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dev: Fix incorrect terminal backlog handling

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The Terminal device currently uses the peek functionality in gem5's
circular buffer implementation to send existing buffered content on
the terminal when a new client attaches. This functionallity is
however not implemented correctly and re-sends the same block multiple
time.

Add the required functionality to peek with an offset into the
circular buffer and change the Terminal::accept() implementation to
send the buffered contents.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Radhika Jagtap <radhika.jagtap@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
This commit is contained in:
Andreas Sandberg 2016-04-27 15:33:58 +01:00
parent 67e93a5846
commit 6d74892b38
2 changed files with 20 additions and 8 deletions
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26
src/base/circlebuf.hh
View file

@ -103,24 +103,36 @@ class CircleBuf
*/
template <class OutputIterator>
void peek(OutputIterator out, size_t len) const {
panic_if(len > size(),
peek(out, 0, len);
}
/**
* Copy buffer contents without advancing the read pointer
*
* @param out Output iterator/pointer
* @param offset Offset into the ring buffer
* @param len Number of elements to copy
*/
template <class OutputIterator>
void peek(OutputIterator out, off_t offset, size_t len) const {
panic_if(offset + len > size(),
"Trying to read past end of circular buffer.\n");
if (_start + len <= buf.size()) {
std::copy(buf.begin() + _start,
buf.begin() + _start + len,
const off_t real_start((offset + _start) % buf.size());
if (real_start + len <= buf.size()) {
std::copy(buf.begin() + real_start,
buf.begin() + real_start + len,
out);
} else {
const size_t head_size(buf.size() - _start);
const size_t head_size(buf.size() - real_start);
const size_t tail_size(len - head_size);
std::copy(buf.begin() + _start, buf.end(),
std::copy(buf.begin() + real_start, buf.end(),
out);
std::copy(buf.begin(), buf.begin() + tail_size,
out + head_size);
}
}
/**
* Copy buffer contents and advance the read pointer
*

2
src/dev/terminal.cc
View file

@ -204,7 +204,7 @@ Terminal::accept()
char buf[1024];
for (size_t i = 0; i < txbuf.size(); i += sizeof(buf)) {
const size_t chunk_len(std::min(txbuf.size() - i, sizeof(buf)));
txbuf.peek(buf, chunk_len);
txbuf.peek(buf, i, chunk_len);
write((const uint8_t *)buf, chunk_len);
}
}