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-rw-r--r--include/sound/pcm.h38
-rw-r--r--sound/core/pcm_memory.c54
2 files changed, 92 insertions, 0 deletions
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index c83a4a79f16b..0ad2d28f2360 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -905,6 +905,44 @@ int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size);
int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream);
+int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
+ size_t size, gfp_t gfp_flags);
+int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream);
+struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
+ unsigned long offset);
+#if 0 /* for kernel-doc */
+/**
+ * snd_pcm_lib_alloc_vmalloc_buffer - allocate virtual DMA buffer
+ * @substream: the substream to allocate the buffer to
+ * @size: the requested buffer size, in bytes
+ *
+ * Allocates the PCM substream buffer using vmalloc(), i.e., the memory is
+ * contiguous in kernel virtual space, but not in physical memory. Use this
+ * if the buffer is accessed by kernel code but not by device DMA.
+ *
+ * Returns 1 if the buffer was changed, 0 if not changed, or a negative error
+ * code.
+ */
+static int snd_pcm_lib_alloc_vmalloc_buffer
+ (struct snd_pcm_substream *substream, size_t size);
+/**
+ * snd_pcm_lib_alloc_vmalloc_32_buffer - allocate 32-bit-addressable buffer
+ * @substream: the substream to allocate the buffer to
+ * @size: the requested buffer size, in bytes
+ *
+ * This function works like snd_pcm_lib_alloc_vmalloc_buffer(), but uses
+ * vmalloc_32(), i.e., the pages are allocated from 32-bit-addressable memory.
+ */
+static int snd_pcm_lib_alloc_vmalloc_32_buffer
+ (struct snd_pcm_substream *substream, size_t size);
+#endif
+#define snd_pcm_lib_alloc_vmalloc_buffer(subs, size) \
+ _snd_pcm_lib_alloc_vmalloc_buffer \
+ (subs, size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO)
+#define snd_pcm_lib_alloc_vmalloc_32_buffer(subs, size) \
+ _snd_pcm_lib_alloc_vmalloc_buffer \
+ (subs, size, GFP_KERNEL | GFP_DMA32 | __GFP_ZERO)
+
#ifdef CONFIG_SND_DMA_SGBUF
/*
* SG-buffer handling
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index caa7796bc2f5..d9727c74b2e1 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -434,3 +434,57 @@ int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
}
EXPORT_SYMBOL(snd_pcm_lib_free_pages);
+
+int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
+ size_t size, gfp_t gfp_flags)
+{
+ struct snd_pcm_runtime *runtime;
+
+ if (PCM_RUNTIME_CHECK(substream))
+ return -EINVAL;
+ runtime = substream->runtime;
+ if (runtime->dma_area) {
+ if (runtime->dma_bytes >= size)
+ return 0; /* already large enough */
+ vfree(runtime->dma_area);
+ }
+ runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
+ if (!runtime->dma_area)
+ return -ENOMEM;
+ runtime->dma_bytes = size;
+ return 1;
+}
+EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
+
+/**
+ * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
+ * @substream: the substream with a buffer allocated by
+ * snd_pcm_lib_alloc_vmalloc_buffer()
+ */
+int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime;
+
+ if (PCM_RUNTIME_CHECK(substream))
+ return -EINVAL;
+ runtime = substream->runtime;
+ vfree(runtime->dma_area);
+ runtime->dma_area = NULL;
+ return 0;
+}
+EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
+
+/**
+ * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
+ * @substream: the substream with a buffer allocated by
+ * snd_pcm_lib_alloc_vmalloc_buffer()
+ * @offset: offset in the buffer
+ *
+ * This function is to be used as the page callback in the PCM ops.
+ */
+struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
+ unsigned long offset)
+{
+ return vmalloc_to_page(substream->runtime->dma_area + offset);
+}
+EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);