d81a6d7176
These aren't modules, but they do make use of these macros, so they will need export.h to get that definition. Previously, they got it via the implicit module.h inclusion. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
78 lines
2.1 KiB
C
78 lines
2.1 KiB
C
/*
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* helpers for managing a buffer for many packets
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*
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* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
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* Licensed under the terms of the GNU General Public License, version 2.
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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(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 error;
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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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