/*
* Isochronous I/O functionality:
* - Isochronous DMA context management
* - Isochronous bus resource management (channels, bandwidth), client side
*
* Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <linux/dma-mapping.h>
#include <linux/errno.h>
#include <linux/firewire.h>
#include <linux/firewire-constants.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>
#include "core.h"
/*
* Isochronous DMA context management
*/
int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
int page_count, enum dma_data_direction direction)
{
int i, j;
dma_addr_t address;
buffer->page_count = page_count;
buffer->direction = direction;
buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
GFP_KERNEL);
if (buffer->pages == NULL)
goto out;
for (i = 0; i < buffer->page_count; i++) {
buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
if (buffer->pages[i] == NULL)
goto out_pages;
address = dma_map_page(card->device, buffer->pages[i],
0, PAGE_SIZE, direction);
if (dma_mapping_error(card->device, address)) {
__free_page(buffer->pages[i]);
goto out_pages;
}
set_page_private(buffer->pages[i], address);
}
return 0;
out_pages:
for (j = 0; j < i; j++) {
address = page_private(buffer->pages[j]);
dma_unmap_page(card->device, address,
PAGE_SIZE, direction);
__free_page(buffer->pages[j]);
}
kfree(buffer->pages);
out:
buffer->pages = NULL;
return -ENOMEM;
}
EXPORT_SYMBOL(fw_iso_buffer_init);
int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
{
unsigned long uaddr;
int i, err;
uaddr = vma->vm_start;
for (i = 0; i < buffer->page_count; i++) {
err = vm_insert_page(vma, uaddr, buffer->pages[i]);
if (err)
return err;
uaddr += PAGE_SIZE;
}
return 0;
}
void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
struct fw_card *card)
{
int i;
dma_addr_t address;
for (i = 0; i < buffer->page_count; i++) {
address = page_private(buffer->pages[i]);
dma_unmap_page(card->device, address,
PAGE_SIZE, buffer->direction);
__free_page(buffer->pages[i]);
}
kfree(buffer->pages);
buffer->pages = NULL;
}
EXPORT_SYMBOL(fw_iso_buffer_destroy);
struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
int type, int channel, int speed, size_t header_size,
fw_iso_callback_t callback, void *callback_data)
{
struct fw_iso_context *ctx;
ctx = card->driver->allocate_iso_context(card,
type, channel, header_size);
if (IS_ERR(ctx))
return ctx;
ctx->card = card;
ctx->type = type;
ctx->channel = channel;
ctx->speed = speed;
ctx->header_size = header_size;
ctx->callback = callback;
ctx->callback_data = callback_data;
return ctx;
}
EXPORT_SYMBOL(fw_iso_context_create);
void fw_iso_context_destroy(struct fw_iso_context *ctx)
{
struct fw_card *card = ctx->card;
card->driver->free_iso_context(ctx);
}
EXPORT_SYMBOL(fw_iso_context_destroy);
int fw_iso_context_start(struct fw_iso_context *ctx,
int cycle, int sync, int tags)
{
return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
}
EXPORT_SYMBOL(fw_iso_context_start);
int fw_iso_context_queue(struct fw_iso_context *ctx,
struct fw_iso_packet *packet,
struct fw_iso_buffer *buffer,
unsigned long payload)
{
struct fw_card *card = ctx->card;
return card->driver->queue_iso(ctx, packet, buffer, payload);
}
EXPORT_SYMBOL(fw_iso_context_queue);
int fw_iso_context_stop(struct fw_iso_context *ctx)
{
return ctx->card->driver->stop_iso(ctx);
}
EXPORT_SYMBOL(fw_iso_context_stop);
/*
* Isochronous bus resource management (channels, bandwidth), client side
*/
static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
int bandwidth, bool allocate, __be32 data[2])
{
int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
/*
* On a 1394a IRM with low contention, try < 1 is enough.
* On a 1394-1995 IRM, we need at least try < 2.
