ath9k: Update spectral scan output data

The sample data received through the spectral scan can be either in big or
little endian byteorder. This information isn't stored in the output file.
Therefore it is not possible for the analyzer software to find the correct byte
order.

It is relative common to get the data from a low end AP in big endian mode and
transfer it to another computer in little endian mode to analyze it. Therefore,
it would be better to store it in network (big endian) byte order.

The extension of the 8 bit bins for each bin to 16 bit is not necessary. This
operation can be done in userspace or on a different machine. Instead the
max_exp defining the amount of shifting required for each bin is exported to
userspace.

The change of the output format requires a change of the type in the sample
tlv to allow the userspace program to correctly detect the bin format.

Reported-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
[siwu@hrz.tu-chemnitz.de: squashed patches, update commit message, rebase, fix endianess bug]
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 2bbdcf89d39a..3714b971d18e 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -1236,11 +1236,13 @@ static int remove_buf_file_handler(struct dentry *dentry)
 void ath_debug_send_fft_sample(struct ath_softc *sc,
                                struct fft_sample_tlv *fft_sample_tlv)
 {
+        int length;
         if (!sc->rfs_chan_spec_scan)
                 return;
 
-        relay_write(sc->rfs_chan_spec_scan, fft_sample_tlv,
-                    fft_sample_tlv->length + sizeof(*fft_sample_tlv));
+        length = __be16_to_cpu(fft_sample_tlv->length) +
+                 sizeof(*fft_sample_tlv);
+        relay_write(sc->rfs_chan_spec_scan, fft_sample_tlv, length);
 }
 
 static struct rchan_callbacks rfs_spec_scan_cb = {