iwlwifi: allow user change protection mechanism for HT

Allow user to change protection mechanism for HT between RTS/CTS and
CTS-to-self through sysfs:

Show current protection mechanism for HT
   cat /sys/class/net/wlan0/device/rts_ht_protection

Change protection mechanism for HT (only allowed while not-associated)
CTS-to-self:
   echo 0 > /sys/class/net/wlan0/device/rts_ht_protection
RTS/CTS:
   echo 1 > /sys/class/net/wlan0/device/rts_ht_protection

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index a3739628c1d6..2a7cc4bdf3fd 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2798,6 +2798,40 @@ static ssize_t show_statistics(struct device *d,
 
 static DEVICE_ATTR(statistics, S_IRUGO, show_statistics, NULL);
 
+static ssize_t show_rts_ht_protection(struct device *d,
+                             struct device_attribute *attr, char *buf)
+{
+        struct iwl_priv *priv = dev_get_drvdata(d);
+
+        return sprintf(buf, "%s\n",
+                priv->cfg->use_rts_for_ht ? "RTS/CTS" : "CTS-to-self");
+}
+
+static ssize_t store_rts_ht_protection(struct device *d,
+                              struct device_attribute *attr,
+                              const char *buf, size_t count)
+{
+        struct iwl_priv *priv = dev_get_drvdata(d);
+        unsigned long val;
+        int ret;
+
+        ret = strict_strtoul(buf, 10, &val);
+        if (ret)
+                IWL_INFO(priv, "Input is not in decimal form.\n");
+        else {
+                if (!iwl_is_associated(priv))
+                        priv->cfg->use_rts_for_ht = val ? true : false;
+                else
+                        IWL_ERR(priv, "Sta associated with AP - "
+                                "Change protection mechanism is not allowed\n");
+                ret = count;
+        }
+        return ret;
+}
+
+static DEVICE_ATTR(rts_ht_protection, S_IWUSR | S_IRUGO,
+                        show_rts_ht_protection, store_rts_ht_protection);
+
 
 /*****************************************************************************
  *
@@ -2854,6 +2888,7 @@ static struct attribute *iwl_sysfs_entries[] = {
         &dev_attr_statistics.attr,
         &dev_attr_temperature.attr,
         &dev_attr_tx_power.attr,
+        &dev_attr_rts_ht_protection.attr,
 #ifdef CONFIG_IWLWIFI_DEBUG
         &dev_attr_debug_level.attr,
 #endif