[PATCH V5 1/3] USB: serial: f81232: clear overrun flag

[PATCH V5 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>
---
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 | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 0dcdcb4b2cde..d8a0bb7a41f0 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 +284,8 @@ 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 usb_serial *serial = port->serial;
+	struct f81232_private *priv = usb_get_serial_port_data(port);
 	unsigned char *data = urb->transfer_buffer;
 	char tty_flag;
 	unsigned int i;
@@ -315,6 +319,9 @@ static void f81232_process_read_urb(struct urb *urb)
 
 			if (lsr & UART_LSR_OE) {
 				port->icount.overrun++;
+
+				if (!serial->suspending)
+					schedule_work(&priv->lsr_work);
 				tty_insert_flip_char(&port->port, 0,
 						TTY_OVERRUN);
 			}
@@ -556,9 +563,12 @@ 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 +613,21 @@ 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 +638,7 @@ 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 +658,16 @@ 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 +691,7 @@ 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

[PATCH V5 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>
---
v5:
	1: no change

v4:
	1: no change

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 d8a0bb7a41f0..32eff8fad56a 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;
@@ -349,13 +389,53 @@ 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 */
@@ -445,6 +525,7 @@ 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))
@@ -457,11 +538,12 @@ 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)) {
@@ -597,11 +679,12 @@ 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

[PATCH V5 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>
---
v5:
	1: no change

v4:
	1: no change

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 32eff8fad56a..fe28657b4064 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;
@@ -380,13 +381,23 @@ 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)
@@ -522,6 +533,7 @@ 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;
@@ -575,11 +587,16 @@ 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: [PATCH V5 1/3] USB: serial: f81232: clear overrun flag

[Oliver Neukum]

On Mi, 2019-04-03 at 14:26 +0800,  Ji-Ze Hong (Peter Hong)  wrote:
> 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().

Hi,

I am most sorry to complain again. Please forgive me for being less
clear than necessary.

> 
> Cc: Oliver Neukum <oneukum@suse.com>
> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
> ---
> 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 | 37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 0dcdcb4b2cde..d8a0bb7a41f0 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;

Here you need a flag

bool deferred_lsr_work_needed;
> +	struct work_struct lsr_work;
>  	struct work_struct interrupt_work;
>  	struct usb_serial_port *port;
>  };
> @@ -282,6 +284,8 @@ 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 usb_serial *serial = port->serial;
> +	struct f81232_private *priv = usb_get_serial_port_data(port);
>  	unsigned char *data = urb->transfer_buffer;
>  	char tty_flag;
>  	unsigned int i;
> @@ -315,6 +319,9 @@ static void f81232_process_read_urb(struct urb *urb)
>  
>  			if (lsr & UART_LSR_OE) {
>  				port->icount.overrun++;
> +
> +				if (!serial->suspending)
> +					schedule_work(&priv->lsr_work);
Yes, but you cannot just drop it. You also need

else
	priv->deferred_lsr_work_needed = true;
>  				tty_insert_flip_char(&port->port, 0,
>  						TTY_OVERRUN);
>  			}
> @@ -556,9 +563,12 @@ 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 +613,21 @@ 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 +638,7 @@ 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 +658,16 @@ 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;
> +}

And you do need a resume, which you had in version v4 to check
the  deferred_lsr_work_needed flag and schedule the work if it is
set.

	Most sorry
		Oliver