[PATCH 0/3] ALSA: Support for non-contiguous and non-coherent page allocations

[PATCH 0/3] ALSA: Support for non-contiguous and non-coherent page allocations

[Takashi Iwai]

Hi,

here is a patch set to add the support for non-contiguous and
non-coherent page allocations to the ALSA core memalloc helpers.
Currently no driver is using, but this also gave a nice cleanup for
the existing SG-buffer helpers on x86.


Takashi

===

Takashi Iwai (3):
  ALSA: memalloc: Support for non-contiguous page allocation
  ALSA: memalloc: Support for non-coherent page allocation
  ALSA: memalloc: Convert x86 SG-buffer handling with non-contiguous
    type

 include/sound/memalloc.h    |  61 +++++++++--
 sound/core/Makefile         |   1 -
 sound/core/memalloc.c       | 207 +++++++++++++++++++++++++++++++++---
 sound/core/memalloc_local.h |   1 +
 sound/core/pcm_lib.c        |   3 +
 sound/core/pcm_local.h      |   7 ++
 sound/core/pcm_memory.c     |  13 ++-
 sound/core/pcm_native.c     |  16 +++
 sound/core/sgbuf.c          | 201 ----------------------------------
 9 files changed, 282 insertions(+), 228 deletions(-)
 delete mode 100644 sound/core/sgbuf.c

-- 
2.26.2

[PATCH 1/3] ALSA: memalloc: Support for non-contiguous page allocation

[Takashi Iwai]

This patch adds the support for allocation of non-contiguous DMA pages
in the common memalloc helper.  It's another SG-buffer type, but
unlike the existing one, this is directional and requires the explicit
sync / invalidation of dirty pages on non-coherent architectures.

For this enhancement, the following points are changed:
- snd_dma_device stores the DMA direction.
- snd_dma_device stores need_sync flag indicating whether the explicit
  sync is required or not.
- A new variant of helper functions, snd_dma_alloc_dir_pages() and
  *_all() are introduced; the old snd_dma_alloc_pages() and *_all()
  kept as just wrappers with DMA_BIDIRECTIONAL.
- A new helper snd_dma_buffer_sync() is introduced; this gets called
  in the appropriate places.
- A new allocation type, SNDRV_DMA_TYPE_NONCONTIG, is introduced.

When the driver allocates pages with this new type, and it may require
the SNDRV_PCM_INFO_EXPLICIT_SYNC flag set to the PCM hardware.info for
taking the full control of PCM applptr and hwptr changes (that implies
disabling the mmap of control/status data).  When the buffer
allocation is managed by snd_pcm_set_managed_buffer(), this flag is
automatically set depending on the result of dma_need_sync()
internally.  Otherwise, if the buffer is managed manually, the driver
has to set the flag explicitly, too.

The explicit sync between CPU and device for non-coherent memory is
performed at the points before and after read/write transfer as well
as the applptr/hwptr syncptr ioctl.  In the case of mmap mode,
user-space is supposed to call the syncptr ioctl with the hwptr flag
to update and fetch the status at first; this corresponds to CPU-sync.
Then user-space advances the applptr via syncptr ioctl again with
applptr flag, and this corresponds to the device sync with flushing.

Other than the DMA direction and the explicit sync, the usage of this
new buffer type is almost equivalent with the existing
SNDRV_DMA_TYPE_DEV_SG; you can get the page and the address via
snd_sgbuf_get_page() and snd_sgbuf_get_addr(), also calculate the
continuous pages via snd_sgbuf_get_chunk_size().

For those SG-page handling, the non-contig type shares the same ops
with the vmalloc handler.  As we do always vmap the SG pages at first,
the actual address can be deduced from the vmapped address easily
without iterating the SG-list.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/memalloc.h    |  46 +++++++++++++--
 sound/core/memalloc.c       | 109 +++++++++++++++++++++++++++++++++---
 sound/core/memalloc_local.h |   1 +
 sound/core/pcm_lib.c        |   3 +
 sound/core/pcm_local.h      |   7 +++
 sound/core/pcm_memory.c     |  13 ++++-
 sound/core/pcm_native.c     |  16 ++++++
 7 files changed, 180 insertions(+), 15 deletions(-)

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index b197e3f431c1..1457eba1ac53 100644
--- a/include/sound/memalloc.h
+++ b/include/sound/memalloc.h
@@ -9,16 +9,20 @@
 #ifndef __SOUND_MEMALLOC_H
 #define __SOUND_MEMALLOC_H
 
+#include <linux/dma-direction.h>
 #include <asm/page.h>
 
 struct device;
 struct vm_area_struct;
+struct sg_table;
 
 /*
  * buffer device info
  */
 struct snd_dma_device {
 	int type;			/* SNDRV_DMA_TYPE_XXX */
+	enum dma_data_direction dir;	/* DMA direction */
+	bool need_sync;			/* explicit sync needed? */
 	struct device *dev;		/* generic device */
 };
 
