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/Makefile b/drivers/tty/Makefile
index 9ebb54a..71f6a99 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -6,7 +6,7 @@
obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o
obj-$(CONFIG_N_HDLC) += n_hdlc.o
obj-$(CONFIG_N_GSM) += n_gsm.o
-obj-$(CONFIG_N_SMUX) += n_smux.o
+obj-$(CONFIG_N_SMUX) += n_smux.o smux_debug.o
obj-$(CONFIG_N_SMUX_LOOPBACK) += smux_test.o smux_loopback.o
obj-$(CONFIG_SMUX_CTL) += smux_ctl.o
obj-$(CONFIG_TRACE_ROUTER) += n_tracerouter.o
diff --git a/drivers/tty/n_smux.c b/drivers/tty/n_smux.c
index be4db95..20ed9fc 100644
--- a/drivers/tty/n_smux.c
+++ b/drivers/tty/n_smux.c
@@ -178,59 +178,6 @@
SMUX_PWR_OFF_FLUSH,
};
-/**
- * Logical Channel Structure. One instance per channel.
- *
- * Locking Hierarchy
- * Each lock has a postfix that describes the locking level. If multiple locks
- * are required, only increasing lock hierarchy numbers may be locked which
- * ensures avoiding a deadlock.
- *
- * Locking Example
- * If state_lock_lhb1 is currently held and the TX list needs to be
- * manipulated, then tx_lock_lhb2 may be locked since it's locking hierarchy
- * is greater. However, if tx_lock_lhb2 is held, then state_lock_lhb1 may
- * not be acquired since it would result in a deadlock.
- *
- * Note that the Line Discipline locks (*_lha) should always be acquired
- * before the logical channel locks.
- */
-struct smux_lch_t {
- /* channel state */
- spinlock_t state_lock_lhb1;
- uint8_t lcid;
- unsigned local_state;
- unsigned local_mode;
- uint8_t local_tiocm;
- unsigned options;
-
- unsigned remote_state;
- unsigned remote_mode;
- uint8_t remote_tiocm;
-
- int tx_flow_control;
- int rx_flow_control_auto;
- int rx_flow_control_client;
-
- /* client callbacks and private data */
- void *priv;
- void (*notify)(void *priv, int event_type, const void *metadata);
- int (*get_rx_buffer)(void *priv, void **pkt_priv, void **buffer,
- int size);
-
- /* RX Info */
- struct list_head rx_retry_queue;
- unsigned rx_retry_queue_cnt;
- struct delayed_work rx_retry_work;
-
- /* TX Info */
- spinlock_t tx_lock_lhb2;
- struct list_head tx_queue;
- struct list_head tx_ready_list;
- unsigned tx_pending_data_cnt;
- unsigned notify_lwm;
-};
-
union notifier_metadata {
struct smux_meta_disconnected disconnected;
struct smux_meta_read read;
@@ -310,7 +257,7 @@
/* data structures */
-static struct smux_lch_t smux_lch[SMUX_NUM_LOGICAL_CHANNELS];
+struct smux_lch_t smux_lch[SMUX_NUM_LOGICAL_CHANNELS];
static struct smux_ldisc_t smux;
static const char *tty_error_type[] = {
[TTY_NORMAL] = "normal",
@@ -320,7 +267,7 @@
[TTY_FRAME] = "framing",
};
-static const char *smux_cmds[] = {
+static const char * const smux_cmds[] = {
[SMUX_CMD_DATA] = "DATA",
[SMUX_CMD_OPEN_LCH] = "OPEN",
[SMUX_CMD_CLOSE_LCH] = "CLOSE",
@@ -343,8 +290,30 @@
[SMUX_RX_RETRY_LOW_WM_HIT] = "RX_RETRY_LOW_WM_HIT",
};
-static void *log_ctx;
+static const char * const smux_local_state[] = {
+ [SMUX_LCH_LOCAL_CLOSED] = "CLOSED",
+ [SMUX_LCH_LOCAL_OPENING] = "OPENING",
+ [SMUX_LCH_LOCAL_OPENED] = "OPENED",
+ [SMUX_LCH_LOCAL_CLOSING] = "CLOSING",
+};
+static const char * const smux_remote_state[] = {
+ [SMUX_LCH_REMOTE_CLOSED] = "CLOSED",
+ [SMUX_LCH_REMOTE_OPENED] = "OPENED",
+};
+
+static const char * const smux_mode[] = {
+ [SMUX_LCH_MODE_NORMAL] = "N",
+ [SMUX_LCH_MODE_LOCAL_LOOPBACK] = "L",
+ [SMUX_LCH_MODE_REMOTE_LOOPBACK] = "R",
+};
+
+static const char * const smux_undef[] = {
+ [SMUX_UNDEF_LONG] = "UNDEF",
+ [SMUX_UNDEF_SHORT] = "U",
+};
+
+static void *log_ctx;
static void smux_notify_local_fn(struct work_struct *work);
static DECLARE_WORK(smux_notify_local, smux_notify_local_fn);
@@ -370,7 +339,6 @@
static DECLARE_DELAYED_WORK(smux_delayed_inactivity_work,
smux_inactivity_worker);
-static long msm_smux_tiocm_get_atomic(struct smux_lch_t *ch);
static void list_channel(struct smux_lch_t *ch);
static int smux_send_status_cmd(struct smux_lch_t *ch);
static int smux_dispatch_rx_pkt(struct smux_pkt_t *pkt);
@@ -387,6 +355,45 @@
static void smux_pdev_release(struct device *dev);
/**
+ * local_lch_state() - Return human readable form of local logical state.
