ASoC: tegra: tegra210-mixer: Reject too-short fade durations

DURATION_INV_N3 is computed from BIT_ULL(31 + prescalar) divided
by the configured duration, and then written as a 32-bit RAM value.

Durations of 32 samples or less overflow that value, so reject them
and advertise the valid range through the fade duration control.

Validate the ALSA integer control value as a long before storing it in
the driver's u32 duration field. Use a u32 temporary for duration RAM
writes because the largest valid inverse value can still exceed INT_MAX.

Fixes: 3664538 ("ASoC: tegra: Add per-stream Mixer Fade controls")
Signed-off-by: Sheetal <sheetal@nvidia.com>
Link: https://patch.msgid.link/20260519094858.1426057-1-sheetal@nvidia.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Sheetal

sound/soc/tegra/tegra210_mixer.c

@@ -150,7 +150,7 @@ static int tegra210_mixer_configure_gain(struct snd_soc_component *cmpnt,
 
 	/* Write duration parameters */
 	for (i = 0; i < NUM_DURATION_PARMS; i++) {
-		int val;
+		u32 val;
 
 		if (instant_gain) {
 			val = 1;
@@ -181,6 +181,17 @@ static int tegra210_mixer_configure_gain(struct snd_soc_component *cmpnt,
 	return err;
 }
 
+static int tegra210_mixer_fade_duration_info(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = TEGRA210_MIXER_FADE_DURATION_MIN;
+	uinfo->value.integer.max = TEGRA210_MIXER_FADE_DURATION_MAX;
+
+	return 0;
+}
+
 static int tegra210_mixer_get_fade_duration(struct snd_kcontrol *kcontrol,
 					    struct snd_ctl_elem_value *ucontrol)
 {
@@ -202,9 +213,10 @@ static int tegra210_mixer_put_fade_duration(struct snd_kcontrol *kcontrol,
 	struct snd_soc_component *cmpnt = snd_kcontrol_chip(kcontrol);
 	struct tegra210_mixer *mixer = snd_soc_component_get_drvdata(cmpnt);
 	unsigned int id = mc->reg;
-	u32 duration = ucontrol->value.integer.value[0];
+	long duration = ucontrol->value.integer.value[0];
 
-	if (duration == 0 || duration > TEGRA210_MIXER_FADE_DURATION_MAX)
+	if (duration < (long)TEGRA210_MIXER_FADE_DURATION_MIN ||
+	    duration > TEGRA210_MIXER_FADE_DURATION_MAX)
 		return -EINVAL;
 
 	if (mixer->duration[id] == duration)
@@ -614,10 +626,17 @@ static int tegra210_mixer_fade_status_info(struct snd_kcontrol *kcontrol,
 }
 
 #define FADE_CTRL(id)							\
-	SOC_SINGLE_EXT("RX" #id " Fade Duration", (id) - 1, 0,		\
-		       TEGRA210_MIXER_FADE_DURATION_MAX, 0,		\
-		       tegra210_mixer_get_fade_duration,			\
-		       tegra210_mixer_put_fade_duration),		\
+	{								\
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,			\
+		.name = "RX" #id " Fade Duration",			\
+		.info = tegra210_mixer_fade_duration_info,		\
+		.get = tegra210_mixer_get_fade_duration,			\
+		.put = tegra210_mixer_put_fade_duration,			\
+		.private_value = SOC_SINGLE_VALUE((id) - 1, 0,		\
+				TEGRA210_MIXER_FADE_DURATION_MIN,	\
+				TEGRA210_MIXER_FADE_DURATION_MAX,	\
+				0, 0),					\
+	},								\
 	SOC_SINGLE_EXT("RX" #id " Fade Gain", (id) - 1, 0,		\
 		       TEGRA210_MIXER_GAIN_MAX, 0,			\
 		       tegra210_mixer_get_fade_gain,			\

sound/soc/tegra/tegra210_mixer.h

@@ -87,9 +87,11 @@
 
 #define NUM_GAIN_POLY_COEFFS 9
 #define TEGRA210_MIXER_GAIN_MAX			0x20000
-#define TEGRA210_MIXER_FADE_DURATION_MAX	0x7fffffff
 
 #define TEGRA210_MIXER_PRESCALAR	    6
+#define TEGRA210_MIXER_FADE_DURATION_MIN	\
+	(BIT(TEGRA210_MIXER_PRESCALAR - 1) + 1)
+#define TEGRA210_MIXER_FADE_DURATION_MAX	0x7fffffff
 #define TEGRA210_MIXER_FADE_IDLE	    0
 #define TEGRA210_MIXER_FADE_ACTIVE	  1