ALSA: core: Abstract memory alloc helpers

This patch introduces the ops table to each memory allocation type
(SNDRV_DMA_TYPE_XXX) and abstract the handling for the better code
management.  Then we get separate the page allocation, release and
other tasks for each type, especially for the SG buffer.

Each buffer type has now callbacks in the struct snd_malloc_ops, and
the common helper functions call those ops accordingly.  The former
inline code that is specific to SG-buffer is moved into the local
sgbuf.c, and we can simplify the PCM code without details of memory
handling.

Link: https://lore.kernel.org/r/20210609162551.7842-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/memalloc.h

@@ -9,9 +9,8 @@
 #ifndef __SOUND_MEMALLOC_H
 #define __SOUND_MEMALLOC_H
 
-#include <asm/page.h>
-
 struct device;
+struct page;
 
 /*
  * buffer device info
@@ -64,65 +63,17 @@ static inline unsigned int snd_sgbuf_aligned_pages(size_t size)
 	return (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 }
 
-#ifdef CONFIG_SND_DMA_SGBUF
-/*
- * Scatter-Gather generic device pages
- */
-void *snd_malloc_sgbuf_pages(struct device *device,
-			     size_t size, struct snd_dma_buffer *dmab,
-			     size_t *res_size);
-int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab);
-
-struct snd_sg_page {
-	void *buf;
-	dma_addr_t addr;
-};
-
-struct snd_sg_buf {
-	int size;	/* allocated byte size */
-	int pages;	/* allocated pages */
-	int tblsize;	/* allocated table size */
-	struct snd_sg_page *table;	/* address table */
-	struct page **page_table;	/* page table (for vmap/vunmap) */
-	struct device *dev;
-};
-
-/*
- * return the physical address at the corresponding offset
- */
-static inline dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab,
-					   size_t offset)
-{
-	struct snd_sg_buf *sgbuf = dmab->private_data;
-	dma_addr_t addr;
-
-	if (!sgbuf)
-		return dmab->addr + offset;
-	addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
-	addr &= ~((dma_addr_t)PAGE_SIZE - 1);
-	return addr + offset % PAGE_SIZE;
-}
-
-unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
-				      unsigned int ofs, unsigned int size);
-#else
-/* non-SG versions */
-static inline dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab,
-					    size_t offset)
-{
-	return dmab->addr + offset;
-}
-
-#define snd_sgbuf_get_chunk_size(dmab, ofs, size)	(size)
-
-#endif /* CONFIG_SND_DMA_SGBUF */
-
 /* allocate/release a buffer */
 int snd_dma_alloc_pages(int type, struct device *dev, size_t size,
 			struct snd_dma_buffer *dmab);
 int snd_dma_alloc_pages_fallback(int type, struct device *dev, size_t size,
                                  struct snd_dma_buffer *dmab);
 void snd_dma_free_pages(struct snd_dma_buffer *dmab);
 
+dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset);
+struct page *snd_sgbuf_get_page(struct snd_dma_buffer *dmab, size_t offset);
+unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
+				      unsigned int ofs, unsigned int size);
+
 #endif /* __SOUND_MEMALLOC_H */
 

include/sound/pcm.h

@@ -1254,14 +1254,6 @@ static inline int snd_pcm_lib_alloc_vmalloc_32_buffer
 
 #define snd_pcm_get_dma_buf(substream) ((substream)->runtime->dma_buffer_p)
 
-#ifdef CONFIG_SND_DMA_SGBUF
-/*
- * SG-buffer handling
- */
-#define snd_pcm_substream_sgbuf(substream) \
-	snd_pcm_get_dma_buf(substream)->private_data
-#endif /* SND_DMA_SGBUF */
-
 /**
  * snd_pcm_sgbuf_get_addr - Get the DMA address at the corresponding offset
  * @substream: PCM substream