mirror of https://gitee.com/openkylin/linux.git
510 lines
12 KiB
C
510 lines
12 KiB
C
/*
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*
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*
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* Copyright (C) 2005 Mike Isely <isely@pobox.com>
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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
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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
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "pvrusb2-ioread.h"
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#include "pvrusb2-debug.h"
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <asm/uaccess.h>
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#define BUFFER_COUNT 32
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#define BUFFER_SIZE PAGE_ALIGN(0x4000)
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struct pvr2_ioread {
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struct pvr2_stream *stream;
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char *buffer_storage[BUFFER_COUNT];
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char *sync_key_ptr;
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unsigned int sync_key_len;
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unsigned int sync_buf_offs;
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unsigned int sync_state;
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unsigned int sync_trashed_count;
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int enabled; // Streaming is on
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int spigot_open; // OK to pass data to client
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int stream_running; // Passing data to client now
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/* State relevant to current buffer being read */
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struct pvr2_buffer *c_buf;
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char *c_data_ptr;
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unsigned int c_data_len;
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unsigned int c_data_offs;
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struct mutex mutex;
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};
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static int pvr2_ioread_init(struct pvr2_ioread *cp)
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{
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unsigned int idx;
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cp->stream = NULL;
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mutex_init(&cp->mutex);
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for (idx = 0; idx < BUFFER_COUNT; idx++) {
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cp->buffer_storage[idx] = kmalloc(BUFFER_SIZE,GFP_KERNEL);
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if (!(cp->buffer_storage[idx])) break;
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}
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if (idx < BUFFER_COUNT) {
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// An allocation appears to have failed
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for (idx = 0; idx < BUFFER_COUNT; idx++) {
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if (!(cp->buffer_storage[idx])) continue;
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kfree(cp->buffer_storage[idx]);
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}
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return -ENOMEM;
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}
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return 0;
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}
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static void pvr2_ioread_done(struct pvr2_ioread *cp)
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{
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unsigned int idx;
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pvr2_ioread_setup(cp,NULL);
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for (idx = 0; idx < BUFFER_COUNT; idx++) {
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if (!(cp->buffer_storage[idx])) continue;
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kfree(cp->buffer_storage[idx]);
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}
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}
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struct pvr2_ioread *pvr2_ioread_create(void)
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{
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struct pvr2_ioread *cp;
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cp = kzalloc(sizeof(*cp),GFP_KERNEL);
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if (!cp) return NULL;
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pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_create id=%p",cp);
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if (pvr2_ioread_init(cp) < 0) {
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kfree(cp);
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return NULL;
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}
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return cp;
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}
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void pvr2_ioread_destroy(struct pvr2_ioread *cp)
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{
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if (!cp) return;
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pvr2_ioread_done(cp);
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pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_destroy id=%p",cp);
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if (cp->sync_key_ptr) {
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kfree(cp->sync_key_ptr);
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cp->sync_key_ptr = NULL;
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}
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kfree(cp);
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}
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void pvr2_ioread_set_sync_key(struct pvr2_ioread *cp,
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const char *sync_key_ptr,
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unsigned int sync_key_len)
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{
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if (!cp) return;
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if (!sync_key_ptr) sync_key_len = 0;
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if ((sync_key_len == cp->sync_key_len) &&
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((!sync_key_len) ||
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(!memcmp(sync_key_ptr,cp->sync_key_ptr,sync_key_len)))) return;
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if (sync_key_len != cp->sync_key_len) {
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if (cp->sync_key_ptr) {
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kfree(cp->sync_key_ptr);
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cp->sync_key_ptr = NULL;
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}
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cp->sync_key_len = 0;
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if (sync_key_len) {
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cp->sync_key_ptr = kmalloc(sync_key_len,GFP_KERNEL);
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if (cp->sync_key_ptr) {
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cp->sync_key_len = sync_key_len;
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}
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}
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}
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if (!cp->sync_key_len) return;
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memcpy(cp->sync_key_ptr,sync_key_ptr,cp->sync_key_len);
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}
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static void pvr2_ioread_stop(struct pvr2_ioread *cp)
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{
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if (!(cp->enabled)) return;
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pvr2_trace(PVR2_TRACE_START_STOP,
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"/*---TRACE_READ---*/ pvr2_ioread_stop id=%p",cp);
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pvr2_stream_kill(cp->stream);
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cp->c_buf = NULL;
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cp->c_data_ptr = NULL;
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cp->c_data_len = 0;
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cp->c_data_offs = 0;
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cp->enabled = 0;
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cp->stream_running = 0;
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cp->spigot_open = 0;
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if (cp->sync_state) {
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/ sync_state <== 0");
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cp->sync_state = 0;
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}
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}
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static int pvr2_ioread_start(struct pvr2_ioread *cp)
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{
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int stat;
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struct pvr2_buffer *bp;
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if (cp->enabled) return 0;
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if (!(cp->stream)) return 0;
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pvr2_trace(PVR2_TRACE_START_STOP,
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"/*---TRACE_READ---*/ pvr2_ioread_start id=%p",cp);
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while ((bp = pvr2_stream_get_idle_buffer(cp->stream)) != NULL) {
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stat = pvr2_buffer_queue(bp);
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if (stat < 0) {
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/"
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" pvr2_ioread_start id=%p"
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" error=%d",
