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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778// SPDX-License-Identifier: GPL-2.0-only/* * helpers for managing a buffer for many packets * * Copyright (c) Clemens Ladisch <clemens@ladisch.de> */
#include <linux/firewire.h>#include <linux/export.h>#include <linux/slab.h>#include "packets-buffer.h"
/** * iso_packets_buffer_init - allocates the memory for packets * @b: the buffer structure to initialize * @unit: the device at the other end of the stream * @count: the number of packets * @packet_size: the (maximum) size of a packet, in bytes * @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE */int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit, unsigned int count, unsigned int packet_size, enum dma_data_direction direction){ unsigned int packets_per_page, pages; unsigned int i, page_index, offset_in_page; void *p; int err;
b->packets = kmalloc_objs(*b->packets, count); if (!b->packets) { err = -ENOMEM; goto error; }
packet_size = L1_CACHE_ALIGN(packet_size); packets_per_page = PAGE_SIZE / packet_size; if (WARN_ON(!packets_per_page)) { err = -EINVAL; goto err_packets; } pages = DIV_ROUND_UP(count, packets_per_page);
err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card, pages, direction); if (err < 0) goto err_packets;
for (i = 0; i < count; ++i) { page_index = i / packets_per_page; p = page_address(b->iso_buffer.pages[page_index]); offset_in_page = (i % packets_per_page) * packet_size; b->packets[i].buffer = p + offset_in_page; b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page; }
return 0;
err_packets: kfree(b->packets);error: return err;}EXPORT_SYMBOL(iso_packets_buffer_init);
/** * iso_packets_buffer_destroy - frees packet buffer resources * @b: the buffer structure to free * @unit: the device at the other end of the stream */void iso_packets_buffer_destroy(struct iso_packets_buffer *b, struct fw_unit *unit){ fw_iso_buffer_destroy(&b->iso_buffer, fw_parent_device(unit)->card); kfree(b->packets);}EXPORT_SYMBOL(iso_packets_buffer_destroy);