@@ -45,6 +49,7 @@ struct snd_dma_device {
 #define SNDRV_DMA_TYPE_DEV_IRAM	SNDRV_DMA_TYPE_DEV
 #endif
 #define SNDRV_DMA_TYPE_VMALLOC		7	/* vmalloc'ed buffer */
+#define SNDRV_DMA_TYPE_NONCONTIG	8	/* non-coherent SG buffer */
 
 /*
  * info for buffer allocation
@@ -66,22 +71,55 @@ static inline unsigned int snd_sgbuf_aligned_pages(size_t size)
 }
 
 /* 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_dir_pages(int type, struct device *dev,
+			    enum dma_data_direction dir, size_t size,
+			    struct snd_dma_buffer *dmab);
+
+static inline int snd_dma_alloc_pages(int type, struct device *dev,
+				      size_t size, struct snd_dma_buffer *dmab)
+{
+	return snd_dma_alloc_dir_pages(type, dev, DMA_BIDIRECTIONAL, size, 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);
 int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab,
 			struct vm_area_struct *area);
 
+enum snd_dma_sync_mode { SNDRV_DMA_SYNC_CPU, SNDRV_DMA_SYNC_DEVICE };
+#ifdef CONFIG_HAS_DMA
+void snd_dma_buffer_sync(struct snd_dma_buffer *dmab,
+			 enum snd_dma_sync_mode mode);
+#else
+static inline void snd_dma_buffer_sync(struct snd_dma_buffer *dmab,
+				       enum snd_dma_sync_mode mode) {}
+#endif
+
+void snd_dma_buffer_sync(struct snd_dma_buffer *dmab,
+			 enum snd_dma_sync_mode mode);
+
 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);
 
 /* device-managed memory allocator */
-struct snd_dma_buffer *snd_devm_alloc_pages(struct device *dev, int type,
-					    size_t size);
+struct snd_dma_buffer *snd_devm_alloc_dir_pages(struct device *dev, int type,
+						enum dma_data_direction dir,
+						size_t size);
+
+static inline struct snd_dma_buffer *
+snd_devm_alloc_pages(struct device *dev, int type, size_t size)
+{
+	return snd_devm_alloc_dir_pages(dev, type, DMA_BIDIRECTIONAL, size);
+}
+
+static inline struct sg_table *
+snd_dma_noncontig_sg_table(struct snd_dma_buffer *dmab)
+{
+	return dmab->private_data;
+}
 
 #endif /* __SOUND_MEMALLOC_H */
 
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index c7c943c661e6..11f9a68bf94c 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -10,6 +10,7 @@
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
 #include <linux/genalloc.h>
+#include <linux/highmem.h>
 #include <linux/vmalloc.h>
 #ifdef CONFIG_X86
 #include <asm/set_memory.h>
@@ -39,9 +40,11 @@ static void *__snd_dma_alloc_pages(struct snd_dma_buffer *dmab, size_t size)
 }
 
 /**
- * snd_dma_alloc_pages - allocate the buffer area according to the given type
+ * snd_dma_alloc_dir_pages - allocate the buffer area according to the given
+ *	type and direction
  * @type: the DMA buffer type
  * @device: the device pointer
+ * @dir: DMA direction
  * @size: the buffer size to allocate
  * @dmab: buffer allocation record to store the allocated data
  *
@@ -51,8 +54,9 @@ static void *__snd_dma_alloc_pages(struct snd_dma_buffer *dmab, size_t size)
  * Return: Zero if the buffer with the given size is allocated successfully,
  * otherwise a negative value on error.
  */
-int snd_dma_alloc_pages(int type, struct device *device, size_t size,
-			struct snd_dma_buffer *dmab)
+int snd_dma_alloc_dir_pages(int type, struct device *device,
+			    enum dma_data_direction dir, size_t size,
+			    struct snd_dma_buffer *dmab)
 {
 	if (WARN_ON(!size))
 		return -ENXIO;
@@ -62,6 +66,7 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size,
 	size = PAGE_ALIGN(size);
 	dmab->dev.type = type;
 	dmab->dev.dev = device;
+	dmab->dev.dir = dir;
 	dmab->bytes = 0;
 	dmab->addr = 0;
 	dmab->private_data = NULL;
@@ -71,7 +76,7 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size,
 	dmab->bytes = size;
 	return 0;
 }
-EXPORT_SYMBOL(snd_dma_alloc_pages);
+EXPORT_SYMBOL(snd_dma_alloc_dir_pages);
 
 /**
  * snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
@@ -129,9 +134,10 @@ static void __snd_release_pages(struct device *dev, void *res)
 }
 
 /**
- * snd_devm_alloc_pages - allocate the buffer and manage with devres
+ * snd_devm_alloc_dir_pages - allocate the buffer and manage with devres
  * @dev: the device pointer
  * @type: the DMA buffer type
+ * @dir: DMA direction
  * @size: the buffer size to allocate
  *
  * Allocate buffer pages depending on the given type and manage using devres.
@@ -144,7 +150,8 @@ static void __snd_release_pages(struct device *dev, void *res)
  * The function returns the snd_dma_buffer object at success, or NULL if failed.
  */
 struct snd_dma_buffer *
-snd_devm_alloc_pages(struct device *dev, int type, size_t size)
+snd_devm_alloc_dir_pages(struct device *dev, int type,
+			 enum dma_data_direction dir, size_t size)
 {
 	struct snd_dma_buffer *dmab;
 	int err;
@@ -157,7 +164,7 @@ snd_devm_alloc_pages(struct device *dev, int type, size_t size)
 	if (!dmab)
 		return NULL;
 
