Hi Johan:
Again, I think I'm about ready to post a v5 patchset that addresses your
comments here and elsewhere. I'll include point-by-point response notes
to your comments below.
Thanks!
--Peter
On Thu, 2015-06-11 at 12:26 +0200, Johan Hovold wrote:
> On Mon, Jun 08, 2015 at 02:51:37PM -0500, Peter E. Berger wrote:
> > From: "Peter E. Berger" <pberger@xxxxxxxxxxx>
> >
> > When using newer Edgeport devices such as the EP/416, idle ports are
> > automatically bounced (disconnected and then reconnected) approximately
> > every 60 seconds. This breaks programs (e.g: minicom) where idle periods
> > are common, normal and expected.
> >
> > I confirmed with the manufacturer (Digi International) that some Edgeports
> > now ship from the factory with firmware that expects periodic "heartbeat"
> > queries from the driver to keep idle ports alive. This patch implements
> > heartbeat support using the mechanism Digi suggested (periodically
> > requesting an I2C descriptor address) that appears effective on Edgeports
> > running the newer firmware (that require it) and benign on Edgeport
> > devices running older firmware. Since we know that Edgeport firmware
> > version 4.80 (the version distributed in /lib/firmware/down3.bin and used
> > for Edgeports that are either running still older versions or have no
> > onboard non-volatile firmware image) does not require heartbeat support,
> > this patch only schedules heartbeats on devices running firmware versions
> > newer than 4.80.
> >
> > Signed-off-by: Peter E. Berger <pberger@xxxxxxxxxxx>
> > ---
> > drivers/usb/serial/io_ti.c | 81 +++++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 80 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
> > index 00e1034..4dd3648 100644
> > --- a/drivers/usb/serial/io_ti.c
> > +++ b/drivers/usb/serial/io_ti.c
> > @@ -101,6 +101,7 @@ struct edgeport_serial {
> > struct mutex es_lock;
> > int num_ports_open;
> > struct usb_serial *serial;
> > + struct delayed_work heartbeat_work;
> > int fw_version;
> > };
> >
> > @@ -206,6 +207,18 @@ static void edge_send(struct usb_serial_port *port, struct tty_struct *tty);
> > static int edge_create_sysfs_attrs(struct usb_serial_port *port);
> > static int edge_remove_sysfs_attrs(struct usb_serial_port *port);
> >
> > +/*
> > + * Some release of Edgeport firmware "down3.bin" after version 4.80
> > + * introduced code to automatically disconnect idle or closed devices
> > + * after periods of inactivity, typically ~60 seconds. Digi International
> > + * Tech Support suggests adding driver "heartbeat" code to reset the
> > + * firmware timer by requesting a descriptor record every 15 seconds,
> > + * which should be effective with newer firmware versions that require
> > + * it, and benign with older versions that do not. In practice 40 seconds
> > + * seems often enough.
> > + */
> > +#define FW_HEARTBEAT_VERSION_CUTOFF ((4<<8) + 80)
>
> Add spaces around <<
Done.
>
> > +#define FW_HEARTBEAT_SECS 40
> >
> > static int ti_vread_sync(struct usb_device *dev, __u8 request,
> > __u16 value, __u16 index, u8 *data, int size)
> > @@ -2351,6 +2364,28 @@ static void edge_break(struct tty_struct *tty, int break_state)
> > __func__, status);
> > }
> >
> > +static void edge_heartbeat_work(struct work_struct *taskp)
>
> Call the argument "work" as well.
Done.
>
> > +{
> > + struct edgeport_serial *serial;
> > + struct ti_i2c_desc *rom_desc;
> > +
> > + serial = container_of(taskp, struct edgeport_serial,
> > + heartbeat_work.work);
> > +
> > + rom_desc = kmalloc(sizeof(*rom_desc), GFP_KERNEL);
> > +
> > + /* Descriptor address request is enough to reset the firmware timer */
> > + if (!rom_desc || !get_descriptor_addr(serial, I2C_DESC_TYPE_ION,
> > + rom_desc)) {
> > + dev_warn(&serial->serial->interface->dev,
> > + "%s - Incomplete heartbeat.", __func__);
>
> Missing '\n' on error message (and skip the period).
