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