-	err = snd_dma_alloc_pages(type, dev, size, dmab);
+	err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
 	if (err < 0) {
 		devres_free(dmab);
 		return NULL;
@@ -166,7 +173,7 @@ snd_devm_alloc_pages(struct device *dev, int type, size_t size)
 	devres_add(dev, dmab);
 	return dmab;
 }
-EXPORT_SYMBOL_GPL(snd_devm_alloc_pages);
+EXPORT_SYMBOL_GPL(snd_devm_alloc_dir_pages);
 
 /**
  * snd_dma_buffer_mmap - perform mmap of the given DMA buffer
@@ -185,6 +192,26 @@ int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab,
 }
 EXPORT_SYMBOL(snd_dma_buffer_mmap);
 
+#ifdef CONFIG_HAS_DMA
+/**
+ * snd_dma_buffer_sync - sync DMA buffer between CPU and device
+ * @dmab: buffer allocation information
+ * @mod: sync mode
+ */
+void snd_dma_buffer_sync(struct snd_dma_buffer *dmab,
+			 enum snd_dma_sync_mode mode)
+{
+	const struct snd_malloc_ops *ops;
+
+	if (!dmab || !dmab->dev.need_sync)
+		return;
+	ops = snd_dma_get_ops(dmab);
+	if (ops && ops->sync)
+		ops->sync(dmab, mode);
+}
+EXPORT_SYMBOL_GPL(snd_dma_buffer_sync);
+#endif /* CONFIG_HAS_DMA */
+
 /**
  * snd_sgbuf_get_addr - return the physical address at the corresponding offset
  * @dmab: buffer allocation information
@@ -468,6 +495,71 @@ static const struct snd_malloc_ops snd_dma_wc_ops = {
 	.mmap = snd_dma_wc_mmap,
 };
 #endif /* CONFIG_X86 */
+
+/*
+ * Non-contiguous pages allocator
+ */
+static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	struct sg_table *sgt;
+	void *p;
+
+	sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
+				      DEFAULT_GFP, 0);
+	if (!sgt)
+		return NULL;
+	dmab->dev.need_sync = dma_need_sync(dmab->dev.dev, dmab->dev.dir);
+	p = dma_vmap_noncontiguous(dmab->dev.dev, size, sgt);
+	if (p)
+		dmab->private_data = sgt;
+	else
+		dma_free_noncontiguous(dmab->dev.dev, size, sgt, dmab->dev.dir);
+	return p;
+}
+
+static void snd_dma_noncontig_free(struct snd_dma_buffer *dmab)
+{
+	dma_vunmap_noncontiguous(dmab->dev.dev, dmab->area);
+	dma_free_noncontiguous(dmab->dev.dev, dmab->bytes, dmab->private_data,
+			       dmab->dev.dir);
+}
+
+static int snd_dma_noncontig_mmap(struct snd_dma_buffer *dmab,
+				  struct vm_area_struct *area)
+{
+	return dma_mmap_noncontiguous(dmab->dev.dev, area,
+				      dmab->bytes, dmab->private_data);
+}
+
+static void snd_dma_noncontig_sync(struct snd_dma_buffer *dmab,
+				   enum snd_dma_sync_mode mode)
+{
+	if (mode == SNDRV_DMA_SYNC_CPU) {
+		if (dmab->dev.dir == DMA_TO_DEVICE)
+			return;
+		dma_sync_sgtable_for_cpu(dmab->dev.dev, dmab->private_data,
+					 dmab->dev.dir);
+		invalidate_kernel_vmap_range(dmab->area, dmab->bytes);
+	} else {
+		if (dmab->dev.dir == DMA_FROM_DEVICE)
+			return;
+		flush_kernel_vmap_range(dmab->area, dmab->bytes);
+		dma_sync_sgtable_for_device(dmab->dev.dev, dmab->private_data,
+					    dmab->dev.dir);
+	}
+}
+
+static const struct snd_malloc_ops snd_dma_noncontig_ops = {
+	.alloc = snd_dma_noncontig_alloc,
+	.free = snd_dma_noncontig_free,
+	.mmap = snd_dma_noncontig_mmap,
+	.sync = snd_dma_noncontig_sync,
+	/* re-use vmalloc helpers for get_* ops */
+	.get_addr = snd_dma_vmalloc_get_addr,
+	.get_page = snd_dma_vmalloc_get_page,
+	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
+};
+
 #endif /* CONFIG_HAS_DMA */
 
