[PATCH v2 12/14] iwlwifi: debugFs to enable/disable HT40 support

["Guy, Wey-Yi" <wey-yi.w.guy@intel.com>]

From: Wey-Yi Guy <wey-yi.w.guy@intel.com>

Add debugfs file to enable/disable HT40(40MHz) channel support.
By default, 40MHz is supported if AP can support the function.

By echo "1" to "disable_ht40_mode" file, iwlwifi driver will disable the
40MHz support and only allow 20MHz channel.

Because the information exchange happen during association time,
so enable/disable fat channel only can be performed when it is not
associated with AP.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
v2: namene change from "fat" to "HT40"
---
 drivers/net/wireless/iwlwifi/iwl-core.c    |    4 ++
 drivers/net/wireless/iwlwifi/iwl-debug.h   |    1 +
 drivers/net/wireless/iwlwifi/iwl-debugfs.c |   46
++++++++++++++++++++++++++++
 drivers/net/wireless/iwlwifi/iwl-dev.h     |    1 +
 4 files changed, 52 insertions(+), 0 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c
b/drivers/net/wireless/iwlwifi/iwl-core.c
index 710dd41..a4be19e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -632,6 +632,10 @@ u8 iwl_is_fat_tx_allowed(struct iwl_priv *priv,
                if (!sta_ht_inf->ht_supported)
                        return 0;
        }
+#ifdef CONFIG_IWLWIFI_DEBUG
+       if (priv->disable_ht40)
+               return 0;
+#endif
        return iwl_is_channel_extension(priv, priv->band,
                        le16_to_cpu(priv->staging_rxon.channel),
                        iwl_ht_conf->extension_chan_offset);
diff --git a/drivers/net/wireless/iwlwifi/iwl-debug.h
b/drivers/net/wireless/iwlwifi/iwl-debug.h
index 609a681..8aa93f2 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debug.h
+++ b/drivers/net/wireless/iwlwifi/iwl-debug.h
@@ -88,6 +88,7 @@ struct iwl_debugfs {
 #ifdef CONFIG_IWLWIFI_LEDS
                struct dentry *file_led;
 #endif
+               struct dentry *file_disable_ht40_mode;
        } dbgfs_data_files;
        struct dir_rf_files {
                struct dentry *file_disable_sensitivity;
diff --git a/drivers/net/wireless/iwlwifi/iwl-debugfs.c
b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
index 748dc31..06113bb 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debugfs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
@@ -653,6 +653,49 @@ static ssize_t
iwl_dbgfs_thermal_throttling_read(struct file *file,
        return ret;
 }
 
+static ssize_t iwl_dbgfs_disable_ht40_mode_write(struct file *file,
+                                        const char __user *user_buf,
+                                        size_t count, loff_t *ppos)
+{
+       struct iwl_priv *priv = file->private_data;
+       char buf[8];
+       int buf_size;
+       int ht40_mode;
+
+       memset(buf, 0, sizeof(buf));
+       buf_size = min(count, sizeof(buf) -  1);
+       if (copy_from_user(buf, user_buf, buf_size))
+               return -EFAULT;
+       if (sscanf(buf, "%d", &ht40_mode) != 1)
+               return -EFAULT;
+       if (!iwl_is_associated(priv))
+               priv->disable_ht40 = ht40_mode ? true : false;
+       else {
+               IWL_ERR(priv, "Sta associated with AP - "
+                       "Change fat mode is not allowed\n");
+               return -EINVAL;
+       }
+
+       return count;
+}
+
+static ssize_t iwl_dbgfs_disable_ht40_mode_read(struct file *file,
+                                        char __user *user_buf,
+                                        size_t count, loff_t *ppos)
+{
+       struct iwl_priv *priv = (struct iwl_priv *)file->private_data;
+       char buf[100];
+       int pos = 0;
+       const size_t bufsz = sizeof(buf);
+       ssize_t ret;
+
+       pos += scnprintf(buf + pos, bufsz - pos,
+                       "11n 40Mhz Mode: %s\n",
+                       priv->disable_ht40 ? "Disabled" : "Enabled");
+       ret = simple_read_from_buffer(user_buf, count, ppos, buf, pos);
+       return ret;
+}
+
 DEBUGFS_READ_WRITE_FILE_OPS(sram);
 DEBUGFS_WRITE_FILE_OPS(log_event);
 DEBUGFS_READ_FILE_OPS(nvm);
@@ -667,6 +710,7 @@ DEBUGFS_READ_FILE_OPS(qos);
 DEBUGFS_READ_FILE_OPS(led);
 #endif
 DEBUGFS_READ_FILE_OPS(thermal_throttling);
+DEBUGFS_READ_WRITE_FILE_OPS(disable_ht40_mode);
 
 /*
  * Create the debugfs files and directories
@@ -708,6 +752,7 @@ int iwl_dbgfs_register(struct iwl_priv *priv, const
char *name)
        DEBUGFS_ADD_FILE(led, data);
 #endif
        DEBUGFS_ADD_FILE(thermal_throttling, data);
+       DEBUGFS_ADD_FILE(disable_ht40_mode, data);
        DEBUGFS_ADD_BOOL(disable_sensitivity, rf,
&priv->disable_sens_cal);
        DEBUGFS_ADD_BOOL(disable_chain_noise, rf,
                         &priv->disable_chain_noise_cal);
@@ -747,6 +792,7 @@ void iwl_dbgfs_unregister(struct iwl_priv *priv)
        DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_led);
 #endif
        DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_thermal_throttling);
+       DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_disable_ht40_mode);
        DEBUGFS_REMOVE(priv->dbgfs->dir_data);
        DEBUGFS_REMOVE(priv->dbgfs->dbgfs_rf_files.file_disable_sensitivity);
        DEBUGFS_REMOVE(priv->dbgfs->dbgfs_rf_files.file_disable_chain_noise);
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h
b/drivers/net/wireless/iwlwifi/iwl-dev.h
index facbc3d..0ee3ad2 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1164,6 +1164,7 @@ struct iwl_priv {
        /* debugging info */
        u32 framecnt_to_us;
        atomic_t restrict_refcnt;
+       bool disable_ht40;
 #ifdef CONFIG_IWLWIFI_DEBUGFS
        /* debugfs */
        struct iwl_debugfs *dbgfs;
-- 
1.5.6.3