n_smux: add debugfs node for printing channel states
Add debugfs node that prints detailed state information
for all smux channels.
Change-Id: I727f1c53797ee317856056b8e4d9a8686940ce0f
Signed-off-by: Brent Hronik <bhronik@codeaurora.org>
Signed-off-by: Angshuman Sarkar <angshuman@codeaurora.org>
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>
diff --git a/drivers/tty/smux_debug.c b/drivers/tty/smux_debug.c
new file mode 100644
index 0000000..86377d6
--- /dev/null
+++ b/drivers/tty/smux_debug.c
@@ -0,0 +1,170 @@
+/* drivers/tty/smux_debug.c
+ *
+ * Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/debugfs.h>
+#include <linux/list.h>
+#include <linux/ctype.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/completion.h>
+#include <linux/termios.h>
+#include <linux/smux.h>
+#include "smux_private.h"
+
+#define DEBUG_BUFMAX 4096
+
+
+
+/**
+ * smux_dump_ch() - Dumps the information of a channel to the screen.
+ * @buf: Buffer for status message.
+ * @max: Size of status queue.
+ * @lch_number: Number of the logical channel.
+ * @lch: Pointer to the lch_number'th instance of struct smux_lch_t.
+ *
+ */
+static int smux_dump_ch(char *buf, int max, struct smux_lch_t *lch)
+{
+ int bytes_written;
+ long tiocm_bits;
+ unsigned long flags;
+
+ spin_lock_irqsave(&lch->state_lock_lhb1, flags);
+ spin_lock(&lch->tx_lock_lhb2);
+
+ tiocm_bits = msm_smux_tiocm_get_atomic(lch);
+
+ bytes_written = scnprintf(
+ buf, max,
+ "ch%02d: "
+ "%s(%s) "
+ "%c%c%c%c%c "
+ "%d "
+ "%s(%s) "
+ "%c%c\n",
+ lch->lcid,
+ local_lch_state(lch->local_state), lch_mode(lch->local_mode),
+ (tiocm_bits & TIOCM_DSR) ? 'D' : 'd',
+ (tiocm_bits & TIOCM_CTS) ? 'T' : 't',
+ (tiocm_bits & TIOCM_RI) ? 'I' : 'i',
+ (tiocm_bits & TIOCM_CD) ? 'C' : 'c',
+ lch->tx_flow_control ? 'F' : 'f',
+ lch->tx_pending_data_cnt,
+ remote_lch_state(lch->remote_state), lch_mode(lch->remote_mode),
+ (tiocm_bits & TIOCM_DTR) ? 'R' : 'r',
+ (tiocm_bits & TIOCM_RTS) ? 'S' : 's'
+ );
+
+ spin_unlock(&lch->tx_lock_lhb2);
+ spin_unlock_irqrestore(&lch->state_lock_lhb1, flags);
+
+ return bytes_written;
+}
+
+/**
+ * smux_dump_format_ch() - Informs user of format for channel dump
+ * @buf: Buffer for status message.
+ * @max: Size of status queue.
+ *
+ */
+static int smux_dump_format_ch(char *buf, int max)
+{
+ return scnprintf(
+ buf, max,
+ "ch_id "
+ "local state(mode) tiocm "
+ "tx_queue "
+ "remote state(mode) tiocm\n"
+ "local tiocm: DSR(D) CTS(T) RI(I) DCD(C) FLOW_CONTROL(F)\n"
+ "remote tiocm: DTR(R) RTS(S)\n"
+ "A capital letter indicates set, otherwise, it is not set.\n\n"
+ );
+}
+
+/**
+ * smux_debug_ch() - Log following information about each channel
+ * local open, local mode, remote open, remote mode,
+ * tiocm bits, flow control state and transmit queue size.
+ * Returns the number of bytes written to buf.
+ * @buf Buffer for status message
+ * @max Size of status queue
+ *
+ */
+static int smux_debug_ch(char *buf, int max)
+{
+ int ch_id;
+
+ int bytes_written = smux_dump_format_ch(buf, max);
+
+ for (ch_id = 0; ch_id < SMUX_NUM_LOGICAL_CHANNELS; ch_id++) {
+ bytes_written += smux_dump_ch(buf + bytes_written,
+ max - bytes_written,
+ &smux_lch[ch_id]);
+ }
+
+ return bytes_written;
+
+}
+
+static char debug_buffer[DEBUG_BUFMAX];
+
+static ssize_t debug_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ int (*fill)(char *buf, int max) = file->private_data;
+ int bsize;
+
+ if (*ppos != 0)
+ return 0;
+
+ bsize = fill(debug_buffer, DEBUG_BUFMAX);
+ return simple_read_from_buffer(buf, count, ppos, debug_buffer, bsize);
+}
+
+static int debug_open(struct inode *inode, struct file *file)
+{
+ file->private_data = inode->i_private;
+ return 0;
+}
+
+static const struct file_operations debug_ops = {
+ .read = debug_read,
+ .open = debug_open,
+};
+
+
+static void debug_create(const char *name, mode_t mode,
+ struct dentry *dent,
+ int (*fill)(char *buf, int max))
+{
+ debugfs_create_file(name, mode, dent, fill, &debug_ops);
+}
+
+
+static int __init smux_debugfs_init(void)
+{
+ struct dentry *dent;
+
+ dent = debugfs_create_dir("n_smux", 0);
+ if (IS_ERR(dent))
+ return PTR_ERR(dent);
+
+ debug_create("ch", 0444, dent, smux_debug_ch);
+
+
+ return 0;
+}
+
+late_initcall(smux_debugfs_init);