		/* after this point FW_READY msg should be ignored */
-		sdev->boot_complete = true;
-		return -EIO;
+		/* FW boot successful */
+		break;
 	}
 
 	dev_info(sdev->dev, "firmware boot complete\n");