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cp,stat);
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pvr2_ioread_stop(cp);
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return stat;
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}
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}
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cp->enabled = !0;
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cp->c_buf = NULL;
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cp->c_data_ptr = NULL;
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cp->c_data_len = 0;
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cp->c_data_offs = 0;
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cp->stream_running = 0;
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if (cp->sync_key_len) {
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/ sync_state <== 1");
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cp->sync_state = 1;
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cp->sync_trashed_count = 0;
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cp->sync_buf_offs = 0;
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}
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cp->spigot_open = 0;
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return 0;
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}
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struct pvr2_stream *pvr2_ioread_get_stream(struct pvr2_ioread *cp)
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{
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return cp->stream;
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}
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int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp)
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{
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int ret;
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unsigned int idx;
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struct pvr2_buffer *bp;
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mutex_lock(&cp->mutex); do {
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if (cp->stream) {
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pvr2_trace(PVR2_TRACE_START_STOP,
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"/*---TRACE_READ---*/"
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" pvr2_ioread_setup (tear-down) id=%p",cp);
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pvr2_ioread_stop(cp);
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pvr2_stream_kill(cp->stream);
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if (pvr2_stream_get_buffer_count(cp->stream)) {
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pvr2_stream_set_buffer_count(cp->stream,0);
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}
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cp->stream = NULL;
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}
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if (sp) {
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pvr2_trace(PVR2_TRACE_START_STOP,
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"/*---TRACE_READ---*/"
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" pvr2_ioread_setup (setup) id=%p",cp);
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pvr2_stream_kill(sp);
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ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT);
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if (ret < 0) return ret;
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for (idx = 0; idx < BUFFER_COUNT; idx++) {
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bp = pvr2_stream_get_buffer(sp,idx);
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pvr2_buffer_set_buffer(bp,
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cp->buffer_storage[idx],
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BUFFER_SIZE);
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}
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cp->stream = sp;
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}
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} while (0); mutex_unlock(&cp->mutex);
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return 0;
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}
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int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl)
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{
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int ret = 0;
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if ((!fl) == (!(cp->enabled))) return ret;
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mutex_lock(&cp->mutex); do {
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if (fl) {
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ret = pvr2_ioread_start(cp);
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} else {
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pvr2_ioread_stop(cp);
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}
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} while (0); mutex_unlock(&cp->mutex);
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return ret;
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}
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static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp)
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{
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int stat;
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while (cp->c_data_len <= cp->c_data_offs) {
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if (cp->c_buf) {
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// Flush out current buffer first.
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stat = pvr2_buffer_queue(cp->c_buf);
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if (stat < 0) {
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// Streaming error...
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/"
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" pvr2_ioread_read id=%p"
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" queue_error=%d",
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cp,stat);
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pvr2_ioread_stop(cp);
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return 0;
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}
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cp->c_buf = NULL;
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cp->c_data_ptr = NULL;
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cp->c_data_len = 0;
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cp->c_data_offs = 0;
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}
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// Now get a freshly filled buffer.
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cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream);
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if (!cp->c_buf) break; // Nothing ready; done.
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cp->c_data_len = pvr2_buffer_get_count(cp->c_buf);
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if (!cp->c_data_len) {
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// Nothing transferred. Was there an error?
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stat = pvr2_buffer_get_status(cp->c_buf);
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if (stat < 0) {
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// Streaming error...
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/"
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" pvr2_ioread_read id=%p"
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" buffer_error=%d",
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cp,stat);
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pvr2_ioread_stop(cp);
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// Give up.
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return 0;
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}
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// Start over...
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continue;
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}
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cp->c_data_offs = 0;
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cp->c_data_ptr = cp->buffer_storage[
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pvr2_buffer_get_id(cp->c_buf)];
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}
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return !0;
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}
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static void pvr2_ioread_filter(struct pvr2_ioread *cp)
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{
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unsigned int idx;
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if (!cp->enabled) return;
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if (cp->sync_state != 1) return;
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// Search the stream for our synchronization key. This is made
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// complicated by the fact that in order to be honest with
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// ourselves here we must search across buffer boundaries...
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mutex_lock(&cp->mutex); while (1) {
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// Ensure we have a buffer
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if (!pvr2_ioread_get_buffer(cp)) break;
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if (!cp->c_data_len) break;
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// Now walk the buffer contents until we match the key or
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// run out of buffer data.
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for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
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if (cp->sync_buf_offs >= cp->sync_key_len) break;
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if (cp->c_data_ptr[idx] ==
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cp->sync_key_ptr[cp->sync_buf_offs]) {
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// Found the next key byte
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(cp->sync_buf_offs)++;
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} else {
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// Whoops, mismatched. Start key over...
