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);
+}
+
+static inline void edge_heartbeat_reschedule(struct edgeport_serial
+ *edge_serial)
+{
+ if (edge_serial->fw_version > FW_HEARTBEAT_VERSION_CUTOFF) {
+ schedule_delayed_work(&edge_serial->heartbeat_work,
+ FW_HEARTBEAT_SECS * HZ);
+ }
+}
+
static int edge_startup(struct usb_serial *serial)
{
struct edgeport_serial *edge_serial;
@@ -2401,6 +2444,9 @@ static int edge_startup(struct usb_serial *serial)
return status;
}
+ INIT_DELAYED_WORK(&edge_serial->heartbeat_work, edge_heartbeat_work);
+ edge_heartbeat_reschedule(edge_serial);
+
return 0;
}
@@ -2410,7 +2456,10 @@ 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);
+
+ cancel_delayed_work_sync(&edge_serial->heartbeat_work);
+ kfree(edge_serial);
}
static int edge_port_probe(struct usb_serial_port *port)
@@ -2514,6 +2563,25 @@ 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);
+
+ cancel_delayed_work_sync(&edge_serial->heartbeat_work);
+
+ return 0;
+}
+
+static int edge_resume(struct usb_serial *serial)
+{
+ struct edgeport_serial *edge_serial = usb_get_serial_data(serial);
+
+ edge_heartbeat_reschedule(edge_serial);
+
+ return 0;
+}
+#endif
static struct usb_serial_driver edgeport_1port_device = {
.driver = {
@@ -2546,6 +2614,10 @@ static struct usb_serial_driver edgeport_1port_device = {
.read_int_callback = edge_interrupt_callback,
.read_bulk_callback = edge_bulk_in_callback,
.write_bulk_callback = edge_bulk_out_callback,
+#ifdef CONFIG_PM
+ .suspend = edge_suspend,
+ .resume = edge_resume,
+#endif
};
static struct usb_serial_driver edgeport_2port_device = {
@@ -2579,6 +2651,10 @@ static struct usb_serial_driver edgeport_2port_device = {
.read_int_callback = edge_interrupt_callback,
.read_bulk_callback = edge_bulk_in_callback,
.write_bulk_callback = edge_bulk_out_callback,
+#ifdef CONFIG_PM
+ .suspend = edge_suspend,
+ .resume = edge_resume,
+#endif
};
static struct usb_serial_driver * const serial_drivers[] = {
--
1.8.3.1
--
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