[PATCH 2/2] ASoC: Intel: Skylake: Correct the handling of fmt_config flexible array

[Peter Ujfalusi]

The struct nhlt_format's fmt_config is a flexible array, it must not be
used as normal array.
When moving to the next nhlt_fmt_cfg we need to take into account the data
behind the ->config.caps (indicated by ->config.size).

The logic of the code also changed: it is no longer saves the _last_
fmt_cfg for all found rates.

At the same time prepare the code for converting the fmt_config to a u8
flexible array to prevent further abuse.

Fixes: bc2bd45b1f7f3 ("ASoC: Intel: Skylake: Parse nhlt and register clock device")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi at linux.intel.com>
---
 sound/soc/intel/skylake/skl-nhlt.c | 37 ++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/sound/soc/intel/skylake/skl-nhlt.c b/sound/soc/intel/skylake/skl-nhlt.c
index 366f7bd9bc02..deb7b820325e 100644
--- a/sound/soc/intel/skylake/skl-nhlt.c
+++ b/sound/soc/intel/skylake/skl-nhlt.c
@@ -111,11 +111,12 @@ static void skl_get_ssp_clks(struct skl_dev *skl, struct skl_ssp_clk *ssp_clks,
 	if (fmt->fmt_count == 0)
 		return;
 
+	fmt_cfg = (struct nhlt_fmt_cfg *)fmt->fmt_config;
 	for (i = 0; i < fmt->fmt_count; i++) {
+		struct nhlt_fmt_cfg *saved_fmt_cfg = fmt_cfg;
 		bool present = false;
 
-		fmt_cfg = &fmt->fmt_config[i];
-		wav_fmt = &fmt_cfg->fmt_ext;
+		wav_fmt = &saved_fmt_cfg->fmt_ext;
 
 		channels = wav_fmt->fmt.channels;
 		bps = wav_fmt->fmt.bits_per_sample;
@@ -133,12 +134,18 @@ static void skl_get_ssp_clks(struct skl_dev *skl, struct skl_ssp_clk *ssp_clks,
 		 * derive the rate.
 		 */
 		for (j = i; j < fmt->fmt_count; j++) {
-			fmt_cfg = &fmt->fmt_config[j];
-			wav_fmt = &fmt_cfg->fmt_ext;
+			struct nhlt_fmt_cfg *tmp_fmt_cfg = fmt_cfg;
+
+			wav_fmt = &tmp_fmt_cfg->fmt_ext;
 			if ((fs == wav_fmt->fmt.samples_per_sec) &&
-			   (bps == wav_fmt->fmt.bits_per_sample))
+			   (bps == wav_fmt->fmt.bits_per_sample)) {
 				channels = max_t(u16, channels,
 						wav_fmt->fmt.channels);
+				saved_fmt_cfg = tmp_fmt_cfg;
+			}
+			/* Move to the next nhlt_fmt_cfg */
+			tmp_fmt_cfg = (struct nhlt_fmt_cfg *)(tmp_fmt_cfg->config.caps +
+							      tmp_fmt_cfg->config.size);
 		}
 
 		rate = channels * bps * fs;
@@ -154,8 +161,11 @@ static void skl_get_ssp_clks(struct skl_dev *skl, struct skl_ssp_clk *ssp_clks,
 
 		/* Fill rate and parent for sclk/sclkfs */
 		if (!present) {
+			struct nhlt_fmt_cfg *first_fmt_cfg;
+
+			first_fmt_cfg = (struct nhlt_fmt_cfg *)fmt->fmt_config;
 			i2s_config_ext = (struct skl_i2s_config_blob_ext *)
-						fmt->fmt_config[0].config.caps;
+						first_fmt_cfg->config.caps;
 
 			/* MCLK Divider Source Select */
 			if (is_legacy_blob(i2s_config_ext->hdr.sig)) {
@@ -169,6 +179,9 @@ static void skl_get_ssp_clks(struct skl_dev *skl, struct skl_ssp_clk *ssp_clks,
 
 			parent = skl_get_parent_clk(clk_src);
 
+			/* Move to the next nhlt_fmt_cfg */
+			fmt_cfg = (struct nhlt_fmt_cfg *)(fmt_cfg->config.caps +
+							  fmt_cfg->config.size);
 			/*
 			 * Do not copy the config data if there is no parent
 			 * clock available for this clock source select
@@ -177,9 +190,9 @@ static void skl_get_ssp_clks(struct skl_dev *skl, struct skl_ssp_clk *ssp_clks,
 				continue;
 
 			sclk[id].rate_cfg[rate_index].rate = rate;
-			sclk[id].rate_cfg[rate_index].config = fmt_cfg;
+			sclk[id].rate_cfg[rate_index].config = saved_fmt_cfg;
 			sclkfs[id].rate_cfg[rate_index].rate = rate;
-			sclkfs[id].rate_cfg[rate_index].config = fmt_cfg;
+			sclkfs[id].rate_cfg[rate_index].config = saved_fmt_cfg;
 			sclk[id].parent_name = parent->name;
 			sclkfs[id].parent_name = parent->name;
 
@@ -193,13 +206,13 @@ static void skl_get_mclk(struct skl_dev *skl, struct skl_ssp_clk *mclk,
 {
 	struct skl_i2s_config_blob_ext *i2s_config_ext;
 	struct skl_i2s_config_blob_legacy *i2s_config;
-	struct nhlt_specific_cfg *fmt_cfg;
+	struct nhlt_fmt_cfg *fmt_cfg;
 	struct skl_clk_parent_src *parent;
 	u32 clkdiv, div_ratio;
 	u8 clk_src;
 
-	fmt_cfg = &fmt->fmt_config[0].config;
-	i2s_config_ext = (struct skl_i2s_config_blob_ext *)fmt_cfg->caps;
+	fmt_cfg = (struct nhlt_fmt_cfg *)fmt->fmt_config;
+	i2s_config_ext = (struct skl_i2s_config_blob_ext *)fmt_cfg->config.caps;
 
 	/* MCLK Divider Source Select and divider */
 	if (is_legacy_blob(i2s_config_ext->hdr.sig)) {
@@ -228,7 +241,7 @@ static void skl_get_mclk(struct skl_dev *skl, struct skl_ssp_clk *mclk,
 		return;
 
 	mclk[id].rate_cfg[0].rate = parent->rate/div_ratio;
-	mclk[id].rate_cfg[0].config = &fmt->fmt_config[0];
+	mclk[id].rate_cfg[0].config = fmt_cfg;
 	mclk[id].parent_name = parent->name;
 }
 
-- 
2.37.0