[RFC] mac80211: add debugfs file for current tx rate

[saravanad@posedge.com]

Add a debugfs file showing the current tx rate.
The information available in the rc_stats file
doesn't evidently provides us the current tx rate.
This patch adds the support for the same.

Signed-off-by: Saravana <saravanad@posedge.com>
---
The diff file is generated from wireless-testing git tree.
  net/mac80211/debugfs_sta.c |   16 ++++++++++++++++
  1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 89281d2..85d2279 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -321,6 +321,21 @@ static ssize_t sta_ht_capa_read(struct file *file, 
char __user *userbuf,
  }
  STA_OPS(ht_capa);

+static ssize_t sta_current_tx_rate_read(struct file *file, char __user 
*userbuf,
+				      size_t count, loff_t *ppos)
+{
+	struct sta_info *sta = file->private_data;
+	struct rate_info rinfo;
+	u16 rate;
+	sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
+	rate = cfg80211_calculate_bitrate(&rinfo);
+
+	return mac80211_format_buffer(userbuf, count, ppos, "%d.%d MBit/s\n",
+					rate/10, rate%10);
+
+}
+STA_OPS(current_tx_rate);
+
  #define DEBUGFS_ADD(name) \
  	debugfs_create_file(#name, 0400, \
  		sta->debugfs.dir, sta, &sta_ ##name## _ops);
@@ -369,6 +384,7 @@ void ieee80211_sta_debugfs_add(struct sta_info 
*sta)
  	DEBUGFS_ADD(dev);
  	DEBUGFS_ADD(last_signal);
  	DEBUGFS_ADD(ht_capa);
+	DEBUGFS_ADD(current_tx_rate);

  	DEBUGFS_ADD_COUNTER(rx_packets, rx_packets);
  	DEBUGFS_ADD_COUNTER(tx_packets, tx_packets);