1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * helpers for managing a buffer for many packets
 4 *
 5 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 
 6 */
 7
 8#include <linux/firewire.h>
 9#include <linux/export.h>
10#include <linux/slab.h>
11#include "packets-buffer.h"
12
13/**
14 * iso_packets_buffer_init - allocates the memory for packets
15 * @b: the buffer structure to initialize
16 * @unit: the device at the other end of the stream
17 * @count: the number of packets
18 * @packet_size: the (maximum) size of a packet, in bytes
19 * @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE
20 */
21int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
22			    unsigned int count, unsigned int packet_size,
23			    enum dma_data_direction direction)
24{
25	unsigned int packets_per_page, pages;
26	unsigned int i, page_index, offset_in_page;
27	void *p;
28	int err;
29
30	b->packets = kmalloc_array(count, sizeof(*b->packets), GFP_KERNEL);
31	if (!b->packets) {
32		err = -ENOMEM;
33		goto error;
34	}
35
36	packet_size = L1_CACHE_ALIGN(packet_size);
37	packets_per_page = PAGE_SIZE / packet_size;
38	if (WARN_ON(!packets_per_page)) {
39		err = -EINVAL;
40		goto err_packets;
41	}
42	pages = DIV_ROUND_UP(count, packets_per_page);
43
44	err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card,
45				 pages, direction);
46	if (err < 0)
47		goto err_packets;
48
49	for (i = 0; i < count; ++i) {
50		page_index = i / packets_per_page;
51		p = page_address(b->iso_buffer.pages[page_index]);
52		offset_in_page = (i % packets_per_page) * packet_size;
53		b->packets[i].buffer = p + offset_in_page;
54		b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page;
55	}
56
57	return 0;
58
59err_packets:
60	kfree(b->packets);
61error:
62	return err;
63}
64EXPORT_SYMBOL(iso_packets_buffer_init);
65
66/**
67 * iso_packets_buffer_destroy - frees packet buffer resources
68 * @b: the buffer structure to free
69 * @unit: the device at the other end of the stream
70 */
71void iso_packets_buffer_destroy(struct iso_packets_buffer *b,
72				struct fw_unit *unit)
73{
74	fw_iso_buffer_destroy(&b->iso_buffer, fw_parent_device(unit)->card);
75	kfree(b->packets);
76}
77EXPORT_SYMBOL(iso_packets_buffer_destroy);

 
 1/*
 2 * helpers for managing a buffer for many packets
 3 *
 4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 5 * Licensed under the terms of the GNU General Public License, version 2.
 6 */
 7
 8#include <linux/firewire.h>
 
 9#include <linux/slab.h>
10#include "packets-buffer.h"
11
12/**
13 * iso_packets_buffer_init - allocates the memory for packets
14 * @b: the buffer structure to initialize
15 * @unit: the device at the other end of the stream
16 * @count: the number of packets
17 * @packet_size: the (maximum) size of a packet, in bytes
18 * @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE
19 */
20int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
21			    unsigned int count, unsigned int packet_size,
22			    enum dma_data_direction direction)
23{
24	unsigned int packets_per_page, pages;
25	unsigned int i, page_index, offset_in_page;
26	void *p;
27	int err;
28
29	b->packets = kmalloc(count * sizeof(*b->packets), GFP_KERNEL);
30	if (!b->packets) {
31		err = -ENOMEM;
32		goto error;
33	}
34
35	packet_size = L1_CACHE_ALIGN(packet_size);
36	packets_per_page = PAGE_SIZE / packet_size;
37	if (WARN_ON(!packets_per_page)) {
38		err = -EINVAL;
39		goto error;
40	}
41	pages = DIV_ROUND_UP(count, packets_per_page);
42
43	err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card,
44				 pages, direction);
45	if (err < 0)
46		goto err_packets;
47
48	for (i = 0; i < count; ++i) {
49		page_index = i / packets_per_page;
50		p = page_address(b->iso_buffer.pages[page_index]);
51		offset_in_page = (i % packets_per_page) * packet_size;
52		b->packets[i].buffer = p + offset_in_page;
53		b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page;
54	}
55
56	return 0;
57
58err_packets:
59	kfree(b->packets);
60error:
61	return err;
62}
63EXPORT_SYMBOL(iso_packets_buffer_init);
64
65/**
66 * iso_packets_buffer_destroy - frees packet buffer resources
67 * @b: the buffer structure to free
68 * @unit: the device at the other end of the stream
69 */
70void iso_packets_buffer_destroy(struct iso_packets_buffer *b,
71				struct fw_unit *unit)
72{
73	fw_iso_buffer_destroy(&b->iso_buffer, fw_parent_device(unit)->card);
74	kfree(b->packets);
75}
76EXPORT_SYMBOL(iso_packets_buffer_destroy);