Re: [PATCH 4/4] n_tracerouter and n_tracesink ldisc additions.

From: J Freyensee
Date: Thu May 05 2011 - 13:09:02 EST


On Sun, 2011-04-24 at 03:04 +0200, Jesper Juhl wrote:
> On Fri, 22 Apr 2011, james_p_freyensee@xxxxxxxxxxxxxxx wrote:
>
> > From: J Freyensee <james_p_freyensee@xxxxxxxxxxxxxxx>
> >
> > The n_tracerouter and n_tracesink line discpline drivers use the
> > Linux tty line discpline framework to route trace data coming
> > from a tty port (say UART for example) to the trace sink line
> > discipline driver and to another tty port(say USB). Those
> > these two line discipline drivers can be used together,
> > independently from pti.c, they are part of the original
> > implementation solution of the MIPI P1149.7, compact JTAG, PTI
> > solution for Intel mobile platforms starting with the
> > Medfield platform.
> >
> > Signed-off-by: J Freyensee <james_p_freyensee@xxxxxxxxxxxxxxx>
>
> A few minor comments can be found below.
>
>
> ...
> > +static int n_tracesink_open(struct tty_struct *tty)
> > +{
> > + int retval = -EEXIST;
> > +
> > + mutex_lock(&writelock);
> > + if (this_tty == NULL) {
> > +
> > + this_tty = tty_kref_get(tty);
> > +
>
> pointless blank line. I'd suggest removing it.
>
>
> ...
> > + if (this_tty == NULL)
> > + retval = -EFAULT;
> > + else {
>
> If one branch requires braces, both should have them
>
> } else {
>

It's not this way because it passed checkpatch.pl. In fact, I believe
checkpatch.pl will complain if I add {} to a single if() line.

>
> ...
> > +static void n_tracesink_close(struct tty_struct *tty)
> > +{
> > +
> > + mutex_lock(&writelock);
> > + tty_driver_flush_buffer(tty);
> > + tty_kref_put(this_tty);
> > + this_tty = NULL;
> > + tty->disc_data = NULL;
> > + mutex_unlock(&writelock);
> > +
> > +}
>
> pointless blank line at end of function. Remove it.
>
>
> > +static int __init n_tracesink_init(void)
> > +{
> > + int retval;
> > +
> > + /* Note N_TRACESINK is defined in linux/tty.h */
> > + retval = tty_register_ldisc(N_TRACESINK, &tty_n_tracesink);
> > +
> > + if (retval < 0)
> > + pr_err("%s: Registration failed: %d\n", __func__, retval);
> > +
> > + return retval;
> > +}
>
> How about shortening is a bit - like this?
>
> static int __init n_tracesink_init(void)
> {
> /* Note N_TRACESINK is defined in linux/tty.h */
> int retval = tty_register_ldisc(N_TRACESINK, &tty_n_tracesink);
>
> if (retval < 0)
> pr_err("%s: Registration failed: %d\n", __func__, retval);
>
> return retval;
> }

I can make the minor modification.

>
> ...
> > +static void __exit n_tracesink_exit(void)
> > +{
> > + int retval;
> > +
> > + retval = tty_unregister_ldisc(N_TRACESINK);
> > +
> > + if (retval < 0)
> > + pr_err("%s: Unregistration failed: %d\n", __func__, retval);
> > +}
>
> How about:
>
> static void __exit n_tracesink_exit(void)
> {
> int retval = tty_unregister_ldisc(N_TRACESINK);
>
> if (retval < 0)
> pr_err("%s: Unregistration failed: %d\n", __func__, retval);
> }
>
>
Dido here.

> ...
> > --- a/include/linux/tty.h
> > +++ b/include/linux/tty.h
> > @@ -50,6 +50,8 @@
> > #define N_CAIF 20 /* CAIF protocol for talking to modems */
> > #define N_GSM0710 21 /* GSM 0710 Mux */
> > #define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */
> > +#define N_TRACESINK 23 /* Trace data routing for MIPI P1149.7 */
> > +#define N_TRACEROUTER 24 /* Trace data routing for MIPI P1149.7 */
> >
>
> Lining up those defines would be nice :)
>
>


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