* Let's just do try < 5.
*/
for (try = 0; try < 5; try++) {
new = allocate ? old - bandwidth : old + bandwidth;
if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
break;
data[0] = cpu_to_be32(old);
data[1] = cpu_to_be32(new);
switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
irm_id, generation, SCODE_100,
CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
data, 8)) {
case RCODE_GENERATION:
/* A generation change frees all bandwidth. */
return allocate ? -EAGAIN : bandwidth;
case RCODE_COMPLETE:
if (be32_to_cpup(data) == old)
return bandwidth;
old = be32_to_cpup(data);
/* Fall through. */
}
}
return -EIO;
}
static int manage_channel(struct fw_card *card, int irm_id, int generation,
u32 channels_mask, u64 offset, bool allocate, __be32 data[2])
{
__be32 c, all, old;
int i, retry = 5;
old = all = allocate ? cpu_to_be32(~0) : 0;
for (i = 0; i < 32; i++) {
if (!(channels_mask & 1 << i))
continue;
c = cpu_to_be32(1 << (31 - i));
if ((old & c) != (all & c))
continue;
data[0] = old;
data[1] = old ^ c;
switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
irm_id, generation, SCODE_100,
offset, data, 8)) {
case RCODE_GENERATION:
/* A generation change frees all channels. */
return allocate ? -EAGAIN : i;
case RCODE_COMPLETE:
if (data[0] == old)
return i;
old = data[0];
/* Is the IRM 1394a-2000 compliant? */
if ((data[0] & c) == (data[1] & c))
continue;
/* 1394-1995 IRM, fall through to retry. */
default:
if (retry--)
i--;
}
}
return -EIO;
}
static void deallocate_channel(struct fw_card *card, int irm_id,
int generation, int channel, __be32 buffer[2])
{
u32 mask;
u64 offset;
mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
manage_channel(card, irm_id, generation, mask, offset, false, buffer);
}
/**
* fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
*
* In parameters: card, generation, channels_mask, bandwidth, allocate
* Out parameters: channel, bandwidth
* This function blocks (sleeps) during communication with the IRM.
*
* Allocates or deallocates at most one channel out of channels_mask.
* channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
* (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
* channel 0 and LSB for channel 63.)
* Allocates or deallocates as many bandwidth allocation units as specified.
*
* Returns channel < 0 if no channel was allocated or deallocated.
* Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
*
* If generation is stale, deallocations succeed but allocations fail with
* channel = -EAGAIN.
*
* If channel allocation fails, no bandwidth will be allocated either.
* If bandwidth allocation fails, no channel will be allocated either.
* But deallocations of channel and bandwidth are tried independently
* of each other's success.
*/
void fw_iso_resource_manage(struct fw_card *card, int generation,
u64 channels_mask, int *channel, int *bandwidth,
bool allocate, __be32 buffer[2])
{
u32 channels_hi = channels_mask; /* channels 31...0 */
u32 channels_lo = channels_mask >> 32; /* channels 63...32 */
int irm_id, ret, c = -EINVAL;
spin_lock_irq(&card->lock);
irm_id = card->irm_node->node_id;
spin_unlock_irq(&card->lock);
if (channels_hi)
c = manage_channel(card, irm_id, generation, channels_hi,
CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
allocate, buffer);
if (channels_lo && c < 0) {
c = manage_channel(card, irm_id, generation, channels_lo,
CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
allocate, buffer);
if (c >= 0)
c += 32;
}
*channel = c;
if (allocate && channels_mask != 0 && c < 0)
*bandwidth = 0;
if (*bandwidth == 0)
return;
ret = manage_bandwidth(card, irm_id, generation, *bandwidth,
allocate, buffer);
if (ret < 0)
*bandwidth = 0;
if (allocate && ret < 0 && c >= 0) {
deallocate_channel(card, irm_id, generation, c, buffer);
*channel = ret;
}
}