 /*
@@ -479,6 +571,7 @@ static const struct snd_malloc_ops *dma_ops[] = {
 #ifdef CONFIG_HAS_DMA
 	[SNDRV_DMA_TYPE_DEV] = &snd_dma_dev_ops,
 	[SNDRV_DMA_TYPE_DEV_WC] = &snd_dma_wc_ops,
+	[SNDRV_DMA_TYPE_NONCONTIG] = &snd_dma_noncontig_ops,
 #ifdef CONFIG_GENERIC_ALLOCATOR
 	[SNDRV_DMA_TYPE_DEV_IRAM] = &snd_dma_iram_ops,
 #endif /* CONFIG_GENERIC_ALLOCATOR */
diff --git a/sound/core/memalloc_local.h b/sound/core/memalloc_local.h
index 9f2e0a608b49..a6f3a87194da 100644
--- a/sound/core/memalloc_local.h
+++ b/sound/core/memalloc_local.h
@@ -10,6 +10,7 @@ struct snd_malloc_ops {
 	unsigned int (*get_chunk_size)(struct snd_dma_buffer *dmab,
 				       unsigned int ofs, unsigned int size);
 	int (*mmap)(struct snd_dma_buffer *dmab, struct vm_area_struct *area);
+	void (*sync)(struct snd_dma_buffer *dmab, enum snd_dma_sync_mode mode);
 };
 
 #ifdef CONFIG_SND_DMA_SGBUF
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index a144a3f68e9e..aa630d1e2f46 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -106,6 +106,7 @@ void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_ufram
 		frames -= transfer;
 		ofs = 0;
 	}
+	snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 }
 
 #ifdef CONFIG_SND_DEBUG
@@ -2256,8 +2257,10 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
 			goto _end_unlock;
 		}
 		snd_pcm_stream_unlock_irq(substream);
+		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_CPU);
 		err = writer(substream, appl_ofs, data, offset, frames,
 			     transfer);
+		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 		snd_pcm_stream_lock_irq(substream);
 		if (err < 0)
 			goto _end_unlock;
diff --git a/sound/core/pcm_local.h b/sound/core/pcm_local.h
index fe9689b8a6a6..ecb21697ae3a 100644
--- a/sound/core/pcm_local.h
+++ b/sound/core/pcm_local.h
@@ -73,4 +73,11 @@ void snd_pcm_sync_stop(struct snd_pcm_substream *substream, bool sync_irq);
 		for ((subs) = (pcm)->streams[str].substream; (subs); \
 		     (subs) = (subs)->next)
 
+static inline void snd_pcm_dma_buffer_sync(struct snd_pcm_substream *substream,
+					   enum snd_dma_sync_mode mode)
+{
+	if (substream->runtime->info & SNDRV_PCM_INFO_EXPLICIT_SYNC)
+		snd_dma_buffer_sync(snd_pcm_get_dma_buf(substream), mode);
+}
+
 #endif	/* __SOUND_CORE_PCM_LOCAL_H */
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index 7fbd1ccbb5b0..b70ce3b69ab4 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -32,15 +32,20 @@ module_param(max_alloc_per_card, ulong, 0644);
 MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
 
 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
-			  size_t size, struct snd_dma_buffer *dmab)
+			  int str, size_t size, struct snd_dma_buffer *dmab)
 {
+	enum dma_data_direction dir;
 	int err;
 
 	if (max_alloc_per_card &&
 	    card->total_pcm_alloc_bytes + size > max_alloc_per_card)
 		return -ENOMEM;
 
-	err = snd_dma_alloc_pages(type, dev, size, dmab);
+	if (str == SNDRV_PCM_STREAM_PLAYBACK)
+		dir = DMA_TO_DEVICE;
+	else
+		dir = DMA_FROM_DEVICE;
+	err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
 	if (!err) {
 		mutex_lock(&card->memory_mutex);
 		card->total_pcm_alloc_bytes += dmab->bytes;
@@ -77,7 +82,7 @@ static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
 
 	do {
 		err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
-				     size, dmab);
+				     substream->stream, size, dmab);
 		if (err != -ENOMEM)
 			return err;
 		if (no_fallback)
@@ -177,6 +182,7 @@ static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
 			if (do_alloc_pages(card,
 					   substream->dma_buffer.dev.type,
 					   substream->dma_buffer.dev.dev,
+					   substream->stream,
 					   size, &new_dmab) < 0) {
 				buffer->error = -ENOMEM;
 				pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
@@ -418,6 +424,7 @@ int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
 		if (do_alloc_pages(card,
 				   substream->dma_buffer.dev.type,
 				   substream->dma_buffer.dev.dev,
+				   substream->stream,
 				   size, dmab) < 0) {
 			kfree(dmab);
 			pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 46c643db18eb..0c0a825af773 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -2685,6 +2685,13 @@ int snd_pcm_open_substream(struct snd_pcm *pcm, int stream,
 		goto error;
 	}
 
+	/* automatically set EXPLICIT_SYNC flag in the managed mode whenever
+	 * the DMA buffer requires it
+	 */
+	if (substream->managed_buffer_alloc &&
+	    substream->dma_buffer.dev.need_sync)
+		substream->runtime->hw.info |= SNDRV_PCM_INFO_EXPLICIT_SYNC;
+
 	*rsubstream = substream;
 	return 0;
 
