ASoC: wm_adsp: Report when a control write changes the value

Merge series from Richard Fitzgerald <rf@opensource.cirrus.com>:

Writing a firmware control should be returning 1 if the control value
changed, so these two patches add that.

Though this is an ALSA requirement it is also useful for non-ALSA clients
of cs_dsp to know if the control value changed, so the main handling is
implemented in cs_dsp. TLV controls are specifically an ALSA thing so they
are handled specially in wm_adsp.

Simon Trimmer (2):
  firmware: cs_dsp: cs_dsp_coeff_write_ctrl() should report changed
  ASoC: wm_adsp: Return whether changed when writing controls

 drivers/firmware/cirrus/cs_dsp.c | 17 ++++++++++++-----
 sound/soc/codecs/wm_adsp.c       | 27 ++++++++++++++++++---------
 2 files changed, 30 insertions(+), 14 deletions(-)

--
2.30.2

drivers/firmware/cirrus/cs_dsp.c

@@ -752,7 +752,7 @@ static int cs_dsp_coeff_write_ctrl_raw(struct cs_dsp_coeff_ctl *ctl,
  *
  * Must be called with pwr_lock held.
  *
- * Return: Zero for success, a negative number on error.
+ * Return: < 0 on error, 1 when the control value changed and 0 when it has not.
  */
 int cs_dsp_coeff_write_ctrl(struct cs_dsp_coeff_ctl *ctl,
 			    unsigned int off, const void *buf, size_t len)
@@ -767,16 +767,23 @@ int cs_dsp_coeff_write_ctrl(struct cs_dsp_coeff_ctl *ctl,
 	if (len + off * sizeof(u32) > ctl->len)
 		return -EINVAL;
 
-	if (ctl->flags & WMFW_CTL_FLAG_VOLATILE)
+	if (ctl->flags & WMFW_CTL_FLAG_VOLATILE) {
 		ret = -EPERM;
-	else if (buf != ctl->cache)
-		memcpy(ctl->cache + off * sizeof(u32), buf, len);
+	} else if (buf != ctl->cache) {
+		if (memcmp(ctl->cache + off * sizeof(u32), buf, len))
+			memcpy(ctl->cache + off * sizeof(u32), buf, len);
+		else
+			return 0;
+	}
 
 	ctl->set = 1;
 	if (ctl->enabled && ctl->dsp->running)
 		ret = cs_dsp_coeff_write_ctrl_raw(ctl, off, buf, len);
 
-	return ret;
+	if (ret < 0)
+		return ret;
+
+	return 1;
 }
 EXPORT_SYMBOL_GPL(cs_dsp_coeff_write_ctrl);
 

sound/soc/codecs/wm_adsp.c

@@ -19,6 +19,7 @@
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
+#include <linux/vmalloc.h>
 #include <linux/workqueue.h>
 #include <linux/debugfs.h>
 #include <sound/core.h>
@@ -419,16 +420,21 @@ static int wm_coeff_tlv_put(struct snd_kcontrol *kctl,
 		(struct soc_bytes_ext *)kctl->private_value;
 	struct wm_coeff_ctl *ctl = bytes_ext_to_ctl(bytes_ext);
 	struct cs_dsp_coeff_ctl *cs_ctl = ctl->cs_ctl;
+	void *scratch;
 	int ret = 0;
 
-	mutex_lock(&cs_ctl->dsp->pwr_lock);
+	scratch = vmalloc(size);
+	if (!scratch)
+		return -ENOMEM;
 
-	if (copy_from_user(cs_ctl->cache, bytes, size))
+	if (copy_from_user(scratch, bytes, size)) {
 		ret = -EFAULT;
-	else
-		ret = cs_dsp_coeff_write_ctrl(cs_ctl, 0, cs_ctl->cache, size);
-
-	mutex_unlock(&cs_ctl->dsp->pwr_lock);
+	} else {
+		mutex_lock(&cs_ctl->dsp->pwr_lock);
+		ret = cs_dsp_coeff_write_ctrl(cs_ctl, 0, scratch, size);
+		mutex_unlock(&cs_ctl->dsp->pwr_lock);
+	}
+	vfree(scratch);
 
 	return ret;
 }
@@ -455,7 +461,10 @@ static int wm_coeff_put_acked(struct snd_kcontrol *kctl,
 
 	mutex_unlock(&cs_ctl->dsp->pwr_lock);
 
-	return ret;
+	if (ret < 0)
+		return ret;
+
+	return 1;
 }
 
 static int wm_coeff_get(struct snd_kcontrol *kctl,
@@ -682,10 +691,10 @@ int wm_adsp_write_ctl(struct wm_adsp *dsp, const char *name, int type,
 	int ret;
 
 	ret = cs_dsp_coeff_write_ctrl(cs_ctl, 0, buf, len);
-	if (ret)
+	if (ret < 0)
 		return ret;
 
-	if (cs_ctl->flags & WMFW_CTL_FLAG_SYS)
+	if (ret == 0 || (cs_ctl->flags & WMFW_CTL_FLAG_SYS))
 		return 0;
 
 	ctl = cs_ctl->priv;