On Thu, Jun 18, 2015 at 06:43:36AM -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 schedules heartbeats only on devices running firmware versions
> newer than 4.80.
>
> Signed-off-by: Peter E. Berger <pberger@xxxxxxxxxxx>
> ---
> drivers/usb/serial/io_ti.c | 78 +++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 77 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
> index c76820b..b7c1ea1 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 devices after periods
> + * of inactivity, typically ~60 seconds. This occurs without regard to
> + * whether ports on the device are open or not. Digi International Tech
> + * Support suggested 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)
> +#define FW_HEARTBEAT_SECS 40
>
> /* Timeouts in msecs: firmware downloads take longer */
> #define TI_VSEND_TIMEOUT_DEFAULT 1000
> @@ -2354,6 +2367,36 @@ static void edge_break(struct tty_struct *tty, int break_state)
> __func__, status);
> }
>
> +static void edge_heartbeat_work(struct work_struct *work)
> +{
> + struct edgeport_serial *serial;
> + struct ti_i2c_desc *rom_desc;
> +
> + serial = container_of(work, 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_err(&serial->serial->interface->dev,
> + "%s - Incomplete heartbeat\n", __func__);
> + }
> + kfree(rom_desc);
> +
> + schedule_delayed_work(&serial->heartbeat_work, FW_HEARTBEAT_SECS * HZ);
Use the helper here as well.
> +}
> +
> +static inline void edge_heartbeat_reschedule(struct edgeport_serial
> + *edge_serial)
Odd line break, rename edge_serial or break after void instead if needed.
Perhaps just edge_heartbeat_schedule would have been a better name.
> +{
> + if (edge_serial->fw_version > FW_HEARTBEAT_VERSION_CUTOFF) {
Return if <= cutoff instead.
> + schedule_delayed_work(&edge_serial->heartbeat_work,
> + FW_HEARTBEAT_SECS * HZ);
> + }
> +}
Looks good otherwise.
Thanks,
Johan
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