Done.
>
> Use dev_err.
Done.
>
> > + }
> > + kfree(rom_desc);
> > +
> > + schedule_delayed_work(&serial->heartbeat_work, FW_HEARTBEAT_SECS * HZ);
> > +
>
> Stray newline.
Done.
>
> > +}
> > +
> > static int edge_startup(struct usb_serial *serial)
> > {
> > struct edgeport_serial *edge_serial;
> > @@ -2362,6 +2397,8 @@ static int edge_startup(struct usb_serial *serial)
> > u8 fw_major_version;
> > u8 fw_minor_version;
> >
> > + dev_dbg(&serial->interface->dev, "%s: serial:%s\n", __func__,
> > + serial->dev->serial);
>
> Drop this one.
Done.
>
> > /* create our private serial structure */
> > edge_serial = kzalloc(sizeof(struct edgeport_serial), GFP_KERNEL);
> > if (!edge_serial)
> > @@ -2392,6 +2429,13 @@ static int edge_startup(struct usb_serial *serial)
> > return status;
> > }
> >
> > + if (edge_serial->fw_version > FW_HEARTBEAT_VERSION_CUTOFF) {
> > + INIT_DELAYED_WORK(&edge_serial->heartbeat_work,
> > + edge_heartbeat_work);
>
> Init unconditionally.
Done.
>
> > + schedule_delayed_work(&edge_serial->heartbeat_work,
> > + FW_HEARTBEAT_SECS * HZ);
>
> But only schedule if > cutoff-version, possibly refactor that to an
> inline helper function edge_heartbeat_reschedule().
Done.
>
> > + }
> > +
> > return 0;
> > }
> >
> > @@ -2401,7 +2445,11 @@ static void edge_disconnect(struct usb_serial *serial)
> >
> > static void edge_release(struct usb_serial *serial)
> > {
> > - kfree(usb_get_serial_data(serial));
> > + struct edgeport_serial *edge_serial = usb_get_serial_data(serial);
> > +
> > + if (edge_serial->fw_version > FW_HEARTBEAT_VERSION_CUTOFF)
> > + cancel_delayed_work_sync(&edge_serial->heartbeat_work);
>
> Cancel unconditionally.
Done.
>
> > + kfree(edge_serial);
> > }
> >
> > static int edge_port_probe(struct usb_serial_port *port)
> > @@ -2505,6 +2553,29 @@ static int edge_remove_sysfs_attrs(struct usb_serial_port *port)
> > return 0;
> > }
> >
> > +#ifdef CONFIG_PM
> > +static int edge_suspend(struct usb_serial *serial, pm_message_t message)
> > +{
> > + struct edgeport_serial *edge_serial = usb_get_serial_data(serial);
> > +
> > + if (edge_serial->fw_version > FW_HEARTBEAT_VERSION_CUTOFF)
> > + cancel_delayed_work_sync(&edge_serial->heartbeat_work);
>
> Same here.
Done.
> > +
> > + return 0;
> > +}
> > +
> > +static int edge_resume(struct usb_serial *serial)
> > +{
> > + struct edgeport_serial *edge_serial = usb_get_serial_data(serial);
> > +
> > + if (edge_serial->fw_version > FW_HEARTBEAT_VERSION_CUTOFF) {
> > + schedule_delayed_work(&edge_serial->heartbeat_work,
> > + FW_HEARTBEAT_SECS * HZ);
> > + }
>
> Use helper here as well.
Done.
>
> > +
> > + return 0;
> > +}
> > +#endif
>
> Thanks,
> Johan
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