ASoC: SOF: Xtensa: dump ar registers to restore call stack

On Xtensa platform ar0 is for caller address and ar1 is for stack
address. The ar register dump can be used to rebuild call stack with
FW elf file by debug tools.
Signed-off-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20230919092416.4137-2-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/xtensa/core.c

@@ -132,6 +132,17 @@ static void xtensa_stack(struct snd_sof_dev *sdev, const char *level, void *oops
 				   buf, sizeof(buf), false);
 		dev_printk(level, sdev->dev, "0x%08x: %s\n", stack_ptr + i * 4, buf);
 	}
+
+	if (!xoops->plat_hdr.numaregs)
+		return;
+
+	dev_printk(level, sdev->dev, "AR registers:\n");
+	/* the number of ar registers is a multiple of 4 */
+	for (i = 0; i < xoops->plat_hdr.numaregs; i += 4) {
+		hex_dump_to_buffer(xoops->ar + i, 16, 16, 4,
+				   buf, sizeof(buf), false);
+		dev_printk(level, sdev->dev, "%#x: %s\n", i * 4, buf);
+	}
 }
 
 const struct dsp_arch_ops sof_xtensa_arch_ops = {