Hi Guenter,
On Fri, Apr 21, 2017 at 03:15:52PM -0700, Guenter Roeck wrote:
> +/*
> + * Logging
> + */
> +
> +#ifdef CONFIG_DEBUG_FS
> +
> +static bool tcpm_log_full(struct tcpm_port *port)
> +{
> + return port->logbuffer_tail ==
> + (port->logbuffer_head + 1) % LOG_BUFFER_ENTRIES;
> +}
> +
> +static void _tcpm_log(struct tcpm_port *port, const char *fmt, va_list args)
> +{
> + char tmpbuffer[LOG_BUFFER_ENTRY_SIZE];
> + u64 ts_nsec = local_clock();
> + unsigned long rem_nsec;
> +
> + if (!port->logbuffer[port->logbuffer_head]) {
> + port->logbuffer[port->logbuffer_head] =
> + kzalloc(LOG_BUFFER_ENTRY_SIZE, GFP_KERNEL);
> + if (!port->logbuffer[port->logbuffer_head])
> + return;
> + }
> +
> + vsnprintf(tmpbuffer, sizeof(tmpbuffer), fmt, args);
> +
> + mutex_lock(&port->logbuffer_lock);
> +
> + if (tcpm_log_full(port)) {
> + port->logbuffer_head = max(port->logbuffer_head - 1, 0);
> + strcpy(tmpbuffer, "overflow");
> + }
> +
> + if (port->logbuffer_head < 0 ||
> + port->logbuffer_head >= LOG_BUFFER_ENTRIES) {
> + dev_warn(port->dev,
> + "Bad log buffer index %d\n", port->logbuffer_head);
> + goto abort;
> + }
> +
> + if (!port->logbuffer[port->logbuffer_head]) {
> + dev_warn(port->dev,
> + "Log buffer index %d is NULL\n", port->logbuffer_head);
> + goto abort;
> + }
> +
> + rem_nsec = do_div(ts_nsec, 1000000000);
> + scnprintf(port->logbuffer[port->logbuffer_head],
> + LOG_BUFFER_ENTRY_SIZE, "[%5lu.%06lu] %s",
> + (unsigned long)ts_nsec, rem_nsec / 1000,
> + tmpbuffer);
> + port->logbuffer_head = (port->logbuffer_head + 1) % LOG_BUFFER_ENTRIES;
> +
> +abort:
> + mutex_unlock(&port->logbuffer_lock);
> +}
> +
> +static void tcpm_log(struct tcpm_port *port, const char *fmt, ...)
> +{
> + va_list args;
> +
> + /* Do not log while disconnected and unattached */
> + if (tcpm_port_is_disconnected(port) &&
> + (port->state == SRC_UNATTACHED || port->state == SNK_UNATTACHED ||
> + port->state == DRP_TOGGLING))
> + return;
> +
> + va_start(args, fmt);
> + _tcpm_log(port, fmt, args);
> + va_end(args);
> +}
> +
> +static void tcpm_log_force(struct tcpm_port *port, const char *fmt, ...)
> +{
> + va_list args;
> +
> + va_start(args, fmt);
> + _tcpm_log(port, fmt, args);
> + va_end(args);
> +}
> +
> +static int tcpm_seq_show(struct seq_file *s, void *v)
> +{
> + struct tcpm_port *port = (struct tcpm_port *)s->private;
> + int tail;
> +
> + mutex_lock(&port->logbuffer_lock);
> + tail = port->logbuffer_tail;
> + while (tail != port->logbuffer_head) {
> + seq_printf(s, "%s\n", port->logbuffer[tail]);
> + tail = (tail + 1) % LOG_BUFFER_ENTRIES;
> + }
> + if (!seq_has_overflowed(s))
> + port->logbuffer_tail = tail;
> + mutex_unlock(&port->logbuffer_lock);
> +
> + return 0;
> +}
> +
> +static int tcpm_debug_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, tcpm_seq_show, inode->i_private);
> +}
> +
> +static const struct file_operations tcpm_debug_operations = {
> + .open = tcpm_debug_open,
> + .llseek = seq_lseek,
> + .read = seq_read,
> + .release = single_release,
> +};
> +
> +static struct dentry *rootdir;
> +
> +static int tcpm_debugfs_init(struct tcpm_port *port)
> +{
> + mutex_init(&port->logbuffer_lock);
> + /* /sys/kernel/debug/tcpm/usbcX */
> + if (!rootdir) {
> + rootdir = debugfs_create_dir("tcpm", NULL);
> + if (!rootdir)
> + return -ENOMEM;
> + }
> +
> + port->dentry = debugfs_create_file(dev_name(port->dev),
> + S_IFREG | 0444, rootdir,
> + port, &tcpm_debug_operations);
> +
> + return 0;
> +}
> +
> +static void tcpm_debugfs_exit(struct tcpm_port *port)
> +{
> + debugfs_remove(port->dentry);
> +}
> +
> +#else
>
> +static void tcpm_log(const struct tcpm_port *port, const char *fmt, ...) { }
> +static int tcpm_debugfs_init(const struct tcpm_port *port) { return 0; }
> +static void tcpm_debugfs_exit(const struct tcpm_port *port) { }
> +
> +#endif
I think those should be converted into tracepoints at one point.
Thanks,
--
heikki
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