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firmware: cs_dsp: Cleanup debugfs for wmfw and bin file name

PATCH In review Richard Fitzgerald 2 participants 4 messages Nov 20, 2025 – Nov 21, 2025

Subsystems (2)
Sound Cirrus logic DSP firmware driver
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Richard Fitzgerald

author maintainer
#0 lore raw

cover firmware: cs_dsp: Cleanup debugfs for wmfw and bin file name

These two patches improve the implementation of the debugfs files for the wmfw and bin file names. First patch removes duplicated code. Second patch replaces the old clunkiness of storing the filename with an appended \n. The \n can be appended when the file is read, to keep the stored string sane.

Richard Fitzgerald (2):
firmware: cs_dsp: Factor out common debugfs string read
firmware: cs_dsp: Append \n to debugfs string during read

 drivers/firmware/cirrus/cs_dsp.c       | 56 ++++++++++++--------------
 include/linux/firmware/cirrus/cs_dsp.h |  4 +-
 2 files changed, 28 insertions(+), 32 deletions(-)
Signature · 1 line
2.47.3
author maintainer
#1 lore raw

PATCH 1/2 firmware: cs_dsp: Factor out common debugfs string read

cs_dsp_debugfs_wmfw_read() and cs_dsp_debugfs_bin_read() were identical except for which struct member they printed. Move all this duplicated code into a common function cs_dsp_debugfs_string_read().

The check for dsp->booted has been removed because this is redundant. The two strings are set when the DSP is booted and cleared when the DSP is powered-down.

Access to the string char * must be protected by the pwr_lock mutex. The string is passed into cs_dsp_debugfs_string_read() as a pointer to the char * so that the mutex lock can also be factored out into cs_dsp_debugfs_string_read().

wmfw_file_name and bin_file_name members of struct cs_dsp have been changed to const char *. It makes for a better API to pass a const pointer into cs_dsp_debugfs_string_read().

Signed-off-by Richard Fitzgerald <[email protected]>
---
 drivers/firmware/cirrus/cs_dsp.c       | 45 ++++++++++++--------------
 include/linux/firmware/cirrus/cs_dsp.h |  4 +--
 2 files changed, 23 insertions(+), 26 deletions(-)
drivers/firmware/cirrus/cs_dsp.c +21 -24
index f51047d8ea64..58e41751dbc1 100644
@@ -9,6 +9,7 @@
  *                         Cirrus Logic International Semiconductor Ltd.
  */
 
+#include <linux/cleanup.h>
 #include <linux/ctype.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>

@@ -410,24 +411,30 @@ static void cs_dsp_debugfs_clear(struct cs_dsp *dsp)
 	dsp->bin_file_name = NULL;
 }
 
+static ssize_t cs_dsp_debugfs_string_read(struct cs_dsp *dsp,
+					  char __user *user_buf,
+					  size_t count, loff_t *ppos,
+					  const char **pstr)
+{
+	const char *str;
+
+	scoped_guard(mutex, &dsp->pwr_lock) {
+		str = *pstr;
+		if (!str)
+			return 0;
+
+		return simple_read_from_buffer(user_buf, count, ppos, str, strlen(str));
+	}
+}
+
 static ssize_t cs_dsp_debugfs_wmfw_read(struct file *file,
 					char __user *user_buf,
 					size_t count, loff_t *ppos)
 {
 	struct cs_dsp *dsp = file->private_data;
-	ssize_t ret;
 
-	mutex_lock(&dsp->pwr_lock);
-
-	if (!dsp->wmfw_file_name || !dsp->booted)
-		ret = 0;
-	else
-		ret = simple_read_from_buffer(user_buf, count, ppos,
-					      dsp->wmfw_file_name,
-					      strlen(dsp->wmfw_file_name));
-
-	mutex_unlock(&dsp->pwr_lock);
-	return ret;
+	return cs_dsp_debugfs_string_read(dsp, user_buf, count, ppos,
+					  &dsp->wmfw_file_name);
 }
 
 static ssize_t cs_dsp_debugfs_bin_read(struct file *file,

@@ -435,19 +442,9 @@ static ssize_t cs_dsp_debugfs_bin_read(struct file *file,
 				       size_t count, loff_t *ppos)
 {
 	struct cs_dsp *dsp = file->private_data;
-	ssize_t ret;
 
