[RESEND PATCH V3 1/3] USB: serial: f81232: clear overrun flag

[RESEND PATCH V3 1/3] USB: serial: f81232: clear overrun flag

[Ji-Ze Hong (Peter Hong)]

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@suse.com>
Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
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 | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 0dcdcb4b2cde..722a184db9fa 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -41,12 +41,14 @@ 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;
+	struct work_struct lsr_work;
 	struct work_struct interrupt_work;
 	struct usb_serial_port *port;
 };
@@ -282,6 +284,7 @@ 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 +318,7 @@ 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);
 			}
@@ -556,9 +560,12 @@ static int f81232_open(struct tty_struct *tty, struct usb_serial_port *port)
 
 static void f81232_close(struct usb_serial_port *port)
 {
+	struct f81232_private *port_priv = usb_get_serial_port_data(port);
+
 	f81232_port_disable(port);
 	usb_serial_generic_close(port);
 	usb_kill_urb(port->interrupt_in_urb);
+	flush_work(&port_priv->lsr_work);
 }
 
 static void f81232_dtr_rts(struct usb_serial_port *port, int on)
@@ -603,6 +610,21 @@ 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 +635,7 @@ 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 +655,16 @@ 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 f81232_private *port_priv;
+
+	port_priv = usb_get_serial_port_data(serial->port[0]);
+	flush_work(&port_priv->lsr_work);
+
+	return 0;
+}
+
 static struct usb_serial_driver f81232_device = {
 	.driver = {
 		.owner =	THIS_MODULE,
@@ -655,6 +688,7 @@ 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,
 };
 
 static struct usb_serial_driver * const serial_drivers[] = {
-- 
2.7.4

[RESEND PATCH V3 2/3] USB: serial: f81232: add high baud rate support

[Ji-Ze Hong (Peter Hong)]

The F81232 had 4 clocksource 1.846/18.46/14.77/24MHz and baud rates
can be up to 1.5Mbits with 24MHz.

F81232 Clock registers (106h)

Bit1-0:     Clock source selector
                    00: 1.846MHz.
                    01: 18.46MHz.
                    10: 24MHz.
                    11: 14.77MHz.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
v3:
	1: change the baud_base in f81232_get_serial_info()

 drivers/usb/serial/f81232.c | 105 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 94 insertions(+), 11 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 722a184db9fa..e7862997b6e4 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -28,7 +28,8 @@ static const struct usb_device_id id_table[] = {
 MODULE_DEVICE_TABLE(usb, id_table);
 
 /* Maximum baudrate for F81232 */
-#define F81232_MAX_BAUDRATE		115200
+#define F81232_MAX_BAUDRATE		1500000
+#define F81232_DEF_BAUDRATE		9600
 
 /* USB Control EP parameter */
 #define F81232_REGISTER_REQUEST		0xa0
@@ -44,18 +45,42 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define LINE_STATUS_REGISTER		(0x05 + SERIAL_BASE_ADDRESS)
 #define MODEM_STATUS_REGISTER		(0x06 + SERIAL_BASE_ADDRESS)
 
+/*
+ * F81232 Clock registers (106h)
+ *
+ * Bit1-0:	Clock source selector
+ *			00: 1.846MHz.
+ *			01: 18.46MHz.
+ *			10: 24MHz.
+ *			11: 14.77MHz.
+ */
+#define F81232_CLK_REGISTER		0x106
+#define F81232_CLK_1_846_MHZ		0
+#define F81232_CLK_18_46_MHZ		BIT(0)
+#define F81232_CLK_24_MHZ		BIT(1)
+#define F81232_CLK_14_77_MHZ		(BIT(1) | BIT(0))
+#define F81232_CLK_MASK			GENMASK(1, 0)
+
 struct f81232_private {
 	struct mutex lock;
 	u8 modem_control;
 	u8 modem_status;
+	speed_t baud_base;
 	struct work_struct lsr_work;
 	struct work_struct interrupt_work;
 	struct usb_serial_port *port;
 };
 
