1 // SPDX-License-Identifier: (GPL-2.0-only OR B 1
2 //
3 // This file is provided under a dual BSD/GPLv
4 // redistributing this file, you may do so und
5 //
6 // Copyright(c) 2018-2022 Intel Corporation
7 //
8 // Author: Keyon Jie <yang.jie@linux.intel.com
9 //
10
11 #include <linux/unaligned.h>
12 #include <linux/io-64-nonatomic-lo-hi.h>
13 #include <linux/device.h>
14 #include <sound/memalloc.h>
15 #include <linux/module.h>
16 #include "sof-utils.h"
17
18 /*
19 * Generic buffer page table creation.
20 * Take the each physical page address and dro
21 * bits from each (based on PAGE_SIZE). Then p
22 * into compressed page table.
23 */
24
25 int snd_sof_create_page_table(struct device *d
26 struct snd_dma_b
27 unsigned char *p
28 {
29 int i, pages;
30
31 pages = snd_sgbuf_aligned_pages(size);
32
33 dev_dbg(dev, "generating page table fo
34 dmab->area, size, pages);
35
36 for (i = 0; i < pages; i++) {
37 /*
38 * The number of valid address
39 * idx determines the byte pos
40 * where the current page's ad
41 * in the compressed page_tabl
42 * This can be calculated by m
43 */
44 u32 idx = (5 * i) >> 1;
45 u32 pfn = snd_sgbuf_get_addr(d
46 u8 *pg_table;
47
48 pg_table = (u8 *)(page_table +
49
50 /*
51 * pagetable compression:
52 * byte 0 byte 1 byte
53 * ___________pfn 0__________
54 * .... .... .... .... ....
55 * It is created by:
56 * 1. set current location to
57 * 2. put pfn[i] at current lo
58 * 3. calculate an intermediat
59 * x = (pfn[i+1] << 4) | (p
60 * 4. put x at offset (current
61 * 5. increment current locati
62 * 6. continue to (2)
63 */
64 if (i & 1)
65 put_unaligned_le32((pg
66 pg_
67 else
68 put_unaligned_le32(pfn
69 }
70
71 return pages;
72 }
73 EXPORT_SYMBOL(snd_sof_create_page_table);
74
75 MODULE_LICENSE("Dual BSD/GPL");
76 MODULE_DESCRIPTION("SOF utils");
77
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