ALSA: core: Implement compress page allocation and free routines

Add simple malloc and free methods for memory management for compress
streams. Based on snd_pcm_lib_malloc_pages and snd_pcm_lib_free_pages
implementation.
Signed-off-by: Divya Prakash <divya1.prakash@intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200218143924.10565-3-cezary.rojewski@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/sound/compress_driver.h

@@ -67,6 +67,7 @@ struct snd_compr_runtime {
  * @metadata_set: metadata set flag, true when set
  * @next_track: has userspace signal next track transition, true when set
  * @private_data: pointer to DSP private data
+ * @dma_buffer: allocated buffer if any
  */
 struct snd_compr_stream {
 	const char *name;
@@ -78,6 +79,7 @@ struct snd_compr_stream {
 	bool metadata_set;
 	bool next_track;
 	void *private_data;
+	struct snd_dma_buffer dma_buffer;
 };
 
 /**
@@ -212,6 +214,9 @@ snd_compr_set_runtime_buffer(struct snd_compr_stream *stream,
 	}
 }
 
+int snd_compr_malloc_pages(struct snd_compr_stream *stream, size_t size);
+int snd_compr_free_pages(struct snd_compr_stream *stream);
+
 int snd_compr_stop_error(struct snd_compr_stream *stream,
 			 snd_pcm_state_t state);
 

sound/core/compress_offload.c

@@ -488,6 +488,48 @@ snd_compr_get_codec_caps(struct snd_compr_stream *stream, unsigned long arg)
 }
 #endif /* !COMPR_CODEC_CAPS_OVERFLOW */
 
+int snd_compr_malloc_pages(struct snd_compr_stream *stream, size_t size)
+{
+	struct snd_dma_buffer *dmab;
+	int ret;
+
+	if (snd_BUG_ON(!(stream) || !(stream)->runtime))
+		return -EINVAL;
+	dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
+	if (!dmab)
+		return -ENOMEM;
+	dmab->dev = stream->dma_buffer.dev;
+	ret = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev, size, dmab);
+	if (ret < 0) {
+		kfree(dmab);
+		return ret;
+	}
+
+	snd_compr_set_runtime_buffer(stream, dmab);
+	stream->runtime->dma_bytes = size;
+	return 1;
+}
+EXPORT_SYMBOL(snd_compr_malloc_pages);
+
+int snd_compr_free_pages(struct snd_compr_stream *stream)
+{
+	struct snd_compr_runtime *runtime = stream->runtime;
+
+	if (snd_BUG_ON(!(stream) || !(stream)->runtime))
+		return -EINVAL;
+	if (runtime->dma_area == NULL)
+		return 0;
+	if (runtime->dma_buffer_p != &stream->dma_buffer) {
+		/* It's a newly allocated buffer. Release it now. */
+		snd_dma_free_pages(runtime->dma_buffer_p);
+		kfree(runtime->dma_buffer_p);
+	}
+
+	snd_compr_set_runtime_buffer(stream, NULL);
+	return 0;
+}
+EXPORT_SYMBOL(snd_compr_free_pages);
+
 /* revisit this with snd_pcm_preallocate_xxx */
 static int snd_compr_allocate_buffer(struct snd_compr_stream *stream,
 		struct snd_compr_params *params)