+ * @state: Local logical channel state enum.
+ *
+ */
+const char *local_lch_state(unsigned state)
+{
+ if (state < ARRAY_SIZE(smux_local_state))
+ return smux_local_state[state];
+ else
+ return smux_undef[SMUX_UNDEF_LONG];
+}
+
+/**
+ * remote_lch_state() - Return human readable for of remote logical state.
+ * @state: Remote logical channel state enum.
+ *
+ */
+const char *remote_lch_state(unsigned state)
+{
+ if (state < ARRAY_SIZE(smux_remote_state))
+ return smux_remote_state[state];
+ else
+ return smux_undef[SMUX_UNDEF_LONG];
+}
+
+/**
+ * lch_mode() - Return human readable form of mode.
+ * @mode: Mode of the logical channel.
+ *
+ */
+const char *lch_mode(unsigned mode)
+{
+ if (mode < ARRAY_SIZE(smux_mode))
+ return smux_mode[mode];
+ else
+ return smux_undef[SMUX_UNDEF_SHORT];
+}
+
+/**
* Convert TTY Error Flags to string for logging purposes.
*
* @flag TTY_* flag
@@ -434,6 +441,9 @@
smux.in_reset = 1;
}
+/**
+ * Initialize the lch_structs.
+ */
static int lch_init(void)
{
unsigned int id;
@@ -3307,7 +3317,7 @@
*
* @returns TIOCM status
*/
-static long msm_smux_tiocm_get_atomic(struct smux_lch_t *ch)
+long msm_smux_tiocm_get_atomic(struct smux_lch_t *ch)
{
long status = 0x0;
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);
diff --git a/drivers/tty/smux_private.h b/drivers/tty/smux_private.h
index 4c901c0..b7fc1ce 100644
--- a/drivers/tty/smux_private.h
+++ b/drivers/tty/smux_private.h
@@ -39,6 +39,62 @@
struct tty_struct;
+/**
+ * Logical Channel Structure. One instance per channel.
+ *
+ * Locking Hierarchy
+ * Each lock has a postfix that describes the locking level. If multiple locks
+ * are required, only increasing lock hierarchy numbers may be locked which
+ * ensures avoiding a deadlock.
+ *
+ * Locking Example
+ * If state_lock_lhb1 is currently held and the TX list needs to be
+ * manipulated, then tx_lock_lhb2 may be locked since it's locking hierarchy
+ * is greater. However, if tx_lock_lhb2 is held, then state_lock_lhb1 may
+ * not be acquired since it would result in a deadlock.
+ *
+ * Note that the Line Discipline locks (*_lha) should always be acquired
+ * before the logical channel locks.
+ */
+struct smux_lch_t {
+ /* channel state */
+ spinlock_t state_lock_lhb1;
+ uint8_t lcid;
+ unsigned local_state;
+ unsigned local_mode;
+ uint8_t local_tiocm;
+ unsigned options;
+
+ unsigned remote_state;
+ unsigned remote_mode;
+ uint8_t remote_tiocm;
+
+ int tx_flow_control;
+ int rx_flow_control_auto;
+ int rx_flow_control_client;
+
+ /* client callbacks and private data */
+ void *priv;
+ void (*notify)(void *priv, int event_type, const void *metadata);
+ int (*get_rx_buffer)(void *priv, void **pkt_priv, void **buffer,
+ int size);
+
+ /* RX Info */
+ struct list_head rx_retry_queue;
+ unsigned rx_retry_queue_cnt;
+ struct delayed_work rx_retry_work;
+
+ /* TX Info */
+ spinlock_t tx_lock_lhb2;
+ struct list_head tx_queue;
+ struct list_head tx_ready_list;
+ unsigned tx_pending_data_cnt;
+ unsigned notify_lwm;
+};
+
+/* Each instance of smux_lch_t */
+extern struct smux_lch_t smux_lch[SMUX_NUM_LOGICAL_CHANNELS];
+
/* Packet header. */
struct smux_hdr_t {
uint16_t magic;
@@ -102,6 +158,16 @@
SMUX_LCH_REMOTE_OPENED,
};
+/* Enum used to report various undefined actions */
+enum {
+ SMUX_UNDEF_LONG,
+ SMUX_UNDEF_SHORT,
+};
+
+long msm_smux_tiocm_get_atomic(struct smux_lch_t *ch);
+const char *local_lch_state(unsigned state);
+const char *remote_lch_state(unsigned state);
+const char *lch_mode(unsigned mode);
int smux_assert_lch_id(uint32_t lcid);
void smux_init_pkt(struct smux_pkt_t *pkt);
diff --git a/drivers/tty/smux_test.c b/drivers/tty/smux_test.c
index 4c255a4..a6bd63f 100644
--- a/drivers/tty/smux_test.c
+++ b/drivers/tty/smux_test.c
@@ -1961,7 +1961,7 @@
{
struct dentry *dent;
- dent = debugfs_create_dir("n_smux", 0);
+ dent = debugfs_create_dir("n_smux_test", 0);
if (IS_ERR(dent))
return PTR_ERR(dent);