@@ -2912,6 +2919,8 @@ static snd_pcm_sframes_t snd_pcm_rewind(struct snd_pcm_substream *substream,
 		ret = rewind_appl_ptr(substream, frames,
 				      snd_pcm_hw_avail(substream));
 	snd_pcm_stream_unlock_irq(substream);
+	if (ret >= 0)
+		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 	return ret;
 }
 
@@ -2929,6 +2938,8 @@ static snd_pcm_sframes_t snd_pcm_forward(struct snd_pcm_substream *substream,
 		ret = forward_appl_ptr(substream, frames,
 				       snd_pcm_avail(substream));
 	snd_pcm_stream_unlock_irq(substream);
+	if (ret >= 0)
+		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 	return ret;
 }
 
@@ -2939,6 +2950,7 @@ static int snd_pcm_hwsync(struct snd_pcm_substream *substream)
 	snd_pcm_stream_lock_irq(substream);
 	err = do_pcm_hwsync(substream);
 	snd_pcm_stream_unlock_irq(substream);
+	snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_CPU);
 	return err;
 }
 		
@@ -3000,6 +3012,8 @@ static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
 	sync_ptr.s.status.suspended_state = status->suspended_state;
 	sync_ptr.s.status.audio_tstamp = status->audio_tstamp;
 	snd_pcm_stream_unlock_irq(substream);
+	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL))
+		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 	if (copy_to_user(_sync_ptr, &sync_ptr, sizeof(sync_ptr)))
 		return -EFAULT;
 	return 0;
@@ -3096,6 +3110,8 @@ static int snd_pcm_ioctl_sync_ptr_compat(struct snd_pcm_substream *substream,
 	sstatus.suspended_state = status->suspended_state;
 	sstatus.audio_tstamp = status->audio_tstamp;
 	snd_pcm_stream_unlock_irq(substream);
+	if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
+		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 	if (put_user(sstatus.state, &src->s.status.state) ||
 	    put_user(sstatus.hw_ptr, &src->s.status.hw_ptr) ||
 	    put_user(sstatus.tstamp.tv_sec, &src->s.status.tstamp_sec) ||
-- 
2.26.2

[PATCH 2/3] ALSA: memalloc: Support for non-coherent page allocation

[Takashi Iwai]

Following after the addition of non-contiguous pages, this patch adds
the new contiguous non-coherent page allocation to the standard
memalloc helper.  Like the previous non-contig type, this non-coherent
type is also directional and requires the explicit sync, too.  Hence
the driver using this type of buffer may need to set
SNDRV_PCM_INFO_EXPLICIT_SYNC flag to the PCM hardware.info as well,
unless it's set up in the managed mode.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/memalloc.h |  1 +
 sound/core/memalloc.c    | 47 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index 1457eba1ac53..0bdaa6753282 100644
--- a/include/sound/memalloc.h
+++ b/include/sound/memalloc.h
@@ -50,6 +50,7 @@ struct snd_dma_device {
 #endif
 #define SNDRV_DMA_TYPE_VMALLOC		7	/* vmalloc'ed buffer */
 #define SNDRV_DMA_TYPE_NONCONTIG	8	/* non-coherent SG buffer */
+#define SNDRV_DMA_TYPE_NONCOHERENT	9	/* non-coherent buffer */
 
 /*
  * info for buffer allocation
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 11f9a68bf94c..99681e651223 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -560,6 +560,52 @@ static const struct snd_malloc_ops snd_dma_noncontig_ops = {
 	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
 };
 
+/*
+ * Non-coherent pages allocator
+ */
+static void *snd_dma_noncoherent_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	dmab->dev.need_sync = dma_need_sync(dmab->dev.dev, dmab->dev.dir);
+	return dma_alloc_noncoherent(dmab->dev.dev, size, &dmab->addr,
+				     dmab->dev.dir, DEFAULT_GFP);
+}
+
+static void snd_dma_noncoherent_free(struct snd_dma_buffer *dmab)
+{
+	dma_free_noncoherent(dmab->dev.dev, dmab->bytes, dmab->area,
+			     dmab->addr, dmab->dev.dir);
+}
+
+static int snd_dma_noncoherent_mmap(struct snd_dma_buffer *dmab,
+				    struct vm_area_struct *area)
+{
+	area->vm_page_prot = vm_get_page_prot(area->vm_flags);
+	return dma_mmap_pages(dmab->dev.dev, area,
+			      area->vm_end - area->vm_start,
+			      virt_to_page(dmab->area));
+}
+
+static void snd_dma_noncoherent_sync(struct snd_dma_buffer *dmab,
+				     enum snd_dma_sync_mode mode)
+{
+	if (mode == SNDRV_DMA_SYNC_CPU) {
+		if (dmab->dev.dir != DMA_TO_DEVICE)
+			dma_sync_single_for_cpu(dmab->dev.dev, dmab->addr,
+						dmab->bytes, dmab->dev.dir);
+	} else {
+		if (dmab->dev.dir != DMA_FROM_DEVICE)
+			dma_sync_single_for_device(dmab->dev.dev, dmab->addr,
+						   dmab->bytes, dmab->dev.dir);
+	}
+}
+
+static const struct snd_malloc_ops snd_dma_noncoherent_ops = {
+	.alloc = snd_dma_noncoherent_alloc,
+	.free = snd_dma_noncoherent_free,
+	.mmap = snd_dma_noncoherent_mmap,
+	.sync = snd_dma_noncoherent_sync,
+};
+
 #endif /* CONFIG_HAS_DMA */
 
