[PATCH v2 3/4] ALSA: compress_offload: Add SNDRV_COMPRESS_AVAIL64 ioctl

[Joris Verhaegen <verhaegen@google.com>]

Previous patches introduced ioctl for fetching a 64-bit timestamp via
SNDRV_COMPRESS_TSTAMP64. To provide a consistent API, a 64-bit
version of SNDRV_COMPRESS_AVAIL ioctl is required.

Define a new struct snd_compr_avail64, which embeds the 64-bit
timestamp struct, and define the corresponding SNDRV_COMPRESS_AVAIL64
ioctl command in the UAPI header.

Signed-off-by: Joris Verhaegen <verhaegen@google.com>
Tested-by: Joris Verhaegen <verhaegen@google.com>
Reviewed-by: David Li <dvdli@google.com>
Reviewed-by: Miller Liang <millerliang@google.com>
---
 include/uapi/sound/compress_offload.h | 11 ++++
 sound/core/compress_offload.c         | 88 +++++++++++++++++++++------
 2 files changed, 79 insertions(+), 20 deletions(-)

diff --git a/include/uapi/sound/compress_offload.h b/include/uapi/sound/compress_offload.h
index 2758d9ee3d91..48525a87d98f 100644
--- a/include/uapi/sound/compress_offload.h
+++ b/include/uapi/sound/compress_offload.h
@@ -85,6 +85,16 @@ struct snd_compr_avail {
 	struct snd_compr_tstamp tstamp;
 } __attribute__((packed, aligned(4)));
 
+/**
+ * struct snd_compr_avail64 - avail descriptor with tstamp in 64 bit format
+ * @avail: Number of bytes available in ring buffer for writing/reading
+ * @tstamp: timestamp information
+ */
+struct snd_compr_avail64 {
+	__u64 avail;
+	struct snd_compr_tstamp64 tstamp;
+} __attribute__((packed, aligned(4)));
+
 enum snd_compr_direction {
 	SND_COMPRESS_PLAYBACK = 0,
 	SND_COMPRESS_CAPTURE,
@@ -232,6 +242,7 @@ struct snd_compr_task_status {
 #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_AVAIL64		_IOR('C', 0x23, struct snd_compr_avail64)
 #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 40c1e69961b7..78ba86e0d74f 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -257,12 +257,11 @@ static int snd_compr_update_tstamp64(struct snd_compr_stream *stream,
 	return 0;
 }
 
-static size_t snd_compr_calc_avail(struct snd_compr_stream *stream,
-		struct snd_compr_avail *avail)
+static size_t snd_compr_calc_avail_internal(struct snd_compr_stream *stream,
+					    struct snd_compr_avail *avail32,
+					    struct snd_compr_avail64 *avail64)
 {
-	memset(avail, 0, sizeof(*avail));
-	snd_compr_update_tstamp32(stream, &avail->tstamp);
-	/* Still need to return avail even if tstamp can't be filled in */
+	u64 avail;
 
 	if (stream->runtime->total_bytes_available == 0 &&
 			stream->runtime->state == SNDRV_PCM_STATE_SETUP &&
@@ -284,33 +283,68 @@ static size_t snd_compr_calc_avail(struct snd_compr_stream *stream,
 		}
 	}
 
-	avail->avail = stream->runtime->total_bytes_available -
-			stream->runtime->total_bytes_transferred;
+	avail = stream->runtime->total_bytes_available -
+		stream->runtime->total_bytes_transferred;
 	if (stream->direction == SND_COMPRESS_PLAYBACK)
-		avail->avail = stream->runtime->buffer_size - avail->avail;
+		avail = stream->runtime->buffer_size - avail;
+
+	if (avail32)
+		avail32->avail = avail;
+	if (avail64)
+		avail64->avail = avail;
+
+	pr_debug("ret avail %llu as %zu\n", avail, (size_t)avail);
+	return avail;
+}
+
+static size_t snd_compr_calc_avail32(struct snd_compr_stream *stream,
+				     struct snd_compr_avail *avail)
+{
+	memset(avail, 0, sizeof(*avail));
+	snd_compr_update_tstamp32(stream, &avail->tstamp);
+	/* Still need to return avail even if tstamp can't be filled in */
 
