iwlwifi: adding interrupt counter in debugfs for debugging

This patch adds interrupt statistics report to debugfs, this can help to
understand number of interrupts happened which including HW/SW error for
easier and better debugging.

in /sys/kernel/debug/ieee80211/phyN/iwlagn/data directory
use "cat interrupt" to view the current interrupt counter
use "echo 0 > interrupt" to clear interrupt counter

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>

drivers/net/wireless/iwlwifi/iwl-debugfs.c

@@ -473,6 +473,95 @@ static ssize_t iwl_dbgfs_status_read(struct file *file,
 	return simple_read_from_buffer(user_buf, count, ppos, buf, pos);
 }
 
+static ssize_t iwl_dbgfs_interrupt_read(struct file *file,
+					char __user *user_buf,
+					size_t count, loff_t *ppos) {
+
+	struct iwl_priv *priv = (struct iwl_priv *)file->private_data;
+	int pos = 0;
+	int cnt = 0;
+	char *buf;
+	int bufsz = 24 * 64; /* 24 items * 64 char per item */
+	ssize_t ret;
+
+	buf = kzalloc(bufsz, GFP_KERNEL);
+	if (!buf) {
+		IWL_ERR(priv, "Can not allocate Buffer\n");
+		return -ENOMEM;
+	}
+
+	pos += scnprintf(buf + pos, bufsz - pos,
+			"Interrupt Statistics Report:\n");
+
+	pos += scnprintf(buf + pos, bufsz - pos, "HW Error:\t\t\t %u\n",
+		priv->isr_stats.hw);
+	pos += scnprintf(buf + pos, bufsz - pos, "SW Error:\t\t\t %u\n",
+		priv->isr_stats.sw);
+	if (priv->isr_stats.sw > 0) {
+		pos += scnprintf(buf + pos, bufsz - pos,
+			"\tLast Restarting Code:  0x%X\n",
+			priv->isr_stats.sw_err);
+	}
+#ifdef CONFIG_IWLWIFI_DEBUG
+	pos += scnprintf(buf + pos, bufsz - pos, "Frame transmitted:\t\t %u\n",
+		priv->isr_stats.sch);
+	pos += scnprintf(buf + pos, bufsz - pos, "Alive interrupt:\t\t %u\n",
+		priv->isr_stats.alive);
+#endif
+	pos += scnprintf(buf + pos, bufsz - pos,
+		"HW RF KILL switch toggled:\t %u\n",
+		priv->isr_stats.rfkill);
+
+	pos += scnprintf(buf + pos, bufsz - pos, "CT KILL:\t\t\t %u\n",
+		priv->isr_stats.ctkill);
+
+	pos += scnprintf(buf + pos, bufsz - pos, "Wakeup Interrupt:\t\t %u\n",
+		priv->isr_stats.wakeup);
+
+	pos += scnprintf(buf + pos, bufsz - pos,
+		"Rx command responses:\t\t %u\n",
+		priv->isr_stats.rx);
+	for (cnt = 0; cnt < REPLY_MAX; cnt++) {
+		if (priv->isr_stats.rx_handlers[cnt] > 0)
+			pos += scnprintf(buf + pos, bufsz - pos,
+				"\tRx handler[%36s]:\t\t %u\n",
+				get_cmd_string(cnt),
+				priv->isr_stats.rx_handlers[cnt]);
+	}
+
+	pos += scnprintf(buf + pos, bufsz - pos, "Tx/FH interrupt:\t\t %u\n",
+		priv->isr_stats.tx);
+
+	pos += scnprintf(buf + pos, bufsz - pos, "Unexpected INTA:\t\t %u\n",
+		priv->isr_stats.unhandled);
+
+	ret = simple_read_from_buffer(user_buf, count, ppos, buf, pos);
+	kfree(buf);
+	return ret;
+}
+
+static ssize_t iwl_dbgfs_interrupt_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;
+	u32 reset_flag;
+
+	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", &reset_flag) != 1)
+		return -EFAULT;
+	if (reset_flag == 0)
+		iwl_clear_isr_stats(priv);
+
+	return count;
+}
+
+
 DEBUGFS_READ_WRITE_FILE_OPS(sram);
 DEBUGFS_WRITE_FILE_OPS(log_event);
 DEBUGFS_READ_FILE_OPS(eeprom);
@@ -481,6 +570,7 @@ DEBUGFS_READ_FILE_OPS(rx_statistics);
 DEBUGFS_READ_FILE_OPS(tx_statistics);
 DEBUGFS_READ_FILE_OPS(channels);
 DEBUGFS_READ_FILE_OPS(status);
+DEBUGFS_READ_WRITE_FILE_OPS(interrupt);
 
 /*
  * Create the debugfs files and directories
@@ -516,6 +606,7 @@ int iwl_dbgfs_register(struct iwl_priv *priv, const char *name)
 	DEBUGFS_ADD_FILE(tx_statistics, data);
 	DEBUGFS_ADD_FILE(channels, data);
 	DEBUGFS_ADD_FILE(status, data);
+	DEBUGFS_ADD_FILE(interrupt, data);
 	DEBUGFS_ADD_BOOL(disable_sensitivity, rf, &priv->disable_sens_cal);
 	DEBUGFS_ADD_BOOL(disable_chain_noise, rf,
 			 &priv->disable_chain_noise_cal);
@@ -546,6 +637,7 @@ void iwl_dbgfs_unregister(struct iwl_priv *priv)
 	DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_stations);
 	DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_channels);
 	DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_status);
+	DEBUGFS_REMOVE(priv->dbgfs->dbgfs_data_files.file_interrupt);
 	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);