static void pvr2_ioread_filter(struct pvr2_ioread *cp)
{
unsigned int idx;
if (!cp->enabled) return;
if (cp->sync_state != 1) return;
// Search the stream for our synchronization key. This is made
// complicated by the fact that in order to be honest with
// ourselves here we must search across buffer boundaries...
mutex_lock(&cp->mutex);
while (1) {
// Ensure we have a buffer
if (!pvr2_ioread_get_buffer(cp)) break;
if (!cp->c_data_len) break;
// Now walk the buffer contents until we match the key or
// run out of buffer data.
for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
if (cp->sync_buf_offs >= cp->sync_key_len) break;
if (cp->c_data_ptr[idx] ==
cp->sync_key_ptr[cp->sync_buf_offs]) {
// Found the next key byte
(cp->sync_buf_offs)++;
} else {
// Whoops, mismatched. Start key over...
cp->sync_buf_offs = 0;
}
}
// Consume what we've walked through
cp->c_data_offs += idx;
cp->sync_trashed_count += idx;
// If we've found the key, then update state and get out.
if (cp->sync_buf_offs >= cp->sync_key_len) {
cp->sync_trashed_count -= cp->sync_key_len;
pvr2_trace(PVR2_TRACE_DATA_FLOW,
"/*---TRACE_READ---*/"
" sync_state <== 2 (skipped %u bytes)",
cp->sync_trashed_count);
cp->sync_state = 2;
cp->sync_buf_offs = 0;
break;
}
if (cp->c_data_offs < cp->c_data_len) {
// Sanity check - should NEVER get here
pvr2_trace(PVR2_TRACE_ERROR_LEGS,
"ERROR: pvr2_ioread filter sync problem"
" len=%u offs=%u",
cp->c_data_len,cp->c_data_offs);
// Get out so we don't get stuck in an infinite
// loop.
break;
}
continue; // (for clarity)
}
mutex_unlock(&cp->mutex);
}
static void pvr2_ioread_filter(struct pvr2_ioread *cp)
{
unsigned int idx;
if (!cp->enabled) return;
if (cp->sync_state != 1) return;
mutex_lock(&cp->mutex); while (1) {
if (!pvr2_ioread_get_buffer(cp)) break;
if (!cp->c_data_len) break;
for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
if (cp->sync_buf_offs >= cp->sync_key_len) break;
if (cp->c_data_ptr[idx] ==
cp->sync_key_ptr[cp->sync_buf_offs]) {
(cp->sync_buf_offs)++;
} else {
cp->sync_buf_offs = 0;
}
}
cp->c_data_offs += idx;
cp->sync_trashed_count += idx;
if (cp->sync_buf_offs >= cp->sync_key_len) {
cp->sync_trashed_count -= cp->sync_key_len;
pvr2_trace(PVR2_TRACE_DATA_FLOW,
"/*---TRACE_READ---*/"
" sync_state <== 2 (skipped %u bytes)",
cp->sync_trashed_count);
cp->sync_state = 2;
cp->sync_buf_offs = 0;
break;
}
if (cp->c_data_offs < cp->c_data_len) {
pvr2_trace(PVR2_TRACE_ERROR_LEGS,
"ERROR: pvr2_ioread filter sync problem"
" len=%u offs=%u",
cp->c_data_len,cp->c_data_offs);
break;
}
continue;
} mutex_unlock(&cp->mutex);
}
int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
{
unsigned int copied_cnt;
unsigned int bcnt;
const char *src;
int stat;
int ret = 0;
unsigned int req_cnt = cnt;
if (!cnt) {
pvr2_trace(PVR2_TRACE_TRAP,
"/*---TRACE_READ---*/ pvr2_ioread_read id=%p ZERO Request? Returning zero.",
cp);
return 0;
}
stat = pvr2_ioread_avail(cp);
if (stat < 0) return stat;
cp->stream_running = !0;
mutex_lock(&cp->mutex);
do {
// Suck data out of the buffers and copy to the user
copied_cnt = 0;
if (!buf) cnt = 0;
while (1) {
if (!pvr2_ioread_get_buffer(cp)) {
ret = -EIO;
break;
}
if (!cnt) break;
if (cp->sync_state == 2) {
// We're repeating the sync key data into
// the stream.