-	mutex_lock(&dsp->pwr_lock);
-
-	if (!dsp->bin_file_name || !dsp->booted)
-		ret = 0;
-	else
-		ret = simple_read_from_buffer(user_buf, count, ppos,
-					      dsp->bin_file_name,
-					      strlen(dsp->bin_file_name));
-
-	mutex_unlock(&dsp->pwr_lock);
-	return ret;
+	return cs_dsp_debugfs_string_read(dsp, user_buf, count, ppos,
+					  &dsp->bin_file_name);
 }
 
 static const struct {
include/linux/firmware/cirrus/cs_dsp.h +2 -2
index a66eb7624730..69959032f8f5 100644
@@ -188,8 +188,8 @@ struct cs_dsp {
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_root;
-	char *wmfw_file_name;
-	char *bin_file_name;
+	const char *wmfw_file_name;
+	const char *bin_file_name;
 #endif
 };
Signature · 1 line
2.47.3
author maintainer
#2 lore raw

PATCH 2/2 firmware: cs_dsp: Append \n to debugfs string during read

In reply to Richard Fitzgerald

Append the terminating \n to the string during the debugfs file read instead of creating a string that already has a trailing \n.

This avoids the ugly behaviour of having to include a trailing \n in the filenames stored to wmfw_file_name and bin_file_name in struct cs_dsp.

Signed-off-by Richard Fitzgerald <[email protected]>
---
 drivers/firmware/cirrus/cs_dsp.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)
drivers/firmware/cirrus/cs_dsp.c +8 -9
index 58e41751dbc1..9acdcd75928a 100644
@@ -389,18 +389,14 @@ EXPORT_SYMBOL_NS_GPL(cs_dsp_mem_region_name, "FW_CS_DSP");
 #ifdef CONFIG_DEBUG_FS
 static void cs_dsp_debugfs_save_wmfwname(struct cs_dsp *dsp, const char *s)
 {
-	char *tmp = kasprintf(GFP_KERNEL, "%s\n", s);
-
 	kfree(dsp->wmfw_file_name);
-	dsp->wmfw_file_name = tmp;
+	dsp->wmfw_file_name = kstrdup(s, GFP_KERNEL);
 }
 
 static void cs_dsp_debugfs_save_binname(struct cs_dsp *dsp, const char *s)
 {
-	char *tmp = kasprintf(GFP_KERNEL, "%s\n", s);
-
 	kfree(dsp->bin_file_name);
-	dsp->bin_file_name = tmp;
+	dsp->bin_file_name = kstrdup(s, GFP_KERNEL);
 }
 
 static void cs_dsp_debugfs_clear(struct cs_dsp *dsp)

@@ -416,13 +412,16 @@ static ssize_t cs_dsp_debugfs_string_read(struct cs_dsp *dsp,
 					  size_t count, loff_t *ppos,
 					  const char **pstr)
 {
-	const char *str;
+	const char *str __free(kfree) = NULL;
 
 	scoped_guard(mutex, &dsp->pwr_lock) {
-		str = *pstr;
-		if (!str)
+		if (!*pstr)
 			return 0;
 
+		str = kasprintf(GFP_KERNEL, "%s\n", *pstr);
+		if (!str)
+			return -ENOMEM;
+
 		return simple_read_from_buffer(user_buf, count, ppos, str, strlen(str));
 	}
 }
Signature · 1 line
2.47.3
#3 lore raw
In reply to Richard Fitzgerald
Quoted 11 lines · Richard Fitzgerald

These two patches improve the implementation of the debugfs files for the wmfw and bin file names. First patch removes duplicated code. Second patch replaces the old clunkiness of storing the filename with an appended \n. The \n can be appended when the file is read, to keep the stored string sane.

Richard Fitzgerald (2):
firmware: cs_dsp: Factor out common debugfs string read
firmware: cs_dsp: Append \n to debugfs string during read

[...]

Applied to

https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/2] firmware: cs_dsp: Factor out common debugfs string read

      commit: 78cfd833bc04c0398ca4cfc64704350aebe4d4c2
[2/2] firmware: cs_dsp: Append \n to debugfs string during read
      commit: 3045e29d248bde2a68da425498a656093ee0df69

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark