b1bda4cdc2
Based on Date: Tue, 18 Nov 2008 11:41:27 -0500 From: Jay Fenlason <fenlason@redhat.com> Subject: [Patch V4] Add ISO resource management support with several changes to the ABI and implementation. Only the part of the ABI which enables auto-reallocation and auto-deallocation is included here. This implements ioctls for kernel-assisted allocation of isochronous channels and isochronous bandwidth. The benefits are: - The client does not have to have write access to the /dev/fw* device corresponding to the IRM. - The client does not have to perform reallocation after bus resets. - Channel and bandwidth are deallocated by the kernel if the file is closed before the client deallocated the resources. Thus resources are released even if the client crashes. It is anticipated that future in-kernel code (firewire-core IRM code; the firewire port of firedtv), will use the fw-iso.c portions of this code too. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Tested-by: David Moore <dcm@acm.org>
319 lines
8.2 KiB
C
319 lines
8.2 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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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-constants.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include "fw-topology.h"
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#include "fw-transaction.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_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 i, j;
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dma_addr_t address;
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buffer->page_count = page_count;
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buffer->direction = direction;
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buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
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GFP_KERNEL);
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if (buffer->pages == NULL)
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goto out;
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for (i = 0; i < buffer->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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goto out_pages;
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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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__free_page(buffer->pages[i]);
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goto out_pages;
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}
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set_page_private(buffer->pages[i], address);
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}
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return 0;
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out_pages:
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for (j = 0; j < i; j++) {
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address = page_private(buffer->pages[j]);
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dma_unmap_page(card->device, address,
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PAGE_SIZE, DMA_TO_DEVICE);
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__free_page(buffer->pages[j]);
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}
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kfree(buffer->pages);
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out:
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buffer->pages = NULL;
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return -ENOMEM;
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}
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int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
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{
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unsigned long uaddr;
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int i, ret;
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uaddr = vma->vm_start;
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for (i = 0; i < buffer->page_count; i++) {
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ret = vm_insert_page(vma, uaddr, buffer->pages[i]);
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if (ret)
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return ret;
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uaddr += PAGE_SIZE;
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}
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return 0;
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}
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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; 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, DMA_TO_DEVICE);
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__free_page(buffer->pages[i]);
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}
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kfree(buffer->pages);
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buffer->pages = NULL;
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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 = callback;
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ctx->callback_data = callback_data;
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return ctx;
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}
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void fw_iso_context_destroy(struct fw_iso_context *ctx)
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{
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struct fw_card *card = ctx->card;
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card->driver->free_iso_context(ctx);
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}
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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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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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struct fw_card *card = ctx->card;
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return card->driver->queue_iso(ctx, packet, buffer, payload);
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}
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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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/*
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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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__be32 data[2];
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int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
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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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break;
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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, sizeof(data))) {
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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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__be32 channels_mask, u64 offset, bool allocate)
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{
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__be32 data[2], c, old = allocate ? cpu_to_be32(~0) : 0;
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int i, retry = 5;
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for (i = 0; i < 32; i++) {
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c = cpu_to_be32(1 << (31 - i));
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if (!(channels_mask & c))
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continue;
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if (allocate == !(old & c))
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continue;
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data[0] = old;
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data[1] = old ^ c;
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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, sizeof(data))) {
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case RCODE_GENERATION:
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/* A generation change frees all channels. */
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return allocate ? -EAGAIN : i;
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case RCODE_COMPLETE:
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if (data[0] == old)
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return i;
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old = data[0];
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/* Is the IRM 1394a-2000 compliant? */
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if ((data[0] & c) != (data[1] & c))
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continue;
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/* 1394-1995 IRM, fall through to retry. */
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default:
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if (retry--)
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i--;
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}
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}
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return -EIO;
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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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__be32 mask;
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u64 offset;
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mask = channel < 32 ? cpu_to_be32(1 << (31 - channel)) :
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cpu_to_be32(1 << (63 - channel));
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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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*
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* In parameters: card, generation, channels_mask, bandwidth, allocate
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* Out parameters: channel, bandwidth
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* This function blocks (sleeps) during communication with the IRM.
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* Allocates or deallocates at most one channel out of channels_mask.
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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 (de)allocation fails, bandwidth (de)allocation fails too.
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* If bandwidth allocation fails, no channel will be allocated either.
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* If bandwidth deallocation fails, channel deallocation may still have been
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* successful.
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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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__be32 channels_hi = cpu_to_be32(channels_mask >> 32);
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__be32 channels_lo = cpu_to_be32(channels_mask);
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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, 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, 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 (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 (ret < 0 && c >= 0 && allocate) {
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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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