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-rw-r--r--sound/core/sgbuf.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
new file mode 100644
index 000000000000..8352a5cdb19f
--- /dev/null
+++ b/sound/core/sgbuf.c
@@ -0,0 +1,201 @@
+// 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,
+};