[PATCH V8 1/4] USB: serial: f81232: clear overrun flag
From: Ji-Ze Hong (Peter Hong)
Date: Thu Apr 18 2019 - 22:45:45 EST
The F81232 will report data and LSR with bulk like following format:
bulk-in data: [LSR(1Byte)+DATA(1Byte)][LSR(1Byte)+DATA(1Byte)]...
LSR will auto clear frame/parity/break error flag when reading by H/W,
but overrrun will only cleared when reading LSR. So this patch add a
worker to read LSR when overrun and flush the worker on close() &
suspend().
Cc: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@xxxxxxxxx>
---
v8:
1: Fix usb_submit_urb() in f81232_resume() with GFP_NOIO, not
GFP_KERNEL.
v7:
1: Remove serial->suspending check
2: Add port priv is_port_open to save port open state. We'll
register interrupt-in urb in f81232_resume() when port is
opened.
3: Using usb_kill_urb for read/interrupt urb to ensure urb
stopped.
v6:
1: Add deferred_lsr_work_needed to re-trigger when f81232_resume()
v5:
1: Source code base revert to v3 and remove all v4 changes.
2: Add serial->suspending check in f81232_process_read_urb()
before schedule_work(&priv->lsr_work) to avoid race condition.
v4:
1: Add serial->suspending check in f81232_lsr_worker() to avoid
re-trigger
2: Add port_priv-lsr_work_resched to re-trigger LSR worker
v3:
1: Add flush_work(&port_priv->lsr_work) in f81232_suspend().
v2:
1: Add flush_work(&port_priv->lsr_work) in f81232_close().
drivers/usb/serial/f81232.c | 97 +++++++++++++++++++++++++++++++++++++++++----
1 file changed, 89 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 0dcdcb4b2cde..1f0dd4087d79 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -41,12 +41,15 @@ MODULE_DEVICE_TABLE(usb, id_table);
#define FIFO_CONTROL_REGISTER (0x02 + SERIAL_BASE_ADDRESS)
#define LINE_CONTROL_REGISTER (0x03 + SERIAL_BASE_ADDRESS)
#define MODEM_CONTROL_REGISTER (0x04 + SERIAL_BASE_ADDRESS)
+#define LINE_STATUS_REGISTER (0x05 + SERIAL_BASE_ADDRESS)
#define MODEM_STATUS_REGISTER (0x06 + SERIAL_BASE_ADDRESS)
struct f81232_private {
struct mutex lock;
u8 modem_control;
u8 modem_status;
+ bool is_port_open;
+ struct work_struct lsr_work;
struct work_struct interrupt_work;
struct usb_serial_port *port;
};
@@ -282,6 +285,7 @@ static void f81232_read_int_callback(struct urb *urb)
static void f81232_process_read_urb(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
+ struct f81232_private *priv = usb_get_serial_port_data(port);
unsigned char *data = urb->transfer_buffer;
char tty_flag;
unsigned int i;
@@ -315,6 +319,7 @@ static void f81232_process_read_urb(struct urb *urb)
if (lsr & UART_LSR_OE) {
port->icount.overrun++;
+ schedule_work(&priv->lsr_work);
tty_insert_flip_char(&port->port, 0,
TTY_OVERRUN);
}
@@ -528,37 +533,52 @@ static int f81232_tiocmset(struct tty_struct *tty,
static int f81232_open(struct tty_struct *tty, struct usb_serial_port *port)
{
- int result;
-
- result = f81232_port_enable(port);
- if (result)
- return result;
+ struct f81232_private *port_priv = usb_get_serial_port_data(port);
+ int result = 0;
/* Setup termios */
if (tty)
f81232_set_termios(tty, port, NULL);
+ mutex_lock(&port_priv->lock);
+
+ result = f81232_port_enable(port);
+ if (result)
+ goto end;
+
result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
if (result) {
dev_err(&port->dev, "%s - failed submitting interrupt urb,"
" error %d\n", __func__, result);
- return result;
+ goto end;
}
result = usb_serial_generic_open(tty, port);
if (result) {
usb_kill_urb(port->interrupt_in_urb);
- return result;
+ goto end;
}
- return 0;
+ port_priv->is_port_open = true;
+end:
+ mutex_unlock(&port_priv->lock);
+
+ return result;
}
static void f81232_close(struct usb_serial_port *port)
{
+ struct f81232_private *port_priv = usb_get_serial_port_data(port);
+
+ mutex_lock(&port_priv->lock);
+
f81232_port_disable(port);
usb_serial_generic_close(port);
usb_kill_urb(port->interrupt_in_urb);
+ flush_work(&port_priv->lsr_work);
+ port_priv->is_port_open = false;
+
+ mutex_unlock(&port_priv->lock);
}
static void f81232_dtr_rts(struct usb_serial_port *port, int on)
@@ -603,6 +623,21 @@ static void f81232_interrupt_work(struct work_struct *work)
f81232_read_msr(priv->port);
}
+static void f81232_lsr_worker(struct work_struct *work)
+{
+ struct f81232_private *priv;
+ struct usb_serial_port *port;
+ int status;
+ u8 tmp;
+
+ priv = container_of(work, struct f81232_private, lsr_work);
+ port = priv->port;
+
+ status = f81232_get_register(port, LINE_STATUS_REGISTER, &tmp);
+ if (status)
+ dev_warn(&port->dev, "read LSR failed: %d\n", status);
+}
+
static int f81232_port_probe(struct usb_serial_port *port)
{
struct f81232_private *priv;
@@ -613,6 +648,7 @@ static int f81232_port_probe(struct usb_serial_port *port)
mutex_init(&priv->lock);
INIT_WORK(&priv->interrupt_work, f81232_interrupt_work);
+ INIT_WORK(&priv->lsr_work, f81232_lsr_worker);
usb_set_serial_port_data(port, priv);
@@ -632,6 +668,49 @@ static int f81232_port_remove(struct usb_serial_port *port)
return 0;
}
+static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
+{
+ struct usb_serial_port *port = serial->port[0];
+ struct f81232_private *port_priv = usb_get_serial_port_data(port);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
+ usb_kill_urb(port->read_urbs[i]);
+
+ usb_kill_urb(port->interrupt_in_urb);
+
+ if (port_priv)
+ flush_work(&port_priv->lsr_work);
+
+ return 0;
+}
+
+static int f81232_resume(struct usb_serial *serial)
+{
+ struct usb_serial_port *port = serial->port[0];
+ struct f81232_private *port_priv = usb_get_serial_port_data(port);
+ int result = 0;
+
+ mutex_lock(&port_priv->lock);
+
+ if (port_priv && port_priv->is_port_open) {
+ result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
+ if (result) {
+ dev_err(&port->dev,
+ "%s: submit interrupt urb failed: %d",
+ __func__, result);
+ goto end;
+ }
+ }
+
+ result = usb_serial_generic_resume(serial);
+
+end:
+ mutex_unlock(&port_priv->lock);
+
+ return result;
+}
+
static struct usb_serial_driver f81232_device = {
.driver = {
.owner = THIS_MODULE,
@@ -655,6 +734,8 @@ static struct usb_serial_driver f81232_device = {
.read_int_callback = f81232_read_int_callback,
.port_probe = f81232_port_probe,
.port_remove = f81232_port_remove,
+ .suspend = f81232_suspend,
+ .resume = f81232_resume,
};
static struct usb_serial_driver * const serial_drivers[] = {
--
2.7.4