src = cp->sync_key_ptr + cp->sync_buf_offs;
bcnt = cp->sync_key_len - cp->sync_buf_offs;
} else {
// Normal buffer copy
src = cp->c_data_ptr + cp->c_data_offs;
bcnt = cp->c_data_len - cp->c_data_offs;
}
if (!bcnt) break;
// Don't run past user's buffer
if (bcnt > cnt) bcnt = cnt;
if (copy_to_user(buf,src,bcnt)) {
// User supplied a bad pointer?
// Give up - this *will* cause data
// to be lost.
ret = -EFAULT;
break;
}
cnt -= bcnt;
buf += bcnt;
copied_cnt += bcnt;
if (cp->sync_state == 2) {
// Update offset inside sync key that we're
// repeating back out.
cp->sync_buf_offs += bcnt;
if (cp->sync_buf_offs >= cp->sync_key_len) {
// Consumed entire key; switch mode
// to normal.
pvr2_trace(PVR2_TRACE_DATA_FLOW,
"/*---TRACE_READ---*/ sync_state <== 0");
cp->sync_state = 0;
}
} else {
// Update buffer offset.
cp->c_data_offs += bcnt;
}
}
} while (0);
mutex_unlock(&cp->mutex);
if (!ret) {
if (copied_cnt) {
// If anything was copied, return that count
ret = copied_cnt;
} else {
// Nothing copied; suggest to caller that another
// attempt should be tried again later
ret = -EAGAIN;
}
}
pvr2_trace(PVR2_TRACE_DATA_FLOW,
"/*---TRACE_READ---*/ pvr2_ioread_read id=%p request=%d result=%d",
cp,req_cnt,ret);
return ret;
}
int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
{
unsigned int copied_cnt;
unsigned int bcnt;
const char *src;
int stat;
int ret = 0;
unsigned int req_cnt = cnt;
if (!cnt) {
pvr2_trace(PVR2_TRACE_TRAP,
"/*---TRACE_READ---*/ pvr2_ioread_read id=%p"
" ZERO Request? Returning zero.",cp);
return 0;
}
stat = pvr2_ioread_avail(cp);
if (stat < 0) return stat;
cp->stream_running = !0;
mutex_lock(&cp->mutex); do {
copied_cnt = 0;
if (!buf) cnt = 0;
while (1) {
if (!pvr2_ioread_get_buffer(cp)) {
ret = -EIO;
break;
}
if (!cnt) break;
if (cp->sync_state == 2) {
src = cp->sync_key_ptr + cp->sync_buf_offs;
bcnt = cp->sync_key_len - cp->sync_buf_offs;
} else {
src = cp->c_data_ptr + cp->c_data_offs;
bcnt = cp->c_data_len - cp->c_data_offs;
}
if (!bcnt) break;
if (bcnt > cnt) bcnt = cnt;
if (copy_to_user(buf,src,bcnt)) {
ret = -EFAULT;
break;
}
cnt -= bcnt;
buf += bcnt;
copied_cnt += bcnt;
if (cp->sync_state == 2) {
cp->sync_buf_offs += bcnt;
if (cp->sync_buf_offs >= cp->sync_key_len) {
pvr2_trace(PVR2_TRACE_DATA_FLOW,
"/*---TRACE_READ---*/"
" sync_state <== 0");
cp->sync_state = 0;
}
} else {
cp->c_data_offs += bcnt;
}
}
} while (0); mutex_unlock(&cp->mutex);
if (!ret) {
if (copied_cnt) {
ret = copied_cnt;
} else {
ret = -EAGAIN;
}
}
pvr2_trace(PVR2_TRACE_DATA_FLOW,
"/*---TRACE_READ---*/ pvr2_ioread_read"
" id=%p request=%d result=%d",
cp,req_cnt,ret);
return ret;
}
