[PATCH 20/20] ASoC: mediatek: mt8196: Unwind register clock and cache restore failures

[Pengpeng Hou]

mt8196_afe_runtime_resume() first acquires three register-access clocks
and then replays the register cache.  mt8196_afe_enable_reg_rw_clk()
ignores each clock-enable result and leaks already enabled clocks when a
later rate change fails.  Runtime resume also ignores regcache_sync()
and proceeds with 26 MHz requests and main-clock enable.

Make the register-clock helper acquire transactionally and unwind the
successful prefix on every failure.  Return cache replay errors after
restoring cache-only and dirty state and disabling the three
register-access clocks.

The issue was identified via static analysis and manually reviewed.

Fixes: 7384ecab34eb ("ASoC: mediatek: mt8196: support audio clock control")
Fixes: 57513aabfe5b ("ASoC: mediatek: mt8196: add platform driver")

Assisted-by: LLM
Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 sound/soc/mediatek/mt8196/mt8196-afe-clk.c | 27 ++++++++++++++++++----
 sound/soc/mediatek/mt8196/mt8196-afe-pcm.c |  8 ++++++-
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/sound/soc/mediatek/mt8196/mt8196-afe-clk.c b/sound/soc/mediatek/mt8196/mt8196-afe-clk.c
index 286e39f53ae0..ea0835e73510 100644
--- a/sound/soc/mediatek/mt8196/mt8196-afe-clk.c
+++ b/sound/soc/mediatek/mt8196/mt8196-afe-clk.c
@@ -511,26 +511,43 @@ int mt8196_afe_enable_reg_rw_clk(struct mtk_base_afe *afe)
 	int ret;
 
 	/* bus clock for AFE external access, like DRAM */
-	mt8196_afe_enable_clk(afe, afe_priv->clk[MT8196_CLK_TOP_ADSP_SEL]);
+	ret = mt8196_afe_enable_clk(afe, afe_priv->clk[MT8196_CLK_TOP_ADSP_SEL]);
+	if (ret)
+		return ret;
 
 	/* bus clock for AFE internal access, like AFE SRAM */
-	mt8196_afe_enable_clk(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIOINTBUS]);
+	ret = mt8196_afe_enable_clk(afe,
+				    afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIOINTBUS]);
+	if (ret)
+		goto disable_adsp;
+
 	ret = mt8196_afe_set_clk_rate(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIOINTBUS],
 				      MT8196_AFE_26M);
 	if (ret)
-		return ret;
+		goto disable_intbus;
 
 	/* enable audio h clock */
-	mt8196_afe_enable_clk(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIO_H]);
+	ret = mt8196_afe_enable_clk(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIO_H]);
+	if (ret)
+		goto disable_intbus;
+
 	ret = mt8196_afe_set_clk_rate(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIO_H],
 				      MT8196_AFE_26M);
 	if (ret)
-		return ret;
+		goto disable_audio_h;
 
 	/* AFE hw clock */
 	/* IPM2.0: USE HOPPING & 26M */
 	/* set in the regmap_register_patch */
 	return 0;
+
+disable_audio_h:
+	mt8196_afe_disable_clk(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIO_H]);
+disable_intbus:
+	mt8196_afe_disable_clk(afe, afe_priv->clk[MT8196_CLK_VLP_MUX_AUDIOINTBUS]);
+disable_adsp:
+	mt8196_afe_disable_clk(afe, afe_priv->clk[MT8196_CLK_TOP_ADSP_SEL]);
+	return ret;
 }
 
 int mt8196_afe_disable_reg_rw_clk(struct mtk_base_afe *afe)
diff --git a/sound/soc/mediatek/mt8196/mt8196-afe-pcm.c b/sound/soc/mediatek/mt8196/mt8196-afe-pcm.c
index a1ae8322d8b6..49283f242c00 100644
--- a/sound/soc/mediatek/mt8196/mt8196-afe-pcm.c
+++ b/sound/soc/mediatek/mt8196/mt8196-afe-pcm.c
@@ -2222,7 +2222,13 @@ static int mt8196_afe_runtime_resume(struct device *dev)
 		goto skip_regmap;
 	}
 	regcache_cache_only(afe->regmap, false);
-	regcache_sync(afe->regmap);
+	ret = regcache_sync(afe->regmap);
+	if (ret) {
+		regcache_cache_only(afe->regmap, true);
+		regcache_mark_dirty(afe->regmap);
+		mt8196_afe_disable_reg_rw_clk(afe);
+		return ret;
+	}
 
 	/* set audio 26M request */
 	regmap_update_bits(afe->regmap, AFE_SPM_CONTROL_REQ, 0x1, 0x1);
-- 
2.43.0