-static int calc_baud_divisor(speed_t baudrate)
+static u32 const baudrate_table[] = { 115200, 921600, 1152000, 1500000 };
+static u8 const clock_table[] = { F81232_CLK_1_846_MHZ, F81232_CLK_14_77_MHZ,
+				F81232_CLK_18_46_MHZ, F81232_CLK_24_MHZ };
+
+static int calc_baud_divisor(speed_t baudrate, speed_t clockrate)
 {
-	return DIV_ROUND_CLOSEST(F81232_MAX_BAUDRATE, baudrate);
+	if (!baudrate)
+		return 0;
+
+	return DIV_ROUND_CLOSEST(clockrate, baudrate);
 }
 
 static int f81232_get_register(struct usb_serial_port *port, u16 reg, u8 *val)
@@ -129,6 +154,21 @@ static int f81232_set_register(struct usb_serial_port *port, u16 reg, u8 val)
 	return status;
 }
 
+static int f81232_set_mask_register(struct usb_serial_port *port, u16 reg,
+					u8 mask, u8 val)
+{
+	int status;
+	u8 tmp;
+
+	status = f81232_get_register(port, reg, &tmp);
+	if (status)
+		return status;
+
+	tmp = (tmp & ~mask) | (val & mask);
+
+	return f81232_set_register(port, reg, tmp);
+}
+
 static void f81232_read_msr(struct usb_serial_port *port)
 {
 	int status;
@@ -346,13 +386,53 @@ static void f81232_break_ctl(struct tty_struct *tty, int break_state)
 	 */
 }
 
-static void f81232_set_baudrate(struct usb_serial_port *port, speed_t baudrate)
+static int f81232_find_clk(speed_t baudrate)
+{
+	int idx;
+
+	for (idx = 0; idx < ARRAY_SIZE(baudrate_table); ++idx) {
+		if (baudrate <= baudrate_table[idx] &&
+				baudrate_table[idx] % baudrate == 0)
+			return idx;
+	}
+
+	return -EINVAL;
+}
+
+static void f81232_set_baudrate(struct tty_struct *tty,
+				struct usb_serial_port *port, speed_t baudrate,
+				speed_t old_baudrate)
 {
+	struct f81232_private *priv = usb_get_serial_port_data(port);
 	u8 lcr;
 	int divisor;
 	int status = 0;
+	int i;
+	int idx;
+	speed_t baud_list[] = {baudrate, old_baudrate, F81232_DEF_BAUDRATE};
+
+	for (i = 0; i < ARRAY_SIZE(baud_list); ++i) {
+		idx = f81232_find_clk(baud_list[i]);
+		if (idx >= 0) {
+			baudrate = baud_list[i];
+			tty_encode_baud_rate(tty, baudrate, baudrate);
+			break;
+		}
+	}
 
-	divisor = calc_baud_divisor(baudrate);
+	if (idx < 0)
+		return;
+
+	priv->baud_base = baudrate_table[idx];
+	divisor = calc_baud_divisor(baudrate, priv->baud_base);
+
+	status = f81232_set_mask_register(port, F81232_CLK_REGISTER,
+			F81232_CLK_MASK, clock_table[idx]);
+	if (status) {
+		dev_err(&port->dev, "%s failed to set CLK_REG: %d\n",
+			__func__, status);
+		return;
+	}
 
 	status = f81232_get_register(port, LINE_CONTROL_REGISTER,
 			 &lcr); /* get LCR */
@@ -442,6 +522,7 @@ static void f81232_set_termios(struct tty_struct *tty,
 	u8 new_lcr = 0;
 	int status = 0;
 	speed_t baudrate;
+	speed_t old_baud;
 