 /*
@@ -572,6 +618,7 @@ static const struct snd_malloc_ops *dma_ops[] = {
 	[SNDRV_DMA_TYPE_DEV] = &snd_dma_dev_ops,
 	[SNDRV_DMA_TYPE_DEV_WC] = &snd_dma_wc_ops,
 	[SNDRV_DMA_TYPE_NONCONTIG] = &snd_dma_noncontig_ops,
+	[SNDRV_DMA_TYPE_NONCOHERENT] = &snd_dma_noncoherent_ops,
 #ifdef CONFIG_GENERIC_ALLOCATOR
 	[SNDRV_DMA_TYPE_DEV_IRAM] = &snd_dma_iram_ops,
 #endif /* CONFIG_GENERIC_ALLOCATOR */
-- 
2.26.2

[PATCH 3/3] ALSA: memalloc: Convert x86 SG-buffer handling with non-contiguous type

[Takashi Iwai]

We've had an x86-specific SG-buffer handling code, but now it can be
merged gracefully with the standard non-contiguous DMA pages.

After the migration, SNDRV_DMA_TYPE_DMA_SG becomes identical with
SNDRV_DMA_TYPE_NONCONTIG on x86, while others still fall back to
SNDRV_DMA_TYPE_DEV.

The remaining problem is about the SG-buffer with WC pages: the DMA
core stuff on x86 doesn't treat it well, so we still need some special
handling to manipulate the page attribute manually.  The mmap handler
for SNDRV_DMA_TYPE_DEV_SG_WC still returns -ENOENT intentionally for
the fallback to the default handler.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/memalloc.h |  14 +--
 sound/core/Makefile      |   1 -
 sound/core/memalloc.c    |  51 +++++++++-
 sound/core/sgbuf.c       | 201 ---------------------------------------
 4 files changed, 54 insertions(+), 213 deletions(-)
 delete mode 100644 sound/core/sgbuf.c

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index 0bdaa6753282..df615052dad4 100644
--- a/include/sound/memalloc.h
+++ b/include/sound/memalloc.h
@@ -36,13 +36,6 @@ struct snd_dma_device {
 #define SNDRV_DMA_TYPE_CONTINUOUS	1	/* continuous no-DMA memory */
 #define SNDRV_DMA_TYPE_DEV		2	/* generic device continuous */
 #define SNDRV_DMA_TYPE_DEV_WC		5	/* continuous write-combined */
-#ifdef CONFIG_SND_DMA_SGBUF
-#define SNDRV_DMA_TYPE_DEV_SG		3	/* generic device SG-buffer */
-#define SNDRV_DMA_TYPE_DEV_WC_SG	6	/* SG write-combined */
-#else
-#define SNDRV_DMA_TYPE_DEV_SG	SNDRV_DMA_TYPE_DEV /* no SG-buf support */
-#define SNDRV_DMA_TYPE_DEV_WC_SG	SNDRV_DMA_TYPE_DEV_WC
-#endif
 #ifdef CONFIG_GENERIC_ALLOCATOR
 #define SNDRV_DMA_TYPE_DEV_IRAM		4	/* generic device iram-buffer */
 #else
@@ -51,6 +44,13 @@ struct snd_dma_device {
 #define SNDRV_DMA_TYPE_VMALLOC		7	/* vmalloc'ed buffer */
 #define SNDRV_DMA_TYPE_NONCONTIG	8	/* non-coherent SG buffer */
 #define SNDRV_DMA_TYPE_NONCOHERENT	9	/* non-coherent buffer */
+#ifdef CONFIG_SND_DMA_SGBUF
+#define SNDRV_DMA_TYPE_DEV_SG		SNDRV_DMA_TYPE_NONCONTIG
+#define SNDRV_DMA_TYPE_DEV_WC_SG	6	/* SG write-combined */
+#else
+#define SNDRV_DMA_TYPE_DEV_SG	SNDRV_DMA_TYPE_DEV /* no SG-buf support */
+#define SNDRV_DMA_TYPE_DEV_WC_SG	SNDRV_DMA_TYPE_DEV_WC
+#endif
 
 /*
  * info for buffer allocation
diff --git a/sound/core/Makefile b/sound/core/Makefile
index d774792850f3..2762f03d9b7b 100644
--- a/sound/core/Makefile
+++ b/sound/core/Makefile
@@ -17,7 +17,6 @@ snd-$(CONFIG_SND_JACK)	  += ctljack.o jack.o
 snd-pcm-y := pcm.o pcm_native.o pcm_lib.o pcm_misc.o \
 		pcm_memory.o memalloc.o
 snd-pcm-$(CONFIG_SND_PCM_TIMER) += pcm_timer.o
-snd-pcm-$(CONFIG_SND_DMA_SGBUF) += sgbuf.o
 snd-pcm-$(CONFIG_SND_PCM_ELD) += pcm_drm_eld.o
 snd-pcm-$(CONFIG_SND_PCM_IEC958) += pcm_iec958.o
 
