ASoC: SOF: Drop support for mapped control data

Access through mmapped memory is not supported and it is explicitly
disabled with scontrol->readback_offset = 0; when a control is created.

Remove the dead code and the confusion around this feature.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220330201926.1330402-6-ranjani.sridharan@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/ipc.c

@@ -823,7 +823,6 @@ int snd_sof_ipc_set_get_comp_data(struct snd_sof_control *scontrol, bool set)
 	enum sof_ipc_ctrl_type ctrl_type;
 	struct snd_sof_widget *swidget;
 	bool widget_found = false;
-	size_t send_bytes;
 	u32 ipc_cmd;
 	int err;
 
@@ -847,27 +846,6 @@ int snd_sof_ipc_set_get_comp_data(struct snd_sof_control *scontrol, bool set)
 	if (!swidget->use_count)
 		return 0;
 
-	/* read or write firmware volume */
-	if (scontrol->readback_offset != 0) {
-		/* write/read value header via mmaped region */
-		send_bytes = sizeof(struct sof_ipc_ctrl_value_chan) *
-		cdata->num_elems;
-		if (set)
-			err = snd_sof_dsp_block_write(sdev, SOF_FW_BLK_TYPE_IRAM,
-						      scontrol->readback_offset,
-						      cdata->chanv, send_bytes);
-
-		else
-			err = snd_sof_dsp_block_read(sdev, SOF_FW_BLK_TYPE_IRAM,
-						     scontrol->readback_offset,
-						     cdata->chanv, send_bytes);
-
-		if (err)
-			dev_err_once(sdev->dev, "error: %s TYPE_IRAM failed\n",
-				     set ? "write to" :  "read from");
-		return err;
-	}
-
 	/*
 	 * Select the IPC cmd and the ctrl_type based on the ctrl_cmd and the
 	 * direction

sound/soc/sof/sof-audio.c

@@ -16,9 +16,6 @@ static int sof_kcontrol_setup(struct snd_sof_dev *sdev, struct snd_sof_control *
 {
 	int ret;
 
-	/* reset readback offset for scontrol */
-	scontrol->readback_offset = 0;
-
 	ret = snd_sof_ipc_set_get_comp_data(scontrol, true);
 	if (ret < 0)
 		dev_err(sdev->dev, "error: failed kcontrol value set for widget: %d\n",

sound/soc/sof/sof-audio.h

@@ -247,7 +247,6 @@ struct snd_sof_control {
 	int max_volume_step; /* max volume step for volume_table */
 	int num_channels;
 	unsigned int access;
-	u32 readback_offset; /* offset to mmapped data if used */
 	int info_type;
 	int index; /* pipeline ID */
 	void *priv; /* private data copied from topology */