-	pr_debug("ret avail as %llu\n", avail->avail);
-	return avail->avail;
+	return snd_compr_calc_avail_internal(stream, avail, NULL);
+}
+
+static size_t snd_compr_calc_avail64(struct snd_compr_stream *stream,
+				     struct snd_compr_avail64 *avail)
+{
+	memset(avail, 0, sizeof(*avail));
+	snd_compr_update_tstamp64(stream, &avail->tstamp);
+	/* Still need to return avail even if tstamp can't be filled in */
+
+	return snd_compr_calc_avail_internal(stream, NULL, avail);
 }
 
 static inline size_t snd_compr_get_avail(struct snd_compr_stream *stream)
 {
 	struct snd_compr_avail avail;
 
-	return snd_compr_calc_avail(stream, &avail);
+	return snd_compr_calc_avail32(stream, &avail);
 }
 
-static int
-snd_compr_ioctl_avail(struct snd_compr_stream *stream, unsigned long arg)
+static int snd_compr_ioctl_avail(struct snd_compr_stream *stream,
+				 unsigned long arg, bool is_64bit)
 {
-	struct snd_compr_avail ioctl_avail;
-	size_t avail;
+	union {
+		struct snd_compr_avail avail32;
+		struct snd_compr_avail64 avail64;
+	} ioctrl_avail_u;
+	size_t avail, ioctrl_avail_size;
 
 	if (stream->direction == SND_COMPRESS_ACCEL)
 		return -EBADFD;
 
-	avail = snd_compr_calc_avail(stream, &ioctl_avail);
-	ioctl_avail.avail = avail;
+	if (is_64bit) {
+		avail = snd_compr_calc_avail64(stream, &ioctrl_avail_u.avail64);
+		ioctrl_avail_u.avail64.avail = avail;
+		ioctrl_avail_size = sizeof(ioctrl_avail_u.avail64);
+	} else {
+		avail = snd_compr_calc_avail32(stream, &ioctrl_avail_u.avail32);
+		ioctrl_avail_u.avail32.avail = avail;
+		ioctrl_avail_size = sizeof(ioctrl_avail_u.avail32);
+	}
 
 	switch (stream->runtime->state) {
 	case SNDRV_PCM_STATE_OPEN:
@@ -321,12 +355,24 @@ snd_compr_ioctl_avail(struct snd_compr_stream *stream, unsigned long arg)
 		break;
 	}
 
-	if (copy_to_user((__u64 __user *)arg,
-				&ioctl_avail, sizeof(ioctl_avail)))
+	if (copy_to_user((__u64 __user *)arg, &ioctrl_avail_u,
+			 ioctrl_avail_size))
 		return -EFAULT;
 	return 0;
 }
 
+static int snd_compr_ioctl_avail32(struct snd_compr_stream *stream,
+				   unsigned long arg)
+{
+	return snd_compr_ioctl_avail(stream, arg, false);
+}
+
+static int snd_compr_ioctl_avail64(struct snd_compr_stream *stream,
+				   unsigned long arg)
+{
+	return snd_compr_ioctl_avail(stream, arg, true);
+}
+
 static int snd_compr_write_data(struct snd_compr_stream *stream,
 	       const char __user *buf, size_t count)
 {
@@ -1393,7 +1439,9 @@ static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 	case _IOC_NR(SNDRV_COMPRESS_TSTAMP64):
 		return snd_compr_tstamp64(stream, arg);
 	case _IOC_NR(SNDRV_COMPRESS_AVAIL):
-		return snd_compr_ioctl_avail(stream, arg);
+		return snd_compr_ioctl_avail32(stream, arg);
+	case _IOC_NR(SNDRV_COMPRESS_AVAIL64):
+		return snd_compr_ioctl_avail64(stream, arg);
 	case _IOC_NR(SNDRV_COMPRESS_PAUSE):
 		return snd_compr_pause(stream);
 	case _IOC_NR(SNDRV_COMPRESS_RESUME):
-- 
2.50.0.727.gbf7dc18ff4-goog