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 99681e651223..acdebecf1a2e 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -560,6 +560,50 @@ static const struct snd_malloc_ops snd_dma_noncontig_ops = {
 	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
 };
 
+/* x86-specific SG-buffer with WC pages */
+#ifdef CONFIG_SND_DMA_SGBUF
+#define vmalloc_to_virt(v) (unsigned long)page_to_virt(vmalloc_to_page(v))
+
+static void *snd_dma_sg_wc_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	void *p = snd_dma_noncontig_alloc(dmab, size);
+	size_t ofs;
+
+	if (!p)
+		return NULL;
+	for (ofs = 0; ofs < size; ofs += PAGE_SIZE)
+		set_memory_uc(vmalloc_to_virt(p + ofs), 1);
+	return p;
+}
+
+static void snd_dma_sg_wc_free(struct snd_dma_buffer *dmab)
+{
+	size_t ofs;
+
+	for (ofs = 0; ofs < dmab->bytes; ofs += PAGE_SIZE)
+		set_memory_wb(vmalloc_to_virt(dmab->area + ofs), 1);
+	snd_dma_noncontig_free(dmab);
+}
+
+static int snd_dma_sg_wc_mmap(struct snd_dma_buffer *dmab,
+			      struct vm_area_struct *area)
+{
+	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
+	/* FIXME: dma_mmap_noncontiguous() works? */
+	return -ENOENT; /* continue with the default mmap handler */
+}
+
+const struct snd_malloc_ops snd_dma_sg_wc_ops = {
+	.alloc = snd_dma_sg_wc_alloc,
+	.free = snd_dma_sg_wc_free,
+	.mmap = snd_dma_sg_wc_mmap,
+	.sync = snd_dma_noncontig_sync,
+	.get_addr = snd_dma_vmalloc_get_addr,
+	.get_page = snd_dma_vmalloc_get_page,
+	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
+};
+#endif /* CONFIG_SND_DMA_SGBUF */
+
 /*
  * Non-coherent pages allocator
  */
@@ -619,14 +663,13 @@ static const struct snd_malloc_ops *dma_ops[] = {
 	[SNDRV_DMA_TYPE_DEV_WC] = &snd_dma_wc_ops,
 	[SNDRV_DMA_TYPE_NONCONTIG] = &snd_dma_noncontig_ops,
 	[SNDRV_DMA_TYPE_NONCOHERENT] = &snd_dma_noncoherent_ops,
+#ifdef CONFIG_SND_DMA_SGBUF
+	[SNDRV_DMA_TYPE_DEV_WC_SG] = &snd_dma_sg_wc_ops,
+#endif
 #ifdef CONFIG_GENERIC_ALLOCATOR
 	[SNDRV_DMA_TYPE_DEV_IRAM] = &snd_dma_iram_ops,
 #endif /* CONFIG_GENERIC_ALLOCATOR */
 #endif /* CONFIG_HAS_DMA */
-#ifdef CONFIG_SND_DMA_SGBUF
-	[SNDRV_DMA_TYPE_DEV_SG] = &snd_dma_sg_ops,
-	[SNDRV_DMA_TYPE_DEV_WC_SG] = &snd_dma_sg_ops,
-#endif
 };
 
