[PATCH v3 2/3] ALSA: compress_offload: Add SNDRV_COMPRESS_TSTAMP64 ioctl

[Joris Verhaegen]

The previous patch introduced the internal infrastructure for handling
64-bit timestamps. This patch exposes this capability to user-space.

Define the new ioctl command SNDRV_COMPRESS_TSTAMP64, which allows
applications to fetch the overflow-safe struct snd_compr_tstamp64.

The ioctl dispatch table is updated to handle the new command by
calling a new snd_compr_tstamp64 handler, while the legacy path is
renamed to snd_compr_tstamp32 for clarity.

This patch bumps the SNDRV_COMPRESS_VERSION to 0.4.0.

Reviewed-by: Miller Liang <millerliang at google.com>
Tested-by: Joris Verhaegen <verhaegen at google.com>
Signed-off-by: Joris Verhaegen <verhaegen at google.com>
---
 include/uapi/sound/compress_offload.h |  5 +++--
 sound/core/compress_offload.c         | 19 +++++++++++++------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/include/uapi/sound/compress_offload.h b/include/uapi/sound/compress_offload.h
index abd0ea3f86ee..70b8921601f9 100644
--- a/include/uapi/sound/compress_offload.h
+++ b/include/uapi/sound/compress_offload.h
@@ -13,8 +13,7 @@
 #include <sound/asound.h>
 #include <sound/compress_params.h>
 
-
-#define SNDRV_COMPRESS_VERSION SNDRV_PROTOCOL_VERSION(0, 3, 0)
+#define SNDRV_COMPRESS_VERSION SNDRV_PROTOCOL_VERSION(0, 4, 0)
 /**
  * struct snd_compressed_buffer - compressed buffer
  * @fragment_size: size of buffer fragment in bytes
@@ -208,6 +207,7 @@ struct snd_compr_task_status {
  * Note: only codec params can be changed runtime and stream params cant be
  * SNDRV_COMPRESS_GET_PARAMS: Query codec params
  * SNDRV_COMPRESS_TSTAMP: get the current timestamp value
+ * SNDRV_COMPRESS_TSTAMP64: get the current timestamp value in 64 bit format
  * SNDRV_COMPRESS_AVAIL: get the current buffer avail value.
  * This also queries the tstamp properties
  * SNDRV_COMPRESS_PAUSE: Pause the running stream
@@ -230,6 +230,7 @@ struct snd_compr_task_status {
 						 struct snd_compr_metadata)
 #define SNDRV_COMPRESS_TSTAMP		_IOR('C', 0x20, struct snd_compr_tstamp)
 #define SNDRV_COMPRESS_AVAIL		_IOR('C', 0x21, struct snd_compr_avail)
+#define SNDRV_COMPRESS_TSTAMP64		_IOR('C', 0x22, struct snd_compr_tstamp64)
 #define SNDRV_COMPRESS_PAUSE		_IO('C', 0x30)
 #define SNDRV_COMPRESS_RESUME		_IO('C', 0x31)
 #define SNDRV_COMPRESS_START		_IO('C', 0x32)
diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index d3164aa07158..445220fdb6a0 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -736,18 +736,23 @@ snd_compr_set_metadata(struct snd_compr_stream *stream, unsigned long arg)
 	return retval;
 }
 
-static inline int
-snd_compr_tstamp(struct snd_compr_stream *stream, unsigned long arg)
+static inline int snd_compr_tstamp(struct snd_compr_stream *stream,
+				   unsigned long arg, bool is_32bit)
 {
 	struct snd_compr_tstamp64 tstamp64 = { 0 };
 	struct snd_compr_tstamp tstamp32 = { 0 };
+	const void *copy_from = &tstamp64;
+	size_t copy_size = sizeof(tstamp64);
 	int ret;
 
 	ret = snd_compr_update_tstamp(stream, &tstamp64);
 	if (ret == 0) {
-		snd_compr_tstamp32_from_64(&tstamp32, &tstamp64);
-		ret = copy_to_user((struct snd_compr_tstamp __user *)arg,
-				   &tstamp32, sizeof(tstamp32)) ?
+		if (is_32bit) {
+			snd_compr_tstamp32_from_64(&tstamp32, &tstamp64);
+			copy_from = &tstamp32;
+			copy_size = sizeof(tstamp32);
+		}
+		ret = copy_to_user((void __user *)arg, copy_from, copy_size) ?
 			      -EFAULT :
 			      0;
 	}
@@ -1327,7 +1332,9 @@ static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 
 	switch (cmd) {
 	case SNDRV_COMPRESS_TSTAMP:
-		return snd_compr_tstamp(stream, arg);
+		return snd_compr_tstamp(stream, arg, true);
+	case SNDRV_COMPRESS_TSTAMP64:
+		return snd_compr_tstamp(stream, arg, false);
 	case SNDRV_COMPRESS_AVAIL:
 		return snd_compr_ioctl_avail(stream, arg);
 	case SNDRV_COMPRESS_PAUSE:
-- 
2.50.1.470.g6ba607880d-goog