iwlwifi: dump "Control and Status Register" when detect uCode HW/SW error

When uCode HW/SW error detected, dumping important CSR (Control and Status
Registers) values.
Also add "csr" debugfs file to dump the current values of CSR defined in
CSR table to syslog.

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>
diff --git a/drivers/net/wireless/iwlwifi/iwl-debugfs.c b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
index 21e0f66..2be3549 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debugfs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
@@ -1845,6 +1845,28 @@
 	return count;
 }
 
+static ssize_t iwl_dbgfs_csr_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 csr;
+
+	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", &csr) != 1)
+		return -EFAULT;
+
+	if (priv->cfg->ops->lib->dump_csr)
+		priv->cfg->ops->lib->dump_csr(priv);
+
+	return count;
+}
+
 DEBUGFS_READ_FILE_OPS(rx_statistics);
 DEBUGFS_READ_FILE_OPS(tx_statistics);
 DEBUGFS_READ_WRITE_FILE_OPS(traffic_log);
@@ -1859,6 +1881,7 @@
 DEBUGFS_READ_FILE_OPS(power_save_status);
 DEBUGFS_WRITE_FILE_OPS(clear_ucode_statistics);
 DEBUGFS_WRITE_FILE_OPS(clear_traffic_statistics);
+DEBUGFS_WRITE_FILE_OPS(csr);
 
 /*
  * Create the debugfs files and directories
@@ -1909,6 +1932,7 @@
 	DEBUGFS_ADD_FILE(power_save_status, debug, S_IRUSR);
 	DEBUGFS_ADD_FILE(clear_ucode_statistics, debug, S_IWUSR);
 	DEBUGFS_ADD_FILE(clear_traffic_statistics, debug, S_IWUSR);
+	DEBUGFS_ADD_FILE(csr, debug, S_IWUSR);
 	if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) != CSR_HW_REV_TYPE_3945) {
 		DEBUGFS_ADD_FILE(ucode_rx_stats, debug, S_IRUSR);
 		DEBUGFS_ADD_FILE(ucode_tx_stats, debug, S_IRUSR);
@@ -1966,6 +1990,7 @@
 			file_clear_ucode_statistics);
 	DEBUGFS_REMOVE(priv->dbgfs->dbgfs_debug_files.
 			file_clear_traffic_statistics);
+	DEBUGFS_REMOVE(priv->dbgfs->dbgfs_debug_files.file_csr);
 	if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) != CSR_HW_REV_TYPE_3945) {
 		DEBUGFS_REMOVE(priv->dbgfs->dbgfs_debug_files.
 			file_ucode_rx_stats);