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cp->sync_buf_offs = 0;
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}
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}
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// Consume what we've walked through
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cp->c_data_offs += idx;
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cp->sync_trashed_count += idx;
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// If we've found the key, then update state and get out.
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if (cp->sync_buf_offs >= cp->sync_key_len) {
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cp->sync_trashed_count -= cp->sync_key_len;
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/"
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" sync_state <== 2 (skipped %u bytes)",
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cp->sync_trashed_count);
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cp->sync_state = 2;
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cp->sync_buf_offs = 0;
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break;
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}
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if (cp->c_data_offs < cp->c_data_len) {
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// Sanity check - should NEVER get here
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pvr2_trace(PVR2_TRACE_ERROR_LEGS,
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"ERROR: pvr2_ioread filter sync problem"
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" len=%u offs=%u",
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cp->c_data_len,cp->c_data_offs);
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// Get out so we don't get stuck in an infinite
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// loop.
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break;
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}
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continue; // (for clarity)
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} mutex_unlock(&cp->mutex);
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}
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int pvr2_ioread_avail(struct pvr2_ioread *cp)
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{
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int ret;
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if (!(cp->enabled)) {
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// Stream is not enabled; so this is an I/O error
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return -EIO;
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}
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if (cp->sync_state == 1) {
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pvr2_ioread_filter(cp);
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if (cp->sync_state == 1) return -EAGAIN;
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}
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ret = 0;
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if (cp->stream_running) {
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if (!pvr2_stream_get_ready_count(cp->stream)) {
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// No data available at all right now.
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ret = -EAGAIN;
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}
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} else {
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if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) {
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// Haven't buffered up enough yet; try again later
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ret = -EAGAIN;
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}
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}
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if ((!(cp->spigot_open)) != (!(ret == 0))) {
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cp->spigot_open = (ret == 0);
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/ data is %s",
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cp->spigot_open ? "available" : "pending");
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}
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return ret;
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}
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int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
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{
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unsigned int copied_cnt;
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unsigned int bcnt;
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const char *src;
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int stat;
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int ret = 0;
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unsigned int req_cnt = cnt;
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if (!cnt) {
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pvr2_trace(PVR2_TRACE_TRAP,
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"/*---TRACE_READ---*/ pvr2_ioread_read id=%p"
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" ZERO Request? Returning zero.",cp);
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return 0;
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}
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stat = pvr2_ioread_avail(cp);
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if (stat < 0) return stat;
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cp->stream_running = !0;
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mutex_lock(&cp->mutex); do {
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// Suck data out of the buffers and copy to the user
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copied_cnt = 0;
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if (!buf) cnt = 0;
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while (1) {
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if (!pvr2_ioread_get_buffer(cp)) {
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ret = -EIO;
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break;
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}
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if (!cnt) break;
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if (cp->sync_state == 2) {
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// We're repeating the sync key data into
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// the stream.
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src = cp->sync_key_ptr + cp->sync_buf_offs;
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bcnt = cp->sync_key_len - cp->sync_buf_offs;
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} else {
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// Normal buffer copy
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src = cp->c_data_ptr + cp->c_data_offs;
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bcnt = cp->c_data_len - cp->c_data_offs;
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}
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if (!bcnt) break;
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// Don't run past user's buffer
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if (bcnt > cnt) bcnt = cnt;
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if (copy_to_user(buf,src,bcnt)) {
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// User supplied a bad pointer?
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// Give up - this *will* cause data
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// to be lost.
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ret = -EFAULT;
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break;
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}
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cnt -= bcnt;
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buf += bcnt;
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copied_cnt += bcnt;
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if (cp->sync_state == 2) {
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// Update offset inside sync key that we're
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// repeating back out.
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cp->sync_buf_offs += bcnt;
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if (cp->sync_buf_offs >= cp->sync_key_len) {
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// Consumed entire key; switch mode
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// to normal.
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/"
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" sync_state <== 0");
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cp->sync_state = 0;
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}
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} else {
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// Update buffer offset.
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cp->c_data_offs += bcnt;
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}
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}
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} while (0); mutex_unlock(&cp->mutex);
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if (!ret) {
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if (copied_cnt) {
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// If anything was copied, return that count
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ret = copied_cnt;
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} else {
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// Nothing copied; suggest to caller that another
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// attempt should be tried again later
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ret = -EAGAIN;
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}
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}
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pvr2_trace(PVR2_TRACE_DATA_FLOW,
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"/*---TRACE_READ---*/ pvr2_ioread_read"
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" id=%p request=%d result=%d",
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cp,req_cnt,ret);
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return ret;
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}
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/*
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Stuff for Emacs to see, in order to encourage consistent editing style:
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*** Local Variables: ***
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*** mode: c ***
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*** fill-column: 75 ***
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*** tab-width: 8 ***
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*** c-basic-offset: 8 ***
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*** End: ***
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|
*/
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