 static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab)
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
deleted file mode 100644
index 8352a5cdb19f..000000000000
--- a/sound/core/sgbuf.c
+++ /dev/null
@@ -1,201 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Scatter-Gather buffer
- *
- *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
- */
-
-#include <linux/slab.h>
-#include <linux/mm.h>
-#include <linux/vmalloc.h>
-#include <linux/export.h>
-#include <sound/memalloc.h>
-#include "memalloc_local.h"
-
-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;
-};
-
-/* table entries are align to 32 */
-#define SGBUF_TBL_ALIGN		32
-#define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)
-
-static void snd_dma_sg_free(struct snd_dma_buffer *dmab)
-{
-	struct snd_sg_buf *sgbuf = dmab->private_data;
-	struct snd_dma_buffer tmpb;
-	int i;
-
-	if (!sgbuf)
-		return;
-
-	vunmap(dmab->area);
-	dmab->area = NULL;
-
-	tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
-		tmpb.dev.type = SNDRV_DMA_TYPE_DEV_WC;
-	tmpb.dev.dev = sgbuf->dev;
-	for (i = 0; i < sgbuf->pages; i++) {
-		if (!(sgbuf->table[i].addr & ~PAGE_MASK))
-			continue; /* continuous pages */
-		tmpb.area = sgbuf->table[i].buf;
-		tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
-		tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
-		snd_dma_free_pages(&tmpb);
-	}
-
-	kfree(sgbuf->table);
-	kfree(sgbuf->page_table);
-	kfree(sgbuf);
-	dmab->private_data = NULL;
-}
-
-#define MAX_ALLOC_PAGES		32
-
-static void *snd_dma_sg_alloc(struct snd_dma_buffer *dmab, size_t size)
-{
-	struct snd_sg_buf *sgbuf;
-	unsigned int i, pages, chunk, maxpages;
-	struct snd_dma_buffer tmpb;
-	struct snd_sg_page *table;
-	struct page **pgtable;
-	int type = SNDRV_DMA_TYPE_DEV;
-	pgprot_t prot = PAGE_KERNEL;
-	void *area;
-
-	dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
-	if (!sgbuf)
-		return NULL;
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG) {
-		type = SNDRV_DMA_TYPE_DEV_WC;
-#ifdef pgprot_noncached
-		prot = pgprot_noncached(PAGE_KERNEL);
-#endif
-	}
-	sgbuf->dev = dmab->dev.dev;
-	pages = snd_sgbuf_aligned_pages(size);
-	sgbuf->tblsize = sgbuf_align_table(pages);
-	table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
-	if (!table)
-		goto _failed;
-	sgbuf->table = table;
-	pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
-	if (!pgtable)
-		goto _failed;
-	sgbuf->page_table = pgtable;
-
-	/* allocate pages */
-	maxpages = MAX_ALLOC_PAGES;
-	while (pages > 0) {
-		chunk = pages;
-		/* don't be too eager to take a huge chunk */
-		if (chunk > maxpages)
-			chunk = maxpages;
-		chunk <<= PAGE_SHIFT;
-		if (snd_dma_alloc_pages_fallback(type, dmab->dev.dev,
-						 chunk, &tmpb) < 0) {
-			if (!sgbuf->pages)
-				goto _failed;
-			size = sgbuf->pages * PAGE_SIZE;
-			break;
-		}
-		chunk = tmpb.bytes >> PAGE_SHIFT;
-		for (i = 0; i < chunk; i++) {
-			table->buf = tmpb.area;
-			table->addr = tmpb.addr;
-			if (!i)
-				table->addr |= chunk; /* mark head */
-			table++;
-			*pgtable++ = virt_to_page(tmpb.area);
-			tmpb.area += PAGE_SIZE;
-			tmpb.addr += PAGE_SIZE;
-		}
-		sgbuf->pages += chunk;
-		pages -= chunk;
-		if (chunk < maxpages)
-			maxpages = chunk;
-	}
-
-	sgbuf->size = size;
-	area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
-	if (!area)
-		goto _failed;
-	return area;
-
- _failed:
-	snd_dma_sg_free(dmab); /* free the table */
-	return NULL;
-}
-
-static dma_addr_t snd_dma_sg_get_addr(struct snd_dma_buffer *dmab,
-				      size_t offset)
-{
-	struct snd_sg_buf *sgbuf = dmab->private_data;
-	dma_addr_t addr;
-
-	addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
-	addr &= ~((dma_addr_t)PAGE_SIZE - 1);
-	return addr + offset % PAGE_SIZE;
-}
-
-static struct page *snd_dma_sg_get_page(struct snd_dma_buffer *dmab,
-					size_t offset)
-{
-	struct snd_sg_buf *sgbuf = dmab->private_data;
-	unsigned int idx = offset >> PAGE_SHIFT;
-
-	if (idx >= (unsigned int)sgbuf->pages)
-		return NULL;
-	return sgbuf->page_table[idx];
-}
-
-static unsigned int snd_dma_sg_get_chunk_size(struct snd_dma_buffer *dmab,
-					      unsigned int ofs,
-					      unsigned int size)
-{
-	struct snd_sg_buf *sg = dmab->private_data;
-	unsigned int start, end, pg;
-
-	start = ofs >> PAGE_SHIFT;
-	end = (ofs + size - 1) >> PAGE_SHIFT;
-	/* check page continuity */
-	pg = sg->table[start].addr >> PAGE_SHIFT;
-	for (;;) {
-		start++;
-		if (start > end)
-			break;
-		pg++;
-		if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
-			return (start << PAGE_SHIFT) - ofs;
-	}
-	/* ok, all on continuous pages */
-	return size;
-}
-
-static int snd_dma_sg_mmap(struct snd_dma_buffer *dmab,
-			   struct vm_area_struct *area)
-{
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
-		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
-	return -ENOENT; /* continue with the default mmap handler */
-}
-
-const struct snd_malloc_ops snd_dma_sg_ops = {
-	.alloc = snd_dma_sg_alloc,
-	.free = snd_dma_sg_free,
-	.get_addr = snd_dma_sg_get_addr,
-	.get_page = snd_dma_sg_get_page,
-	.get_chunk_size = snd_dma_sg_get_chunk_size,
-	.mmap = snd_dma_sg_mmap,
-};
-- 
2.26.2

Re: [PATCH 0/3] ALSA: Support for non-contiguous and non-coherent page allocations

[Takashi Iwai]

On Thu, 14 Oct 2021 17:36:59 +0200,
Takashi Iwai wrote:
> 
> Hi,
> 
> here is a patch set to add the support for non-contiguous and
> non-coherent page allocations to the ALSA core memalloc helpers.
> Currently no driver is using, but this also gave a nice cleanup for
> the existing SG-buffer helpers on x86.

It turned out that I created the patch set from a slightly old
branch.  Will resubmit the latest code.


Sorry for the mess.

Takashi