 	/* Don't change anything if nothing has changed */
 	if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
@@ -454,11 +535,12 @@ static void f81232_set_termios(struct tty_struct *tty,
 
 	baudrate = tty_get_baud_rate(tty);
 	if (baudrate > 0) {
-		if (baudrate > F81232_MAX_BAUDRATE) {
-			baudrate = F81232_MAX_BAUDRATE;
-			tty_encode_baud_rate(tty, baudrate, baudrate);
-		}
-		f81232_set_baudrate(port, baudrate);
+		if (old_termios)
+			old_baud = tty_termios_baud_rate(old_termios);
+		else
+			old_baud = F81232_DEF_BAUDRATE;
+
+		f81232_set_baudrate(tty, port, baudrate, old_baud);
 	}
 
 	if (C_PARENB(tty)) {
@@ -594,11 +676,12 @@ static int f81232_get_serial_info(struct tty_struct *tty,
 		struct serial_struct *ss)
 {
 	struct usb_serial_port *port = tty->driver_data;
+	struct f81232_private *priv = usb_get_serial_port_data(port);
 
 	ss->type = PORT_16550A;
 	ss->line = port->minor;
 	ss->port = port->port_number;
-	ss->baud_base = F81232_MAX_BAUDRATE;
+	ss->baud_base = priv->baud_base;
 	return 0;
 }
 
-- 
2.7.4

[RESEND PATCH V3 3/3] USB: serial: f81232: implement break control

[Ji-Ze Hong (Peter Hong)]

Implement Fintek F81232 break on/off with LCR register.
It's the same with 16550A LCR register layout.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
v3:
	1: using shadow_lcr to save LCR in f81232_break_ctl()

 drivers/usb/serial/f81232.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index e7862997b6e4..9377b827313a 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -65,6 +65,7 @@ struct f81232_private {
 	struct mutex lock;
 	u8 modem_control;
 	u8 modem_status;
+	u8 shadow_lcr;
 	speed_t baud_base;
 	struct work_struct lsr_work;
 	struct work_struct interrupt_work;
@@ -377,13 +378,23 @@ static void f81232_process_read_urb(struct urb *urb)
 
 static void f81232_break_ctl(struct tty_struct *tty, int break_state)
 {
-	/* FIXME - Stubbed out for now */
+	struct usb_serial_port *port = tty->driver_data;
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	int status;
 
-	/*
-	 * break_state = -1 to turn on break, and 0 to turn off break
-	 * see drivers/char/tty_io.c to see it used.
-	 * last_set_data_urb_value NEVER has the break bit set in it.
-	 */
+	mutex_lock(&priv->lock);
+
+	if (break_state)
+		priv->shadow_lcr |= UART_LCR_SBC;
+	else
+		priv->shadow_lcr &= ~UART_LCR_SBC;
+
+	status = f81232_set_register(port, LINE_CONTROL_REGISTER,
+					priv->shadow_lcr);
+	if (status)
+		dev_err(&port->dev, "set break failed: %d\n", status);
+
+	mutex_unlock(&priv->lock);
 }
 
 static int f81232_find_clk(speed_t baudrate)
@@ -519,6 +530,7 @@ static int f81232_port_disable(struct usb_serial_port *port)
 static void f81232_set_termios(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
+	struct f81232_private *priv = usb_get_serial_port_data(port);
 	u8 new_lcr = 0;
 	int status = 0;
 	speed_t baudrate;
@@ -572,11 +584,16 @@ static void f81232_set_termios(struct tty_struct *tty,
 		break;
 	}
 
+	mutex_lock(&priv->lock);
+
+	new_lcr |= (priv->shadow_lcr & UART_LCR_SBC);
 	status = f81232_set_register(port, LINE_CONTROL_REGISTER, new_lcr);
 	if (status) {
 		dev_err(&port->dev, "%s failed to set LCR: %d\n",
 			__func__, status);
 	}
+
+	mutex_unlock(&priv->lock);
 }
 
 static int f81232_tiocmget(struct tty_struct *tty)
-- 
2.7.4

Re: [RESEND PATCH V3 1/3] USB: serial: f81232: clear overrun flag

[Oliver Neukum]

On Mo, 2019-04-01 at 14:00 +0800,  Ji-Ze Hong (Peter Hong)  wrote:

Hi,
I am afraid there is a race condiion in this code.


