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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
379 lines
9.6 KiB
C
379 lines
9.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Isochronous I/O functionality:
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* - Isochronous DMA context management
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* - Isochronous bus resource management (channels, bandwidth), client side
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*
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* Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
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*/
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#include <linux/dma-mapping.h>
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#include <linux/errno.h>
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#include <linux/firewire.h>
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#include <linux/firewire-constants.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <linux/export.h>
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#include <asm/byteorder.h>
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#include "core.h"
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/*
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* Isochronous DMA context management
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*/
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int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
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{
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int i;
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buffer->page_count = 0;
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buffer->page_count_mapped = 0;
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buffer->pages = kmalloc_array(page_count, sizeof(buffer->pages[0]),
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GFP_KERNEL);
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if (buffer->pages == NULL)
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return -ENOMEM;
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for (i = 0; i < page_count; i++) {
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buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
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if (buffer->pages[i] == NULL)
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break;
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}
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buffer->page_count = i;
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if (i < page_count) {
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fw_iso_buffer_destroy(buffer, NULL);
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return -ENOMEM;
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}
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return 0;
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}
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int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
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enum dma_data_direction direction)
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{
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dma_addr_t address;
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int i;
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buffer->direction = direction;
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for (i = 0; i < buffer->page_count; i++) {
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address = dma_map_page(card->device, buffer->pages[i],
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0, PAGE_SIZE, direction);
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if (dma_mapping_error(card->device, address))
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break;
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set_page_private(buffer->pages[i], address);
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}
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buffer->page_count_mapped = i;
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if (i < buffer->page_count)
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return -ENOMEM;
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return 0;
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}
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int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
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int page_count, enum dma_data_direction direction)
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{
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int ret;
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ret = fw_iso_buffer_alloc(buffer, page_count);
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if (ret < 0)
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return ret;
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ret = fw_iso_buffer_map_dma(buffer, card, direction);
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if (ret < 0)
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fw_iso_buffer_destroy(buffer, card);
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return ret;
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}
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EXPORT_SYMBOL(fw_iso_buffer_init);
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void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
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struct fw_card *card)
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{
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int i;
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dma_addr_t address;
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for (i = 0; i < buffer->page_count_mapped; i++) {
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address = page_private(buffer->pages[i]);
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dma_unmap_page(card->device, address,
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PAGE_SIZE, buffer->direction);
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}
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for (i = 0; i < buffer->page_count; i++)
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__free_page(buffer->pages[i]);
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kfree(buffer->pages);
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buffer->pages = NULL;
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buffer->page_count = 0;
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buffer->page_count_mapped = 0;
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}
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EXPORT_SYMBOL(fw_iso_buffer_destroy);
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/* Convert DMA address to offset into virtually contiguous buffer. */
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size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
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{
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size_t i;
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dma_addr_t address;
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ssize_t offset;
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for (i = 0; i < buffer->page_count; i++) {
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address = page_private(buffer->pages[i]);
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offset = (ssize_t)completed - (ssize_t)address;
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if (offset > 0 && offset <= PAGE_SIZE)
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return (i << PAGE_SHIFT) + offset;
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}
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return 0;
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}
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struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
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int type, int channel, int speed, size_t header_size,
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fw_iso_callback_t callback, void *callback_data)
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{
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struct fw_iso_context *ctx;
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ctx = card->driver->allocate_iso_context(card,
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type, channel, header_size);
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if (IS_ERR(ctx))
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return ctx;
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ctx->card = card;
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ctx->type = type;
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ctx->channel = channel;
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ctx->speed = speed;
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ctx->header_size = header_size;
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ctx->callback.sc = callback;
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ctx->callback_data = callback_data;
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return ctx;
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}
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EXPORT_SYMBOL(fw_iso_context_create);
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void fw_iso_context_destroy(struct fw_iso_context *ctx)
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{
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ctx->card->driver->free_iso_context(ctx);
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}
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EXPORT_SYMBOL(fw_iso_context_destroy);
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int fw_iso_context_start(struct fw_iso_context *ctx,
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int cycle, int sync, int tags)
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{
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return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
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}
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EXPORT_SYMBOL(fw_iso_context_start);
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int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
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{
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return ctx->card->driver->set_iso_channels(ctx, channels);
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}
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int fw_iso_context_queue(struct fw_iso_context *ctx,
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struct fw_iso_packet *packet,
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struct fw_iso_buffer *buffer,
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unsigned long payload)
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{
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return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
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}
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EXPORT_SYMBOL(fw_iso_context_queue);
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void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
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{
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ctx->card->driver->flush_queue_iso(ctx);
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}
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EXPORT_SYMBOL(fw_iso_context_queue_flush);
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int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
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{
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return ctx->card->driver->flush_iso_completions(ctx);
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}
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EXPORT_SYMBOL(fw_iso_context_flush_completions);
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int fw_iso_context_stop(struct fw_iso_context *ctx)
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{
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return ctx->card->driver->stop_iso(ctx);
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}
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EXPORT_SYMBOL(fw_iso_context_stop);
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/*
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* Isochronous bus resource management (channels, bandwidth), client side
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*/
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static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
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int bandwidth, bool allocate)
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{
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int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
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__be32 data[2];
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/*
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* On a 1394a IRM with low contention, try < 1 is enough.
