[PATCH] iwlwifi: set fixed rate through debugfs

This patch adds fixed rate setting through debugfs

$ echo <rate_n_flags> > \
/sys/kernel/debug/ieee80211/phy<X>/stations/<mac>/rate_scale_table

Currently there is no way to turn to rate scaling working again.
Will be fixed in later.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-4965-rs.c

@@ -124,6 +124,8 @@ struct iwl_rate_scale_priv {
 	struct iwl_scale_tbl_info lq_info[LQ_SIZE];
 #ifdef CONFIG_MAC80211_DEBUGFS
 	struct dentry *rs_sta_dbgfs_scale_table_file;
+	struct iwl_rate dbg_fixed;
+	struct iwl_priv *drv;
 #endif
 };
 
@@ -136,6 +138,14 @@ static void rs_fill_link_cmd(struct iwl_rate_scale_priv *lq_data,
 			     struct iwl_link_quality_cmd *tbl);
 
 
+#ifdef CONFIG_MAC80211_DEBUGFS
+static void rs_dbgfs_set_mcs(struct iwl_rate_scale_priv *rs_priv,
+				struct iwl_rate *mcs, int index);
+#else
+static void rs_dbgfs_set_mcs(struct iwl_rate_scale_priv *rs_priv,
+				struct iwl_rate *mcs, int index)
+{}
+#endif
 static s32 expected_tpt_A[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186, 186
 };
@@ -1866,6 +1876,9 @@ static void rs_rate_init(void *priv_rate, void *priv_sta,
 	IWL_DEBUG_HT("MIMO RATE 0x%X SISO MASK 0x%X\n", crl->active_siso_rate,
 		     crl->active_mimo_rate);
 #endif /*CONFIG_IWLWIFI_HT*/
+#ifdef CONFIG_MAC80211_DEBUGFS
+	crl->drv = priv;
+#endif
 
 	if (priv->assoc_station_added)
 		priv->lq_mngr.lq_ready = 1;
@@ -1885,6 +1898,8 @@ static void rs_fill_link_cmd(struct iwl_rate_scale_priv *lq_data,
 	struct iwl_rate new_rate;
 	struct iwl_scale_tbl_info tbl_type = { 0 };
 
+	rs_dbgfs_set_mcs(lq_data, tx_mcs, index);
+
 	rs_get_tbl_info_from_mcs(tx_mcs, lq_data->phymode,
 				  &tbl_type, &rate_idx);
 
@@ -1919,6 +1934,8 @@ static void rs_fill_link_cmd(struct iwl_rate_scale_priv *lq_data,
 					ant_toggle_count = 1;
 				}
 			}
+
+			rs_dbgfs_set_mcs(lq_data, &new_rate, index);
 			lq_cmd->rs_table[index].rate_n_flags =
 					cpu_to_le32(new_rate.rate_n_flags);
 			repeat_rate--;
@@ -1947,6 +1964,7 @@ static void rs_fill_link_cmd(struct iwl_rate_scale_priv *lq_data,
 
 		use_ht_possible = 0;
 
+		rs_dbgfs_set_mcs(lq_data, &new_rate, index);
 		lq_cmd->rs_table[index].rate_n_flags =
 				cpu_to_le32(new_rate.rate_n_flags);
 
@@ -2002,7 +2020,54 @@ static int open_file_generic(struct inode *inode, struct file *file)
 	file->private_data = inode->i_private;
 	return 0;
 }
+static void rs_dbgfs_set_mcs(struct iwl_rate_scale_priv *rs_priv,
+				struct iwl_rate *mcs, int index)
+{
+	const u32 cck_rate = 0x820A;
+	if (rs_priv->dbg_fixed.rate_n_flags) {
+		if (index < 12)
+			mcs->rate_n_flags = rs_priv->dbg_fixed.rate_n_flags;
+		else
+			mcs->rate_n_flags = cck_rate;
+		IWL_DEBUG_RATE("Fixed rate ON\n");
+		return;
+	}
+
+	IWL_DEBUG_RATE("Fixed rate OFF\n");
+}
 
+static ssize_t rs_sta_dbgfs_scale_table_write(struct file *file,
+			const char __user *user_buf, size_t count, loff_t *ppos)
+{
+	struct iwl_rate_scale_priv *rs_priv = file->private_data;
+	char buf[64];
+	int buf_size;
+	u32 parsed_rate;
+
+	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, "%x", &parsed_rate) == 1)
+		rs_priv->dbg_fixed.rate_n_flags = parsed_rate;
+	else
+		rs_priv->dbg_fixed.rate_n_flags = 0;
+
+	rs_priv->active_rate = 0x0FFF;
+	rs_priv->active_siso_rate = 0x1FD0;
+	rs_priv->active_mimo_rate = 0x1FD0;
+
+	IWL_DEBUG_RATE("sta_id %d rate 0x%X\n",
+		rs_priv->lq.sta_id, rs_priv->dbg_fixed.rate_n_flags);
+
+	if (rs_priv->dbg_fixed.rate_n_flags) {
+		rs_fill_link_cmd(rs_priv, &rs_priv->dbg_fixed, &rs_priv->lq);
+		rs_send_lq_cmd(rs_priv->drv, &rs_priv->lq, CMD_ASYNC);
+	}
+
+	return count;
+}
 static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
 			char __user *user_buf, size_t count, loff_t *ppos)
 {
@@ -2013,9 +2078,11 @@ static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
 	struct iwl_rate_scale_priv *rs_priv = file->private_data;
 
 	desc += sprintf(buff+desc, "sta_id %d\n", rs_priv->lq.sta_id);
-	desc += sprintf(buff+desc, "failed=%d success=%d rate=%X\n",
+	desc += sprintf(buff+desc, "failed=%d success=%d rate=0%X\n",
 			rs_priv->total_failed, rs_priv->total_success,
 			rs_priv->active_rate);
+	desc += sprintf(buff+desc, "fixed rate 0x%X\n",
+			rs_priv->dbg_fixed.rate_n_flags);
 	desc += sprintf(buff+desc, "general:"
 		"flags=0x%X mimo-d=%d s-ant0x%x d-ant=0x%x\n",
 		rs_priv->lq.general_params.flags,
@@ -2045,6 +2112,7 @@ static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
 }
 
 static const struct file_operations rs_sta_dbgfs_scale_table_ops = {
+	.write = rs_sta_dbgfs_scale_table_write,
 	.read = rs_sta_dbgfs_scale_table_read,
 	.open = open_file_generic,
 };