> @@ -315,6 +318,7 @@ static void f81232_process_read_urb(struct urb *urb)
>  
>  			if (lsr & UART_LSR_OE) {
>  				port->icount.overrun++;
> +				schedule_work(&priv->lsr_work);

Unconditionally scheduled

>  				tty_insert_flip_char(&port->port, 0,
>  						TTY_OVERRUN);
>  			}

[..] 
> +static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
> +{
> +	struct f81232_private *port_priv;
> +
> +	port_priv = usb_get_serial_port_data(serial->port[0]);
> +	flush_work(&port_priv->lsr_work);
> +
> +	return 0;
> +}
> +
>  static struct usb_serial_driver f81232_device = {
>  	.driver = {
>  		.owner =	THIS_MODULE,
> @@ -655,6 +688,7 @@ 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,

Please have a look at:
int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct usb_serial *serial = usb_get_intfdata(intf);
        int i, r = 0;


        serial->suspending = 1;


        /*
         * serial->type->suspend() MUST return 0 in system sleep context,
         * otherwise, the resume callback has to recover device from
         * previous suspend failure.
         */
        if (serial->type->suspend) {
                r = serial->type->suspend(serial, message);
                if (r < 0) {
                        serial->suspending = 0;
                        goto err_out;
                }
        }


        for (i = 0; i < serial->num_ports; ++i)
                usb_serial_port_poison_urbs(serial->port[i]);
err_out:
        return r;
}
EXPORT_SYMBOL(usb_serial_suspend);

As you can see, the suspend method is called first and then the URBs
are poisoned. That means that after you have flushed the work, it may
be submitted again. The fix would be to test the 'suspending' flag
before you schedule work (and recheck the need to schedule it
during resume)

	Regards
		Oliver

Re: [RESEND PATCH V3 1/3] USB: serial: f81232: clear overrun flag

[Ji-Ze Hong (Peter Hong)]

Oliver Neukum 於 2019/4/1 下午 04:34 寫道:
> On Mo, 2019-04-01 at 14:00 +0800,  Ji-Ze Hong (Peter Hong)  wrote:
> 
> Hi,
> I am afraid there is a race condiion in this code.
> 
> 
>> @@ -315,6 +318,7 @@ static void f81232_process_read_urb(struct urb *urb)
>>   
>>   			if (lsr & UART_LSR_OE) {
>>   				port->icount.overrun++;
>> +				schedule_work(&priv->lsr_work);
> 
> Unconditionally scheduled
> 
>>   				tty_insert_flip_char(&port->port, 0,
>>   						TTY_OVERRUN);
>>   			}
> 
> [..]
>> +static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
>> +{
>> +	struct f81232_private *port_priv;
>> +
>> +	port_priv = usb_get_serial_port_data(serial->port[0]);
>> +	flush_work(&port_priv->lsr_work);
>> +
>> +	return 0;
>> +}
>> +
>>   static struct usb_serial_driver f81232_device = {
>>   	.driver = {
>>   		.owner =	THIS_MODULE,
>> @@ -655,6 +688,7 @@ 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,
> 
> Please have a look at:
> int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
> {
>          struct usb_serial *serial = usb_get_intfdata(intf);
>          int i, r = 0;
> 
> 
>          serial->suspending = 1;
> 
> 
>          /*
>           * serial->type->suspend() MUST return 0 in system sleep context,
>           * otherwise, the resume callback has to recover device from
>           * previous suspend failure.
>           */
>          if (serial->type->suspend) {
>                  r = serial->type->suspend(serial, message);
>                  if (r < 0) {
>                          serial->suspending = 0;
>                          goto err_out;
>                  }
>          }
> 
> 
>          for (i = 0; i < serial->num_ports; ++i)
>                  usb_serial_port_poison_urbs(serial->port[i]);
> err_out:
>          return r;
> }
> EXPORT_SYMBOL(usb_serial_suspend);
> 
> As you can see, the suspend method is called first and then the URBs
> are poisoned. That means that after you have flushed the work, it may
> be submitted again. The fix would be to test the 'suspending' flag
> before you schedule work (and recheck the need to schedule it
> during resume)

Thanks for report the race condition issue. It's seems the same bug
in f81534.c. I'll try to fix it on f81232.c then fix f81534.c too.

-- 
With Best Regards,
Peter Hong