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* On a 1394-1995 IRM, we need at least try < 2.
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* Let's just do try < 5.
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*/
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for (try = 0; try < 5; try++) {
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new = allocate ? old - bandwidth : old + bandwidth;
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if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
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return -EBUSY;
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data[0] = cpu_to_be32(old);
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data[1] = cpu_to_be32(new);
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switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
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irm_id, generation, SCODE_100,
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CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
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data, 8)) {
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case RCODE_GENERATION:
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/* A generation change frees all bandwidth. */
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return allocate ? -EAGAIN : bandwidth;
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case RCODE_COMPLETE:
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if (be32_to_cpup(data) == old)
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return bandwidth;
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old = be32_to_cpup(data);
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/* Fall through. */
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}
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}
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return -EIO;
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}
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static int manage_channel(struct fw_card *card, int irm_id, int generation,
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u32 channels_mask, u64 offset, bool allocate)
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{
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__be32 bit, all, old;
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__be32 data[2];
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int channel, ret = -EIO, retry = 5;
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old = all = allocate ? cpu_to_be32(~0) : 0;
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for (channel = 0; channel < 32; channel++) {
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if (!(channels_mask & 1 << channel))
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continue;
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ret = -EBUSY;
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bit = cpu_to_be32(1 << (31 - channel));
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if ((old & bit) != (all & bit))
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continue;
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data[0] = old;
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data[1] = old ^ bit;
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switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
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irm_id, generation, SCODE_100,
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offset, data, 8)) {
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case RCODE_GENERATION:
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/* A generation change frees all channels. */
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return allocate ? -EAGAIN : channel;
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case RCODE_COMPLETE:
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if (data[0] == old)
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return channel;
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old = data[0];
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/* Is the IRM 1394a-2000 compliant? */
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if ((data[0] & bit) == (data[1] & bit))
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continue;
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fallthrough; /* It's a 1394-1995 IRM, retry */
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default:
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if (retry) {
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retry--;
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channel--;
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} else {
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ret = -EIO;
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}
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}
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}
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return ret;
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}
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static void deallocate_channel(struct fw_card *card, int irm_id,
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int generation, int channel)
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{
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u32 mask;
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u64 offset;
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mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
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offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
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CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
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manage_channel(card, irm_id, generation, mask, offset, false);
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}
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/**
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* fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
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* @card: card interface for this action
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* @generation: bus generation
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* @channels_mask: bitmask for channel allocation
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* @channel: pointer for returning channel allocation result
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* @bandwidth: pointer for returning bandwidth allocation result
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* @allocate: whether to allocate (true) or deallocate (false)
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*
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* In parameters: card, generation, channels_mask, bandwidth, allocate
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* Out parameters: channel, bandwidth
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*
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* This function blocks (sleeps) during communication with the IRM.
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*
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* Allocates or deallocates at most one channel out of channels_mask.
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* channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
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* (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
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* channel 0 and LSB for channel 63.)
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* Allocates or deallocates as many bandwidth allocation units as specified.
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*
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* Returns channel < 0 if no channel was allocated or deallocated.
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* Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
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*
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* If generation is stale, deallocations succeed but allocations fail with
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* channel = -EAGAIN.
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*
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* If channel allocation fails, no bandwidth will be allocated either.
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* If bandwidth allocation fails, no channel will be allocated either.
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* But deallocations of channel and bandwidth are tried independently
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* of each other's success.
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*/
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void fw_iso_resource_manage(struct fw_card *card, int generation,
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u64 channels_mask, int *channel, int *bandwidth,
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bool allocate)
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{
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u32 channels_hi = channels_mask; /* channels 31...0 */
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u32 channels_lo = channels_mask >> 32; /* channels 63...32 */
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int irm_id, ret, c = -EINVAL;
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spin_lock_irq(&card->lock);
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irm_id = card->irm_node->node_id;
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spin_unlock_irq(&card->lock);
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if (channels_hi)
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c = manage_channel(card, irm_id, generation, channels_hi,
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CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
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allocate);
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if (channels_lo && c < 0) {
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c = manage_channel(card, irm_id, generation, channels_lo,
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CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
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allocate);
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if (c >= 0)
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c += 32;
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}
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*channel = c;
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if (allocate && channels_mask != 0 && c < 0)
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*bandwidth = 0;
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if (*bandwidth == 0)
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return;
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ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
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if (ret < 0)
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*bandwidth = 0;
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if (allocate && ret < 0) {
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if (c >= 0)
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deallocate_channel(card, irm_id, generation, c);
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*channel = ret;
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}
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}
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EXPORT_SYMBOL(fw_iso_resource_manage);
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